6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of May 2021

(Commission File No. 001-38215)

NUCANA PLC

(Translation of registrant’s name into English)

3 Lochside Way

Edinburgh EH12 9DT

United Kingdom

(Address of registrant’s principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F  ☒                Form 40-F  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (1):  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (7):  ☐

Other Events

On May 19, 2021, NuCana plc (the “Company”) issued a press release announcing its first quarter 2021 financial results. The Company’s unaudited condensed consolidated financial statements as of March 31, 2021 are attached as Exhibit 99.1 and are incorporated by reference herein. The Company’s Management’s Discussion and Analysis of Financial Condition and Results of Operations is attached as Exhibit 99.2 hereto and is incorporated by reference herein. The press release is attached as Exhibit 99.3 hereto and is incorporated by reference herein.

The information in the attached Exhibits 99.1 and 99.2 shall be deemed to be incorporated by reference into the registration statements on Form F-3 (File Number 333-227624) and Form S-8 (File Number  333-223476 and File Number 333-248135), and related prospectuses, as such registration statements and prospectuses may be amended from time to time, and to be a part thereof from the date on which this report is filed, to the extent not superseded by documents or reports subsequently filed or furnished.

The information in the attached Exhibit 99.3 is being furnished and shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section, nor shall it be deemed incorporated by reference in any filing made by the Company under the Securities Act of 1933, as amended, or the Exchange Act, except as otherwise set forth herein or as shall be expressly set forth by specific reference in such a filing.

Exhibits

99.1	Unaudited Condensed Consolidated Financial Statements as of March 31, 2021 and for the Three Months Ended March 31, 2021 and 2020
99.2	Management’s Discussion and Analysis of Financial Condition and Results of Operations for the Three Months Ended March 31, 2021 and 2020
99.3	Press Release dated May 19, 2021
101	The following materials from this Report on Form 6-K are formatted in XBRL (eXtensible Business Reporting Language): (i) Unaudited Condensed Consolidated Statements of Operations for the Three Months ended March 31, 2021 and 2020, (ii) Unaudited Condensed Consolidated Statements of Comprehensive Loss for the Three Months ended March 31, 2021 and 2020, (iii) Unaudited Condensed Consolidated Statements of Financial Position as at March 31, 2021 and December 31, 2020, (iv) Unaudited Condensed Consolidated Statements of Changes in Equity for the Three Months ended March 31, 2021 and 2020, (v) Unaudited Condensed Consolidated Statements of Cash Flows for the Three Months ended March 31, 2021 and 2020 and (vi) Notes to the Unaudited Condensed Consolidated Financial Statements.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

NuCana plc
By:	/s/ Donald Munoz
Name:	Donald Munoz
Title:	Chief Financial Officer

Date: May 19, 2021

EX-99.1

Exhibit 99.1

NUCANA PLC

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

			For the Three Months Ended March 31,
	Notes		2021			2020
			(in thousands, except per share data)
			£			£
Research and development expenses				(8,706	)		(5,938	)
Administrative expenses				(2,104	)		(1,609	)
Net foreign exchange (losses) gains				(677	)		2,127
Operating loss				(11,487	)		(5,420	)
Finance income				24			144
Loss before tax				(11,463	)		(5,276	)
Income tax credit		3		1,702			1,310
Loss for the period				(9,761	)		(3,966	)
Basic and diluted loss per share		4		(0.19	)		(0.12	)

The accompanying notes form an integral part of these unaudited condensed consolidated financial statements.

NUCANA PLC

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS

	For the Three Months Ended March 31,
	2021			2020
	(in thousands)
	£			£
Loss for the period		(9,761	)		(3,966	)
Other comprehensive (expense) income:
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations		(3	)		21
Other comprehensive (expense) income for the period		(3	)		21
Total comprehensive loss for the period		(9,764	)		(3,945	)
Attributable to:
Equity holders of the Company		(9,764	)		(3,945	)

The accompanying notes form an integral part of these unaudited condensed consolidated financial statements.

2

NUCANA PLC

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL POSITION

AS AT

		March 31, 2021			December 31, 2020
		(in thousands)
	Notes	£			£
Assets
Non-current assets
Intangible assets	5		4,764			4,753
Property, plant and equipment			1,098			1,189
Deferred tax asset	3		40			44
			5,902			5,986
Current assets
Prepayments, accrued income and other receivables			4,813			4,628
Current income tax receivable	3		11,529			9,822
Cash and cash equivalents	6		78,625			87,356
			94,967			101,806
Total assets			100,869			107,792
Equity and liabilities
Capital and reserves
Share capital and share premium	8		143,135			142,937
Other reserves			67,470			66,887
Accumulated deficit			(119,146	)		(110,594	)
Total equity attributable to equity holders of the Company			91,459			99,230
Non-current liabilities
Provisions			46			46
Lease liabilities			296			367
			342			413
Current liabilities
Trade payables			3,542			2,257
Payroll taxes and social security			159			177
Accrued expenditure			5,087			5,437
Lease liabilities			280			278
			9,068			8,149
Total liabilities			9,410			8,562
Total equity and liabilities			100,869			107,792

The accompanying notes form an integral part of these unaudited condensed consolidated financial statements.

3

NUCANA PLC

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY

	For the Three Months Ended March 31,
	Share capital		Share premium		Own share reserve			Share option reserve			Foreign currency translation reserve			Capital reserve		Accumulated deficit			Total equity attributable to equity holders
	(in thousands)
	£		£		£			£			£			£		£			£
Balance at January 1, 2020		1,299		79,541		(339	)		20,620			(10	)		42,466		(80,055	)		63,522
Loss for the period		—		—		—			—			—			—		(3,966	)		(3,966	)
Other comprehensive income for the period		—		—		—			—			21			—		—			21
Total comprehensive loss for the period		—		—		—			—			21			—		(3,966	)		(3,945	)
Share-based payments		—		—		—			856			—			—		—			856
Balance at March 31, 2020		1,299		79,541		(339	)		21,476			11			42,466		(84,021	)		60,433
Balance at January 1, 2021		2,047		140,890		(339	)		24,782			(22	)		42,466		(110,594	)		99,230
Loss for the period		—		—		—			—			—			—		(9,761	)		(9,761	)
Other comprehensive expense for the period		—		—		—			—			(3	)		—		—			(3	)
Total comprehensive loss for the period		—		—		—			—			(3	)		—		(9,761	)		(9,764	)
Share-based payments		—		—		—			1,795			—			—		—			1,795
Exercise of share options		39		159		—			(1,088	)		—			—		1,088			198
Lapse of share options		—		—		—			(121	)		—			—		121			—
Balance at March 31, 2021		2,086		141,049		(339	)		25,368			(25	)		42,466		(119,146	)		91,459

The accompanying notes form an integral part of these unaudited condensed consolidated financial statements.

4

NUCANA PLC

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

	For the Three Months Ended March 31,
	2021			2020
	(in thousands)
	£			£
Cash flows from operating activities
Loss for the period		(9,761	)		(3,966	)
Adjustments for:
Income tax credit		(1,702	)		(1,310	)
Amortization and depreciation		222			217
Finance income		(24	)		(144	)
Interest expense on lease liabilities		6			—
Share-based payments		1,795			856
Net foreign exchange losses (gains)		664			(2,164	)
		(8,800	)		(6,511	)
Movements in working capital:
(Increase) decrease in prepayments, accrued income and other receivables		(191	)		423
Increase in trade payables		1,285			44
Decrease in payroll taxes, social security and accrued expenditure		(368	)		(165	)
Movements in working capital		726			302
Cash used in operations		(8,074	)		(6,209	)
Net income tax received		—			—
Net cash used in operating activities		(8,074	)		(6,209	)
Cash flows from investing activities
Interest received		24			187
Payments for property, plant and equipment		(4	)		(10	)
Payments for intangible assets		(138	)		(398	)
Net cash used in investing activities		(118	)		(221	)
Cash flows from financing activities
Payments for lease liabilities		(74	)		(73	)
Proceeds from issue of share capital		198			—
Net cash from (used in) financing activities		124			(73	)
Net decrease in cash and cash equivalents		(8,068	)		(6,503	)
Cash and cash equivalents at beginning of period		87,356			51,962
Effect of exchange rate changes on cash and cash equivalents		(663	)		2,141
Cash and cash equivalents at end of period		78,625			47,600

The accompanying notes form an integral part of these unaudited condensed consolidated financial statements.

5

NUCANA PLC

NOTES TO THE UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

1. General information

NuCana plc (“NuCana” or the “Company”) is a clinical-stage biopharmaceutical company developing a portfolio of new medicines to treat cancer. NuCana is harnessing the power of phosphoramidate chemistry to generate new medicines called ProTides. These compounds have the potential to improve cancer treatment by enhancing the efficacy and safety of several current standards of care.

The Company has ordinary shares in the form of American Depositary Shares (“ADSs”) registered with the US Securities and Exchange Commission (the “SEC”) and has been listed on The Nasdaq Global Select Market (“Nasdaq”) since October 2, 2017. The Company is incorporated in England and Wales and domiciled in the United Kingdom. The Company’s registered office is located at 77/78 Cannon Street, London EC4N 6AF, United Kingdom and its principal place of business is located at 3 Lochside Way, Edinburgh, EH12 9DT, United Kingdom.

The Company has two wholly owned subsidiaries, NuCana, Inc. and NuCana BioMed Trustee Company Limited (together referred to as the “Group”).

The financial information presented in these unaudited condensed consolidated financial statements does not constitute the Group’s statutory accounts within the meaning of section 434 of the U.K. Companies Act 2006.

The Group’s statutory accounts for the year ended December 31, 2020 have not yet been reported on by the Company’s auditor or delivered to the Registrar of Companies. The Company filed its Annual Report on Form 20-F for the year ended December 31, 2020 with the SEC on March 4, 2021, which included the Company’s Consolidated Financial Statements for its fiscal year ended December 31, 2020. Those financial statements have been reported on by the Company’s auditor. The report of the auditor was (i) unqualified and (ii) did not include a reference to any matters to which the auditors drew attention by way of emphasis without qualifying their report.

2. Significant accounting policies

Basis of preparation

The unaudited condensed consolidated financial statements (the “financial statements”) for the three months ended March 31, 2021 have been prepared in accordance with International Accounting Standard 34, “Interim Financial Reporting” (“IAS 34”). The significant accounting policies and methods of computation applied in the preparation of the financial statements are consistent with those applied in the Company’s annual financial statements for the year ended December 31, 2020. No new standards, amendments or interpretations have had an impact on the financial statements for the three months ended March 31, 2021. The financial statements comprise the financial statements of the Group at March 31, 2021. The financial statements are presented in pounds sterling, which is also the Company’s functional currency. All values are rounded to the nearest thousand, except where otherwise indicated.

The financial statements do not include all the information and disclosures required in the annual financial statements, and should be read in conjunction with the Company’s annual financial statements for the year ended December 31, 2020.

In the opinion of management, these unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of the results of operations, financial position and cash flows. The results of operations for the three months ended March 31, 2021 are not necessarily indicative of the results that can be expected for the Company’s fiscal year ending December 31, 2021.

Going concern

In common with many companies in the biopharmaceutical sector, the Company incurs significant expenditure in its early years as it researches and develops its potential products for market.

The Company’s board of directors, having reviewed the operating budgets and development plans, considers that the Company has adequate resources to continue in operation for the foreseeable future. The board of directors is therefore satisfied that it is appropriate to adopt the going concern basis of accounting in preparing the financial statements. The Company believes that its cash and cash equivalents of £78.6 million at March 31, 2021 will be sufficient to fund its current operating plan for at least the next 12 months. Further, the directors have conducted an assessment of the impact of COVID-19 on the going concern status of the Company and have concluded that it will not have a significant negative impact on the cash outflows of the Company over the period assessed for going concern purposes.

6

As the Company continues to incur losses, the transition to profitability is dependent upon the successful development, approval and commercialization of its product candidates and achieving a level of revenues adequate to support its cost structure. The Company may never achieve profitability, and unless and until it does, it will continue to need to raise additional capital. There can be no assurances, however, that additional funding will be available on acceptable terms.

COVID-19

In response to the COVID-19 pandemic, all of the Company’s offices have been closed with employees continuing their work outside of the offices and the Company has restricted on-site staff access to only those required to execute their job responsibilities.

During the early months of the pandemic the Company announced that there was some temporary interruption to the enrollment of new patients in the Company’s ongoing clinical trials. In May 2020, the Company further announced that enrollment of new patients in the Company’s clinical trials had re-commenced. While the Company continues to evaluate the impact of COVID-19 on its operations, the Company believes that this pandemic will inevitably cause some delays to the timing of initiation and completion of its clinical trials. The Company is continuing to monitor the impact of COVID-19.

COVID-19 has had no impact on the judgements and estimates used in the preparation of these financial statements.

Judgements and estimates

The accounting estimates and judgements made by management in applying the Group’s accounting policies that have the most significant effect on the amounts included within these financial statements were the same as those that applied to the annual financial statements for the year ended December 31, 2020.    

3. Income tax

	For the Three Months Ended March 31,
	2021			2020
	(in thousands)
	£			£
Current tax:
In respect of current period U.K.		1,706			1,315
In respect of current period U.S.		—			—
		1,706			1,315
Deferred tax:
In respect of current period U.S.		(4	)		(4	)
In respect of prior period U.S.		—			(1	)
Income tax credit		1,702			1,310

The income tax credit recognized primarily represents the U.K. research and development tax credit. In the United Kingdom, the Company is able to surrender some of its losses for a cash rebate of up to 33.35% of expenditure related to eligible research and development projects.

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Current income tax receivable
U.K. tax		11,525		9,818
U.S. tax		4		4
		11,529		9,822
Deferred tax asset
U.S. deferred tax asset		40		44

7

4. Basic and diluted loss per share

	For the Three Months Ended March 31,
	2021			2020
	(in thousands, except per share data)
	£			£
Loss for the period		(9,761	)		(3,966	)
Basic and diluted weighted average number of shares		51,649			32,479
	£			£
Basic and diluted loss per share		(0.19	)		(0.12	)

Basic loss per share is calculated by dividing the loss for the period attributable to the equity holders of the Company by the weighted average number of shares outstanding during the period.

The potential shares issued through equity settled transactions were considered to be anti-dilutive as they would have decreased the loss per share and were therefore excluded from the calculation of diluted loss per share.

5. Intangible assets

Intangible assets comprise patents with a carrying value of £4.6 million as of March 31, 2021 (as of December 31, 2020: £4.6 million) and computer software with a carrying value of £0.2 million as of March 31, 2021 (as of December 31, 2020: £0.2 million).

During the three months ended March 31, 2021, the Company acquired intangible assets with a cost of £0.1 million in relation to patents. There were no disposals of intangible assets in the three months ended March 31, 2021.

6. Cash and cash equivalents

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Cash and cash equivalents		78,625		87,356

Cash and cash equivalents comprise cash at banks with deposit maturity terms of three months or less, which is subject to insignificant risk of changes in value. Cash at banks earns interest at fixed or variable rates based on the terms agreed for each account.

7. Share-based payments

The Company has six share-based payment plans for employees, directors and consultants. The share options granted will be settled in equity. Options granted under each of the six plans have a maximum life of 10 years. If the Company determines, and at its discretion, an arrangement may be made under the 2020 Long-Term Incentive Plan to substitute the right to acquire shares with a cash alternative of equivalent value.

As detailed in the table below, during the three months ended March 31, 2021, 1,501,663 share options were granted under the 2020 Long-Term Incentive Plan (three months ended March 31, 2020: no share options granted). Options granted under this plan will vest if the option holder remains under respective contract of employment or contract of service for the agreed vesting period. The share options granted in the period will vest over a period of up to four years.

8

The fair values of options granted were determined using the Black-Scholes model that takes into account factors specific to the share incentive plan such as the assumption that the options are exercised at a point in time of up to two years after vesting. This has been incorporated into the measurement by means of actuarial modelling. As NuCana plc was unlisted until October 2, 2017, it is not possible to derive historical volatility from the Company’s ADSs prior to October 2017. For options with an estimated life of greater than three years, the underlying expected volatility was determined by using the average of the historical volatility of similar listed entities as a proxy. Options granted with an estimated life of three years or less, have been valued using the Company’s own historical volatility rates.

	Options granted on
	January 13, 2021			February 10, 2021			February 10, 2021			February 10, 2021
Vesting dates		January 13, 2022			February 10, 2022			February 10, 2022			February 10, 2022
		January 13, 2023			February 10, 2023			February 10, 2023			February 10, 2023
		January 13, 2024			February 10, 2024			February 10, 2024			February 10, 2024
		January 13, 2025			February 10, 2025			February 10, 2025			February 10, 2025
Volatility		81.42	%		81.45	%		87.66	%		83.86	%
Dividend yield		0	%		0	%		0	%		0	%
Risk-free investment rate		0.01	%		0.11	%		0.01	%		0.05	%
Fair value of option at grant date	£	2.37		£	2.74		£	4.49		£	4.49
Fair value of share at grant date	£	3.92		£	4.53		£	4.53		£	4.53
Exercise price at date of grant	£	3.92		£	4.53		£	0.04		£	0.04
Lapse date		January 13, 2031			February 10, 2031			—			February 10, 2031
Expected option life (years)		4.50			4.50			2.50			3.50
Number of options granted		200,000			872,775			91,888			337,000

For the three months ended March 31, 2021, the Company has recognized £1.8 million of share-based payment expense in the statement of operations (three months ended March 31, 2020: £0.9 million).

8. Share capital and share premium

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Share capital		2,086		2,047
Share premium		141,049		140,890
		143,135		142,937

	March 31, 2021		December 31, 2020
	Number (in thousands)
Issued share capital comprises:
Ordinary shares of £0.04 each		52,162		51,175

	Number of shares		Share capital		Share premium
	(in thousands)
Fully paid shares:			£		£
Balance at December 31, 2020		51,175		2,047		140,890
Issue of shares on exercise of options		987		39		159
Balance at March 31, 2021		52,162		2,086		141,049

9

9. Contingent liabilities

Under its U.K. share-based payment plan, the Company granted unapproved share options that have fully vested. If and when these share options are exercised, the Company will be liable for the Employer Class 1 National Insurance payable to HMRC in the United Kingdom. This contingent liability will be determined based on the market value of the shares on exercise less the exercise price paid by the option holders, at the prevailing rate of Employer National Insurance (currently 13.8%). Based on the closing price of the Company’s ADSs on the Nasdaq Global Select Market on March 31, 2021, the last trading day of the period to which these financial statements relate, and assuming full exercise of all outstanding and vested unapproved share options on that date, the Employer National Insurance contingent liability would have been £0.8 million (December 31, 2020: £0.8 million).

10

EX-99.2

Exhibit 99.2

MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

You should read the following discussion and analysis of financial condition and results of operations together with the unaudited condensed consolidated financial statements and the related notes to those statements included as Exhibit 99.1 to this Report on Form 6-K submitted to the Securities and Exchange Commission, or the SEC, on May 19, 2021. We also recommend that you read our discussion and analysis of financial condition and results of operations together with our audited financial statements and the notes thereto, and the section entitled “Risk Factors”, each of which appear in our Annual Report on Form 20-F for the year ended December 31, 2020 filed with the SEC on March 4, 2021 (the “Annual Report”).

We present our unaudited condensed consolidated financial statements in pounds sterling and in accordance with International Accounting Standard 34, “Interim Financial Reporting,” or IAS 34, which may differ in material respects from generally accepted accounting principles in other jurisdictions, including generally accepted accounting principles in the United States, or U.S. GAAP.

Unless otherwise indicated or the context otherwise requires, all references to “NuCana,” the “Company,” “we,” “our,” “us” or similar terms refer to NuCana plc and its consolidated subsidiaries.

The statements in this discussion regarding industry outlook, our expectations regarding our future performance, liquidity and capital resources and other non-historical statements are forward-looking statements. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause the Company’s actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. These risks and uncertainties include, but are not limited to, the risks and uncertainties set forth in the “Risk Factors” section of our Annual Report and any subsequent reports that we file with the SEC.

Company Overview

We are a clinical-stage biopharmaceutical company focused on significantly improving treatment outcomes for cancer patients by applying our ProTide^™ technology to transform some of the most widely prescribed chemotherapy agents, nucleoside analogs, into more effective and safer medicines. While these conventional agents remain part of the standard of care for the treatment of many solid and hematological tumors, their efficacy is limited by cancer cell resistance mechanisms and they are often poorly tolerated. Utilizing our proprietary technology, we are developing new medicines, ProTides, designed to overcome key cancer resistance mechanisms and generate much higher concentrations of anti-cancer metabolites in cancer cells. Our most advanced ProTide candidates, Acelarin^® and NUC-3373, are new chemical entities derived from the nucleoside analogs gemcitabine and 5-fluorouracil, respectively, two widely used chemotherapy agents. Acelarin is currently being evaluated in a Phase 3 clinical trial for patients with biliary tract cancer. In May 2021, the Phase 3 clinical trial for patients with metastatic pancreatic cancer for which enrollment had been suspended was closed. NUC-3373 is currently in a Phase 1 clinical trial in patients with advanced solid tumors and a Phase 1b clinical trial in patients with advanced colorectal cancer. Our third ProTide, NUC-7738, is a transformation of a novel nucleoside analog (3’-deoxyadenosine) that has never been successfully developed or approved as a chemotherapy but has shown potent anti-cancer activity in preclinical studies. We are evaluating NUC-7738 in a Phase 1 clinical trial for patients with advanced solid tumors. We have retained worldwide rights to these lead product candidates as well as our preclinical product candidates, all of which we refer to as ProTides.

COVID-19

During the early months of the pandemic we announced that there was some temporary interruption to the enrollment of new patients in our ongoing clinical trials. In May 2020, we further announced that enrollment of new patients in our clinical trials had re-commenced. While we continue to evaluate the impact of COVID-19 on our operations, we believe that this pandemic will inevitably cause some delays to the timing of initiation and completion of our clinical trials. We continue to monitor the impact of COVID-19.

Financial Operations Overview

Revenues

We do not have any approved products. Accordingly, we have not generated any revenue, and we do not expect to generate any revenue from the sale of any products unless and until we obtain regulatory approvals for, and commercialize any of, our product candidates. In the future, we will seek to generate revenue primarily from product sales and, potentially, regional or global collaborations with strategic partners.

Operating Expenses

We classify our operating expenses into two categories: research and development expenses and administrative expenses. Personnel costs, including salaries, benefits, bonuses and share-based payment expense, comprise a component of each of these expense categories. We allocate expenses associated with personnel costs based on the function performed by the respective employees.

Research and Development Expenses

The largest component of our total operating expenses since our inception has been costs related to our research and development activities, including the preclinical and clinical development of our product candidates.

Research and development costs are expensed as incurred. Our research and development expense primarily consists of:

• costs incurred under agreements with contract research organizations, or CROs, and investigative sites that conduct preclinical studies and clinical trials;

• costs related to manufacturing active pharmaceutical ingredients and drug products for preclinical studies and clinical trials;

• salaries and personnel-related costs, including bonuses, benefits and any share-based payment expense, for our personnel performing research and development activities or managing those activities that have been out-sourced;

• fees paid to consultants and other third parties who support our product candidate development;

• other costs incurred in seeking regulatory approval for our product candidates; and

• payments under our license agreements.

The successful development of our ProTides is highly uncertain. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later stage clinical trials. Accordingly, we expect research and development costs to increase significantly for the foreseeable future as programs progress. However, we do not believe that it is possible at this time to accurately project total program specific expenses through commercialization. We are also unable to predict when, if ever, material net cash inflows will commence from our product candidates to offset these expenses. Our expenditures on current and future preclinical and clinical development programs are subject to numerous uncertainties in timing and cost to completion.

The duration, costs and timing of clinical trials and development of our product candidates will depend on a variety of factors including:

• the scope, rate of progress, results and expenses of our ongoing and future clinical trials, preclinical studies and research and development activities;

• the potential need for additional clinical trials or preclinical studies requested by regulatory agencies;

• potential uncertainties in clinical trial enrollment rates or drop-out or discontinuation rates of patients;

• competition with other drug development companies in, and the related expense of, identifying and enrolling patients in our clinical trials and contracting with third-party manufacturers for the production of the drug product needed for our clinical trials;

• the achievement of milestones requiring payments under in-licensing agreements;

• any significant changes in government regulation;

• the terms and timing of any regulatory approvals;

• the expense of filing, prosecuting, defending and enforcing patent claims and other intellectual property rights; and

• the ability to market, commercialize and achieve market acceptance for any of our product candidates, if approved.

We track research and development expenses on a program-by-program basis for both clinical-stage and preclinical product candidates. Manufacturing and non-clinical research and development expenses are assigned or allocated to individual product candidates, where appropriate.

Administrative Expenses

Administrative expenses consist of personnel costs, allocated expenses and other expenses for outside professional services, including legal, audit and accounting services. Personnel costs consist of salaries, bonuses, benefits and share-based payment expense. Other administrative expenses include office related costs, professional fees and costs of our information systems. We anticipate that our administrative expenses will continue to increase in the future as we increase our headcount to support our continued research and development and potential commercialization of our product candidates. We also incur expenses as a public company, including expenses related to compliance with the rules and regulations of the SEC and The Nasdaq Global Select Market, additional insurance expenses, and expenses related to investor relations and other administrative and professional services.

Net Foreign Exchange Gains (Losses)

Net foreign exchange gains (losses) primarily includes gains or losses on cash held in U.S. dollars.

Finance Income

Finance income relates to interest earned on our cash and cash equivalents.

Income Tax Credit

We are subject to corporate taxation in the United Kingdom and our wholly owned U.S. subsidiary, NuCana, Inc., is subject to corporate taxation in the United States. Due to the nature of our business, we have generated losses since inception in the United Kingdom. Our income tax credit recognized represents the sum of the research and development tax credits recoverable in the United Kingdom and in the United States, and income tax payable in the United States.

As a company that carries out extensive research and development activities, we benefit from the U.K. and U.S. research and development tax credit regimes. In the United Kingdom, we are able to surrender some of our losses for a cash rebate of up to 33.35% of eligible expenditures on qualifying research and development projects. In the United States, we are able to offset the research and development credits against corporation tax payable. Qualifying expenditures in the United Kingdom largely comprise clinical trial and manufacturing costs, employment costs for relevant staff and consumables incurred as part of research and development projects. In the United Kingdom, where we receive the larger proportion of the research and development credit, certain subcontracted qualifying research and development expenditures are eligible for a cash rebate of up to 21.68%. A large portion of costs relating to our research and development, clinical trials and manufacturing activities are eligible for inclusion within these tax credit cash rebate claims.

We may not be able to continue to claim research and development tax credits in the United Kingdom in the future under the current research and development tax credit scheme because we may no longer qualify as a small or medium-sized company.

Results of Operations

Comparison of the Three Months Ended March 31, 2021 and March 31, 2020

The following table summarizes the results of our operations for the three months ended March 31, 2021 and 2020.

	For the Three Months Ended March 31,
	2021			2020
	(unaudited)
	(in thousands)
	£			£
Research and development expenses		(8,706	)		(5,938	)
Administrative expenses		(2,104	)		(1,609	)
Net foreign exchange (losses) gains		(677	)		2,127
Operating loss		(11,487	)		(5,420	)
Finance income		24			144
Loss before tax		(11,463	)		(5,276	)
Income tax credit		1,702			1,310
Loss for the period		(9,761	)		(3,966	)
Other comprehensive (expense) income:
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations		(3	)		21
Total comprehensive loss for the period		(9,764	)		(3,945	)

Research and Development Expenses

Research and development expenses were £8.7 million for the three months ended March 31, 2021 as compared to £5.9 million for the three months ended March 31, 2020, an increase of £2.8 million. The increase resulted primarily from higher expenses incurred related to clinical trials of £4.2 million in the three months ended March 31, 2021, compared with £3.1 million in the three months ended March 31, 2020. Non-clinical and manufacturing costs increased by £0.6 million for the three months ended March 31, 2021 as compared to the three months ended March 31, 2020. Other research and development costs increased in the three months ended March 31, 2021 by £1.1 million consistent with higher share-based payment expenses and patent costs.

The following table gives a breakdown of the research and development costs incurred by product candidate for the three months ended March 31, 2021 and 2020:

	For the Three Months Ended March 31,
	2021		2020
	(in thousands)
	£		£
Acelarin		5,130		3,276
NUC-3373		1,960		1,631
NUC-7738		1,024		664
Other		592		367
		8,706		5,938

Administrative Expenses

Administrative expenses were £2.1 million for the three months ended March 31, 2021 as compared to £1.6 million for the three months ended March 31, 2020, an increase of £0.5 million. The increase was primarily related to higher share-based payment expenses and insurance costs, partly offset by lower professional fees.

Net Foreign Exchange (Losses) Gains

For the three months ended March 31, 2021, we reported a net foreign exchange loss of £0.7 million as compared to a net foreign exchange gain of £2.1 million for the three months ended March 31, 2020. In the three months ended March 31, 2021, the loss arose from cash balances held in U.S. dollars and the U.S. dollar depreciating relative to the U.K. pound sterling. Conversely in the three months ended March 31, 2020, the gain arose from cash balances held in U.S. dollars and the U.S. dollar appreciating relative to the U.K. pound sterling.

Finance Income

Finance income represents bank interest and was £24,000 for the three months ended March 31, 2021 and £0.1 million for the three months ended March 31, 2020. The decrease in bank interest resulted from lower rates of interest being earned on cash deposits.

Income Tax Credit

The income tax credit for the three months ended March 31, 2021, which is largely comprised of U.K. research and development tax credits, amounted to £1.7 million as compared to £1.3 million for the three months ended March 31, 2020. The increase in the income tax credit was primarily attributable to an increase in our eligible research and development expenses.

Liquidity and Capital Resources

Overview

Since our inception, we have incurred significant operating losses and negative cash flows. We anticipate that we will continue to incur losses for at least the next several years. We expect that our research and development and administrative expenses will increase in connection with conducting clinical trials and seeking marketing approval for our product candidates, as well as costs associated with operating as a public company. As a result, we will need additional capital to fund our operations, which we may obtain from additional equity financings, debt financings, research funding, collaborations, contract and grant revenue or other sources.

As of March 31, 2021 and December 31, 2020, we had cash and cash equivalents of £78.6 million and £87.4 million, respectively. We do not currently have any approved products and have never generated any revenue from product sales. To date we have financed our operations primarily through the issuances of our equity securities.

In October 2018, we entered into an “at-the-market” (ATM) sales agreement with Cowen and Company, LLC, or Cowen, pursuant to which we may sell from time to time, ADSs having an aggregate offering price of up to $100.0 million through Cowen, acting as our agent. Sales of our ADSs pursuant to this ATM program are subject to certain conditions specified in the sales agreement. Sales under the ATM program are registered on a shelf registration statement on Form F-3 that we filed with the SEC in October 2018, and which permits the offering, issuance and sale by us of up to a maximum aggregate offering price of $400.0 million of our securities, inclusive of our ADSs sold under the ATM program.

Cash Flows

Comparison of the Three Months Ended March 31, 2021 and March 31, 2020

The following table summarizes the results of our cash flows for the three months ended March 31, 2021 and 2020.

	For the Three Months Ended March 31,
	2021			2020
	(unaudited) (in thousands)
	£			£
Net cash used in operating activities		(8,074	)		(6,209	)
Net cash used in investing activities		(118	)		(221	)
Net cash from (used in) financing activities		124			(73	)
Net decrease in cash and cash equivalents		(8,068	)		(6,503	)

Operating Activities

The net cash used in operating activities was £8.1 million for the three months ended March 31, 2021 as compared to £6.2 million for the three months ended March 31, 2020, a net increase in cash outflows of £1.9 million. Operating loss cash outflows were higher by £2.3 million for the three months ended March 31, 2021, primarily reflecting higher research and development costs. The increase in operating loss cash outflows was offset by working capital inflows of £0.7 million in the three months ended March 31, 2021 as compared to working capital inflows of £0.3 million in the three months ended March 31, 2020.

Investing Activities

The net cash used in investing activities was £0.1 million for the three months ended March 31, 2021 as compared to £0.2 million for the three months ended March 31, 2020. Interest received for the three months ended March 31, 2021 was £24,000 compared with £0.2 million for the three months ended March 31, 2020. In the three months ended March 31, 2021, cash used to acquire intangible assets was lower by £0.3 million than in the three months ended March 31, 2020.

Financing Activities

The net cash from financing activities was £0.1 million for the three months ended March 31, 2021 as compared to net cash used in financing activities of £0.1 million for the three months ended March 31, 2020. In the three months ended March 31, 2021 proceeds from the issue of share capital was £0.2 million. There was no such cash inflow in the three months ended March 31, 2020.

Operating and Capital Expenditure Requirements

We have not achieved profitability on an annual basis since our inception, and we expect to incur net losses in the future. We expect that our operating expenses will increase as we continue to invest in our research and development programs, exploit our ProTide pipeline and build out our organization with additional employees.

We believe that our existing capital resources will be sufficient to fund our operations, including currently anticipated research and development activities and planned capital spending, for at least the next 12 months.

Our future funding requirements will depend on many factors, including but not limited to:

• the scope, rate of progress and cost of our clinical trials, preclinical programs and other related activities;

• the extent of success in our early preclinical and clinical stage research programs, which will determine the amount of funding required to further the development of our product candidates;

• the progress that we make in developing new product candidates based on our proprietary ProTide technology;

• the cost of manufacturing clinical supplies and establishing commercial supplies of our product candidates and any products that we may develop;

• the costs involved in filing and prosecuting patent applications and enforcing and defending potential patent claims;

• the outcome, timing and cost of regulatory approvals of our ProTide product candidates;

• the cost and timing of establishing sales, marketing and distribution capabilities;

• the costs of hiring additional skilled employees to support our continued growth and the related costs of leasing additional office space; and

• developments related to COVID-19 and its impact on the costs and timing associated with the conduct of our clinical trials, preclinical programs and other related activities.

Legal Proceedings

From time to time, we may be party to litigation that arises in the ordinary course of our business. Other than as discussed below, we do not have any pending litigation that, separately or in the aggregate, would, in the opinion of management, have a material adverse effect on our results of operations, financial condition or cash flows.

In 2018, we were granted a European patent from the European Patent Office (EPO), EP 2955190, that covers the composition of matter of a small genus of phosphoramidate nucleotide compounds that includes sofosbuvir, sold under the brand name Sovaldi^®, a leading drug for the treatment of hepatitis C sold by Gilead Sciences, Inc. Sofosbuvir and our drug Acelarin share a similar chemical structure, and sofosbuvir is covered by the claims in our patent, which predates Gilead’s patent on sofosbuvir by several years. Later in 2018, Gilead filed an Opposition to our patent at the EPO in an attempt to revoke it. In February 2021, the EPO Opposition Division disagreed with Gilead and upheld amended patent claims that cover sofosbuvir. We believe this decision is correct, and is a further confirmation of the groundbreaking work of our late Chief Scientific Officer, Professor Christopher McGuigan, as the creator of the ProTide prodrug strategy to deliver nucleotides for the treatment of patients with cancer or viral infections. However, we expect that Gilead will appeal the decision of the Opposition Division to the EPO Technical Boards of Appeal, and there can be no assurance as to the outcome of such an appeal. The Boards of Appeal could disagree with the Opposition Division, in whole or part, and revoke our patent, or agree with the Opposition Division and uphold our patent.

A European patent can be asserted against infringers, in this case Gilead, in national courts in Europe, even before a final decision of the EPO Technical Boards of Appeal, and can also be challenged in national courts. Following the affirmance of our European patent by the EPO Opposition Division, in February 2021, Gilead Sciences, Inc. and Gilead Sciences Limited filed a lawsuit against us in the Patents Court of the High Court of Justice of England and Wales requesting revocation of the UK part of EP 2955190. The lawsuit is proceeding. In March 2021, we filed a counterclaim against Gilead Sciences, Inc. and Gilead Sciences Limited alleging infringement of our patent resulting from acts including the sale of Sovaldi^®, as well as its combination products Harvoni^®, Vosevi^® and Epclusa^®, in the United Kingdom. In April 2021, we initiated legal proceedings against Gilead Sciences Ireland UC and Gilead Sciences GmbH in the German Regional Court of Dusseldorf for patent infringement for the sale of Sovaldi as well as its combination products Harvoni, Vosevi and Epclusa in Germany. We intend to vigorously defend our patent rights and the foundational work of Professor McGuigan.

The appeal of the decision upholding our patent by the EPO Opposition Division, the litigation in the UK Patents Court with Gilead and potential future infringement or validity litigation in Europe with Gilead may subject us to significant legal expense and may be a distraction to management. There can be no assurance that our patent covering sofosbuvir will be upheld as valid and infringed by any national court in Europe, or upheld as valid by the European Technical Boards of Appeal. See “Risk Factors — Intellectual property litigation could cause us to spend substantial resources and distract our personnel from their normal responsibilities” in our Annual Report on Form 20-F for the year ended December 31, 2020.

This litigation does not affect the patent protection on any of our product candidates, including Acelarin, which are covered by separate patents that are not involved in this litigation.

EX-99.3

Exhibit 99.3

NuCana Reports First Quarter 2021 Financial Results and Provides Business Update

Presented Encouraging Clinical Data at ASCO-GI and AACR

Additional Clinical Data Announcements and Study Initiations Expected in 2021

Edinburgh, United Kingdom, May 19, 2021 (GLOBE NEWSWIRE) – NuCana plc (NASDAQ: NCNA) announced financial results for the first quarter ended March 31, 2021 and provided an update on its broad clinical program with its transformative ProTide therapeutics.

As of March 31, 2021, NuCana had cash and cash equivalents of £78.6 million compared to £87.4 million as of December 31, 2020. NuCana continues to advance its various clinical programs and reported a net loss of £9.8 million for the quarter ended March 31, 2021, as compared to a loss of £4.0 million for the quarter ended March 31, 2020. Basic and diluted loss per share was £0.19 for the quarter ended March 31, 2021, as compared to £0.12 per share for quarter ended March 31, 2020.

“We are very pleased with our momentum in 2021,” said Hugh S. Griffith, NuCana’s Founder and Chief Executive Officer. “In January, we presented data at the American Society of Clinical Oncology Gastrointestinal Cancers Symposium (ASCO-GI) from the NuTide:302 study demonstrating NUC-3373’s encouraging efficacy signals and favorable safety profile in patients with advanced colorectal cancer. Among the efficacy-evaluable population, a disease control rate of 62% was achieved. In addition, NUC-3373 was well tolerated with no hand-foot syndrome or neutropenia as well as lower rates of diarrhea, mucositis and stomatitis as compared to historical data for 5-FU and capecitabine in the frontline treatment of patients with colorectal cancer.”

Mr. Griffith continued: “In April, we were excited to present five posters at the American Association for Cancer Research (AACR) Annual Meeting. NUC-3373 maintained the encouraging 62% disease control rate in the efficacy-evaluable population in the NuTide:302 study. The poster also detailed three patients who experienced reductions in their target lesions of 40%, 28% and 15% and several patients who achieved a longer progression-free survival on NUC-3373 than they had on their prior therapy. We also presented additional clinical data from the ongoing Phase I study of NUC-7738. These data demonstrated NUC-7738’s encouraging anti-cancer activity and favorable tolerability profile. Three case studies described patients who achieved tumor volume reductions and prolonged stable disease on NUC-7738. Other AACR posters showed NUC-3373-treated colon cancer cells are able to activate a natural killer cell response and described how NUC-7738 was designed to overcome the key cancer resistance mechanisms which have prevented the clinical development of its parent nucleoside analog, 3’-deoxyadenosine. Overall, these presentations highlighted the potential of our ProTides to significantly improve the treatment outcomes for patients with cancer.”

Mr. Griffith concluded: “We are excited with the progress we have made so far in 2021. We remain focused on continuing to drive recruitment across all of our ongoing studies, including our Phase III study of Acelarin plus cisplatin in patients with biliary tract cancer as well as initiating new studies, including our second Phase III study evaluating NUC-3373 in combination with other agents for patients with colorectal cancer. We look forward to providing additional updates as we go through 2021.”

Anticipated 2021 Milestones

• Acelarin is a ProTide transformation of gemcitabine. In 2021, NuCana expects to:

• Complete recruitment sufficient to enable the first interim analysis in 2022 of the Phase III study of Acelarin combined with cisplatin as a first-line treatment for patients with advanced biliary tract cancer.

• NUC-3373 is a ProTide transformation of the active anti-cancer metabolite of 5-FU. In 2021, NuCana expects to:

• Report data from the Phase Ib study (NuTide:302) of NUC-3373 in combination with other agents with which 5-FU is typically combined, such as leucovorin, oxaliplatin and irinotecan in patients with advanced colorectal cancer;

• Initiate and report data from a Phase Ib expansion / Phase II study of NUC-3373 in combination with other agents for patients with colorectal cancer;

• Initiate a Phase III study of NUC-3373 in combination with other agents for patients with colorectal cancer; and

• Report data from the Phase I study (NuTide:301) of NUC-3373 in patients with advanced solid tumors.

• NUC-7738 is a ProTide transformation of a novel nucleoside analog, 3’-deoxyadenosine. In 2021, NuCana expects to:

• Report data from the Phase I study (NuTide:701) of NUC-7738 in patients with advanced solid tumors; and

• Initiate a Phase II study of NUC-7738 in patients with solid tumors.

About NuCana

NuCana is a clinical-stage biopharmaceutical company focused on significantly improving treatment outcomes for patients with cancer by applying our ProTide technology to transform some of the most widely prescribed chemotherapy agents, nucleoside analogs, into more effective and safer medicines. While these conventional agents remain part of the standard of care for the treatment of many solid and hematological tumors, their efficacy is limited by cancer cell resistance mechanisms and they are often poorly tolerated. Utilizing our proprietary technology, we are developing new medicines, ProTides, designed to overcome key cancer resistance mechanisms and generate much higher concentrations of anti-cancer metabolites in cancer cells. NuCana’s robust pipeline includes three ProTides in clinical development. Acelarin and NUC-3373, are new chemical entities derived from the nucleoside analogs gemcitabine and 5-fluorouracil, respectively, two widely used chemotherapy agents. Acelarin is in a Phase III study for patients with advanced biliary tract cancer. NUC-3373 is in a Phase I study for the potential treatment of a wide range of patients with advanced solid tumors and a Phase Ib study for patients with metastatic colorectal cancer. Our third ProTide, NUC-7738, is a transformation of a novel nucleoside analog (3’-deoxyadenosine) and is in a Phase I study for patients with advanced solid tumors.

Forward-Looking Statements

This press release may contain “forward-looking” statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are based on the beliefs and assumptions and on information currently available to management of NuCana plc (the “Company”). All statements other than statements of historical fact contained in this press release are forward-looking statements, including statements concerning the Company’s planned and ongoing clinical studies for the Company’s product candidates and the potential advantages of those product candidates, including Acelarin, NUC-3373 and NUC-7738; the initiation, enrollment, timing, progress, release of data from and results of those planned and ongoing clinical studies; the Company’s goals with respect to the development, regulatory pathway and potential use, if approved, of each of its product candidates; and the utility of prior non-clinical and clinical data in determining future clinical results. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “expects,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “potential” or “continue” or the negative of these terms or other comparable terminology. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause the Company’s actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. These risks and uncertainties include, but are not limited to, the risks and uncertainties set forth in the “Risk Factors” section of the Company’s Annual Report on Form 20-F for the year ended December 31, 2020 filed with the Securities and Exchange Commission (“SEC”) on March 4, 2021, and subsequent reports that the Company files with the SEC. Forward-looking statements represent the Company’s beliefs and assumptions only as of the date of this press release. Although the Company believes that the expectations reflected in the forward-looking statements are reasonable, it cannot guarantee future results, levels of activity, performance or achievements. Except as required by law, the Company assumes no obligation to publicly update any forward-looking statements for any reason after the date of this press release to conform any of the forward-looking statements to actual results or to changes in its expectations.

Unaudited Condensed Consolidated Statements of Operations

	For the Three Months Ended March 31,
	2021			2020
	(in thousands, except per share data)
	£			£
Research and development expenses		(8,706	)		(5,938	)
Administrative expenses		(2,104	)		(1,609	)
Net foreign exchange (losses) gains		(677	)		2,127
Operating loss		(11,487	)		(5,420	)
Finance income		24			144
Loss before tax		(11,463	)		(5,276	)
Income tax credit		1,702			1,310
Loss for the period		(9,761	)		(3,966	)
Basic and diluted loss per share		(0.19	)		(0.12	)

Unaudited Condensed Consolidated Statements of Financial Position

	March 31, 2021			December 31, 2020
	(in thousands)
	£			£
Assets
Non-current assets
Intangible assets		4,764			4,753
Property, plant and equipment		1,098			1,189
Deferred tax asset		40			44
		5,902			5,986
Current assets
Prepayments, accrued income and other receivables		4,813			4,628
Current income tax receivable		11,529			9,822
Cash and cash equivalents		78,625			87,356
		94,967			101,806
Total assets		100,869			107,792
Equity and liabilities
Capital and reserves
Share capital and share premium		143,135			142,937
Other reserves		67,470			66,887
Accumulated deficit		(119,146	)		(110,594	)
Total equity attributable to equity holders of the Company		91,459			99,230
Non-current liabilities
Provisions		46			46
Lease liabilities		296			367
		342			413
Current liabilities
Trade payables		3,542			2,257
Payroll taxes and social security		159			177
Accrued expenditure		5,087			5,437
Lease liabilities		280			278
		9,068			8,149
Total liabilities		9,410			8,562
Total equity and liabilities		100,869			107,792

Unaudited Condensed Consolidated Statements of Cash Flows

	For the Three Months Ended March 31,
	2021			2020
	(in thousands)
	£			£
Cash flows from operating activities
Loss for the period		(9,761	)		(3,966	)
Adjustments for:
Income tax credit		(1,702	)		(1,310	)
Amortization and depreciation		222			217
Finance income		(24	)		(144	)
Interest expense on lease liabilities		6			—
Share-based payments		1,795			856
Net foreign exchange losses (gains)		664			(2,164	)
		(8,800	)		(6,511	)
Movements in working capital:
(Increase) decrease in prepayments, accrued income and other receivables		(191	)		423
Increase in trade payables		1,285			44
Decrease in payroll taxes, social security and accrued expenditure		(368	)		(165	)
Movements in working capital		726			302
Cash used in operations		(8,074	)		(6,209	)
Net income tax received		—			—
Net cash used in operating activities		(8,074	)		(6,209	)
Cash flows from investing activities
Interest received		24			187
Payments for property, plant and equipment		(4	)		(10	)
Payments for intangible assets		(138	)		(398	)
Net cash used in investing activities		(118	)		(221	)
Cash flows from financing activities
Payments for lease liabilities		(74	)		(73	)
Proceeds from issue of share capital		198			—
Net cash from (used in) financing activities		124			(73	)
Net decrease in cash and cash equivalents		(8,068	)		(6,503	)
Cash and cash equivalents at beginning of period		87,356			51,962
Effect of exchange rate changes on cash and cash equivalents		(663	)		2,141
Cash and cash equivalents at end of period		78,625			47,600

For more information, please contact:

NuCana plc

Hugh S. Griffith

Chief Executive Officer

+44 131 357 1111

info@nucana.com

Westwicke, an ICR Company

Chris Brinzey

+1 339-970-2843

chris.brinzey@westwicke.com

RooneyPartners

Marion Janic

+1 212-223-4017

mjanic@rooneyco.com

XML

Cover Page	3 Months Ended
	Mar. 31, 2021
Cover [Abstract]
Document Type	6-K
Amendment Flag	false
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Registrant Name	NUCANA PLC
Entity Central Index Key	0001709626
Current Fiscal Year End Date	--12-31

XML

Unaudited Condensed Consolidated Statements of Operations - GBP (£) £ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Profit or loss [abstract]
Research and development expenses	£ (8,706)	£ (5,938)
Administrative expenses	(2,104)	(1,609)
Net foreign exchange (losses) gains	(677)	2,127
Operating loss	(11,487)	(5,420)
Finance income	24	144
Loss before tax	(11,463)	(5,276)
Income tax credit	1,702	1,310
Loss for the period	£ (9,761)	£ (3,966)
Basic and diluted loss per share	£ (0.19)	£ (0.12)

XML

Unaudited Condensed Consolidated Statements of Comprehensive Loss - GBP (£) £ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of comprehensive income [abstract]
Loss for the period	£ (9,761)	£ (3,966)
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations	(3)	21
Other comprehensive (expense) income for the period	(3)	21
Total comprehensive loss for the period	(9,764)	(3,945)
Attributable to:
Equity holders of the Company	£ (9,764)	£ (3,945)

XML

Unaudited Condensed Consolidated Statements of Financial Position - GBP (£) £ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Non-current assets
Intangible assets	£ 4,764	£ 4,753
Property, plant and equipment	1,098	1,189
Deferred tax asset	40	44
Total non-current assets	5,902	5,986
Current assets
Prepayments, accrued income and other receivables	4,813	4,628
Current income tax receivable	11,529	9,822
Cash and cash equivalents	78,625	87,356
Total current assets	94,967	101,806
Total assets	100,869	107,792
Capital and reserves
Share capital and share premium	143,135	142,937
Other reserves	67,470	66,887
Accumulated deficit	(119,146)	(110,594)
Total equity attributable to equity holders of the Company	91,459	99,230
Non-current liabilities
Provisions	46	46
Lease liabilities	296	367
Total non-current liabilities	342	413
Current liabilities
Trade payables	3,542	2,257
Payroll taxes and social security	159	177
Accrued expenditure	5,087	5,437
Lease liabilities	280	278
Total current liabilities	9,068	8,149
Total liabilities	9,410	8,562
Total equity and liabilities	£ 100,869	£ 107,792

XML

Unaudited Condensed Consolidated Statements of Changes In Equity - GBP (£) £ in Thousands	Total	Share Capital [member]	Share Premium [member]	Own Share Reserve [member]	Share Option Reserve [member]	Foreign Currency Translation Reserve [member]	Capital Reserve [member]	Accumulated Deficit [member]
Beginning balance at Dec. 31, 2019	£ 63,522	£ 1,299	£ 79,541	£ (339)	£ 20,620	£ (10)	£ 42,466	£ (80,055)
Loss for the period	(3,966)							(3,966)
Other comprehensive income (expense) for the year	21					21
Total comprehensive loss for the period	(3,945)					21		(3,966)
Share-based payments	856				856
Ending balance at Mar. 31, 2020	60,433	1,299	79,541	(339)	21,476	11	42,466	(84,021)
Beginning balance at Dec. 31, 2020	99,230	2,047	140,890	(339)	24,782	(22)	42,466	(110,594)
Loss for the period	(9,761)							(9,761)
Other comprehensive income (expense) for the year	(3)					(3)
Total comprehensive loss for the period	(9,764)					(3)		(9,761)
Share-based payments	1,795				1,795
Exercise of share options	198	39	159		(1,088)			1,088
Lapse of share options					(121)			121
Ending balance at Mar. 31, 2021	£ 91,459	£ 2,086	£ 141,049	£ (339)	£ 25,368	£ (25)	£ 42,466	£ (119,146)

XML

Unaudited Condensed Consolidated Statements of Cash Flows - GBP (£) £ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities
Loss for the period	£ (9,761)	£ (3,966)
Adjustments for:
Income tax credit	(1,702)	(1,310)
Amortization and depreciation	222	217
Finance income	(24)	(144)
Interest expense on lease liabilities	6
Share-based payments	1,795	856
Net foreign exchange losses (gains)	664	(2,164)
Cash flows from (used in) operations before changes in working capital	(8,800)	(6,511)
Movements in working capital:
(Increase) decrease in prepayments, accrued income and other receivables	(191)	423
Increase in trade payables	1,285	44
Decrease in payroll taxes, social security and accrued expenditure	(368)	(165)
Movements in working capital	726	302
Cash used in operations	(8,074)	(6,209)
Net income tax received
Net cash used in operating activities	(8,074)	(6,209)
Cash flows from investing activities
Interest received	24	187
Payments for property, plant and equipment	(4)	(10)
Payments for intangible assets	(138)	(398)
Net cash used in investing activities	(118)	(221)
Cash flows from financing activities
Payments for lease liabilities	(74)	(73)
Proceeds from issue of share capital	198
Net cash from (used in) financing activities	124	(73)
Net decrease in cash and cash equivalents	(8,068)	(6,503)
Cash and cash equivalents at beginning of period	87,356	51,962
Effect of exchange rate changes on cash and cash equivalents	(663)	2,141
Cash and cash equivalents at end of period	£ 78,625	£ 47,600

XML

General Information

3 Months Ended

Mar. 31, 2021

Disclosure Of General Information About Financial Statements [Abstract]

General information

1. General information

NuCana plc (“NuCana” or the “Company”) is a clinical-stage biopharmaceutical company developing a portfolio of new medicines to treat cancer. NuCana is harnessing the power of phosphoramidate chemistry to generate new medicines called ProTides. These compounds have the potential to improve cancer treatment by enhancing the efficacy and safety of several current standards of care.

The Company has ordinary shares in the form of American Depositary Shares (“ADSs”) registered with the US Securities and Exchange Commission (the “SEC”) and has been listed on The Nasdaq Global Select Market (“Nasdaq”) since October 2, 2017. The Company is incorporated in England and Wales and domiciled in the United Kingdom. The Company’s registered office is located at 77/78 Cannon Street, London EC4N 6AF, United Kingdom and its principal place of business is located at 3 Lochside Way, Edinburgh, EH12 9DT, United Kingdom.

The Company has two wholly owned subsidiaries, NuCana, Inc. and NuCana BioMed Trustee Company Limited (together referred to as the “Group”).

The financial information presented in these unaudited condensed consolidated financial statements does not constitute the Group’s statutory accounts within the meaning of section 434 of the U.K. Companies Act 2006.

The Group’s statutory accounts for the year ended December 31, 2020 have not yet been reported on by the Company’s auditor or delivered to the Registrar of Companies. The Company filed its Annual Report on Form 20-F for the year ended December 31, 2020 with the SEC on March 4, 2021, which included the Company’s Consolidated Financial Statements for its fiscal year ended December 31, 2020. Those financial statements have been reported on by the Company’s auditor. The report of the auditor was (i) unqualified and (ii) did not include a reference to any matters to which the auditors drew attention by way of emphasis without qualifying their report.

XML

Significant Accounting Policies

3 Months Ended

Mar. 31, 2021

Disclosure Of Summary Of Significant Accounting Policies [Abstract]

Significant accounting policies

2. Significant accounting policies

Basis of preparation

The unaudited condensed consolidated financial statements (the “financial statements”) for the three months ended March 31, 2021 have been prepared in accordance with International Accounting Standard 34, “Interim Financial Reporting” (“IAS 34”). The significant accounting policies and methods of computation applied in the preparation of the financial statements are consistent with those applied in the Company’s annual financial statements for the year ended December 31, 2020. No new standards, amendments or interpretations have had an impact on the financial statements for the three months ended March 31, 2021. The financial statements comprise the financial statements of the Group at March 31, 2021. The financial statements are presented in pounds sterling, which is also the Company’s functional currency. All values are rounded to the nearest thousand, except where otherwise indicated.

The financial statements do not include all the information and disclosures required in the annual financial statements, and should be read in conjunction with the Company’s annual financial statements for the year ended December 31, 2020.

In the opinion of management, these unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of the results of operations, financial position and cash flows. The results of operations for the three months ended March 31, 2021 are not necessarily indicative of the results that can be expected for the Company’s fiscal year ending December 31, 2021.

Going concern

In common with many companies in the biopharmaceutical sector, the Company incurs significant expenditure in its early years as it researches and develops its potential products for market.

The Company’s board of directors, having reviewed the operating budgets and development plans, considers that the Company has adequate resources to continue in operation for the foreseeable future. The board of directors is therefore satisfied that it is appropriate to adopt the going concern basis of accounting in preparing the financial statements. The Company believes that its cash and cash equivalents of £78.6 million at March 31, 2021 will be sufficient to fund its current operating plan for at least the next 12 months. Further, the directors have conducted an assessment of the impact of COVID-19 on the going concern status of the Company and have concluded that it will not have a significant negative impact on the cash outflows of the Company over the period assessed for going concern purposes.

As the Company continues to incur losses, the transition to profitability is dependent upon the successful development, approval and commercialization of its product candidates and achieving a level of revenues adequate to support its cost structure. The Company may never achieve profitability, and unless and until it does, it will continue to need to raise additional capital. There can be no assurances, however, that additional funding will be available on acceptable terms.

COVID-19

In response to the COVID-19 pandemic, all of the Company’s offices have been closed with employees continuing their work outside of the offices and the Company has restricted on-site staff access to only those required to execute their job responsibilities.

During the early months of the pandemic the Company announced that there was some temporary interruption to the enrollment of new patients in the Company’s ongoing clinical trials. In May 2020, the Company further announced that enrollment of new patients in the Company’s clinical trials had re-commenced. While the Company continues to evaluate the impact of COVID-19 on its operations, the Company believes that this pandemic will inevitably cause some delays to the timing of initiation and completion of its clinical trials. The Company is continuing to monitor the impact of COVID-19.

COVID-19 has had no impact on the judgements and estimates used in the preparation of these financial statements.

Judgements and estimates

The accounting estimates and judgements made by management in applying the Group’s accounting policies that have the most significant effect on the amounts included within these financial statements were the same as those that applied to the annual financial statements for the year ended December 31, 2020.    

XML

Income Tax

3 Months Ended

Mar. 31, 2021

Major Components Of Tax Expense Income [Abstract]

Income tax

3. Income tax

	For the Three Months Ended March 31,
	2021			2020
	(in thousands)
	£			£
Current tax:
In respect of current period U.K.		1,706			1,315
In respect of current period U.S.		—			—
		1,706			1,315
Deferred tax:
In respect of current period U.S.		(4	)		(4	)
In respect of prior period U.S.		—			(1	)
Income tax credit		1,702			1,310

The income tax credit recognized primarily represents the U.K. research and development tax credit. In the United Kingdom, the Company is able to surrender some of its losses for a cash rebate of up to 33.35% of expenditure related to eligible research and development projects.

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Current income tax receivable
U.K. tax		11,525		9,818
U.S. tax		4		4
		11,529		9,822
Deferred tax asset
U.S. deferred tax asset		40		44

XML

Basic and Diluted Loss Per Share

3 Months Ended

Mar. 31, 2021

Earnings Per Share [Abstract]

Basic and diluted loss per share

4. Basic and diluted loss per share

	For the Three Months Ended March 31,
	2021			2020
	(in thousands, except per share data)
	£			£
Loss for the period		(9,761	)		(3,966	)
Basic and diluted weighted average number of shares		51,649			32,479
	£			£
Basic and diluted loss per share		(0.19	)		(0.12	)

Basic loss per share is calculated by dividing the loss for the period attributable to the equity holders of the Company by the weighted average number of shares outstanding during the period.

The potential shares issued through equity settled transactions were considered to be anti-dilutive as they would have decreased the loss per share and were therefore excluded from the calculation of diluted loss per share.

XML

Intangible Assets

3 Months Ended

Mar. 31, 2021

Disclosure Of Intangible Assets [Abstract]

Intangible assets

5. Intangible assets

Intangible assets comprise patents with a carrying value of £4.6 million as of March 31, 2021 (as of December 31, 2020: £4.6 million) and computer software with a carrying value of £0.2 million as of March 31, 2021 (as of December 31, 2020: £0.2 million).

During the three months ended March 31, 2021, the Company acquired intangible assets with a cost of £0.1 million in relation to patents. There were no disposals of intangible assets in the three months ended March 31, 2021.

XML

Cash and Cash Equivalents

3 Months Ended

Mar. 31, 2021

Cash And Cash Equivalents [Abstract]

Cash and cash equivalents

6. Cash and cash equivalents

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Cash and cash equivalents		78,625		87,356

Cash and cash equivalents comprise cash at banks with deposit maturity terms of three months or less, which is subject to insignificant risk of changes in value. Cash at banks earns interest at fixed or variable rates based on the terms agreed for each account.

XML

Share-based Payments

3 Months Ended

Mar. 31, 2021

Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Abstract]

Share-based payments

7. Share-based payments

The Company has six share-based payment plans for employees, directors and consultants. The share options granted will be settled in equity. Options granted under each of the six plans have a maximum life of 10 years. If the Company determines, and at its discretion, an arrangement may be made under the 2020 Long-Term Incentive Plan to substitute the right to acquire shares with a cash alternative of equivalent value.

As detailed in the table below, during the three months ended March 31, 2021, 1,501,663 share options were granted under the 2020 Long-Term Incentive Plan (three months ended March 31, 2020: no share options granted). Options granted under this plan will vest if the option holder remains under respective contract of employment or contract of service for the agreed vesting period. The share options granted in the period will vest over a period of up to four years.

The fair values of options granted were determined using the Black-Scholes model that takes into account factors specific to the share incentive plan such as the assumption that the options are exercised at a point in time of up to two years after vesting. This has been incorporated into the measurement by means of actuarial modelling. As NuCana plc was unlisted until October 2, 2017, it is not possible to derive historical volatility from the Company’s ADSs prior to October 2017. For options with an estimated life of greater than three years, the underlying expected volatility was determined by using the average of the historical volatility of similar listed entities as a proxy. Options granted with an estimated life of three years or less, have been valued using the Company’s own historical volatility rates.

	Options granted on
	January 13, 2021			February 10, 2021			February 10, 2021			February 10, 2021
Vesting dates		January 13, 2022			February 10, 2022			February 10, 2022			February 10, 2022
		January 13, 2023			February 10, 2023			February 10, 2023			February 10, 2023
		January 13, 2024			February 10, 2024			February 10, 2024			February 10, 2024
		January 13, 2025			February 10, 2025			February 10, 2025			February 10, 2025
Volatility		81.42	%		81.45	%		87.66	%		83.86	%
Dividend yield		0	%		0	%		0	%		0	%
Risk-free investment rate		0.01	%		0.11	%		0.01	%		0.05	%
Fair value of option at grant date	£	2.37		£	2.74		£	4.49		£	4.49
Fair value of share at grant date	£	3.92		£	4.53		£	4.53		£	4.53
Exercise price at date of grant	£	3.92		£	4.53		£	0.04		£	0.04
Lapse date		January 13, 2031			February 10, 2031			—			February 10, 2031
Expected option life (years)		4.50			4.50			2.50			3.50
Number of options granted		200,000			872,775			91,888			337,000

For the three months ended March 31, 2021, the Company has recognized £1.8 million of share-based payment expense in the statement of operations (three months ended March 31, 2020: £0.9 million).

XML

Share Capital and Share Premium

3 Months Ended

Mar. 31, 2021

Disclosure Of Classes Of Share Capital [Abstract]

Share capital and share premium

8. Share capital and share premium

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Share capital		2,086		2,047
Share premium		141,049		140,890
		143,135		142,937

	March 31, 2021		December 31, 2020
	Number (in thousands)
Issued share capital comprises:
Ordinary shares of £0.04 each		52,162		51,175

	Number of shares		Share capital		Share premium
	(in thousands)
Fully paid shares:			£		£
Balance at December 31, 2020		51,175		2,047		140,890
Issue of shares on exercise of options		987		39		159
Balance at March 31, 2021		52,162		2,086		141,049

XML

Contingent Liabilities

3 Months Ended

Mar. 31, 2021

Disclosure Of Contingent Liabilities [Abstract]

Contingent liabilities

9. Contingent liabilities

Under its U.K. share-based payment plan, the Company granted unapproved share options that have fully vested. If and when these share options are exercised, the Company will be liable for the Employer Class 1 National Insurance payable to HMRC in the United Kingdom. This contingent liability will be determined based on the market value of the shares on exercise less the exercise price paid by the option holders, at the prevailing rate of Employer National Insurance (currently 13.8%). Based on the closing price of the Company’s ADSs on the Nasdaq Global Select Market on March 31, 2021, the last trading day of the period to which these financial statements relate, and assuming full exercise of all outstanding and vested unapproved share options on that date, the Employer National Insurance contingent liability would have been £0.8 million (December 31, 2020: £0.8 million).

XML

Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2021

Disclosure Of Summary Of Significant Accounting Policies [Abstract]

Basis of preparation

Basis of preparation

The unaudited condensed consolidated financial statements (the “financial statements”) for the three months ended March 31, 2021 have been prepared in accordance with International Accounting Standard 34, “Interim Financial Reporting” (“IAS 34”). The significant accounting policies and methods of computation applied in the preparation of the financial statements are consistent with those applied in the Company’s annual financial statements for the year ended December 31, 2020. No new standards, amendments or interpretations have had an impact on the financial statements for the three months ended March 31, 2021. The financial statements comprise the financial statements of the Group at March 31, 2021. The financial statements are presented in pounds sterling, which is also the Company’s functional currency. All values are rounded to the nearest thousand, except where otherwise indicated.

The financial statements do not include all the information and disclosures required in the annual financial statements, and should be read in conjunction with the Company’s annual financial statements for the year ended December 31, 2020.

In the opinion of management, these unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of the results of operations, financial position and cash flows. The results of operations for the three months ended March 31, 2021 are not necessarily indicative of the results that can be expected for the Company’s fiscal year ending December 31, 2021.

Going concern

Going concern

In common with many companies in the biopharmaceutical sector, the Company incurs significant expenditure in its early years as it researches and develops its potential products for market.

The Company’s board of directors, having reviewed the operating budgets and development plans, considers that the Company has adequate resources to continue in operation for the foreseeable future. The board of directors is therefore satisfied that it is appropriate to adopt the going concern basis of accounting in preparing the financial statements. The Company believes that its cash and cash equivalents of £78.6 million at March 31, 2021 will be sufficient to fund its current operating plan for at least the next 12 months. Further, the directors have conducted an assessment of the impact of COVID-19 on the going concern status of the Company and have concluded that it will not have a significant negative impact on the cash outflows of the Company over the period assessed for going concern purposes.

As the Company continues to incur losses, the transition to profitability is dependent upon the successful development, approval and commercialization of its product candidates and achieving a level of revenues adequate to support its cost structure. The Company may never achieve profitability, and unless and until it does, it will continue to need to raise additional capital. There can be no assurances, however, that additional funding will be available on acceptable terms.

COVID-19

COVID-19

In response to the COVID-19 pandemic, all of the Company’s offices have been closed with employees continuing their work outside of the offices and the Company has restricted on-site staff access to only those required to execute their job responsibilities.

During the early months of the pandemic the Company announced that there was some temporary interruption to the enrollment of new patients in the Company’s ongoing clinical trials. In May 2020, the Company further announced that enrollment of new patients in the Company’s clinical trials had re-commenced. While the Company continues to evaluate the impact of COVID-19 on its operations, the Company believes that this pandemic will inevitably cause some delays to the timing of initiation and completion of its clinical trials. The Company is continuing to monitor the impact of COVID-19.

COVID-19 has had no impact on the judgements and estimates used in the preparation of these financial statements.

Judgements and estimates

Judgements and estimates

The accounting estimates and judgements made by management in applying the Group’s accounting policies that have the most significant effect on the amounts included within these financial statements were the same as those that applied to the annual financial statements for the year ended December 31, 2020.    

XML

Income Tax (Tables)

3 Months Ended

Mar. 31, 2021

Major Components Of Tax Expense Income [Abstract]

Schedule of Major Components of Income Tax

	For the Three Months Ended March 31,
	2021			2020
	(in thousands)
	£			£
Current tax:
In respect of current period U.K.		1,706			1,315
In respect of current period U.S.		—			—
		1,706			1,315
Deferred tax:
In respect of current period U.S.		(4	)		(4	)
In respect of prior period U.S.		—			(1	)
Income tax credit		1,702			1,310

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Current income tax receivable
U.K. tax		11,525		9,818
U.S. tax		4		4
		11,529		9,822
Deferred tax asset
U.S. deferred tax asset		40		44

XML

Basic and Diluted Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2021

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Loss Per Share

	For the Three Months Ended March 31,
	2021			2020
	(in thousands, except per share data)
	£			£
Loss for the period		(9,761	)		(3,966	)
Basic and diluted weighted average number of shares		51,649			32,479
	£			£
Basic and diluted loss per share		(0.19	)		(0.12	)

XML

Cash and Cash Equivalents (Tables)

3 Months Ended

Mar. 31, 2021

Cash And Cash Equivalents [Abstract]

Schedule of Cash and Cash Equivalents

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Cash and cash equivalents		78,625		87,356

XML

Share-based Payments (Tables)

3 Months Ended

Mar. 31, 2021

Text block [abstract]

Summary of Principal Assumptions Used for Valuation of Share Options

	Options granted on
	January 13, 2021			February 10, 2021			February 10, 2021			February 10, 2021
Vesting dates		January 13, 2022			February 10, 2022			February 10, 2022			February 10, 2022
		January 13, 2023			February 10, 2023			February 10, 2023			February 10, 2023
		January 13, 2024			February 10, 2024			February 10, 2024			February 10, 2024
		January 13, 2025			February 10, 2025			February 10, 2025			February 10, 2025
Volatility		81.42	%		81.45	%		87.66	%		83.86	%
Dividend yield		0	%		0	%		0	%		0	%
Risk-free investment rate		0.01	%		0.11	%		0.01	%		0.05	%
Fair value of option at grant date	£	2.37		£	2.74		£	4.49		£	4.49
Fair value of share at grant date	£	3.92		£	4.53		£	4.53		£	4.53
Exercise price at date of grant	£	3.92		£	4.53		£	0.04		£	0.04
Lapse date		January 13, 2031			February 10, 2031			—			February 10, 2031
Expected option life (years)		4.50			4.50			2.50			3.50
Number of options granted		200,000			872,775			91,888			337,000

XML

Share Capital and Share Premium (Tables)

3 Months Ended

Mar. 31, 2021

Disclosure Of Classes Of Share Capital [Abstract]

Summary of Share Capital and Share Premium

	March 31, 2021		December 31, 2020
	(in thousands)
	£		£
Share capital		2,086		2,047
Share premium		141,049		140,890
		143,135		142,937

	March 31, 2021		December 31, 2020
	Number (in thousands)
Issued share capital comprises:
Ordinary shares of £0.04 each		52,162		51,175

Summary of Movement in the Share Capital

	Number of shares		Share capital		Share premium
	(in thousands)
Fully paid shares:			£		£
Balance at December 31, 2020		51,175		2,047		140,890
Issue of shares on exercise of options		987		39		159
Balance at March 31, 2021		52,162		2,086		141,049

XML

General Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2021 Subsidiary
Disclosure Of General Information About Financial Statements [Abstract]
Description of nature of entity's operations	clinical-stage biopharmaceutical company developing a portfolio of new medicines to treat cancer​​​​​​​
Name of reporting entity	NuCana plc
Domicile of entity	United Kingdom
Country of incorporation	England and Wales
Number of subsidiaries	2
Name of subsidiary	NuCana, Inc. and NuCana BioMed Trustee Company Limited

XML

Significant Accounting Policies - Additional Information (Detail) - GBP (£) £ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Disclosure Of Summary Of Significant Accounting Policies [Abstract]
Cash and cash equivalents	£ 78,625	£ 87,356	£ 47,600	£ 51,962

XML

Income Tax - Schedule of Major Components of Income Tax Credit (Detail) - GBP (£) £ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Current tax:
Total current tax	£ 1,706	£ 1,315
Deferred tax:
Income tax credit	1,702	1,310
U.K. [member]
Current tax:
In respect of current period	1,706	1,315
Deferred tax:
In respect of current period	(4)	(4)
U.S. [member]
Current tax:
In respect of current period		0
Deferred tax:
In respect of prior period	£ 0	£ (1)

XML

Income Tax - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2021
U.K. [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Percentage of losses surrendered for R&D tax credit	33.35%

XML

Income Tax - Schedule of Major Components of Income Tax Assets (Detail) - GBP (£) £ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current income tax receivable
Current income tax receivable	£ 11,529	£ 9,822
Deferred tax asset
Deferred tax asset	40	44
U.K. [member]
Current income tax receivable
Current income tax receivable	11,525	9,818
U.S. [member]
Current income tax receivable
Current income tax receivable	4	4
Deferred tax asset
Deferred tax asset	£ 40	£ 44

XML

Basic and Diluted Loss per Share - Schedule of Basic and Diluted Loss Per Share (Detail) - GBP (£) £ / shares in Units, £ in Thousands, shares in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Loss for the period	£ (9,761)	£ (3,966)
Basic and diluted weighted average number of shares	51,649	32,479
Basic and diluted loss per share	£ (0.19)	£ (0.12)

XML

Intangible Assets - Additional Information (Detail) - GBP (£) £ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	£ 4,764	£ 4,753
Patents [member]
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	4,600	4,600
Intangible assets, acquired	100
Computer Software [member]
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	£ 200	£ 200

XML

Cash and Cash Equivalents - Schedule of Detailed Information About Cash and Cash Equivalents (Detail) - GBP (£) £ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	£ 78,625	£ 87,356	£ 47,600	£ 51,962

XML

Share-based Payments - Additional Information (Details) £ in Millions	3 Months Ended
	Mar. 31, 2021 GBP (£) shares	Mar. 31, 2020 GBP (£) shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share-based payment expense | £	£ 1.8	£ 0.9
Long-Term Incentive Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of share options granted in share-based payment arrangement | shares	1,501,663	0
Share options granted, vesting period	4 years

XML

Share Based Payments - Summary of Principal Assumptions used for Valuation of Share Options (Detail) - 3 months ended Mar. 31, 2021 - 2020 Share Options [member]	GBP (£) shares Subsidiary yr £ / shares	GBP (£) shares Subsidiary yr $ / shares
Grant Date June 10, 2020 [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Lapse date	Jan. 13, 2031	Jan. 13, 2031
Grant Date January 13, 2021 [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	81.42%	81.42%
Dividend yield	0.00%	0.00%
Risk-free investment rate	0.01%	0.01%
Fair value of option at grant date | £	£ 2,370	£ 2,370
Fair value of share at grant date	£ 3.92
Exercise price at date of grant	£ 3.92
Expected option life (years) | yr	4.50	4.50
Number of options granted | shares	200,000	200,000
Grant Date January 13, 2021 [Member] | Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 13, 2022	Jan. 13, 2022
Grant Date January 13, 2021 [Member] | Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 13, 2023	Jan. 13, 2023
Grant Date January 13, 2021 [Member] | Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 13, 2024	Jan. 13, 2024
Grant Date January 13, 2021 [Member] | Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 13, 2025	Jan. 13, 2025
Grant Date February 10, 2021 [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	81.45%	81.45%
Dividend yield	0.00%	0.00%
Risk-free investment rate	0.11%	0.11%
Fair value of option at grant date | £	£ 2,740	£ 2,740
Fair value of share at grant date	£ 4.53
Exercise price at date of grant	£ 4.53
Lapse date	Feb. 10, 2031	Feb. 10, 2031
Expected option life (years) | yr	4.50	4.50
Number of options granted | shares	872,775	872,775
Grant Date February 10, 2021 [Member] | Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2022	Feb. 10, 2022
Grant Date February 10, 2021 [Member] | Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2023	Feb. 10, 2023
Grant Date February 10, 2021 [Member] | Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2024	Feb. 10, 2024
Grant Date February 10, 2021 [Member] | Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2025	Feb. 10, 2025
Grant Date February 10, 2021 One [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	87.66%	87.66%
Dividend yield	0.00%	0.00%
Risk-free investment rate	0.01%	0.01%
Fair value of option at grant date | £	£ 4,490	£ 4,490
Fair value of share at grant date	£ 4.53
Exercise price at date of grant	£ 0.04
Expected option life (years) | yr	2.50	2.50
Number of options granted | shares	91,888	91,888
Grant Date February 10, 2021 One [Member] | Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2022	Feb. 10, 2022
Grant Date February 10, 2021 One [Member] | Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2023	Feb. 10, 2023
Grant Date February 10, 2021 One [Member] | Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2024	Feb. 10, 2024
Grant Date February 10, 2021 One [Member] | Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2025	Feb. 10, 2025
Grant Date February 10, 2021 Two [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	83.86%	83.86%
Dividend yield	0.00%	0.00%
Risk-free investment rate	0.05%	0.05%
Fair value of option at grant date | £	£ 4,490	£ 4,490
Fair value of share at grant date | $ / shares		£ 4.53
Exercise price at date of grant | $ / shares		£ 0.04
Lapse date	Feb. 10, 2031	Feb. 10, 2031
Expected option life (years) | yr	3.50	3.50
Number of options granted | Subsidiary	337,000	337,000
Grant Date February 10, 2021 Two [Member] | Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2022	Feb. 10, 2022
Grant Date February 10, 2021 Two [Member] | Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2023	Feb. 10, 2023
Grant Date February 10, 2021 Two [Member] | Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2024	Feb. 10, 2024
Grant Date February 10, 2021 Two [Member] | Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2025	Feb. 10, 2025

XML

Share Capital and Share Premium - Summary of Share Capital and Share Premium (Detail) - GBP (£) £ in Thousands, shares in Thousands	Mar. 31, 2021	Dec. 31, 2020
Disclosure Of Classes Of Share Capital [Abstract]
Share capital	£ 2,086	£ 2,047
Share premium	141,049	140,890
Share capital and share premium	£ 143,135	£ 142,937
Ordinary shares of £0.04 each	52,162	51,175

XML

Share Capital and Share Premium - Summary of Share Capital and Share Premium (Parenthetical) (Detail) - £ / shares	Mar. 31, 2021	Dec. 31, 2020
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Par value per share	£ 0.04	£ 0.04

XML

Share Capital and Share Premium - Summary of Movement in the Share Capital (Detail) £ in Thousands, shares in Thousands	3 Months Ended
	Mar. 31, 2021 GBP (£) shares
Disclosure of classes of share capital [line items]
Beginning balance, Shares | shares	51,175
Beginning balance	£ 99,230
Issue of shares on exercise of options | shares	987
Issue of shares on exercise of options	£ 198
Ending balance, Shares | shares	52,162
Ending balance	£ 91,459
Share Capital [member]
Disclosure of classes of share capital [line items]
Beginning balance	2,047
Issue of shares on exercise of options	39
Ending balance	2,086
Share Premium [member]
Disclosure of classes of share capital [line items]
Beginning balance	140,890
Issue of shares on exercise of options	159
Ending balance	£ 141,049

XML

Contingent Liabilities - Additional Information (Detail) - GBP (£) £ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Disclosure Of Contingent Liabilities [Abstract]
Prevailing rate of employer national insurance	13.80%
Employer national insurance contingent liability	£ 0.8	£ 0.8