6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of October 2018

(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):  ☐

The information in the attached Exhibits 99.1 and 99.2 shall be deemed to be incorporated by reference into the Company’s Registration Statement on Form S-8 (Registration Number 333-223476) and any related prospectuses, as such Registration Statement 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be amended from time to time, and to be a part thereof from the date on which this report is filed, to the extent not superseded by documents or reports subsequently filed or furnished.

Exhibits

Exhibit No.	Description
99.1	Unaudited Condensed Consolidated Financial Statements as of June 30, 2018 and for the Three and Six Months Ended June 30, 2018 and 2017
99.2	Management’s Discussion and Analysis for the Three and Six Months Ended June 30, 2018 and 2017
101	The following materials from this Report on Form 6-K formatted in XBRL (eXtensible Business Reporting Language): (i) Unaudited Condensed Consolidated Statements of Operations for the Three and Six Month Periods ended June 30, 2018 and 2017, (ii) Unaudited Condensed Consolidated Statements Comprehensive Loss for the Three and Six Month periods ended June 30, 2018 and 2017 (iii) Unaudited Condensed Consolidated Statements of Financial Position as at June 30, 2018 and December 31, 2017, (iv) Unaudited Condensed Consolidated Statements of Changes in Equity for the Six Month Periods ended June 30, 2018 and 2017, (v) Unaudited Condensed Consolidated Statements of Cash Flows for the Six Month Periods ended June 30, 2018 and 2017 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: October 1, 2018

EX-99.1

Exhibit 99.1

NUCANA PLC

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

			For the Three Months Ended June 30,						For the Six Months Ended June 30,
	Notes		2018			2017			2018			2017
			(in thousands, except per share data)
			£			£			£			£
Research and development expenses				(5,158	)		(2,077	)		(8,863	)		(3,689	)
Administrative expenses				(1,402	)		(313	)		(2,642	)		(637	)
Initial public offering related expenses		3		—			(1,034	)		—			(1,066	)
Net foreign exchange gains (losses)				3,607			(113	)		1,059			(161	)
Operating loss				(2,953	)		(3,537	)		(10,446	)		(5,553	)
Finance income				252			44			442			91
Loss before tax				(2,701	)		(3,493	)		(10,004	)		(5,462	)
Income tax credit		4		1,383			745			2,292			1,077
Loss for the period				(1,318	)		(2,748	)		(7,712	)		(4,385	)
Basic and diluted loss per share		5		(0.04	)		(0.11	)		(0.24	)		(0.18	)

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

1

NUCANA PLC

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS

	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2018			2017			2018			2017
	(in thousands)
	£			£			£			£
Loss for the period		(1,318	)		(2,748	)		(7,712	)		(4,385	)
Other comprehensive expense:
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations		9			—			4			(1	)
Other comprehensive income (expense) for the period		9			—			4			(1	)
Total comprehensive loss for the period		(1,309	)		(2,748	)		(7,708	)		(4,386	)
Attributable to:
Equity holders of the Company		(1,309	)		(2,748	)		(7,708	)		(4,386	)

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

			June 30, 2018			December 31, 2017
			(in thousands)
	Notes		£			£
Assets
Non-current assets
Intangible assets		6		2,485			1,938
Property, plant and equipment				495			358
Deferred tax asset		4		32			81
				3,012			2,377
Current assets
Prepayments, accrued income and other receivables				1,737			3,050
Current income tax receivable		4		4,660			4,225
Cash and cash equivalents		7		81,469			86,703
				87,866			93,978
Total assets				90,878			96,355
Equity and liabilities
Capital and reserves
Share capital and share premium		9		80,508			80,508
Other reserves				59,072			58,071
Accumulated deficit				(52,871	)		(45,159	)
Total equity attributable to equity holders of the Company				86,709			93,420
Non-current liabilities
Provisions				26			18
Current liabilities
Trade payables				2,123			1,120
Payroll taxes and social security				103			157
Accrued expenditure				1,917			1,640
				4,143			2,917
Total liabilities				4,169			2,935
Total equity and liabilities				90,878			96,355

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 Six Months Ended June 30,
	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 December 31, 2016		663		42,770			(339	)		4,406		(3	)		—		(22,256	)		25,241
Loss for the period		—		—			—			—		—			—		(4,385	)		(4,385	)
Other comprehensive expense for the period		—		—			—			—		(1	)		—		—			(1	)
Total comprehensive loss for the period		—		—			—			—		(1	)		—		(4,385	)		(4,386	)
Share-based payments		—		—			—			532		—			—		—			532
Reduction in share premium		—		(42,466	)		—			—		—			42,466		—			—
Balance at June 30, 2017		663		304			(339	)		4,938		(4	)		42,466		(26,641	)		21,387
Balance at December 31, 2017		1,272		79,236			(339	)		15,955		(11	)		42,466		(45,159	)		93,420
Loss for the period		—		—			—			—		—			—		(7,712	)		(7,712	)
Other comprehensive income for the period		—		—			—			—		4			—		—			4
Total comprehensive loss for the period		—		—			—			—		4			—		(7,712	)		(7,708	)
Share-based payments		—		—			—			997		—			—		—			997
Balance at June 30, 2018		1,272		79,236			(339	)		16,952		(7	)		42,466		(52,871	)		86,709

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 Six Months Ended June 30,
	2018			2017
	(in thousands)
	£			£
Cash flows from operating activities
Loss for the period		(7,712	)		(4,385	)
Adjustments for:
Income tax credit		(2,292	)		(1,077	)
Amortization and depreciation		164			84
Finance income		(442	)		(91	)
Share-based payments		997			532
Initial public offering (IPO) related expenses		—			1,066
Net foreign exchange (gains) losses		(1,112	)		142
		(10,397	)		(3,729	)
Movements in working capital:
Decrease in prepayments, accrued income and other receivables		1,358			609
Increase (decrease) in trade payables		1,003			(477	)
Increase (decrease) in payroll taxes, social security and accrued expenditure		231			(230	)
Movements in working capital		2,592			(98	)
Cash used in operations		(7,805	)		(3,827	)
Net income tax credit received		1,906			235
Net cash used in operating activities		(5,899	)		(3,592	)
Cash flows from investing activities
Interest received		429			98
Payments for property, plant and equipment		(200	)		(5	)
Payments for intangible assets		(648	)		(492	)
Net cash used in investing activities		(419	)		(399	)
Cash flows from financing activities
IPO related expenses included in statement of operations		—			(73	)
Net cash used in financing activities		—			(73	)
Net decrease in cash and cash equivalents		(6,318	)		(4,064	)
Cash and cash equivalents at beginning of period		86,703			19,990
Foreign currency translation differences		1,084			(8	)
Cash and cash equivalents at end of period		81,469			15,918

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. We are 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.

On August 29, 2017 the Company re-registered as a public limited company and changed its name from NuCana BioMed Limited to NuCana plc.

The Company has had American Depository Receipts (“ADRs”) registered with the US Securities and Exchange Commission (“SEC”) and is listed on Nasdaq since October 2, 2017. The Company is incorporated in England and Wales and domiciled in the United Kingdom.

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

The comparative figures for the year ended December 31, 2017 are not the Group’s statutory accounts for that financial year within the meaning of section 434 of the Companies Act 2006. Those accounts have been reported on by the Company’s auditor and delivered to the Registrar of Companies. The report of the auditor was (i) unqualified, (ii) did not include a reference to any matters to which the auditors drew attention by way of emphasis without qualifying their report, and (iii) did not contain a statement under section 498 (2) or (3) of the Companies Act 2006.

2. Significant accounting policies

Basis of preparation

The unaudited condensed consolidated financial statements (the “financial statements”) for the three and six months ended June 30, 2018 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, 2017. No new standards, amendments or interpretations have had an impact on the financial statements for the six months ended June 30, 2018.

The financial statements comprise the financial statements of the Company and its subsidiaries at June 30, 2018. 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 as at December 31, 2017.

The unaudited condensed consolidated statement of cash flows for the six months ended June 30, 2017 has been restated to be consistent with the presentation of foreign exchange differences and IPO related expenses in the annual financial statements for the year ended December 31, 2017.

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 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 £81.5 million at June 30, 2018, will be sufficient to fund its current operating plan for at least the next 12 months. 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.

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, 2017.

6

NUCANA PLC

NOTES TO THE UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

3. IPO related expenses

	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2018		2017		2018		2017
	(in thousands)				(in thousands)
	£		£		£		£
IPO related expenses		—		1,034		—		1,066

IPO related expenses primarily relate to legal, accounting and other advisors’ fees in relation to the Company’s listing on Nasdaq which completed on October 2, 2017.

4. Income tax

	For the Three Months Ended June 30,					For the Six Months Ended June 30,
	2018			2017		2018			2017
	(in thousands)					(in thousands)
	£			£		£			£
Current tax		1,393			745		2,341			1,077
Deferred tax		(10	)		—		(49	)		—
Income tax credit		1,383			745		2,292			1,077

The income tax credit recognized primarily represents the U.K. research and development tax credit. In the U.K. 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.

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Current income tax receivable
U.K. tax		4,641		4,207
U.S. tax		19		18
		4,660		4,225
Deferred tax asset
U.S. deferred tax asset		32		81

7

NUCANA PLC

NOTES TO THE UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

5. Basic and diluted loss per share

	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2018			2017			2018			2017
	(in thousands, except per share data)
	£			£			£			£
Loss for the period		(1,318	)		(2,748	)		(7,712	)		(4,385	)
Basic and diluted weighted average number of shares		31,811			24,185			31,811			24,185
	£			£			£			£
Basic and diluted loss per share		(0.04	)		(0.11	)		(0.24	)		(0.18	)

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.

8

NUCANA PLC

NOTES TO THE UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

6. Intangible assets

Intangible assets comprise patents with a carrying value of £2.4 million as of June 30, 2018 (as of December 31, 2017: £1.8 million) and computer software with a carrying value of £0.1 million as of June 30, 2018 (as of December 31, 2017: £0.1 million).

During the six months ended June 30, 2018, the Company acquired intangible assets with a cost of £0.6 million in relation to patents (six months ended June 30, 2017: £0.4 million in relation to patents and £0.1 million in relation to computer software).

There were no disposals of intangible assets in the six months ended June 30, 2018 (six months ended June 30, 2017: £nil).

7. Cash and cash equivalents

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Cash and cash equivalents		81,469		86,703

Cash and cash equivalents comprise cash at bank with maturities of three months or less and earn interest at fixed or variable rates based on the terms agreed for each account.

9

NUCANA PLC

NOTES TO THE UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

8. Share-based payments

The Company has three share-based payment plans for employees, directors and consultants. The share options granted will be settled in equity.

On April 11, 2018 and May 8, 2018, 79,000 and 62,000 share options respectively were granted under the U.K. share-based payment plans. Options granted under these plans 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 under these plans will vest equally over a period of four years, with the exception of options granted to a consultant, which vested immediately.

The fair values of options granted were determined using the Black-Scholes model that takes into account factors specific to the share incentive plan. As NuCana plc listed on October 2, 2017, it is not possible to derive historical volatility from the Company’s own share price. The underlying expected volatility was therefore determined by using the historical volatility of similar listed entities as a proxy. The volatility percentage applied to each tranche is the average of the historical volatility of comparable companies to NuCana plc.

The following weighted average principal assumptions were used in calculating the fair values of options granted:

	Options granted on
	Apr 11, 2018			Apr 11, 2018			May 8, 2018
Vesting dates		Apr 11, 2019			Apr 11, 2018			May 8, 2019
		Apr 11, 2020						May 8, 2020
		Apr 11, 2021						May 8, 2021
		Apr 11, 2022						May 8, 2022
Volatility		64.48	%		60.06	%		65.80	%
Dividend yield		0	%		0	%		0	%
Risk-free investment rate		1.04	%		0.83	%		1.02	%
Fair value of option at grant date	£	8.97		£	17.35		£	8.63
Fair value of share at grant date	£	17.51		£	17.51		£	16.57
Exercise price at date of grant	£	17.51		£	0.16		£	16.57
Lapse date		Apr 11, 2028			Apr 11, 2028			May 8, 2028
Expected option life (years)		4.50			2.00			4.50
Number of options granted		71,500			7,500			62,000

For the six months ended June 30, 2018, the Company has recognized £1.0 million of share-based payment expense in the statement of operations (six months ended June 30, 2017: £0.5 million). For the three months ended June 30, 2018, the Company has recognized £0.6 million of share-based payment expense in the statement of operations (three months ended June 30, 2017: £0.3 million).

10

NUCANA PLC

NOTES TO THE UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

9. Share capital and share premium

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Share capital		1,272		1,272
Share premium		79,236		79,236
		80,508		80,508
	June 30, 2018		December 31, 2017
	Number (in thousands)
Issued share capital comprises:
Ordinary shares of £0.04 each		31,811		31,811

	Number of shares		Share capital		Share premium
	(in thousands)
Fully paid shares:			£		£
Balance at December 31, 2017		31,811		1,272		79,236
Balance at June 30, 2018		31,811		1,272		79,236

10. Contingent liabilities

Under the 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 U.K. 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 share price of ADSs on the Nasdaq Global Select Market on June 29, 2018, 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 £4.1 million (December 31, 2017: £2.1 million).

11

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 operating results 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 October 1, 2018. 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, which appear in our Annual Report on Form 20-F for the year ended December 31, 2017 filed with the SEC on March 22, 2018, or 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 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 three clinical trials, including a Phase 1b trial for patients with biliary tract cancer, a Phase 2 trial for patients with ovarian cancer and a Phase 3 trial for patients with pancreatic cancer. NUC-3373 is currently in a Phase 1 trial for the potential treatment of a wide range of 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.

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 portion 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

Research and development expenses are the largest component of our total operating expenses and relate to our research and development activities, including the clinical and preclinical 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 clinical trials and preclinical studies;

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

• 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;

• the costs involved in filing and prosecuting patent applications;

• costs of related office space allocated to our research and development function, materials and equipment; and

• payments under our license agreements.

The successful development of our product candidates 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 to 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

• 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 nonclinical research and development expenses are assigned or allocated to individual product candidates.

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 facility-related costs not otherwise allocated to research and development expense, 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 associated with operating as a public company, including expenses related to compliance with the rules and regulations of the SEC and Nasdaq, additional insurance expenses and expenses related to investor relations and other administrative and professional services.

Initial Public Offering Related Expenses

Initial public offering, or IPO, related expenses primarily relates to legal, accounting and other advisors’ fees incurred in relation to our IPO which closed on October 2, 2017.

Net Foreign Exchange Gains (Losses)

Net foreign exchange gains (losses) primarily includes gains or losses on cash held in U.S. dollars and on advances paid to suppliers.

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 United States as well as 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 expenditures related to eligible research and development projects. In the United States, we are able to offset the research and development credits against corporation tax payable. Qualifying expenditures 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. However, we may be able to file under a large company scheme.

Results of Operations

Comparison of the Three Months Ended June 30, 2018 and June 30, 2017

The following table summarizes the results of our operations for the three months ended June 30, 2018 and June 30, 2017.

	For the Three Months Ended June 30,
	2018			2017
	(unaudited)
	(in thousands)
	£			£
Research and development expenses		(5,158	)		(2,077	)
Administrative expenses		(1,402	)		(313	)
Initial public offering related expenses		—			(1,034	)
Net foreign exchange gains (losses)		3,607			(113	)
Operating loss		(2,953	)		(3,537	)
Finance income		252			44
Loss before tax		(2,701	)		(3,493	)
Income tax credit		1,383			745
Loss for the period		(1,318	)		(2,748	)
Other comprehensive expense:
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations		9			—
Total comprehensive loss for the period	£	(1,309	)	£	(2,748	)

Research and Development Expenses

Research and development expenses were £5.2 million for the three months ended June 30, 2018 as compared to £2.1 million for the three months ended June 30, 2017, an increase of £3.1 million. The increase related to higher clinical trial costs due to the number and size of clinical trials being performed and a higher number of research and development personnel.

The following table gives a breakdown of the research and development costs incurred by product candidate for the three months ended June 30, 2018 and 2017:

	For the Three Months Ended June 30,
	2018		2017
	(in thousands)
	£		£
Acelarin		2,929		1,140
NUC-3373		1,539		509
NUC-7738		248		124
Other		442		304
	£	5,158	£	2,077

Administrative Expenses

Administrative expenses were £1.4 million for the three months ended June 30, 2018 as compared to £0.3 million for the three months ended June 30, 2017. The increase was largely attributable to expenses associated with operating as a public company and increased personnel expenses.

Initial Public Offering Related Expenses

No IPO related expenses were incurred in the three months ended June 30, 2018 following the closing of the IPO on October 2, 2017.

Net Foreign Exchange Gains (Losses)

For the three months ended June 30, 2018, we reported a net foreign exchange gain of £3.6 million as compared to a net foreign exchange loss of £0.1 million for the three months ended June 30, 2017. In the three months ended June 30, 2018, the gain arose from higher average cash balances held in U.S. dollars and the appreciation of the U.S. dollar relative to the U.K. pound sterling.

Finance Income

Finance income represents bank interest and was £0.3 million for the three months ended June 30, 2018 and £44,000 for the three months ended June 30, 2017. The increase in bank interest resulted from higher average cash balances following the closing of the IPO on October 2, 2017, and higher rates of interest achieved.

Income Tax Credit

The income tax credit for the three months ended June 30, 2018, which is largely comprised of U.K. research and development tax credits, amounted to £1.4 million as compared to £0.7 million for the three months ended June 30, 2017. The increase in the income tax credit was primarily attributable to an increase in our eligible research and development expenses.

Results of Operations

Comparison of the Six Months Ended June 30, 2018 and June 30, 2017

The following table summarizes the results of our operations for the six months ended June 30, 2018 and June 30, 2017.

	For the Six Months Ended June 30,
	2018			2017
	(in thousands)
	£			£
Research and development expenses		(8,863	)		(3,689	)
Administrative expenses		(2,642	)		(637	)
Initial public offering related expenses		—			(1,066	)
Net foreign exchange gains (losses)		1,059			(161	)
Operating loss		(10,446	)		(5,553	)
Finance income		442			91
Loss before tax		(10,004	)		(5,462	)
Income tax credit		2,292			1,077
Loss for the period		(7,712	)		(4,385	)
Other comprehensive expense:
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations		4			(1	)
Total comprehensive loss for the period	£	(7,708	)	£	(4,386	)

Research and Development Expenses

Research and development expenses were £8.9 million for the six months ended June 30, 2018 as compared to £3.7 million for the six months ended June 30, 2017, an increase of £5.2 million. The increase related to higher clinical trial costs due to the number and size of clinical trials being performed; and a higher number of research and development personnel.

The following table gives a breakdown of the research and development costs incurred by product candidate for the six months ended June 30, 2018 and 2017:

	For the Six Months Ended June 30,
	2018		2017
	(in thousands)
	£		£
Acelarin		4,761		2,248
NUC-3373		2,765		816
NUC-7738		492		267
Other		845		358
	£	8,863	£	3,689

Administrative Expenses

Administrative expenses were £2.6 million for the six months ended June 30, 2018 as compared to £0.6 million for the six months ended June 30, 2017. The increase was largely attributable to expenses associated with operating as a public company and increased personnel expenses.

Initial Public Offering Related Expenses

No IPO related expenses were incurred in the six months ended June 30, 2018 following the closing of the IPO on October 2, 2017.

Net Foreign Exchange Gains (Losses)

For the six months ended June 30, 2018, we reported a net foreign exchange gain of £1.1 million as compared to a net foreign exchange loss of £0.2 million for the six months ended June 30, 2017. In the six months ended June 30, 2018, the gain arose from higher average cash balances held in U.S. dollars. The U.S. dollar depreciated relative to the U.K. pound sterling during the three months ended March 31, 2018 resulting in a loss in the first quarter of 2018 but subsequently appreciated in the second quarter of 2018 resulting in an overall net gain of £1.1 million for the six months ended June 30, 2018.

Finance Income

Finance income represents bank interest and was £0.4 million for the six months ended June 30, 2018 and £0.1 million for the six months ended June 30, 2017. The increase in bank interest resulted from higher average cash balances following the closing of the IPO on October 2, 2017, and higher rates of interest achieved.

Income Tax Credit

The income tax credit for the six months ended June 30, 2018, which is largely comprised of U.K. research and development tax credits, amounted to £2.3 million as compared to £1.1 million for the six months ended June 30, 2017. The increase in the 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 December 31, 2017 and June 30, 2018, we had cash and cash equivalents of £86.7 million and £81.5 million, respectively. We do not currently have any approved products and have never generated any revenue from product sales or otherwise. To date, we have financed our operations primarily through the issuances of our equity securities. In October 2017, we completed our IPO, in which we sold 7,596,505 American Depository Shares, or ADS, including 929,505 ADSs sold upon partial exercise of the underwriters’ option to purchase additional ADSs. The ADSs were sold at an initial public offering price of $15.00 per ADS for total gross proceeds of $114 million.

Cash Flows

Comparison of the Six Months Ended June 30, 2018 and June 30, 2017

The following table summarizes the results of our cash flows for the six months ended June 30, 2018 and June 30, 2017.

	For the Six Months ended June 30,
	2018			2017
	(in thousands)
	£			£
Net cash used in operating activities		(5,899	)		(3,592	)
Net cash used in investing activities		(419	)		(399	)
Net cash used in financing activities		—			(73	)
Net decrease in cash and cash equivalents	£	(6,318	)	£	(4,064	)

Operating Activities

The net cash used in operations increased to £5.9 million for the six months ended June 30, 2018 from £3.6 million for the six months ended June 30, 2017. This was primarily due to higher research and development and administrative expenses which were partially offset by advanced payments made to suppliers in prior years and increased trade payables as of June 30, 2018.

Investing Activities

The net cash used in investing activities was £0.4 million for the six months ended June 30, 2018 as compared to £0.4 million for the six months ended June 30, 2017. The six months ended June 30, 2018 included higher payments in respect of acquisitions of tangible and intangible assets. This was offset by an increase in interest received on cash deposits due to proceeds received from the IPO.

Financing Activities

There were no cash flows for the six months ended June 30, 2018 following the closing of the IPO on October 2, 2017.

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, build and expand 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, at least through the first quarter of 2020.

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 clinical-stage research and early preclinical 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; and

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

XML

Document and Entity Information	6 Months Ended
	Jun. 30, 2018
Document - Document and Entity Information [Abstract]
Document Type	6-K
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	H1
Trading Symbol	NCNA
Entity Registrant Name	NUCANA PLC
Entity Central Index Key	0001709626
Current Fiscal Year End Date	--12-31

XML

Condensed Consolidated Statements of Operations - GBP (£) £ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Profit or loss [abstract]
Research and development expenses	£ (5,158)	£ (2,077)	£ (8,863)	£ (3,689)
Administrative expenses	(1,402)	(313)	(2,642)	(637)
Initial public offering related expenses		(1,034)		(1,066)
Net foreign exchange gains (losses)	3,607	(113)	1,059	(161)
Operating loss	(2,953)	(3,537)	(10,446)	(5,553)
Finance income	252	44	442	91
Loss before tax	(2,701)	(3,493)	(10,004)	(5,462)
Income tax credit	1,383	745	2,292	1,077
Loss for the period	£ (1,318)	£ (2,748)	£ (7,712)	£ (4,385)
Basic and diluted loss per share	£ (0.04)	£ (0.11)	£ (0.24)	£ (0.18)

XML

Condensed Consolidated Statements of Comprehensive Loss - GBP (£) £ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of comprehensive income [abstract]
Loss for the period	£ (1,318)	£ (2,748)	£ (7,712)	£ (4,385)
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations	9		4	(1)
Other comprehensive income (expense) for the period	9		4	(1)
Total comprehensive loss for the period	(1,309)	(2,748)	(7,708)	(4,386)
Attributable to:
Equity holders of the Company	£ (1,309)	£ (2,748)	£ (7,708)	£ (4,386)

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Condensed Consolidated Statements of Financial Position - GBP (£) £ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Non-current assets
Intangible assets	£ 2,485	£ 1,938
Property, plant and equipment	495	358
Deferred tax asset	32	81
Total non-current assets	3,012	2,377
Current assets
Prepayments, accrued income and other receivables	1,737	3,050
Current income tax receivable	4,660	4,225
Cash and cash equivalents	81,469	86,703
Total current assets	87,866	93,978
Total assets	90,878	96,355
Capital and reserves
Share capital and share premium	80,508	80,508
Other reserves	59,072	58,071
Accumulated deficit	(52,871)	(45,159)
Total equity attributable to equity holders of the Company	86,709	93,420
Non-current liabilities
Provisions	26	18
Current liabilities
Trade payables	2,123	1,120
Payroll taxes and social security	103	157
Accrued expenditure	1,917	1,640
Total current liabilities	4,143	2,917
Total liabilities	4,169	2,935
Total equity and liabilities	£ 90,878	£ 96,355

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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, 2016	£ 25,241	£ 663	£ 42,770	£ (339)	£ 4,406	£ (3)		£ (22,256)
Loss for the period	(4,385)							(4,385)
Other comprehensive expense for the period	(1)					(1)
Total comprehensive loss for the period	(4,386)					(1)		(4,385)
Share-based payments	532				532
Reduction in share premium			(42,466)				£ 42,466
Ending balance at Jun. 30, 2017	21,387	663	304	(339)	4,938	(4)	42,466	(26,641)
Beginning balance at Dec. 31, 2017	93,420	1,272	79,236	(339)	15,955	(11)	42,466	(45,159)
Loss for the period	(7,712)							(7,712)
Other comprehensive expense for the period	4					4
Total comprehensive loss for the period	(7,708)					4		(7,712)
Share-based payments	997				997
Ending balance at Jun. 30, 2018	£ 86,709	£ 1,272	£ 79,236	£ (339)	£ 16,952	£ (7)	£ 42,466	£ (52,871)

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Condensed Consolidated Statements of Cash Flows - GBP (£) £ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Loss for the period	£ (7,712)	£ (4,385)
Adjustments for:
Income tax credit	(2,292)	(1,077)
Amortization and depreciation	164	84
Finance income	(442)	(91)
Share-based payments	997	532
Initial public offering (IPO) related expenses		1,066
Net foreign exchange (gains) losses	(1,112)	142
Cash flows from (used in) operations before changes in working capital	(10,397)	(3,729)
Movements in working capital:
Decrease in prepayments, accrued income and other receivables	1,358	609
Increase (decrease) in trade payables	1,003	(477)
Increase (decrease) in payroll taxes, social security and accrued expenditure	231	(230)
Movements in working capital	2,592	(98)
Cash used in operations	(7,805)	(3,827)
Net income tax credit received	1,906	235
Net cash used in operating activities	(5,899)	(3,592)
Cash flows from investing activities
Interest received	429	98
Payments for property, plant and equipment	(200)	(5)
Payments for intangible assets	(648)	(492)
Net cash used in investing activities	(419)	(399)
Cash flows from financing activities
IPO related expenses included in statement of operations		(73)
Net cash used in financing activities		(73)
Net decrease in cash and cash equivalents	(6,318)	(4,064)
Cash and cash equivalents at beginning of period	86,703	19,990
Foreign currency translation differences	1,084	(8)
Cash and cash equivalents at end of period	£ 81,469	£ 15,918

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General information

6 Months Ended

Jun. 30, 2018

Text block1 [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. We are 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.

On August 29, 2017 the Company re-registered as a public limited company and changed its name from NuCana BioMed Limited to NuCana plc.

The Company has had American Depository Receipts (“ADRs”) registered with the US Securities and Exchange Commission (“SEC”) and is listed on Nasdaq since October 2, 2017. The Company is incorporated in England and Wales and domiciled in the United Kingdom.

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

The comparative figures for the year ended December 31, 2017 are not the Group’s statutory accounts for that financial year within the meaning of section 434 of the Companies Act 2006. Those accounts have been reported on by the Company’s auditor and delivered to the Registrar of Companies. The report of the auditor was (i) unqualified, (ii) did not include a reference to any matters to which the auditors drew attention by way of emphasis without qualifying their report, and (iii) did not contain a statement under section 498 (2) or (3) of the Companies Act 2006.

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Significant accounting policies

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Significant accounting policies

2. Significant accounting policies

Basis of preparation

The unaudited condensed consolidated financial statements (the “financial statements”) for the three and six months ended June 30, 2018 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, 2017. No new standards, amendments or interpretations have had an impact on the financial statements for the six months ended June 30, 2018.

The financial statements comprise the financial statements of the Company and its subsidiaries at June 30, 2018. 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 as at December 31, 2017.

The unaudited condensed consolidated statement of cash flows for the six months ended June 30, 2017 has been restated to be consistent with the presentation of foreign exchange differences and IPO related expenses in the annual financial statements for the year ended December 31, 2017.

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 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 £81.5 million at June 30, 2018, will be sufficient to fund its current operating plan for at least the next 12 months. 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.

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, 2017.

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IPO related expenses

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

IPO related expenses

3. IPO related expenses

	For the three months ended June 30,				For the six months ended June 30,
	2018		2017		2018		2017
	(in thousands)				(in thousands)
	£		£		£		£
IPO related expenses		—		1,034		—		1,066

IPO related expenses primarily relate to legal, accounting and other advisors’ fees in relation to the Company’s listing on Nasdaq which completed on October 2, 2017.

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Income tax

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Income tax

4. Income tax

	For the three months ended June 30,					For the six months ended June 30,
	2018			2017		2018			2017
	(in thousands)					(in thousands)
	£			£		£			£
Current tax		1,393			745		2,341			1,077
Deferred tax		(10	)		—		(49	)		—
Income tax credit		1,383			745		2,292			1,077

The income tax credit recognized primarily represents the U.K. research and development tax credit. In the U.K. 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.

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Current income tax receivable
U.K. tax		4,641		4,207
U.S. tax		19		18
		4,660		4,225
Deferred tax asset
U.S. deferred tax asset		32		81

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Basic and diluted loss per share

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Basic and diluted loss per share

5. Basic and diluted loss per share

	For the three months ended June 30,						For the six months ended June 30,
	2018			2017			2018			2017
	(in thousands, except per share data)
	£			£			£			£
Loss for the period		(1,318	)		(2,748	)		(7,712	)		(4,385	)
Basic and diluted weighted average number of shares		31,811			24,185			31,811			24,185
	£			£			£			£
Basic and diluted loss per share		(0.04	)		(0.11	)		(0.24	)		(0.18	)

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.

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Intangible assets

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Intangible assets

6. Intangible assets

Intangible assets comprise patents with a carrying value of £2.4 million as of June 30, 2018 (as of December 31, 2017: £1.8 million) and computer software with a carrying value of £0.1 million as of June 30, 2018 (as of December 31, 2017: £0.1 million).

During the six months ended June 30, 2018, the Company acquired intangible assets with a cost of £0.6 million in relation to patents (six months ended June 30, 2017: £0.4 million in relation to patents and £0.1 million in relation to computer software).

There were no disposals of intangible assets in the six months ended June 30, 2018 (six months ended June 30, 2017: £nil).

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Cash and cash equivalents

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Cash and cash equivalents

7. Cash and cash equivalents

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Cash and cash equivalents		81,469		86,703

Cash and cash equivalents comprise cash at bank with maturities of three months or less and earn interest at fixed or variable rates based on the terms agreed for each account.

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Share-based payments

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Share-based payments

8. Share-based payments

The Company has three share-based payment plans for employees, directors and consultants. The share options granted will be settled in equity.

On April 11, 2018 and May 8, 2018, 79,000 and 62,000 share options respectively were granted under the U.K. share-based payment plans. Options granted under these plans 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 under these plans will vest equally over a period of four years, with the exception of options granted to a consultant, which vested immediately.

The fair values of options granted were determined using the Black-Scholes model that takes into account factors specific to the share incentive plan. As NuCana plc listed on October 2, 2017, it is not possible to derive historical volatility from the Company’s own share price. The underlying expected volatility was therefore determined by using the historical volatility of similar listed entities as a proxy. The volatility percentage applied to each tranche is the average of the historical volatility of comparable companies to NuCana plc.

The following weighted average principal assumptions were used in calculating the fair values of options granted:

	Options granted on
	Apr 11, 2018			Apr 11, 2018			May 8, 2018
Vesting dates		Apr 11, 2019			Apr 11, 2018			May 8, 2019
		Apr 11, 2020						May 8, 2020
		Apr 11, 2021						May 8, 2021
		Apr 11, 2022						May 8, 2022
Volatility		64.48	%		60.06	%		65.80	%
Dividend yield		0	%		0	%		0	%
Risk-free investment rate		1.04	%		0.83	%		1.02	%
Fair value of option at grant date	£	8.97		£	17.35		£	8.63
Fair value of share at grant date	£	17.51		£	17.51		£	16.57
Exercise price at date of grant	£	17.51		£	0.16		£	16.57
Lapse date		Apr 11, 2028			Apr 11, 2028			May 8, 2028
Expected option life (years)		4.50			2.00			4.50
Number of options granted		71,500			7,500			62,000

For the six months ended June 30, 2018, the Company has recognized £1.0 million of share-based payment expense in the statement of operations (six months ended June 30, 2017: £0.5 million). For the three months ended June 30, 2018, the Company has recognized £0.6 million of share-based payment expense in the statement of operations (three months ended June 30, 2017: £0.3 million).

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Share capital and share premium

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Share capital and share premium

9. Share capital and share premium

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Share capital		1,272		1,272
Share premium		79,236		79,236
		80,508		80,508
	June 30, 2018		December 31, 2017
	Number (in thousands)
Issued share capital comprises:
Ordinary shares of £0.04 each		31,811		31,811

	Number of shares		Share capital		Share premium
	(in thousands)
Fully paid shares:			£		£
Balance at December 31, 2017		31,811		1,272		79,236
Balance at June 30, 2018		31,811		1,272		79,236

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Contingent liabilities

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Contingent liabilities

10. Contingent liabilities

Under the 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 U.K. 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 share price of ADSs on the Nasdaq Global Select Market on June 29, 2018, 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 £4.1 million (December 31, 2017: £2.1 million).

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Significant accounting policies (Policies)

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Basis of preparation

Basis of preparation

The unaudited condensed consolidated financial statements (the “financial statements”) for the three and six months ended June 30, 2018 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, 2017. No new standards, amendments or interpretations have had an impact on the financial statements for the six months ended June 30, 2018.

The financial statements comprise the financial statements of the Company and its subsidiaries at June 30, 2018. 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 as at December 31, 2017.

The unaudited condensed consolidated statement of cash flows for the six months ended June 30, 2017 has been restated to be consistent with the presentation of foreign exchange differences and IPO related expenses in the annual financial statements for the year ended December 31, 2017.

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 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 £81.5 million at June 30, 2018, will be sufficient to fund its current operating plan for at least the next 12 months. 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.

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, 2017.

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IPO related expenses (Tables)

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Summary of Initial Public Offering Related Expenses

	For the three months ended June 30,				For the six months ended June 30,
	2018		2017		2018		2017
	(in thousands)				(in thousands)
	£		£		£		£
IPO related expenses		—		1,034		—		1,066

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Income tax (Tables)

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Schedule of Major Components of Income Tax

	For the three months ended June 30,					For the six months ended June 30,
	2018			2017		2018			2017
	(in thousands)					(in thousands)
	£			£		£			£
Current tax		1,393			745		2,341			1,077
Deferred tax		(10	)		—		(49	)		—
Income tax credit		1,383			745		2,292			1,077

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Current income tax receivable
U.K. tax		4,641		4,207
U.S. tax		19		18
		4,660		4,225
Deferred tax asset
U.S. deferred tax asset		32		81

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Basic and diluted loss per share (Tables)

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Schedule of Basic and Diluted Loss Per Share

	For the three months ended June 30,						For the six months ended June 30,
	2018			2017			2018			2017
	(in thousands, except per share data)
	£			£			£			£
Loss for the period		(1,318	)		(2,748	)		(7,712	)		(4,385	)
Basic and diluted weighted average number of shares		31,811			24,185			31,811			24,185
	£			£			£			£
Basic and diluted loss per share		(0.04	)		(0.11	)		(0.24	)		(0.18	)

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Cash and cash equivalents (Tables)

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Schedule of Detailed Information About Cash And Cash Equivalents

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Cash and cash equivalents		81,469		86,703

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Share-based payments (Tables)

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Summary of Principal Assumptions Used for Valuation of Share Options

The following weighted average principal assumptions were used in calculating the fair values of options granted:

	Options granted on
	Apr 11, 2018			Apr 11, 2018			May 8, 2018
Vesting dates		Apr 11, 2019			Apr 11, 2018			May 8, 2019
		Apr 11, 2020						May 8, 2020
		Apr 11, 2021						May 8, 2021
		Apr 11, 2022						May 8, 2022
Volatility		64.48	%		60.06	%		65.80	%
Dividend yield		0	%		0	%		0	%
Risk-free investment rate		1.04	%		0.83	%		1.02	%
Fair value of option at grant date	£	8.97		£	17.35		£	8.63
Fair value of share at grant date	£	17.51		£	17.51		£	16.57
Exercise price at date of grant	£	17.51		£	0.16		£	16.57
Lapse date		Apr 11, 2028			Apr 11, 2028			May 8, 2028
Expected option life (years)		4.50			2.00			4.50
Number of options granted		71,500			7,500			62,000

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Share capital and share premium (Tables)

6 Months Ended

Jun. 30, 2018

Text block1 [abstract]

Summary of Share Capital and Share Premium

	June 30, 2018		December 31, 2017
	(in thousands)
	£		£
Share capital		1,272		1,272
Share premium		79,236		79,236
		80,508		80,508
	June 30, 2018		December 31, 2017
	Number (in thousands)
Issued share capital comprises:
Ordinary shares of £0.04 each		31,811		31,811

Summary of Movement in the Share Capital

	Number of shares		Share capital		Share premium
	(in thousands)
Fully paid shares:			£		£
Balance at December 31, 2017		31,811		1,272		79,236
Balance at June 30, 2018		31,811		1,272		79,236

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General Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2018 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
Explanation of change in name of reporting entity	On August 29, 2017 the Company re-registered as a public limited company and changed its name from NuCana BioMed Limited to 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.

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Significant Accounting Policies - Additional Information (Detail) - GBP (£) £ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Disclosure of summary of significant accounting policies [Abstract]
Cash and cash equivalents	£ 81,469	£ 86,703	£ 15,918	£ 19,990

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IPO Related Expenses - Summary of Initial Public Offering Related Expenses (Detail) - GBP (£) £ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Material income and expense [abstract]
IPO related expenses	£ 1,034	£ 1,066

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Income Tax - Schedule of Major Components of Income Tax Credit (Detail) - GBP (£) £ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Major components of tax expense (income) [abstract]
Current tax	£ 1,393	£ 745	£ 2,341	£ 1,077
Deferred tax	(10)		(49)
Income tax credit	£ 1,383	£ 745	£ 2,292	£ 1,077

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Income tax - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2018
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%

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Income Tax - Schedule of Major Components of Income Tax Assets (Detail) - GBP (£) £ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current income tax receivable
Current income tax receivable	£ 4,660	£ 4,225
Deferred tax asset
Deferred tax asset	32	81
U.K. [member]
Current income tax receivable
Current income tax receivable	4,641	4,207
U.S. [member]
Current income tax receivable
Current income tax receivable	19	18
Deferred tax asset
Deferred tax asset	£ 32	£ 81

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Basic and Diluted Loss per Share - Schedule of Basic and Diluted Loss Per Share (Detail) - GBP (£) £ / shares in Units, £ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings per share [abstract]
Loss for the period	£ (1,318)	£ (2,748)	£ (7,712)	£ (4,385)
Basic and diluted weighted average number of shares	31,811	24,185	31,811	24,185
Basic and diluted loss per share	£ (0.04)	£ (0.11)	£ (0.24)	£ (0.18)

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Intangible Assets - Additional Information (Detail) - GBP (£)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	£ 2,485,000		£ 1,938,000
Disposal of intangible	0	£ 0
Patents [member]
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	2,400,000		1,800,000
Intangible assets, acquired	600,000	400,000
Computer Software [member]
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	£ 100,000		£ 100,000
Intangible assets, acquired		£ 100,000

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Cash and Cash Equivalents - Schedule of Detailed Information About Cash and Cash Equivalents (Detail) - GBP (£) £ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Cash and cash equivalents [abstract]
Cash and cash equivalents	£ 81,469	£ 86,703	£ 15,918	£ 19,990

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Share Based Payments - Additional Information (Detail) £ in Millions			3 Months Ended		6 Months Ended
	May 08, 2018	Apr. 11, 2018	Jun. 30, 2018 GBP (£)	Jun. 30, 2017 GBP (£)	Jun. 30, 2018 GBP (£)	Jun. 30, 2017 GBP (£)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share-based payment expense			£ 0.6	£ 0.3	£ 1.0	£ 0.5
U.K. Share-Based Payment Plans [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of share options granted in share-based payment arrangement	62,000	79,000
Share options granted, vesting period					4 years

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Share Based Payments - Summary of Principal Assumptions used for Valuation of Share Options (Detail) - 2018 Share Options [member]	6 Months Ended
	Jun. 30, 2018 GBP (£) shares yr
Grant Date Apr 11, 2018 One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	64.48%
Dividend yield	0.00%
Risk-free investment rate	1.04%
Fair value of option at grant date	£ 8.97
Fair value of share at grant date	17.51
Exercise price at date of grant	£ 17.51
Lapse date	Apr. 11, 2028
Expected option life (years) | yr	4.50
Number of options granted | shares	71,500
Grant Date Apr 11, 2018 Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	60.06%
Dividend yield	0.00%
Risk-free investment rate	0.83%
Fair value of option at grant date	£ 17.35
Fair value of share at grant date	17.51
Exercise price at date of grant	£ 0.16
Lapse date	Apr. 11, 2028
Expected option life (years) | yr	2.00
Number of options granted | shares	7,500
Grant Date May 8, 2018 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	65.80%
Dividend yield	0.00%
Risk-free investment rate	1.02%
Fair value of option at grant date	£ 8.63
Fair value of share at grant date	16.57
Exercise price at date of grant	£ 16.57
Lapse date	May 08, 2028
Expected option life (years) | yr	4.50
Number of options granted | shares	62,000
Vesting Dates One [member] | Grant Date Apr 11, 2018 One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 11, 2019
Vesting Dates One [member] | Grant Date Apr 11, 2018 Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 11, 2018
Vesting Dates One [member] | Grant Date May 8, 2018 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	May 08, 2019
Vesting Dates Two [member] | Grant Date Apr 11, 2018 One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 11, 2020
Vesting Dates Two [member] | Grant Date May 8, 2018 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	May 08, 2020
Vesting Dates Three [member] | Grant Date Apr 11, 2018 One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 11, 2021
Vesting Dates Three [member] | Grant Date May 8, 2018 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	May 08, 2021
Vesting Dates Four [member] | Grant Date Apr 11, 2018 One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 11, 2022
Vesting Dates Four [member] | Grant Date May 8, 2018 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	May 08, 2022

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Share Capital and Share Premium - Summary of Share Capital and Share Premium (Detail) - GBP (£) £ in Thousands, shares in Thousands	Jun. 30, 2018	Dec. 31, 2017
Disclosure of classes of share capital [abstract]
Share capital	£ 1,272	£ 1,272
Share premium	79,236	79,236
Share capital and share premium	£ 80,508	£ 80,508
Ordinary shares of £0.04 each	31,811	31,811

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Share Capital and Share Premium - Summary of Share Capital and Share Premium (Parenthetical) (Detail)	Jun. 30, 2018 £ / shares
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Par value per share	£ 0.04

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Share Capital and Share Premium - Summary of Movement in the Share Capital (Detail) - GBP (£) £ in Thousands, shares in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Disclosure of classes of share capital [line items]
Beginning balance, Shares	31,811
Ending balance, Shares	31,811	31,811
Beginning balance	£ 93,420	£ 21,387	£ 25,241
Ending balance	86,709	93,420	21,387
Share Premium [member]
Disclosure of classes of share capital [line items]
Beginning balance	79,236	304	42,770
Ending balance	79,236	79,236	304
Share Capital [member]
Disclosure of classes of share capital [line items]
Beginning balance	1,272	663	663
Ending balance	£ 1,272	£ 1,272	£ 663

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Contingent Liabilities - Additional Information (Detail) - GBP (£) £ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Disclosure of contingent liabilities [abstract]
Employer national insurance contingent liability	£ 4.1	£ 2.1
Prevailing rate of employer national insurance	13.80%