8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 19, 2014

TESARO, Inc.

(Exact name of registrant as specified in its charter)

Delaware (state or other jurisdiction of
incorporation) 001-35587 (Commission File Number) 27-2249687 (I.R.S. Employer Identification No.)

1000 Winter Street Suite 3300 Waltham, Massachusetts	02451
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code:  (339) 970-0900

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

oWritten communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

oSoliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

oPre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

oPre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Section 2 — Financial Information

Item 2.02Results of Operations and Financial Condition.

On February 19, 2014, TESARO, Inc. issued a press release announcing its operating results for the quarter and year ended December 31, 2013. A copy of the press release is attached to this current report as Exhibit 99.1 and is incorporated herein by reference. TESARO, Inc. has scheduled a conference call and webcast for 4:15 p.m. Eastern time on February 19, 2014 to discuss its operating results for the quarter and year ended December 31, 2013, and slides for that call are attached to this report as Exhibit 99.2 and are incorporated herein by reference.

The information contained in this report, including Exhibit 99.1 and Exhibit 99.2, is being furnished to the Securities and Exchange Commission and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to liabilities under that section. Furthermore, such information shall not be deemed to be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Section 9 — Financial Statements and Exhibits

Item 9.01Financial Statements and Exhibits.

(d)Exhibits.

Exhibit No.	Description
99.1	TESARO, Inc. press release dated February 19, 2014 announcing operating results for the quarter and year ended December 31, 2013.
99.2	TESARO, Inc. slides for February 19, 2014 conference call and webcast for the quarter and year ended December 31, 2013.

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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 hereunto duly authorized.

	TESARO, Inc.
	By:	/s/ Edward C. English
		Edward C. English
		Vice President of Finance and Administration
Dated: February 19, 2014

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EXHIBIT INDEX

Exhibit No.	Description
99.1	TESARO, Inc. press release dated February 19, 2014 announcing operating results for the quarter and year ended December 31, 2013.
99.2	TESARO, Inc. slides for February 19, 2014 conference call and webcast for the quarter and year ended December 31, 2013.

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EX-99.1

Exhibit 99.1

FOR RELEASE ON FEBRUARY 19, 2014 at 4:01 PM ET

TESARO ANNOUNCES FOURTH-QUARTER AND FULL-YEAR 2013

OPERATING RESULTS

·Oral Rolapitant New Drug Application on Track for Submission to U.S. FDA in Mid-2014

·Niraparib Phase 3 NOVA and BRAVO Trials Continue to Advance

·Cash and Cash Equivalents Totaled Approximately $130 Million as of December 31, 2013

·Successful Follow-On Offering Raised Approximately $94 Million in February 2014

WALTHAM, MA, February 19, 2014 — TESARO, Inc. (NASDAQ: TSRO), an oncology-focused biopharmaceutical company, today reported financial results for fourth-quarter and full-year 2013.

“During 2013, TESARO successfully completed two Phase 3 trials of oral rolapitant, advanced the IV formulation of rolapitant, initiated two new pivotal trials for niraparib, and presented the first clinical data for TSR-011,” said Lonnie Moulder, CEO of TESARO. “We intend to build on the significant progress the company has made by submitting the NDA for oral rolapitant, continuing to enroll our Phase 3 niraparib trials, and presenting data at key medical meetings in 2014. Following the recent completion of a follow-on offering of common stock, we believe we are well positioned to fund the launch of oral rolapitant, advance and expand the niraparib development program and execute on potential business development opportunities.”

Recent Business Highlights

·In December, the Company announced that two Phase 3 trials of oral rolapitant, one in patients receiving moderately emetogenic chemotherapy (MEC) and one in patients receiving cisplatin-based highly emetogenic chemotherapy (HEC), each met the primary endpoint of complete response (CR) in the delayed (24 to 120 hour) timeframe following chemotherapy.

·Enrollment of the third and final Phase 3 trial of oral rolapitant, which is being conducted in patients receiving cisplatin-based HEC, is expected to conclude during the first quarter of 2014. TESARO anticipates that results from this study will be available in the second quarter of 2014.

·The clinical trial of intravenous (IV) rolapitant is well underway, and the Company anticipates finalizing the dose that will provide comparable exposure to the oral formulation by the end of the first quarter of 2014.

·The Phase 3 NOVA study of niraparib in patients with high grade serous, platinum-sensitive ovarian cancer, including those with germline BRCA mutations, continues to enroll patients at sites around the world.

·The Company expects to initiate patient treatment during the first quarter of 2014 in the Phase 3 BRAVO study of niraparib in breast cancer patients with germline BRCA mutations.

·TESARO continues to evaluate the clinical activity of a 60 milligram fractionated dose of TSR-011 in an ongoing trial in both ALK-positive and TRK-positive patients.

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Fourth-Quarter 2013 Financial Results

·TESARO reported a net loss of $23.3 million, or $0.72 per share, for the fourth quarter of 2013, compared to a net loss of $18.7 million, or $0.70 per share, for the fourth quarter of 2012.

·Research and development expenses increased to $18.9 million for the fourth quarter of 2013, compared to $15.6 million for the fourth quarter of 2012, driven primarily by higher costs related to our expanded development activities.

·General and administrative expenses increased to $4.5 million for the fourth quarter of 2013, compared to $2.1 million for the fourth quarter of 2012, primarily related to higher non-cash stock-based compensation expense. Excluding the contribution from stock-based compensation, general and administrative expenses increased by $0.9 million for the fourth quarter of 2013 compared to the same period in 2012, primarily as a result of increases in headcount and professional services fees.

·Operating expenses as described above include total non-cash stock-based compensation expense of $2.7 million for the fourth quarter of 2013, compared to $0.8 million for the fourth quarter of 2012.

·As of December 31, 2013, TESARO had approximately $130 million in cash and cash equivalents, no debt and 32.7 million outstanding shares of common stock. This ending cash and cash equivalents balance represents a decrease of $26 million compared to the prior quarter, and excludes approximately $94 million in net proceeds resulting from a follow-on offering of 3.2 million shares of common stock that was completed in February 2014.

Full-Year 2013 Financial Results

·TESARO reported a net loss of $92.4 million, or $2.93 per share, for 2013, compared to a net loss of $61.8 million, or $4.51 per share, for 2012.

·Research and development expenses increased to $75.7 million for 2013, compared to $47.2 million for 2012, driven primarily by higher costs related to our expanded development activities.

·General and administrative expenses increased to $14.8 million for 2013, compared to $6.7 million for 2012, primarily related to higher non-cash stock-based compensation expense, increased headcount and increased professional services fees.

·Operating expenses as described above include total non-cash stock-based compensation expense of $7.8 million for 2013, compared to $1.8 million in 2012.

2014 Corporate Objectives

TESARO anticipates achieving the following key objectives:

·Announce results from the final Phase 3 trial of oral rolapitant in patients receiving cisplatin-based HEC during the second quarter of 2014;

·Submit abstracts for rolapitant, niraparib and TSR-011 to medical conferences this year, including meetings of the American Society of Clinical Oncology (ASCO), the Multinational Association

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of Supportive Care in Cancer (MASCC) and the European Society for Medical Oncology (ESMO);

·Submit the oral rolapitant New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) in mid-2014;

·Finalize the dose of IV rolapitant during the first quarter of 2014 for further evaluation in a subsequent clinical trial, with a goal of supporting a future submission for registration following regulatory approval of the oral formulation of rolapitant;

·Advance the Phase 3 trial (NOVA) of niraparib as a potential maintenance therapy for patients with ovarian cancer and the Phase 3 trial (BRAVO) of niraparib in breast cancer patients with germline BRCA mutations;

·Begin enrollment in a Phase 1 study of niraparib in patients with Ewing’s sarcoma by mid-year;

·Identify additional tumor targets in order to expand the niraparib clinical development program;

·Further evaluate the clinical activity of a fractionated 60 milligram dose of TSR-011 in ALK-positive and TRK-positive patients; and

·Continue to evaluate potential business development opportunities to expand TESARO’s oncology portfolio.

Today’s Conference Call and Webcast

TESARO will host a conference call to discuss the Company’s fourth-quarter 2013 accomplishments and financial results today at 4:15 p.m. Eastern time. The accompanying slide presentation and live webcast of the conference call can be accessed by visiting the TESARO website at www.tesarobio.com. The call can be accessed by dialing (877) 853-5334 (U.S. and Canada) or (970) 315-0307 (international). A replay of the webcast will be archived on the Company’s website for 30 days following the call.

About TESARO

TESARO is an oncology-focused biopharmaceutical company dedicated to improving the lives of cancer patients by acquiring, developing and commercializing safer and more effective therapeutics. For more information, visit www.tesarobio.com.

Investor/Media Contact:

Jennifer Davis

Sr. Director, Corporate Development & Investor Relations

+1.781.325.1116 or jdavis@tesarobio.com

To the extent that statements contained in this press release are not descriptions of historical facts regarding TESARO, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “expect,” “anticipate,” “estimate,” “intend,” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to

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identify forward-looking statements. Examples of forward looking statements contained in this press release include, among others, statements regarding our expectations regarding our development plans for our product candidates and statements under the heading 2014 Corporate Objectives. Forward-looking statements in this release involve substantial risks and uncertainties that could cause our clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the initiation of future clinical trials, availability of data from ongoing clinical trials, expectations for regulatory approvals, and other matters that could affect the availability or commercial potential of our drug candidates. TESARO undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of the Company in general, see TESARO’s Annual Report on Form 10-K for the year ended December 31, 2012, and Quarterly Report on Form 10-Q for the quarter ended September 30, 2013.

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TESARO, Inc.

Unaudited Condensed Consolidated Statements of Operations

(in thousands, except per share amounts)

	Three Months Ended December 31,						Year Ended December 31,
	2012			2013			2012			2013
Expenses:
Research and development (1)	$	15,642		$	18,882		$	47,200		$	75,725
General and administrative (1)	2,095			4,465			6,715			14,780
Acquired in-process research and development	1,000			—			8,000			1,940
Total expenses	18,737			23,347			61,915			92,445
Loss from operations	(18,737		)	(23,347		)	(61,915		)	(92,445		)
Interest income	40			7			152			83
Net loss	$	(18,697	)	$	(23,340	)	$	(61,763	)	$	(92,362	)
Net loss per share applicable to common stockholders - basic and diluted	$	(0.70	)	$	(0.72	)	$	(4.51	)	$	(2.93	)
Weighted-average number of common shares used in net loss per share applicable to common stockholders - basic and diluted	26,740			32,597			13,696			31,559

(1) Expenses include the following amounts of non-cash stock-based compensation expense:

Research and development	$	227	$	655	$	544	$	2,034
General and administrative	570		2,026		1,259		5,725

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TESARO, Inc.

Unaudited Condensed Consolidated Balance Sheets

(in thousands)

	December 31, 2012		December 31, 2013
Assets
Current assets:
Cash and cash equivalents	$	125,445	$	130,310
Other current assets	1,175		4,029
Total current assets	126,620		134,339
Property and equipment, net	219		440
Other assets	541		799
Total assets	$	127,380	$	135,578
Liabilities and stockholders’ equity
Current liabilities:
Accounts payable	$	3,170	$	1,869
Accrued expenses	8,545		10,541
Other current liabilities	3		13
Total current liabilities	11,718		12,423
Other non-current liabilities	—		3
Commitments and contingencies
Total stockholders’ equity	115,662		123,152
Total liabilities and stockholders’ equity	$	127,380	$	135,578

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EX-99.2

Exhibit 99.2

Fourth-Quarter & Full-Year 2013 Operating Results February 19, 2014

Safe Harbor Statement Statements made in this presentation about TESARO, Inc. that are not descriptions of historical facts are forward-looking statements reflecting the current beliefs and expectations of management. Forward-looking statements are sometimes identified by words such as “plan,” “may,” “will,” “expect,” and similar expressions referencing future events, conditions or circumstances. These forward-looking statements involve substantial risks and uncertainties that could cause our clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Actual results could differ materially from those expressed or implied by these forward-looking statements as a result of various factors, including, without limitation, the various risks described in our Annual Report on Form 10-K for the year ended December 31, 2012 and our subsequent filings with the SEC. TESARO, Inc. undertakes no obligation to update or revise any forward-looking statement for any reason. Rolapitant, niraparib and TSR-011 are investigational products that have not been approved by any regulatory agency. The most frequently observed adverse events in the two completed rolapitant Phase 3 studies were balanced across treatment arms and included fatigue, alopecia and loss of appetite. Phase 1 data indicate that the most frequently observed adverse events for niraparib at a 300 milligram dose included grade 1/2 anemia, fatigue and nausea. Phase 1 data indicate that TSR-011 was well tolerated at therapeutic dose levels, and the most frequently occurring dose limiting toxicities included ECG changes and dysaethesia, both of which were reversible.

Lonnie Moulder Chief Executive Officer

2013 Accomplishments IPO: Initial Public Offering ENGOT: European Network of Gynaecological Oncology Trials Groups BIG: Breast International Group IND: Investigational New Drug application 2010 2011 2012 2013 Series B Financing Completed IPO Completed Follow-on Stock Offering Completed Partnerships with ENGOT and BIG Announced TESARO Founded; Series A Financing Secured Rolapitant In-Licensed Niraparib In-Licensed TSR-011 IND Cleared TSR-011 Phase 1 Trial Initiated First Two Pivotal Trials of Rolapitant Successfully Completed Niraparib Phase 3 Trial in Ovarian Cancer Initiated Initial Phase 1 TSR-011 Data Presented Rolapitant IV Clinical Program Initiated TSR-011 In-Licensed Phase 3 Trials of Rolapitant Initiated Develop Acquire Commercialize

1 2 3 4 5 6 7 Building on Progress Made in 2013: Well Positioned for Execution in 2014 Submit NDA for oral rolapitant Finalize IV rolapitant dose for advancement Execute on NOVA and BRAVO studies of niraparib Define strategy for niraparib evaluation in additional tumor types Evaluate fractionated 60mg dose of TSR-011 in ALK+ and TRK+ tumor types Present additional data for rolapitant, niraparib, TSR-011 Continue to evaluate potential business development opportunities NDA: New Drug Application IV: Intravenous

Ted English Vice President, Finance & Administration

Q4 2013 Financial Results Three Months Ended December 31, 2013 Three Months Ended December 31, 2012 Expenses: Research & Development $18,882 $15,642 General & Administrative 4,465 2,095 Acquired In-process R&D - 1,000 Total Expenses 23,347 18,737 Loss from Operations (23,347) (18,737) Interest Income 7 40 Net Loss ($23,340) ($18,697) Loss per Share ($0.72) ($0.70)

FY 2013 Financial Results Year Ended December 31, 2013 Year Ended December 31, 2012 Expenses: Research & Development $75,725 $47,200 General & Administrative 14,780 6,715 Acquired In-process R&D 1,940 8,000 Total Expenses 92,445 61,915 Loss from Operations (92,445) (61,915) Interest Income 83 152 Net Loss ($92,362) ($61,763) Loss per Share ($2.93) ($4.51)

Mary Lynne Hedley, Ph.D. President

MEC: Moderately emetogenic chemotherapy HEC: Highly emetogenic chemotherapy ASCO: American Society of Clinical Oncology Development Programs Update Phase 3 NOVA trial enrollment in line with expectations Phase 3 BRAVO trial to initiate patient treatment shortly Define strategy for niraparib evaluation in additional tumor types Niraparib Initial Phase 1 data presented at the European Cancer Congress and 15th World Conference on Lung Cancer Continuing evaluation of a fractionated 60mg dose in ALK+ and TRK+ patients TSR-011 Primary endpoint achieved in each of two Phase 3 trials (MEC and HEC) Enrollment nearly complete in final Phase 3 trial (HEC); data from all three trials to be presented at ASCO 2014 Oral NDA submission on track for mid-2014 Finalize IV dose Rolapitant

Rolapitant IV: Bioequivalence Program Underway to Address Largest Market Segment Initial Results of a Human Dose Ascending Study Indicate that the IV Formulation is Likely to Achieve Bioequivalence to a 200mg Oral Dose Log-Mean ± SE Rolapitant Plasma Concentration (ng/mL) 0 24 48 72 96 120 1 10 100 1,000 10,000 7 5 4 3 2 7 5 4 3 2 7 5 4 3 2 7 5 4 3 2 Time (h) REF (Oral) 200 mg IV 20 mg IV 50 mg IV 100 mg IV 150 mg IV 200 mg

Development Programs Update Phase 3 NOVA trial enrollment in line with expectations Phase 3 BRAVO trial to initiate patient treatment shortly Define strategy for niraparib evaluation in additional tumor types Niraparib Initial Phase 1 data presented at the European Cancer Congress and 15th World Conference on Lung Cancer Continuing evaluation of a fractionated 60mg dose in ALK+ and TRK+ patients TSR-011 Primary endpoint achieved in each of two Phase 3 trials (MEC and HEC) Enrollment nearly complete in final Phase 3 trial (HEC); data from all three trials to be presented at ASCO 2014 Oral NDA submission on track for mid-2014 Finalize IV dose Rolapitant

Evaluating Additional Tumor Types Platinum sensitivity Small Cell Lung BRCA, ATM mutations Gastric ERCC-1 mutations Non-Small Cell Lung Front-line indications Breast & Ovarian HR deficiency in 20–25% ETS gene fusions (TMPR552-ERG; 50% of prostate) Prostate

Development Programs Update Phase 3 NOVA trial enrollment line with expectations Phase 3 BRAVO trial to initiate patient treatment shortly Define strategy for niraparib evaluation in additional tumor types Niraparib Initial Phase 1 data presented at the European Cancer Congress and 15th World Conference on Lung Cancer Continuing evaluation of a fractionated 60mg dose in ALK+ and TRK+ patients TSR-011 Primary endpoint achieved in each of two Phase 3 trials (MEC and HEC) Enrollment nearly complete in final Phase 3 trial (HEC); data from all three trials to be presented at ASCO 2014 Oral NDA submission on track for mid-2014 Finalize IV dose Rolapitant

Plan to develop TSR-011 patients with NSCLC whose tumors have altered ALK or TRK proteins Enrollment ongoing for ALK+ and TRK+ patients at a fractionated 60mg dose Patient receiving 60mg BID dose had a RECIST partial response Phase 1/2 study ongoing to assess safety and anti-tumor activity Based on information from Phase 1/2, design optimal Phase 2/3 clinical trials that will be used to support future regulatory submissions TSR-011 Development Plan ALK+ ALKi Naïve NSCLC ALK+ or TRKmut, Non-NSCLC Dose Escalation NSCLC: Non-small cell lung cancer BID: Twice daily TID: Three times daily

Lonnie Moulder Chief Executive Officer

WW: Worldwide RA: Receptor antagonist Commercial Perspective Rolapitant Large U.S. market: 5 million doses; ~$1.5B annually Expanded utilization of NK-1 RAs supported by current guidelines Low price compared to anti-cancer agents Differentiated from competing products Primary detail position for TESARO Compelling product gross margin Significant market: >$3B WW for first two indications Opportunity to introduce a new product class Mechanism enables targeted patient selection, which allows for strategic R&D investments Compelling product gross margin Will leverage rolapitant commercial infrastructure at time of launch Niraparib

Commercial Organization: Hiring Targeted for Late in NDA Review Process Approximately 120 Total Headcount Opportunity for Significant Leverage: Anticipate Rolapitant P&L to Break Even at Annual Sales of ~$50-60M

CINV: chemotherapy-induced nausea & vomiting ALKi: ALK-inhibitor KOL: key opinion leader TESARO is Positioned for Success Cash and equivalents of ~$130M as of 12/31/2013 Net proceeds of ~$94M from February 2014 follow-on offering Well Capitalized Commercial, development and regulatory experience in oncology Relationships with KOLs and national oncology networks Experienced Team Promising Pipeline Rolapitant: Differentiated profile; unmet market need that can be addressed via education and adherence to existing guidelines Niraparib: Two Phase 3 trials; Phase 1 data demonstrated high response rates among heavily pre-treated patients TSR-011: Compelling Phase 1 data in ALKi-resistant patients Significant Revenue Opportunities Rolapitant: $1.5B U.S. CINV market Niraparib: >$3B WW initial indications

[LOGO]

Complete final Phase 3 trial of oral rolapitant Advance IV rolapitant clinical program Present data at ASCO, MASCC and ESMO Submit NDA for oral rolapitant to the U.S. FDA in mid-2014 Continue to advance niraparib Phase 3 NOVA and BRAVO trials Expand the niraparib clinical development program and initiate the trial in Ewing’s sarcoma Identify optimal dosing schedule for TSR-011 and continue to evaluate activity in ALK+ and TRK+ patients ASCO: American Society of Clinical Oncology MASCC: Multinational Association of Supportive Care in Cancer ESMO: European Society for Medical Oncology 2014 Key Priorities

Fourth-Quarter and Full-Year 2013 Operating Results February 19, 2014