ASCO Investor & Analyst Briefing May 30, 2015

ASCO Investor & Analyst Briefing May 30, 2015 1

Lonnie Moulder Co-Founder & CEO 2

Safe Harbor Statement Statements made in this presentation that are not descriptions of historical facts are forwardlooking statements reflecting the current beliefs and expectations of management. Forwardlooking statements are sometimes identified by words such as plan, may, will, expect, and similar expressions referencing future events, conditions or circumstances. Such forward-looking statements include statements regarding the expected timing of our rolapitant and niraparib clinical trials, our regulatory filings related thereto, and potential product launches; our expectation to have oral and IV formulations of rolapitant; our expectations regarding our intellectual property and market exclusivity rights; the potential market opportunity for our product candidates; the expected attributes and advantages of our product candidates; our expected transition to an integrated commercial state company; and our 2015 corporate goals. These forward-looking statements involve substantial risks and uncertainties that could cause our future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements, including, among others, uncertainties inherent in the execution and completion of clinical trials, uncertainties surrounding the timing of availability of data from our clinical trials, ongoing discussions with and potential actions by regulatory authorities, patient accrual rates for clinical trials, other factors affecting the timing of availability of data from or initiation of our clinical trials, uncertainties regarding competition in the markets for our product candidates, and other uncertainties that could affect the availability or commercial potential of our drug candidates, as well as the detailed risks described in our Annual Report on Form 10-K for the year ended December 31, 2014, our subsequent filings with the SEC, and our preliminary prospectus supplement dated March 2, 2015. TESARO, Inc. undertakes no obligation to update or revise any forward-looking statement for any reason. 3

Agenda Rolapitant CINV Market Opportunity & IV Update Niraparib Program Overview & Biomarker Strategy Immuno-Oncology Update Q&A 4

TESARO: Strong Financial and Strategic Position Near-Term Commercial Opportunity Late-Stage Pipeline Addresses Large Markets Balanced Product Pipeline Strong Financial Position Rolapitant 09/05/15 PDUFA Q4 2015 Launch CINV: $1.5B Ovarian: $4B Breast: $1B Includes 5 Programs in Phase 2 or 3 ~$399M in Cash & Equiv. as of 03/31/15 PROVEN MANAGEMENT TEAM 5

TESARO: A Balanced Portfolio of Product Candidates Compound Therapeutic Area Discovery Pre-clinical Phase 1 Phase 2 Phase 3 Registration Rolapitant Oral NK-1 receptor antagonist Rolapitant IV Niraparib PARP Inhibitor Niraparib + bevacizumab Niraparib + chemotherapy TSR-011 ALK and TRK Inhibitor TSR-042 Anti-PD-1 mab Anti-TIM-3 mab CINV in A/C-breast cancer/ MEC treated patients CINV in cisplatin (HEC) treated patients CINV in cisplatin (HEC) treated patients CINV Ovarian Cancer Maintenance (NOVA) Ovarian Cancer Treatment (QUADRA) BRCA+ Breast Cancer (BRAVO) Ovarian Cancer Maintenance (AVANOVA)* Ewing s sarcoma** NSCLC, others Various tumor types Various tumor types Anti-LAG-3 mab Anti-TIM-3/PD-1 dual reactive mab Anti-LAG-3/PD-1 dual reactive mab Undisclosed mab Various tumor types Various tumor types Various tumor types Various tumor types CINV: Chemotherapy-induced nausea & vomiting; mab: Monoclonal antibody; A/C: anthracycline/cyclophosphamide; MEC: Moderately emetogenic chemotherapy; HEC: Highly emetogenic chemotherapy; NSCLC: Non-small cell lung cancer. * In collaboration with ENGOT, the European Network for Gynaecological Oncological Trial groups. ** In collaboration with SARC, the Sarcoma Alliance for Research through Collaboration. 6

Rolapitant A Selective NK-1 Receptor Antagonist (RA) with a Long Half-Life in Development for the Prevention of Chemotherapy- Induced Nausea & Vomiting (CINV) 7

ROLAPITANT PIPELINE: Oral and IV Formulations in Development Compound Therapeutic Area Discovery Preclinical Ph 1 Ph 2 Ph 3 Registration Rolapitant Oral NK-1 receptor antagonist CINV in A/C-breast cancer / MEC-treated patients CINV in cisplatin (HEC) treated patients CINV in cisplatin (HEC) treated patients Rolapitant IV CINV 8

ROLAPITANT: Overview Established CINV prevention guidelines support significant unmet need and potential for additional NK-1 RA utilization Successful global registration program; September 5, 2015 PDUFA date Profile includes: Long half-life and duration of action, sustained coverage Oral and IV formulations, which will allow full market access Reduced potential for CYP3A4 drug-drug interactions Potential to be clinically meaningful product for patients and healthcare providers Composition of matter protection until 2023 U.S. exclusivity into 2028 with expected Hatch-Waxman European data / market exclusivity of 8 + 2 (+1) years Approval and launch will transform TESARO into an integrated development and commercial stage company 9

ROLAPITANT: Despite Available Therapies, Significant Unmet Need Remains in CINV NCCN Guidelines Version 1.2013 Antiemesis Perception vs. Reality 2 in Delayed CINV 91% Agent AC combination defined as either doxorubicin or epirubicin with cyclophosphamide s Cisplatin Carboplatin 1 Cyclophosphamide >1,500mg/m 2 Doxorubicin >60mg/m 2 Dacarbazine Epirubicin >90mg/m 2 Ifosfamide >2g/m per 2 dose Mechlorethamine Streptozocin 76% 43% 59% Start before chemotherapy Serotonin (5-HT 3 ) receptor antagonist AND Steroid AND Neurokinin 1 antagonist No Delayed Nausea Perception of HCPs No Delayed Vomiting Actual Patient Experience Opportunity to Educate HCPs Regarding Antiemesis Guidelines and Actual Patient CINV Experience 1 For selected patients as appropriate. 2 J Support Oncol 2004;2(suppl 1):1-12. HCPs: Healthcare Providers. 10

ROLAPITANT: Community Oncology Market Study (n=135) Respondent Type Practice Setting Oncology Nurse 33% Hospital or Health-System Owned Practice 19% 67% Medical Oncologist 81% Physician- Owned Community Practice 51% of Oncologists Participating in this Market Study Reported Having an In-house Pharmacy for Oral Dispensing Source: Xcenda market research 11

ROLAPITANT: Two-thirds of Respondents Have Guidelines Within Their Practice That Dictate Antiemetic Prescribing Variance From Practice Guidelines 56% 34% 6% 4% 0% of the Time (Never) No More Than 10% of the Time 11% 25% of the Time More Than 25% of the Time 90% of Oncologists Vary from Practice Guidelines <10% of the Time *Respondents limited to those who indicated they have a practice formulary Source: Xcenda market research 12

ROLAPITANT: What Are the Top Factors That Influence the Choice of Antiemetic Regimen? Evidence of Efficacy 3.4 Practice Treatment Guidelines or Clinical Pathways 2.0 Insurance Requirements 2.0 Availability in My Practice 1.6 0 1 2 3 4 The Most Influential Factors in Selecting Antiemetic Therapy Are Efficacy, Following Practice or Clinical Pathways, and Insurance Coverage Source: Xcenda market research 13

ROLAPITANT: Improvement in Delayed CINV is Viewed as the Most Important Data Point Which Patients? (N=135) Likelihood of Using Product X 50% 50% 64% Oncologists (n=90) Oncology Nurses (n=45) 4.7 5.2 5.5 6.7 0 1 2 3 4 5 6 7 With Highly Emetogenic Regimens 2% With Moderately Emetogenic Regimens All Patients, if Reimbursement Was Assured Patients Who Might Have Compliance/ Adherence Issues with a Multi-day NK-1 Antagonist For Patients Who Experience Delayed CINV Despite the Use of the Currently Approved NK-1 Antagonist For Other Types of Patients Overall (n=65) Likelihood of Stocking in In-house Pharmacy 6.0 Most Important Data Point 1 2 3 4 5 6 7 84% of Respondents Felt the Data Demonstrating a Statistically Significant Improvement in Delayed CINV Was Sufficiently Encouraging to Lead Them to Use Product X Source: Xcenda market research 14

ROLAPITANT: Large U.S. Revenue Opportunity ROLAPITANT Peak Sales Opportunity # of Potential Doses Potential Revenue IV IV OPPORTUNITY (at $300 / Dose) 1M $300M 2M $600M 3M $900M 80% ORAL OPPORUNITY (at $450 / Dose) 0.25M $113M 0.5M $225M 0.75M $338M 20% Oral Dollar figures reflect current NK-1 RA pricing of ~$300/cycle for IV and ~$450 for oral. 15

ROLAPITANT: Significant Potential Value Proposition for Patients and HCPs 1 Provides potential protection from CINV for up to five days 2 Single dose administered just prior to chemotherapy 3 Reduced risk of CYP3A4-mediated drug interactions 4 Use in combination with standard dose of 5-HT 3 RA and dex 5 Oral and IV formulations in development to address entire market 6 Expanded NK-1 use supported by existing anti-emetic guidelines TESARO Is Positioned to Transform into an Integrated Development and Commercial Company *Source: IMS data and Company estimates. RA: receptor antagonist. 16

ROLAPITANT: U.S. Launch Planned for Q4 2015 Key Commercial Strategy Success Factors 1 2 3 4 Potential Profile Promotional Activities Educational Efforts Key Account Collaborations Long half-life Sustained delayed phase efficacy Reduced risk of CYP3A4 DDIs IV & oral formulations Dedicated sales force Focused, right-sized commercial organization (~120) Adherence to NCCN, ASCO guidelines Goal to increase awareness of need Focus on nurses Contracting opportunity Leverage clinical trial experience Patient support program DDIs: Drug-Drug Interactions. 17

Mary Lynne Hedley, Ph.D. Co-Founder, President & COO 18

ROLAPITANT IV: Clinical Program Overview Study # of Subjects Dosed IV Status Single Ascending Dose / Multiple Ascending Dose (SAD/MAD) 77* Complete Bioequivalence (BE) 61** Complete Open-Label Safety Dose Escalation/Cohort Expansion ~100 Ongoing Open-Label Safety Drug Interaction (DDI) ~100 Ongoing * n= 57 (SAD) and n=20 (MAD) ** N = 123 subjects (n=62 dosed orally) 19

ROLAPITANT IV: Bioequivalence Study Design 123 Healthy Volunteers 1:1 Randomization 200 mg Oral Rolapitant (n=62) 185 mg IV Rolapitant (n=61) Endpoints Bioequivalence, determined by AUC 0-t and AUC 0- Safety, tolerability 20

ROLAPITANT IV: Bioequivalence Study Results Similar Exposure (AUC) For Oral and IV Formulations 21

Niraparib A Potentially Best-in-Class PARP Inhibitor in Phase 3 for Ovarian and Breast Cancers 22

NIRAPARIB PIPELINE: A Portfolio of Opportunities Compound Therapeutic Area Discovery Preclinical Ph 1 Ph 2 Ph 3 Registration 2L Ovarian Cancer Maintenance (NOVA) Niraparib Ovarian Cancer Treatment (QUADRA) 1L Ovarian Cancer Maintenance (PRIMA) To Begin 2H 2015 BRCA+ Breast Cancer (BRAVO) Niraparib + pembrolizumab Triple Negative Breast & Ovarian Cancers To Begin 2H 2015 Ovarian Cancer Niraparib Maintenance + bevacizumab (AVANOVA) Niraparib + chemotherapy Ewing s sarcoma 23

NIRAPARIB: Key Phase 1 Results Phase 1 RECIST Response Data 75% Platinum Sensitive HGSOC at Phase 3 Dose (300 mg) 46% Platinum- Sensitive HGSOC Across All Doses 50% 50% Platinum- Sensitive gbrcamut HGSOC Across All Doses BRCA-Positive Breast Cancer Patients Across All Doses Durable responses >1 year in platinum sensitive ovarian patients, regardless of gbrcamut status 431 days in gbrca+ patients 444 days in gbrca- patients Heavily pre-treated patient population Median prior systemic regimens: 6 in ovarian patients 5 in breast patients AE profile typical for PARPi class DLT of thrombocytopenia Highly Compelling Response Rates and Durations in Heavily Pretreated Patients HGSOC: High grade serous ovarian cancer. DLT: Dose limiting toxicity. 24

NIRAPARIB: Building an Ovarian Cancer Franchise 2nd Line (Recurrent) Maintenance NOVA Trial PFS primary endpoint Efficacy analyses in prespecified gbrca mut and nongbrca/hrd+ patients Data expected in Q4 2015 Ovarian Treatment QUADRA Trial ORR primary endpoint Efficacy analyses in prespecified gbrca mut and HRD+ subgroups Phase 2 trial ongoing Initial data expected in early 2016 1st Line Maintenance PRIMA Trial PFS primary endpoint Will enroll gbrca mut and HRD+ patients Phase 3 trial to begin 2H 2015 AVANOVA and anti-pd-1 mab Combination Trials Will Further Characterize Niraparib in Ovarian Cancer PFS: Progression free survival. ORR: Overall response rate. HRD: Homologous recombination deficiency. 25

NIRAPARIB: MyChoice HRD Test Can Discriminate High vs. Low HRD Tumors HRD Distribution of 561 Ovarian Tumors: BRCA Deficient Tumors Include Germ Line, Somatic and BRCA Promoter Methylated 26

NIRAPARIB: HRD Scoring of Breast and Ovarian Patient-Derived Xenografts 4.5 BRCA1 met 3.5 BRCA2 mut 3 2.5 BRCA1 mut 4 2 1.5 BRCA wt 1 0.5 0 0 10 20 30 40 50 60 70 80 90 HRD score Sensitive to niraparib Resistant to niraparib HRD Score Identifies Niraparib Sensitive and Resistant Tumors; Equivalent Response Rates Observed in HRD+ and BRCA Mutant Tumors 27

NIRAPARIB: Phase 3 Trial in 2 nd Line (Recurrent) Ovarian Cancer Maintenance (NOVA Trial) High Grade Serous Ovarian Cancer, Platinum Sensitive, Relapsed Response to Platinum Treatment n=490 gbrca mut Non-gBRCA mut / HRD 2:1 Randomization 2:1 Randomization Niraparib 300 mg Placebo Niraparib 300 mg Placebo n=120 n=60 n=207 n=103 Endpoint Assessment Endpoint Assessment Primary Endpoint PFS; >90% power to detect 4.5 month improvement (HR 0.50 in both cohorts) Assumption: 4.5 month PFS for control arms Expanded enrollment of non-gbrcamut cohort to complete 1Q 2015. PFS: Progression free survival. TNBC: Triple negative breast cancer. HRD: Homologous recombination deficiency. 28

NIRAPARIB: Preliminary HRD Distribution in NOVA Tumors HRD Distribution of gbrcamut Tumors HRD Distribution of 106 Tumors from Non-gBRCA mut Cohort 16 18 14 gbrca mut cohort 16 BRCA wild type Tumor BRCA1 mut Number of tumor samples 12 10 8 6 4 Number of tumor samples 14 12 10 8 6 4 2 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 HRD score HRD score Nearly All gbrca and tbrca Mutant Tumors Have High HRD Scores; A total of 57% of the non-gbrca mut cohort have deficiencies in HR 29

NIRAPARIB: Approximately 2/3 of Patients Enrolled in the Phase 3 NOVA Trial are HRD+ HRD Biomarker Negative (~1/3) nongbrca mut ~65% gbrca mut ~35% HRD+ (~2/3) Overall, approximately 35% of patients enrolling into NOVA are gbrca mutant and 65% are non-gbrca mutant Nearly all patients who have a gbrca mutation have a positive HRD score Approximately half of patients who are non-gbrca mut are projected to be HRD+ Data Presented at ASCO 2015 Meeting 30

NIRAPARIB: Announced Today: Clinical Collaboration with Merck Phase 1/2 trial of niraparib plus KEYTRUDA (pembrolizumab) Goal to evaluate preliminary safety and efficacy of this combination Plan to enroll patients with triple-negative breast cancer or ovarian cancer Response rates with anti-pd-1 mab monotherapy: 11.5% in ovarian cancer (1) 18.5% in triple negative breast cancer (2) External expenses to be shared equally Collaboration led by joint development committee Expected to begin by YE 2015 Pembrolizumab data presentations: 1 Results from Varga et. al, ASCO 2015; pembrolizumab abstract #5510; best overall (confirmed) response (keynote-012). 2 Results from Nanda R., et.al., San Antonio Breast Cancer Symposium 2014; pembrolizumab abstract SI-09; overall response. KEYTRUDA is a trademark of Merck & Co., Inc. 31

NIRAPARIB: Combination Therapy: Rationale for Combining PARPi and Anti-PD-1 Niraparib Plus Anti-PD-1 in TNBC Two Non-mutually Exclusive Hypotheses 1. PARPi can trigger cell death and increased inflammation and consequently increased CD8+ TILs with immune checkpoint modulators 2. PARPi will selectively increase somatic mutations in tumors and result in neo-antigens which will trigger CD8+ TILs with immune checkpoint modulation Cell deathmediated inflam. Experimental Pre-clinical Data is Available Indicating the Potential for Synergy with PARPi and Immune Checkpoint Inhibitors 1. Veliparib has demonstrated synergy with anti- CTLA-4 in BRCA deficient pre-clinical models 2. Niraparib has demonstrated synergy with anti-pd-1 in a preclinical syngeneic model Neoantigens Immunosurveillance 32

NIRAPARIB: Potential Value Proposition 1 2 Compelling RECIST response rate and durability in heavily pre-treated patients Convenient, once per day oral dosing 3 Broad development program in ovarian cancer 4 Broad development program in breast cancer 5 Biomarker incorporation potentially allows for patient selection 6 Potential for combinations with immuno-oncology and other targeted agents 33

Immuno-Oncology Portfolio Monospecific Antibodies Targeting PD-1, TIM-3 and LAG-3 Plus Dual Specific Antibodies Targeting PD-1/TIM-3 and PD-1/LAG-3 34

Immuno-Oncology: Advancing Our Early Stage Pipeline Compound Indication Discovery Preclinical Ph 1 Ph 2 Ph 3 Registration TSR-042 Anti-PD-1 mab Anti-TIM-3 mab Various tumor types Various tumor types Anti-LAG-3 mab Anti-TIM-3/PD-1 dual reactive mab Anti-LAG-3/PD-1 dual reactive mab Undisclosed mab Various tumor types Various tumor types Various tumor types Various tumor types 35

Immuno- Oncology: TESARO s Vision & Strategy TESARO s I-O portfolio: Three known checkpoint inhibitors PD-1, TIM-3 and LAG-3 Three bi-specific antibodies PD-1/TIM3 and PD-1/LAG-3 Additional undisclosed bispecific Immune modulators are likely to treat many tumor types May be most effective when used in combination therapy Potential to combine with TESARO pipeline molecules Establish collaborations with other companies that have complementary approaches 36

Immuno- Oncology: TSR-042: A Potent Anti-PD-1 Antibody Biacore Binding Kinetics to Human PD-1 Blocks PD-L1 and PD-L2 Binding to PD-1 in a Competitive Cell Based Assay PD-L1 or PD-L2 -DyL650 TSR-042 Backup PD-1 CHO TSR-042 Backup K D 2.4 nm 6.7 nm Ligand TSR-042 (IC50) Backup (IC50) PD-L1-DyL650 1.8 nm 2.1 nm PD-L2-DyL650 1.5 nm 1.8 nm 37

Immuno- Oncology: TSR-042 Enhances Activation of Human T Cells Increased IL-2 Production in MLR Assay 2,000 IL-2 Concentration (pg/ml) 1,500 1,000 500 0 No Antibody 0.001 0.01 0.1 1 10 100 mab (nm) TSR-042 Backup Isotype Control EC 50 67pM 133pM 38

Immuno- Oncology: Anti-TIM-3 Antibodies Enhance Activation of Human T Cells Increased IL-2 Production in T Cell Activation Assay 2,000 IL-2 Concentration (pg/ml) 1,500 1,000 500 0 0.01 0.1 1 10 100 1000 mab (nm) Anti-TIM-3 Lead Anti-TIM-3 Back up IgG Control EC 50 2.0 nm 3.0 nm 39

Immuno- Oncology: Anti-TIM-3 Antibody Further Enhances Anti-PD-1 Activation of Human T Cells Increased IL-2 Production in Combination with Anti-PD-1 in MLR Assay 3,000 IL-2 Concentration (pg/ml) 2,000 1,000 0 0.001 0.01 0.1 1 10 100 mab (nm) Anti-TIM-3 + 2 ng/ml anti-pd-1 Anti-TIM-3 + 20 ng/ml anti-pd-1 Anti-TIM-3 Lead EC 50 0.93 nm 0.47 nm 3.0 nm 40

Immuno- Oncology: Optimized Tumor Regression with Combination Anti-TIM3 and Anti-PD1 in the MC38 Model PBS Anti-TIM3 Tumor Volume (mm 3 ) Tumor Volume (mm 3 ) Days Post Randomization Days Post Randomization Anti-PD1 Anti-TIM3 + Anti-PD1 Tumor Volume (mm 3 ) Tumor Volume (mm 3 ) Days Post Randomization Days Post Randomization = DOSING DAYS. Note: Each antibody dosed at 10mg/kg on days 1, 4, 8 and 11 post randomization. 41

Immuno- Oncology: Anti-LAG-3 Antibodies Enhance Activation of Human T Cells Increased IL-2 Production in MLR Assay 2,000 IL-2 Concentration (pg/ml) 1,500 1,000 500 0 0.1 1 10 100 1000 mab (nm) Anti-LAG-3 Lead Anti-LAG-3 Reference Anti-LAG-3 Reference EC 50 0.8nM 6.0nM 3.0nM 42

Immuno- Oncology: Anti-LAG-3 Antibody Further Enhances Anti-PD-1 Activation of Human T Cells Increased IL-2 Production in Combination with Anti-PD-1 in MLR Assay 3,000 IL-2 Concentration (pg/ml) 2,000 1,000 0 0.01 0.1 1 10 100 mab (nm) Anti-LAG-3 + 2 ng/ml anti-pd-1 Anti-LAG-3 + 20 ng/ml anti-pd-1 Anti-LAG-3 alone EC 50 200 pm 27 pm 800 pm 43

Immuno- Oncology: Optimized Tumor Regression with Combination Anti-LAG3 and Anti-PD1 in the Colon26 Model PBS Anti-PD-1 Anti-LAG-3 2000 2000 2000 Tumor Volume (mm 3 ) 1500 1000 500 Tumor Volume (mm 3 ) 1500 1000 500 Tumor Volume (mm 3 ) 1500 1000 500 0 0 5 10 15 20 25 30 35 40 45 50 55 0 0 5 10 15 20 25 30 35 40 45 50 55 0 0 5 10 15 20 25 30 35 40 45 50 55 Days Post Tumor Inoculation Days Post Tumor Inoculation Days Post Tumor Inoculation Anti-LAG-3 + anti-pd-1 Tumor Volume (mm 3 ) 400 350 300 250 200 150 100 50 0 0 10 20 30 40 50 60 70 80 90 100 110 120 Days Post Tumor Inoculation Tumor Re-challenge Day 85 = DOSING DAYS. Note: Each antibody dosed at 10mg/kg on days 4, 7, 11 and 14 post tumor inoculation. 44

Immuno- Oncology: Summary: TESARO s Immunotherapy Antibody Program PD-1, LAG-3 and TIM-3 Are Key Immune Checkpoint Receptors That Negatively Regulate T Cell Activation Exhausted T cell Reinvigorated T cell Cytokines Effector mechanisms Additional combination studies ongoing IND for anti-pd-1 antibody targeted for EOY 2015 Anti-TIM-3 and anti-lag-3 antibodies targeted for INDs in 2016 Activation signal TCR Ag MHC Inhibitory signal PD-1 LAG-3 TIM-3 Activation signal TCR Ag MHC αpd-1 αtim-3 αlag-3 Bispecific Lead generation in progress Anti-LAG-3/anti-PD-1 Anti-TIM-3/anti-PD-1 Undisclosed APC or Tumor Cell APC or Tumor Cell 45

Lonnie Moulder Co-Founder & CEO 46

TESARO: 2015 Is a Transformative Year Rolapitant Niraparib Early Stage Pipeline Establish a full-scale oncology U.S. commercial organization by end of Q3 2015 Oral rolapitant PDUFA goal date September 5, 2015 Launch oral rolapitant in Q4 2015, pending regulatory approval Submit NDA for IV rolapitant following commercial launch of oral rolapitant Advance the QUADRA trial Report data from NOVA in Q4 2015 Advance the BRAVO trial Initiate PRIMA trial, pembrolizumab combination trial, and SCLC trial in 2H 2015 Enroll additional ALK+, ALKi-naïve patients to enable registration decision Submit IND for TSR-042 by year end Advance IND enabling studies for anti-tim-3 and anti-lag-3 clinical candidates NDA: New Drug Application. IV: Intravenous. SCLC: Small cell lung cancer. IND: Investigational New Drug. 47

Q&A 48

ASCO Investor & Analyst Briefing May 30, 2015 49

Appendix 50

NIRAPARIB: Registration Trial for Treatment of Ovarian Cancer (QUADRA Trial) High Grade Serous Ovarian Cancer, Platinum Resistant or Platinum Sensitive, gbrca mut or HRD Received 3 or More Lines of Chemotherapy N=225 Niraparib 300 mg Daily Treatment Endpoint Assessment Primary Endpoint Overall Response Rate (ORR) 51

NIRAPARIB: Phase 3 Trial in 1 st Line Ovarian Cancer Maintenance (PRIMA Trial) High Grade Serous Ovarian Cancer Responded to 1 st Line Platinum Chemotherapy, with No Evidence of Progression, No Disease >2cm and Normal CA125 Tumor Biomarker Positive Ovarian Cancer 2:1 Randomization Niraparib N=192 Placebo N=96 Primary Endpoint PFS Power assumptions: 13* vs. 20 months, HR=0.625, 90% power *Control from ICON 7, OVAR 16 and erlotinib studies. 52

NIRAPARIB: PARP Inhibitor Peak Market Opportunity in Ovarian Cancer of Approximately $4 Billion United States Europe 2L (Recurrent) Maintenance 2L (Recurrent) Maintenance Treatment Treatment 1L Maintenance 1L Maintenance 0 5 10 15 20 Patients (000s) 0 5 10 15 20 Patients (000s) gbrca mut Non-gBRCA mut /HRD + Non-gBRCA mut / HRD- Other/Ineligible Approximately 40,000 Eligible Patients in the U.S. and Europe 1L: 1st Line; 2L: 2nd Line; Treatment: 3 or more lines of previous therapy. Dollar figures reflect current PARP inhibitor pricing. Source: Company estimates. 53

NIRAPARIB: PARP Inhibitor Peak Market Opportunity in gbrca mut Breast Cancer Exceeds $1 Billion U.S. Europe 0 2 4 6 8 10 12 gbrca mut Patients (000s) 1L Patients 2L Patients 3L Patients Approximately 20,000 Eligible Patients in the U.S. and Europe 1L: 1st Line metastatic/recurrent; 2L: 2nd Line metastatic; 3L: 3rd Line metastatic. Dollar figures reflect current PARP inhibitor pricing. Source: Company estimates. 54

Immuno- Oncology: Generating Antibodies with In Vitro Somatic Hypermutation SHM-XEL System for Ab Discovery & Optimization Harnessing the natural mechanism of antibody maturation in vitro Starting Library Evolving Library More evolved Library Evolved Library Ab genes have evolved to use SHM for efficient selection of high affinity Abs Mammalian cell display of intact, fully-functional IgG Allows selection of antibodies in their native format Co-selection for high expression level and developability parameters High throughput selection using FACs 55

Immuno- Oncology: Optimal Therapeutic Antibody Properties Controlled Selection for Optimal Therapeutic Properties Affinity Functionality Human Species Cross-Reactivity Sequences Expression Biophysical Properties To low pm KD values e.g., neutralization, signaling, apoptosis induction, effector functions Low immunogenic potential To facilitate preclinical toxicology V-region glycosylation sites, deamidation & isomerization motifs etc. Well expressed in mammalian cells e.g., thermal stability, solubility, aggregation propensity AnaptysBio Technology Allows Selection for Optimal Properties and Circumvents the Need to Isolate Large Panels of Screening Antibodies 56