Merck and Pfizer Announce Discontinuation of Phase III JAVELIN Ovarian PARP 100 Trial in Previously Untreated Advanced Ovarian Cancer

DARMSTADT,Germany and NEW YORK,March 20,2019 -- Merck and Pfizer Inc. (NYSE:PFE) today announced the discontinuation of the ongoing Phase III JAVELIN Ovarian PARP 100 study evaluating the efficacy and safety of avelumab in combination with chemotherapy followed by maintenance therapy of avelumab in combination with talazoparib,* a poly (ADP-ribose) polymerase (PARP) inhibitor,versus an active comparator in treatment-naïve patients with locally advanced or metastatic ovarian cancer (Stage III or Stage IV). The alliance has notified health authorities and trial investigators of the decision to discontinue the trial.

The decisionwas based on several emerging factors since the trial's initiation,including the previously announced interim results from JAVELIN Ovarian 100. The alliance determined that the degree of benefit observed with avelumab in frontline ovarian cancer in that study does not support continuation of the JAVELIN Ovarian PARP 100 trial in an unselected patient population and emphasizes the need to better understand the role of immunotherapy in ovarian cancer. Additional factors include the rapidly changing treatment landscape andthe approval of a PARP inhibitor in the frontlinemaintenance setting. The decision to discontinue the JAVELIN Ovarian PARP 100 trial was not made for safety reasons.

The alliance between Merck and Pfizer was the first to test an immunotherapy in this indication,given the significant unmet need in the treatment of ovarian cancer. Four out of five women with ovarian cancer are diagnosed with disease that has spread to the lymph nodes or to distant organs.1 Most women with advanced ovarian cancer ultimately die within five years due to refractory,resistant or recurrent disease.2,3

JAVELIN Ovarian PARP 100 (B9991030) is an open-label,international,multi-center,randomized study designed to evaluate the efficacy and safety of avelumab in combination with chemotherapy followed by maintenance therapy of avelumab in combination with talazoparib versus an active comparator in treatment-naïve patients with locally advanced or metastatic ovarian cancer (Stage III or Stage IV). The primary endpoint is progression-free survival (PFS) as determined based on blinded independent central review (BICR) assessment per RECIST v1.1.

The decision to discontinue the JAVELIN Ovarian PARP 100 trial does not impact the currently approved indications for avelumab or the remainder of the ongoing JAVELIN clinical development program. The program involves at least 30 clinical programs and more than 9,000 patients evaluated across more than 15 different tumor types,including breast,gastric/gastro-esophageal junction,and head and neck cancers,Merkel cell carcinoma,non-small cell lung cancer,and urothelial carcinoma.

*Avelumab and talazoparib are under clinical investigation for the treatment of advanced ovarian cancer and have not been demonstrated to be safe and effective for this use.

About Avelumab (BAVENCIO®)

Avelumab (BAVENCIO®) is a human anti-programmed death ligand-1 (PD-L1) antibody. Avelumab has been shown in preclinical models to engage both the adaptive and innate immune functions. By blocking the interaction of PD-L1 with PD-1 receptors,avelumab has been shown to release the suppression of the T cell-mediated antitumor immune response in preclinical models.4-6 Avelumab has also been shown to induce NK cell-mediated direct tumor cell lysis via antibody-dependent cell-mediated cytotoxicity (ADCC) in vitro.6-8 In November 2014,Merck and Pfizer announced a strategic alliance to co-develop and co-commercialize avelumab.

BAVENCIO Approved Indications

In September 2017,the European Commission granted conditional marketing authorization for BAVENCIO as a monotherapy for the treatment of adult patients with metastatic Merkel cell carcinoma (MCC). BAVENCIOis currently approved for patients with MCC in more than 45 countries globally,with the majority of these approvals in a broad indication that is not limited to a specific line of treatment.

In the US,the FDA granted accelerated approval for BAVENCIO for the treatment of (i) adults and pediatric patients 12 years and older with metastatic Merkel cell carcinoma (mMCC) and (ii) patients with locally advanced or metastatic urothelial carcinoma (mUC) who have disease progression during or following platinum-containing chemotherapy,or have disease progression within 12months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy. These indications are approved under accelerated approval based on tumor response rate and duration of response. Continued approval for these indications may be contingent upon verification and description of clinical benefit in confirmatory trials.

BAVENCIO Safety Profile from the EU Summary of Product Characteristics (SmPC)

The special warnings and precautions for use for BAVENCIOinclude infusion-related reactions and immune-related adverse reactions (such as pneumonitis,hepatitis,colitis,endocrinopathies,nephritis and renal dysfunction,and other adverse reactions).

The SmPC list of the most common adverse reactions in patients with solid tumors includes fatigue,nausea,diarrhea,decreased appetite,constipation,infusion-related reactions,and weight loss and vomiting.

Indication for talazoparib (TALZENNA®) from the US Prescribing Information

TALZENNA is a poly (ADP-ribose) polymerase (PARP) inhibitor indicated for the treatment of adult patients with deleterious or suspected deleterious germline breast cancer susceptibility gene (BRCA)-mutated (gBRCAm) human epidermal growth factor receptor 2 (HER2)-negative locally advanced or metastatic breast cancer. Select patients for therapy based on an FDA-approved companion diagnostic for TALZENNA.

Important Safety Information from the TALZENNA US Prescribing Information

Myelodysplastic Syndrome/Acute Myeloid Leukemia (MDS/AML) have been reported in patients who received TALZENNA. Overall,MDS/AML have been reported in 2 out of 584 (0.3%) solid tumor patients treated with TALZENNA in clinical studies.

Myelosuppression consisting of anemia,leukopenia/neutropenia,and/or thrombocytopenia have been reported in patients treated with TALZENNA. Grade ≥3 anemia,neutropenia,and thrombocytopenia were reported,respectively,in 39%,21%,and 15% of patients receiving TALZENNA. Discontinuation due to anemia,and thrombocytopenia occurred,in 0.7%,0.3%,and 0.3% of patients.

Monitor complete blood counts for cytopenia at baseline and monthly thereafter. Do not start TALZENNA until patients have adequately recovered from hematological toxicity caused by previous therapy. If hematological toxicity occurs,dose modifications (dosing interruption with or without dose reduction) are recommended. With respect to MDS/AML,for prolonged hematological toxicities,interrupt TALZENNA and monitor blood counts weekly until recovery. If the levels have not recovered after 4 weeks,refer the patient to a hematologist for further investigations. If MDS/AML is confirmed,discontinue TALZENNA.

TALZENNA can cause fetal harm when administered to pregnant women. Advise women of reproductive potential to use effective contraception during treatment and for at least 7 months following the last dose. A pregnancy test is recommended for females of reproductive potential prior to initiating TALZENNA treatment. Advise male patients with female partners of reproductive potential or who are pregnant to use effective contraception during treatment with TALZENNA and for at least 4months after receiving the last dose. Based on animal studies,TALZENNA may impair fertility in males of reproductive potential. Advise women not to breastfeed while taking TALZENNA and for at least 1 month after receiving the last dose because of the potential for serious adverse reactions in nursing infants.

The most common adverse reactions (≥20%)of any grade for TALZENNA vs chemotherapy were fatigue (62% vs 50%),anemia (53% vs 18%),nausea (49% vs 47%),neutropenia (35% vs 43%),headache (33% vs 22%),thrombocytopenia (27% vs 7%),vomiting (25% vs 23%),alopecia (25% vs 28%),diarrhea (22% vs 26%),and decreased appetite (21% vs 22%).

Themost frequently reported Grade ≥3 adverse reactions (≥5%)for TALZENNA vs chemotherapy were anemia (39% vs 5%),neutropenia (21% vs 36%),and thrombocytopenia (15% vs 2%).

The most common lab abnormalities (≥25%)for TALZENNA vs chemotherapy were decreases in hemoglobin (90% vs 77%),leukocytes (84% vs 73%),lymphocytes (76% vs 53%),neutrophils (68% vs 70%),platelets (55% vs 29%),and calcium (28% vs 16%) and increases in glucose (54% vs 51%),aspartate aminotransferase (37% vs 48%),alkaline phosphatase (36% vs 34%),and alanine aminotransferase (33% vs 37%).

Coadministration with P-gp inhibitors or BCRP inhibitorsmay increase TALZENNA exposure. If coadministering with the P-gp inhibitors amiodarone,carvedilol,clarithromycin,itraconazole,or verapamil is unavoidable,reduce the TALZENNA dose to 0.75 mg once daily. When the P-gp inhibitor is discontinued,increase the TALZENNA dose (after 3–5 half-lives of the P-gp inhibitor) to the dose used prior to the initiation of the P-gp inhibitor. When co-administering TALZENNA with other known P-gp inhibitors or BCRP inhibitors,monitor patients for potential increased adverse reactions.

For patients with moderaterenal impairment,the recommended dose of TALZENNA is 0.75 mg once daily. No dose adjustment is required for patients with mild renal impairment. TALZENNA has not been studied in patients with severe renal impairment or in patients requiring hemodialysis.

TALZENNA has not been studied in patients with moderate or severehepatic impairment. No dose adjustment is required for patients with mild hepatic impairment.

Please see full US Prescribing Information available at http://www.TALZENNA.com.

About Merck-Pfizer Alliance

Immuno-oncology is a top priority for Merck and Pfizer. The global strategic alliance between Merck and Pfizer enables the companies to benefit from each other's strengths and capabilities and further explore the therapeutic potential of avelumab,an anti-PD-L1 antibody initially discovered and developed by Merck. The immuno-oncology alliance is jointly developing and commercializing avelumab. The alliance is focused on developing high-priority international clinical programs to investigate avelumab as a monotherapy as well as combination regimens,and is striving to find new ways to treat cancer.

All Merck Press Releases are distributed by e-mail at the same time they become available on the Merck Website. Please go to www.merckgroup.com/subscribe to register online,change your selection or discontinue this service.

About Merck

Merck,a leading science and technology company,operates across healthcare,life science and performance materials. Around 52,000 employees work to make a positive difference to millions of people's lives every day by creating more joyful and sustainable ways to live. From advancing gene editing technologies and discovering unique ways to treat the most challenging diseases to enabling the intelligence of devices – Merck is everywhere. In 2018,Merck generated sales of € 14.8 billion in 66 countries.

Scientific exploration and responsible entrepreneurship have been key to Merck's technological and scientific advances. This is how Merck has thrived since its founding in 1668. The founding family remains the majority owner of the publicly listed company. Merck holds the global rights to the Merck name and brand. The only exceptions are the United States and Canada,where the business sectors of Merck operate as EMD Serono in healthcare,MilliporeSigma in life science,and EMD Performance Materials.

Pfizer Inc.: Working together for a healthier world®

At Pfizer,we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality,safety and value in the discovery,development and manufacture of health care products. Our global portfolio includes medicines and vaccines as well as many of the world's best-known consumer health care products. Every day,Pfizer colleagues work across developed and emerging markets to advance wellness,prevention,treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies,we collaborate with health care providers,governments and local communities to support and expand access to reliable,affordable health care around the world. For more than 150 years,we have worked to make a difference for all who rely on us. We routinely post information that may be important to investors on our website atwww.pfizer.com. In addition,to learn more,please visit us onwww.pfizer.comand follow us on Twitter at @Pfizer and @Pfizer_News,LinkedIn,YouTube and like us on Facebook at Facebook.com/Pfizer.

Pfizer Disclosure Notice

The information contained in this release is as of March 19,2019. Pfizer assumes no obligation to update forward-looking statementscontained in this release as the result of new information or future events or developments.

This release contains forward-looking information about avelumab (BAVENCIO),the Merck-Pfizer Alliance involving avelumab,and clinical development plans,including their potential benefits,that involves substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. Risks and uncertainties include,among other things,uncertainties regarding the commercial success of avelumab; the uncertainties inherent in research and development,including the ability to meet anticipated clinical endpoints,commencement and/or completion dates for our clinical trials,regulatory submission dates,regulatory approval dates and/or launch dates,as well as the possibility of unfavorable new clinical data and further analyses of existing clinical data; risks associated with interim data; the risk that clinical trial data are subject to differing interpretations and assessments by regulatory authorities; whether regulatory authorities will be satisfied with the design of and results from our clinical studies; whether and when any drug applications may be filed in any jurisdictions for any potential indications for avelumab,combination therapies or talazoparib; whether and when regulatory authorities in any jurisdictions where applications are pending or may be submitted for avelumab,combination therapies or talazoparib may approve any such applications,which will depend on myriad factors,including making a determination as to whether the product's benefits outweigh its known risks and determination of the product's efficacy,and,if approved,whether they will be commercially successful; decisions by regulatory authorities impacting labeling,safety,manufacturing processes and/or other matters that could affect the availability or commercial potential of avelumab,combination therapies or talazoparib; and competitive developments.

A further description of risks and uncertainties can be found in Pfizer's Annual Report on Form 10-K for the fiscal year ended December 31,2018,and in its subsequent reports on Form 10-Q,including in the sections thereof captioned "Risk Factors" and "Forward-Looking Information and Factors That May Affect Future Results",as well as in its subsequent reports on Form 8-K,all of which are filed with the U.S. Securities and Exchange Commission and available at www.sec.gov and www.pfizer.com.

References

SEER Cancer Stat Facts: Ovarian Cancer. National Cancer Institute. Bethesda,MD,https://seer.cancer.gov/statfacts/html/ovary.html. Accessed March 2019.

Ledermann,JA,Raja FA,Fotopoulou C,et al. Newly diagnosed and relapsed epithelial ovarian carcinoma: ESMO Clinical Practice Guidelines for diagnosis,treatment and follow-up. Ann Oncol. 2013; 24 (Supplement 6): vi24–vi32,doi:10.1093/annonc/mdt333.

Ozol,RJ. Challenges for chemotherapy in ovarian cancer. Ann Oncol. 2006;17(5):v181-187.

Dolan DE,Gupta S. PD-1 pathway inhibitors: changing the landscape of cancer immunotherapy. Cancer Control. 2014;21(3):231-237.

Dahan R,Sega E,Engelhardt J,et al. FcγRs modulate the anti-tumor activity of antibodies targeting the PD-1/PD-L1 axis. Cancer Cell. 2015;28(3):285-295.

Boyerinas B,Jochems C,Fantini M,et al. Antibody-dependent cellular cytotoxicity activity of a novel anti-PD-L1 antibody avelumab (MSB0010718C) on human tumor cells. Cancer Immunol Res. 2015;3(10):1148-1157.

Kohrt HE,Houot R,Marabelle A,et al. Combination strategies to enhance antitumor ADCC. Immunotherapy. 2012;4(5):511-527.

Hamilton G,Rath B. Avelumab: combining immune checkpoint inhibition and antibody-dependent cytotoxicity. Expert Opin Biol Ther. 2017;17(4):515-523.

Your Contacts

Merck

Media Relations:+49-6151-72-6328,friederike.segeberg@merckgroup.com

Investor Relations: +49-6151-72-3321,investor.relations@merckgroup.com

Pfizer

Media Relations: +1-212-733-6213,jessica.m.smith@pfizer.com

Investor Relations: +1-212-733-8160,ryan.crowe@pfizer.com

Photo - http://mma.prnewswire.com/media/611425/Merck_Pfizer_Logo.jpg