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NEWS RELEASE

Clovis Oncology Highlights Rubraca® (rucaparib) Updated Data from the Ongoing TRITON2 Clinical Trial in Patients with mCRPC and Exploratory and Integrated Analyses in Recurrent Ovarian Cancer at the ESMO Congress 2019

9/29/2019

43.9% conrmed objective response rate (ORR) in 57 RECIST * -evaluable patients with metastatic castration- resistant prostate cancer (mCRPC) and a BRCA1/2 mutation

52.0% conrmed prostate-specic antigen (PSA) response in 98 PSA-evaluable patients with mCRPC and a BRCA1/2 mutation

The safety pro le of Rubraca was consistent with prior reports from TRITON2 and for those patients with ovarian cancer and other solid tumors

Supplemental new drug application (NDA) for Rubraca in BRCA1/2-mutant advanced prostate cancer on track for Q4 2019

Clovis Oncology also highlights eCcacy and safety of Rubraca in recurrent ovarian cancer

BOULDER, Colo.--(BUSINESSWIRE)-- Clovis Oncology, Inc. (NASDAQ: CLVS) today announced updated data from the Phase 2 TRITON2 trial at the European Society for Medical Oncology (ESMO) Congress 2019, reinforcing the potential of Rubraca® (rucaparib) for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) with a BRCA1/2 mutation. The data show a 43.9% conCrmed objective response rate (ORR) by investigator assessment in 57 RECIST*/PCWG3** response-evaluable patients with a BRCA1/2 mutation. When assessed by independent radiological review, the response rate was similar (40.4%). In addition, a 52.0% con rmed prostate- speciGc antigen (PSA) response rate was observed in 98 response-evaluable patients with a BRCA1/2 mutation. ConQrmed radiographic responses were durable, with 60 percent lasting 24 weeks or longer (15/25).

The TRITON2 data will be used to support the Dling of Clovis Oncology's planned supplemental NDA to the Food and Drug Administration (FDA) for Rubraca in BRCA1/2-mutant advanced prostate cancer.

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"The updated data from the TRITON2 trial con rm the potential role of rucaparib in treating metastatic castration- resistant prostate cancer," said Wassim Abida, M.D., Medical Oncologist, Memorial Sloan Kettering Cancer Center, and principal investigator for the TRITON2 study. "These data speciGcally demonstrate the eWcacy of rucaparib in eligible mCRPC patients with a BRCA1/2 mutation and reinforce the known safety pro le in this treatment setting, showing it has the potential to oJer clinical bene t to eligible patients."

ConQrmed investigator-assessed RECIST* and PSA responses were also observed in patients with alterations in other DDR genes, including ATM, CDK12, CHEK2, PALB2, BRIP1, FANCA, and RAD51B.

The median duration of follow-up (as of July 2, 2019) for patients in TRITON2 was 13.1 months (range 4.1-28.5 months) with the safety proVle consistent with prior reports. The most common any-gradetreatment-emergent adverse events (TEAE) >20% in the TRITON2 trial were asthenia/fatigue (55.3%), nausea (49.5%), anemia/decreased hemoglobin (37.9%), decreased appetite (27.9%), transient increased aspartate transaminase/alanine aminotransferase (ALT/AST) (24.7%), constipation (24.7%), vomiting (22.1%) and diarrhea (21.1%).

Clovis Oncology is further evaluating the potential of Rubraca to treat advanced prostate cancer in the TRITON3 clinical trial - a multicenter, randomized, open-label Phase 3 study of Rubraca versus physician's choice of therapy - for patients with mCRPC. TRITON3 is currently enrolling patients with BRCA1/2-mutant and ATM-mutant (both inclusive of germline and somatic) tumors with a primary objective of assessing radiographic progression-free survival (PFS) in these patients.

Rubraca in Recurrent Ovarian Cancer

An exploratory data analysis from the pivotal Phase 3 ARIEL3 trial evaluating Rubraca for the maintenance treatment of recurrent ovarian cancer assessed PFS in the subgroups who had achieved a partial response (PR) or complete response (CR) on the most recent platinum regimen. The data show that PFS was longer in patients receiving Rubraca than placebo regardless of whether patients achieved a CR or PR on their last platinum-based regimen. Patients in the intent-to-treat population who received rucaparib treatment had a signi cantly greater reduction in risk for progression or death versus placebo whether they had achieved a CR (hazard ratio of 0.33

[95% CI, 0.23-0.49]; rucaparib, n=126; placebo, n=64) or a PR (hazard ratio of 0.38 [95% CI, 0.30-0.49]; rucaparib, n=249; placebo, n=125) to their last platinum-based therapy. Improvements in investigator-assessed PFS were also demonstrated in patients from the BRCA mutant and BRCA mutant or BRCA wild type/high loss of heterozygosity populations who were treated with Rubraca compared with placebo. The safety proEle in Rubraca-treated patients who had either a CR or PR to their last platinum-based chemotherapy was consistent with that of the ITT population reported. Among patients with residual disease at baseline, conGrmed RECIST responses were seen in a number of patients treated with rucaparib, including 23/104 (22.1%) patients with non-measurable but assessable disease at baseline.

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An integrated analysis of safety data from Study 10, ARIEL2 and ARIEL3 are consistent with the known safety proále of Rubraca in patients with platinum-sensitive, recurrent ovarian cancer, in both the treatment and maintenance settings. The analysis included 937 patients treated with Rubraca in the treatment (Study 10 and ARIEL2, n=565) and maintenance (ARIEL3, n=372) settings. Overall, 102/937 (10.9%) patients discontinued due to any grade treatment- related TEAE (treatment setting: 53/565 [9.4%]); (maintenance setting: 49/372 [13.2%]). The most frequent any grade adverse events leading to discontinuation were asthenia/fatigue (23/937 [2.5%]), anemia/ hemoglobin decreased (20/937 [2.1%]) and thrombocytopenia/platelets decreased (19/937 [2.0%]). The most frequent grade ≥3 treatment-related TEAE leading to discontinuation was anemia/hemoglobin decreased (15/937 [1.6%]) and asthenia/fatigue (7/937 [0.7%]).

"The ARIEL3 data presented at ESMO this year demonstrate that rucaparib contributes to a signi cant increase in progression-free survival over placebo, irrespective of whether a patient had CR or PR to previous platinum-based therapy and provides strong evidence for e cacy in women with recurrent ovarian cancer in the second-line maintenance setting," said Professor Jonathan Ledermann, M.D., Professor of Medical Oncology, UCL Cancer Institute and UCL Hospitals, London, Global Principal Investigator for non-U.S. sites in the ARIEL3 study. "The current data provide physicians with a compelling argument to make maintenance therapy essential for all eligible patients, including women who have had a complete response."

Data from the Study 10, ARIEL2 and ARIEL3 trials supported the approvals of Rubraca for the treatment and maintenance treatment of recurrent ovarian cancer in the U.S. and EU. The European Commission authorization of Rubraca, resulted in Rubraca being the Prst poly (ADP ribose) polymerase (PARP) inhibitor to be approved for both treatment and maintenance treatment among eligible women with ovarian cancer in the EU.

"Rubraca continues to demonstrate meaningful clinical bene t in the recurrent ovarian cancer treatment and maintenance settings, and our updated prostate data are highly consistent with the data presented at ESMO last year," said Patrick J. MahaCy, President and CEO of Clovis Oncology. "We are moving forward with plans to le an sNDA in advanced mCRPC by the end of 2019, and we believe that, similar to its ovarian cancer proGle, Rubraca may o[er an important treatment option for patients with advanced prostate cancer, for whom new options are needed. We are committed to further exploring the potential of Rubraca and look forward to starting the tumor- agnostic study before year-end and furthering our combination studies that are now enrolling patients."

Clovis Oncology's ESMO Rubraca poster presentations are available online at clovisoncology.com.

Clovis Analyst/Investor Event at ESMO Webcast Details

In addition, the Company will present greater detail about its planned sNDA ling and regulatory strategy in mCRPC

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at its Investor/Analyst event today at 6:30pm CEST, which will be webcast live and available via replay from the following link: https://ir.clovisoncology.com/investors-and-news/events-and-presentations/event- details/2019/Investor-Analyst-Presentation-at-ESMO-2019/default.aspx.

About Rubraca® (rucaparib)

Rubraca is an oral, small molecule inhibitor of PARP1, PARP2 and PARP3 that is being developed in multiple tumor types, including ovarian and mCRPC, as monotherapy, and in combination with other anti-cancer agents. Exploratory studies in other tumor types are also underway.

Rubraca U.S. FDA approved indications

Rubraca is indicated as monotherapy for the maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in CR or PR to platinum-based chemotherapy.

Rubraca is indicated as monotherapy for the treatment of adult patients with deleterious BRCA mutations (germline and/or somatic) associated epithelial ovarian, fallopian tube, or primary peritoneal cancer who have been treated with ≥2 chemotherapies and selected for therapy based on an FDA-approved companion diagnostic for Rubraca.

Select important safety information

MDS/AML occurs uncommonly in patients treated with Rubraca, and are potentially fatal adverse reactions. In approximately 1100 treated patients, MDS/AML occurred in 12 patients (1.1%), including those in long-term follow- up. Of these, ve occurred during treatment or during the 28-day safety follow-up (0.5%). The duration of Rubraca treatment prior to the diagnosis of MDS/AML ranged from 1 month to approximately 28 months. The cases were typical of secondary MDS/cancer therapy-related AML; in all cases, patients had received previous platinum- containing regimens and/or other DNA-damaging agents. Do not start Rubraca until patients have recovered from hematological toxicity caused by previous chemotherapy (grade ≥1).

Monitor complete blood counts for cytopenia at baseline and monthly thereafter for clinically signiUcant changes during treatment. For prolonged hematological toxicities (>4 weeks), interrupt Rubraca or reduce dose (see Dosage and Administration [2.2] in full Prescribing Information) and monitor blood counts weekly until recovery. If the levels have not recovered to grade 1 or less after 4 weeks, or if MDS/AML is suspected, refer the patient to a hematologist for further investigations, including bone marrow analysis and blood sample cytogenetic analysis. If MDS/AML is con rmed, discontinue Rubraca.

Based on its mechanism of action and Pndings from animal studies, Rubraca can cause fetal harm when

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administered to a pregnant woman. Apprise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use eVective contraception during treatment and for 6 months following the last dose of Rubraca.

Most common adverse reactions in ARIEL3 (≥20%, grade 1-4) were nausea (76%), fatigue/asthenia (73%), abdominal pain/distention (46%), rash (43%), dysgeusia (40%), anemia (39%), AST/ALT elevation (38%), constipation (37%), vomiting (37%), diarrhea (32%), thrombocytopenia (29%), nasopharyngitis/upper respiratory tract infection (29%), stomatitis (28%), decreased appetite (23%) and neutropenia (20%).

Most common laboratory abnormalities in ARIEL3 (≥25%, grade 1-4) were increase in creatinine (98%), decrease in hemoglobin (88%), increase in cholesterol (84%), increase in ALT (73%), increase in AST (61%), decrease in platelets (44%), decrease in leukocytes (44%), decrease in neutrophils (38%), increase in alkaline phosphatase (37%) and decrease in lymphocytes (29%).

Most common adverse reactions in Study 10 and ARIEL2 (≥20%, grade 1-4) were nausea (77%), asthenia/fatigue (77%), vomiting (46%), anemia (44%), constipation (40%), dysgeusia (39%), decreased appetite (39%), diarrhea (34%), abdominal pain (32%), dyspnea (21%) and thrombocytopenia (21%).

Most common laboratory abnormalities in Study 10 and ARIEL2 (≥35%; grade 1-4) were increase in creatinine (92%), increase in ALT (74%), increase in AST (73%), decrease in hemoglobin (67%), decrease in lymphocytes (45%), increase in cholesterol (40%), decrease in platelets (39%) and decrease in absolute neutrophil count (35%).

Co-administration of Rubraca can increase the systemic exposure of CYP1A2, CYP3A, CYP2C9, or CYP2C19 substrates, which may increase the risk of toxicities of these drugs. Adjust dosage of CYP1A2, CYP3A, CYP2C9, or CYP2C19 substrates, if clinically indicated. If co-administration with warfarin (a CYP2C9 substrate) cannot be avoided, consider increasing frequency of international normalized ratio monitoring. Because of the potential for serious adverse reactions in breast-fed children from Rubraca, advise lactating women not to breastfeed during treatment with Rubraca and for 2 weeks after the last dose. You may report side eHects to the FDA at 1-800-FDA- 1088 or www.fda.gov/medwatch. You may also report side e ects to Clovis Oncology, Inc. at 1-844-258-7662.

Click here for full Prescribing Information and additional important safety information.

Rubraca® (rucaparib) European Union (EU) authorized use and Important Safety Information

Rubraca is indicated as monotherapy for the maintenance treatment of adult patients with platinum-sensitive relapsed high-grade epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in response (complete or partial) to platinum-based chemotherapy.

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