Clovis Oncology’s Rubraca® (Rucaparib) Significantly Improves Progression-Free Survival in First-line Maintenance Treatment in Women with Ovarian Cancer Regardless of Their Biomarker Status in Phase 3 ATHENA-MONO Trial

Clovis Oncology, Inc. (NASDAQ: CLVS) today announced positive top-line data from the monotherapy arm of the ATHENA (GOG 3020/ENGOT-ov45) trial (ATHENA-MONO) demonstrating that Rubraca as maintenance treatment successfully achieved the primary endpoint of significantly improved investigator-assessed progression-free survival (PFS) compared with placebo. Benefit was observed in both primary efficacy analyses of newly-diagnosed patients with advanced ovarian cancer following successful treatment with platinum-based chemotherapy: those who had homologous recombination deficiency (HRD-positive)¹, including deleterious BRCA mutations, as well as all patients randomized in the trial (overall intent-to-treat population (ITT)). Benefit in PFS was also seen in the exploratory subgroups of patients with HRD-negative² and BRCA mutant (BRCAm) tumors. The safety of Rubraca observed in the ATHENA-MONO study was consistent with both the US and European labels.

Based on these results, the Company plans to submit a supplemental New Drug Application (sNDA) to the US FDA during the second quarter of 2022 followed by a Type II Variation to the EMA during the third quarter of 2022 for a first-line maintenance treatment indication for women with advanced ovarian cancer regardless of biomarker status who have responded to first-line platinum-based chemotherapy.

“The results from the ATHENA-MONO study of Rubraca in first-line maintenance treatment ovarian cancer exceeded our expectations in terms of significant improvement in PFS versus placebo in each of the primary efficacy populations, including the all-comers or intent-to-treat population,” said Patrick J. Mahaffy, President and CEO of Clovis Oncology. “We believe that the positive results from ATHENA-MONO demonstrate that Rubraca will provide an important new treatment option for women with advanced ovarian cancer in the first-line maintenance setting, and we look forward to submitting these data to the regulatory authorities in the US and Europe during Q2 and Q3 2022, respectively. Most importantly, I would like to thank the patients, physicians, and our colleagues whose commitment to this trial made these results possible, which now offer the potential to make a difference in the lives of many women with advanced ovarian cancer. We would also like to thank GOG and ENGOT for their partnership in conducting this large and very important trial.”

“While PARP inhibitors have shown efficacy as first-line maintenance treatment for patients with advanced ovarian cancer, questions still remain about the patient population that may benefit from their use. The results of ATHENA-MONO address many of these unanswered questions and expands the opportunity for rucaparib in all patients regardless of biomarker status,” said Bradley J. Monk, MD, FACOG, FACS, at GOG Foundation, HonorHealth Research Institute, University of Arizona College of Medicine, Creighton University School of Medicine, Phoenix, AZ and global primary investigator of the ATHENA trial.

“I believe the significant improvement in PFS demonstrated in the ATHENA-MONO trial underscores the importance of first-line maintenance therapy and the benefit that rucaparib can provide to women with advanced ovarian cancer irrespective of HRD status,” said Rebecca S. Kristeleit, MD, PhD, of Guy’s and St Thomas’ NHS Foundation Trust in London and lead ENGOT/NCRI National Cancer Research Institute (https://www.ncri.org.uk/) investigator of the ATHENA trial. “Ovarian cancer remains a leading cause of cancer-related death among women, which highlights the continued need for new treatment options and strategies for women with newly-diagnosed disease. The ATHENA-MONO study demonstrates the role of rucaparib monotherapy in the first-line maintenance treatment setting for advanced ovarian cancer.”

ATHENA is a double-blind, placebo-controlled, Phase 3 trial of rucaparib in first-line ovarian cancer maintenance treatment. It has two parts which are statistically independent. The top-line results reported today are from the ATHENA-MONO part (rucaparib vs placebo) with results from the ATHENA-COMBO part (rucaparib+nivolumab vs rucaparib) now expected in Q1 2023 based on a slower than expected event count.

ATHENA-MONO enrolled 538 women with high-grade ovarian, fallopian tube, or primary peritoneal cancer. The primary efficacy analysis evaluated two prospectively defined molecular sub-groups in a step-down manner: 1) HRD-positive (inclusive of BRCAm tumors), and 2) all patients randomized (ITT) in ATHENA-MONO.

Following is a summary of the primary efficacy analyses by investigator review, the primary analysis of ATHENA-MONO.

Significant Improvement in PFS in the HRD-positive Patient Population

By investigator review, the rucaparib arm (n=185) successfully achieved statistical significance over the placebo arm (n=49) for the primary endpoint of PFS with a hazard ratio of 0.47 (95% CI: 0.31-0.72). The median PFS for the HRD-positive patient population treated with rucaparib was 28.7 months vs 11.3 months among those who received placebo (p=0.0004).

Significant Improvement in PFS in All Patients Studied (ITT or all comers)

Rucaparib also showed statistical significance in all 538 patients randomized in the ATHENA-MONO comparison. By investigator review, the rucaparib arm (n=427) successfully achieved statistical significance over the placebo arm (n=111) for the primary endpoint of PFS with a hazard ratio of 0.52 (95% CI: 0.40-0.68). The median PFS for all patients enrolled in ATHENA-MONO and treated with rucaparib was 20.2 months vs 9.2 months among those who received placebo (p<0.0001).

Treatment Benefit in PFS Endpoint for Exploratory HRD-negative Subgroup

By investigator review, the PFS endpoint in the exploratory subgroup of HRD-negative demonstrated a hazard ratio of 0.65 (95% CI: 0.45-0.95). The median PFS for these patients treated with rucaparib (n=189) was 12.1 months vs. 9.1 months for those who received placebo (n=49) (p=0.0284).

Treatment Benefit in PFS Endpoint for Exploratory BRCAm Subgroup

By investigator review, the PFS endpoint in the exploratory subgroup of BRCAm demonstrated a hazard ratio of 0.40 (95% CI: 0.21-0.75). The median PFS for these patients treated with rucaparib (n=91) was Not Reached vs 14.7 months for those who received placebo (n=24) (p=0.0041).

Results were consistent for the germline BRCA (n=68) and somatic BRCA (n=33) and unknown (n=14) populations.

Summary of ATHENA-MONO Safety

The safety of Rubraca observed in ATHENA-MONO was consistent with both the current US and European labels. The most common (≥5%) treatment-emergent grade 3/4 adverse events (TEAEs) among all patients treated with rucaparib in the monotherapy portion of the ATHENA study were anemia/decreased hemoglobin (28.7%), neutropenia (14.6%), ALT/AST increase (10.6%), and thrombocytopenia (7.1%). The discontinuation rate for TEAEs was 11.8% for rucaparib-treated patients and 5.5% for the placebo arm. The rate of treatment-emergent myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) in the rucaparib arm was 0.2%, and no patients on the placebo arm experienced treatment-emergent MDS/AML.

Clovis Oncology plans to provide an expanded description of the ATHENA-MONO results in a scientific session at a medical meeting later this year; these data have been submitted for presentation at the American Society of Clinical Oncology Annual Meeting in June 2022.

Rubraca is not currently approved in the first-line ovarian cancer maintenance setting. Clovis intends to provide these data to US and European regulatory authorities and is on track to submit filings during the second and third quarters of 2022, respectively, in those geographies.

Conference Call Details

Clovis will hold a conference call to discuss the ATHENA-MONO results this morning, March 31, at 8:30am ET. The conference call will be simultaneously webcast on the Company’s web site at www.clovisoncology.com, and archived for future review. Dial-in numbers for the conference call are as follows: US participants 888.440.4615, International participants 646.960.0682, conference ID: 2259685.

About the ATHENA Clinical Trial

ATHENA (GOG 3020/ENGOT-ov45) (NCT03522246) is an international, randomized, double-blind, phase III trial consisting of two separate and fully independently powered study comparisons evaluating Rubraca monotherapy (ATHENA-MONO) and Rubraca in combination with nivolumab (ATHENA-COMBO) as maintenance treatment for patients with newly diagnosed advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer. ATHENA enrolled approximately 1000 patients across 24 countries, all women with newly diagnosed ovarian cancer who responded to their first-line chemotherapy. The trial completed accrual in 2020 and was conducted in association with the Gynecologic Oncology Group (GOG) in the US and the European Network of Gynaecological Oncological Trial groups (ENGOT) in Europe. GOG and ENGOT are the two largest cooperative groups in the US and Europe dedicated to the treatment of gynecological cancers.

ATHENA-MONO is evaluating the benefit of Rubraca monotherapy versus placebo in 538 women in this patient population. The primary efficacy analysis evaluated two prospectively defined molecular sub-groups in a step-down manner: 1) HRD-positive (inclusive of BRCA mutant) tumors, and 2) the intent-to-treat population, or all patients treated in ATHENA-MONO.

The ATHENA-COMBO portion of the trial, anticipated to readout in Q1 2023, is evaluating the magnitude of benefit of adding Opdivo (nivolumab) to Rubraca monotherapy in the ovarian cancer first-line maintenance treatment setting. ATHENA-COMBO is anticipated to be the first Phase 3 dataset to readout evaluating the combination of a PARP inhibitor and an immune checkpoint inhibitor as maintenance treatment following completion and response to front-line chemotherapy.

About Ovarian Cancer

Ovarian cancer is the eighth leading cause of cancer-related death among women worldwide. In 2020, GLOBOCAN estimated 314,000 women received a new diagnosis of ovarian cancer and approximately 207,200 women died from ovarian cancer. According to the American Cancer Society, an estimated more than 19,000 women will be diagnosed with ovarian cancer in the United States and there will be an estimated nearly 13,000 deaths from ovarian cancer in 2022. According to GLOBOCAN, an estimated 66,000 women in Europe are diagnosed each year with ovarian cancer, and ovarian cancer is among those cancers with the highest rate of deaths. According to the NIH National Cancer Institute, more than 75% of women are diagnosed with ovarian cancer at an advanced stage.

Despite recent advances in the therapeutic landscape of newly diagnosed ovarian cancer, advanced ovarian cancer is still considered incurable for the majority of patients, and the optimal treatment strategy has yet to be determined.ⁱ Although most respond initially to this treatment, 80% of patients with advanced ovarian cancer will have a recurrence and require subsequent therapies.ⁱⁱ

About Biomarkers in Ovarian Cancer

In the high-grade epithelial ovarian cancer setting, a patient’s tumor can be classified based on the genetic biomarker status: those with homologous recombination deficiencies, or HRD-positive, include those with a mutation of the BRCA gene (BRCAm), inclusive of germline and somatic mutations of BRCA, which represent approximately 25 percent of patients^iii,iv; and those with a range of genetic abnormalities other than BRCAm, which result in other homologous recombination deficiencies that represent an additional estimated 25 percent of patients (HRD-positive, BRCAwt)^v; in addition, those whose test results show no deficiencies in homologous recombination repair (HRD-negative) represent the remaining approximate 50 percent of patients.^vi

About Rubraca (rucaparib)

Rucaparib is an oral, small molecule inhibitor of PARP1, PARP2 and PARP3 being developed in multiple tumor types, including ovarian and metastatic castration-resistant prostate cancers, as monotherapy, and in combination with other anti-cancer agents. Exploratory studies in other tumor types are also underway.

Rubraca is an unlicensed medical product outside of the US and Europe.

Rubraca Ovarian Cancer US FDA Approved Indications

Rubraca is indicated for the maintenance treatment of adult women with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy.

Rubraca is indicated for the treatment of adult women with a deleterious BRCA mutation (germline and/or somatic)-associated epithelial ovarian, fallopian tube, or primary peritoneal cancer who have been treated with two or more chemotherapies. Select patients for therapy based on an FDA-approved companion diagnostic for Rubraca.

Select Important Safety Information

Myelodysplastic Syndrome (MDS)/Acute Myeloid Leukemia (AML) have occurred in patients treated with Rubraca, and are potentially fatal adverse reactions. In 1146 treated patients, MDS/AML occurred in 20 patients (1.7%), including those in long term follow-up. Of these, 8 occurred during treatment or during the 28 day safety follow-up (0.7%). The duration of Rubraca treatment prior to the diagnosis of MDS/AML ranged from 1 month to approximately 53 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 significant changes during treatment. For prolonged hematological toxicities (> 4 weeks), interrupt Rubraca or reduce dose 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 for cytogenetics. If MDS/AML is confirmed, discontinue Rubraca.

Based on its mechanism of action and findings from animal studies, Rubraca can cause fetal harm when administered to a pregnant woman. Apprise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use effective 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 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%).

Co-administration of rucaparib 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 (INR) 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.

Please Click here for full Prescribing Information for Rubraca.

You may also report side effects to Clovis Oncology, Inc. at 1-415-409-7220 (US toll) or 1-844-CLVS-ONC (1-844-258-7662; US toll-free).

Rubraca (rucaparib) European Union (EU) including Northern Ireland, and Great Britain (GB) 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.

Rubraca is indicated as monotherapy treatment of adult patients with platinum sensitive, relapsed or progressive, BRCA mutated (germline and/or somatic), high-grade epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have been treated with ≥2 prior lines of platinum-based chemotherapy, and who are unable to tolerate further platinum-based chemotherapy.

Efficacy of Rubraca as treatment for relapsed or progressive epithelial ovarian cancer (EOC), fallopian tube cancer (FTC), or primary peritoneal cancer (PPC) has not been investigated in patients who have received prior treatment with a PARP inhibitor. Therefore, use in this patient population is not recommended.

Summary warnings and precautions:

Hematological toxicity

During treatment with Rubraca, events of myelosuppression (anemia, neutropenia, thrombocytopenia) may be observed and are typically first observed after 8–10 weeks of treatment with Rubraca. These reactions are manageable with routine medical treatment and/or dose adjustment for more severe cases. Complete blood count testing prior to starting treatment with Rubraca, and monthly thereafter, is advised. Patients should not start Rubraca treatment until they have recovered from hematological toxicities caused by previous chemotherapy (CTCAE grade ≥1).

Supportive care and institutional guidelines should be implemented for the management of low blood counts for the treatment of anemia and neutropenia. Rubraca should be interrupted or dose reduced according to Table 1 (see Posology and Method of Administration [4.2] of the Summary of Product Characteristics [SPC]) and blood counts monitored weekly until recovery. If the levels have not recovered to CTCAE grade 1 or better after 4 weeks, the patient should be referred to a hematologist for further investigations.

MDS/AML

MDS/AML, including cases with fatal outcome, have been reported in patients who received Rubraca. The duration of therapy with Rubraca in patients who developed MDS/AML varied from less than 1 month to approximately 28 months.

If MDS/AML is suspected, the patient should be referred to a hematologist for further investigations, including bone marrow analysis and blood sampling for cytogenetics. If, following investigation for prolonged hematological toxicity, MDS/AML is confirmed, Rubraca should be discontinued.

Photosensitivity

Photosensitivity has been observed in patients treated with Rubraca. Patients should avoid spending time in direct sunlight because they may burn more easily during Rubraca treatment; when outdoors, patients should wear a hat and protective clothing, and use sunscreen and lip balm with sun protection factor of 50 or greater.

Gastrointestinal toxicities

Gastrointestinal toxicities (nausea and vomiting) are frequently reported with Rubraca and are generally low grade (CTCAE grade 1 or 2) and may be managed with dose reduction (refer to Posology and Method of Administration [4.2], Table 1 of the SPC) or interruption. Antiemetics, such as 5-HT3 antagonists, dexamethasone, aprepitant and fosaprepitant, can be used as treatment for nausea/vomiting and may also be considered for prophylactic (i.e. preventative) use prior to starting Rubraca. It is important to proactively manage these events to avoid prolonged or more severe events of nausea/vomiting which have the potential to lead to complications such as dehydration or hospitalization.

Embryofetal toxicity

Rubraca can cause fetal harm when administered to a pregnant woman based on its mechanism of action and findings from animal studies. In an animal reproduction study, administration of Rubraca to pregnant rats during the period of organogenesis resulted in embryo-fetal toxicity at exposures below those in patients receiving the recommended human dose of 600 mg twice daily (see Preclinical Safety Data [5.3] of the SPC).

Pregnancy/contraception

Pregnant women should be informed of the potential risk to a fetus. Women of reproductive potential should be advised to use effective contraception during treatment and for 6 months following the last dose of Rubraca (see section 4.6 of the SPC). A pregnancy test before initiating treatment is recommended in women of reproductive potential.

Click here to access the current EU SmPC (including for Northern Ireland). Click here to access the current GB SmPC.

Healthcare professionals should report any suspected adverse reactions via their national reporting systems.

About Clovis Oncology

Clovis Oncology, Inc. is a biopharmaceutical company focused on acquiring, developing, and commercializing innovative anti-cancer agents in the US, Europe, and additional international markets. Clovis Oncology targets development programs at specific subsets of cancer populations, and simultaneously develops, with partners, for those indications that require them, diagnostic tools intended to direct a compound in development to the population that is most likely to benefit from its use. Clovis Oncology is headquartered in Boulder, Colorado, with additional office locations in the US and Europe. Please visit www.clovisoncology.com for more information.

To the extent that statements contained in this press release are not descriptions of historical facts regarding Clovis Oncology, 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. Examples of forward-looking statements contained in this press release include, among others, statements regarding our expectations concerning future regulatory activities, expectations for submission of regulatory filings, our plans to present final or interim data on ongoing clinical trials, our plans to submit additional data to, or meet with, the FDA with respect to the status of or plans for ongoing or planned trials, the timing and pace of commencement of enrollment in and conduct of our clinical trials, the potential results of such clinical trials and the potential for marketing authorizations for new indications, our expectations regarding the suitability of Rubraca, and our plans to develop Rubraca in additional indications and tumor types. Such forward-looking statements involve substantial risks and uncertainties that could cause our future results, performance or achievements to differ significantly from that expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in our clinical development programs for our drug candidates and those of our partners, whether future study results will be consistent with study findings to date, the timing of availability of data from our clinical trials and the initiation, enrollment, timing and results of our planned clinical trials and the corresponding development pathways, effectiveness and suitability of diagnostic tests, the risk that final results of ongoing trials may differ from initial or interim results as a result of factors such as final results from a larger patient population may be different from initial or interim results from a smaller patient population, the risk that additional pre-clinical or clinical studies may not support further development in certain additional indications or tumor types, and actions by the FDA, the EMA or other regulatory authorities regarding data required to support drug applications and whether to approve drug applications. Clovis Oncology does not undertake to update or revise any forward-looking statements. A further description of risks and uncertainties can be found in Clovis Oncology’s filings with the Securities and Exchange Commission, including its Annual Report on Form 10-K and its reports on Form 10-Q and Form 8-K.

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¹ HRD-positive may also be referred to as HR-deficient, HRD, HRD+, HRd, or biomarker positive

² HRD-negative may also be referred to as HR-proficient, HRD-, HRp, or biomarker negative

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ⁱ Monk BJ et al. ATHENA (GOG-3020/ENGOT-ov45): a randomized, phase III trial to evaluate rucaparib as monotherapy (ATHENA–MONO) and rucaparib in combination with nivolumab (ATHENA–COMBO) as maintenance treatment following frontline platinum-based chemotherapy in ovarian cancer. Int J Gynecol Cancer. 2021;0:1–6.

ⁱⁱ Hanker LC et al. The impact of second to sixth line therapy on survival of relapsed ovarian cancer after primary taxane/platinum-based therapy. Ann Oncol. 2012;23(10):2605-2612. doi:10.1093/annonc/mds203.

ⁱⁱⁱ Pal T, Permuth-Wey J, Betts JA, et al. BRCA1 and BRCA2 mutations account for a large proportion of ovarian carcinoma cases. Cancer. 2005;104(12):2807-2816.

^iv Pennington KP, Walsh T, Harrell MI, et al. Germline and somatic mutations in homologous recombination genes predict platinum response and survival in ovarian, fallopian tube, and peritoneal carcinomas. Clin Cancer Res. 2014;20(3):764-775.

^v Konstantinopoulos PA, Ceccaldi R, Shapiro GI, D’Andrea AD. Homologous recombination deficiency: exploiting the fundamental vulnerability of ovarian cancer. Cancer Discov. 2015;5(11):1137-1154

^vi Quesada S, Fabbro M, Jerome Solassol. Toward more comprehensive homologous recombination deficiency assays in ovarian cancer part 2: medical perspectives, Cancers. 2022; 14, 1098.

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Contact information

Clovis Investor Contacts:
Anna Sussman, 303.625.5022
asussman@clovisoncology.com
or
Breanna Burkart, 303.625.5023
bburkart@clovisoncology.com

Clovis Media Contacts:
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Lisa Guiterman, 301.347.7964
clovismedia@clovisoncology.com
Europe
Jake Davis, +44 (0) 20.3946.3538
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