CLVS Clovis Oncology Inc

On December 21, 2020, Clovis Oncology, Inc. (the “Company”) announced topline data from the randomized Phase 3 ARIEL4 study of Rubraca, which met its primary endpoint of improved investigator-assessed progression-free survival (InvPFS) compared to chemotherapy in relapsed ovarian cancer patients with a tumor mutation of BRCA who have received two or more prior lines of chemotherapy.

The ARIEL4 study (NCT02855944) is a Phase 3 multicenter, randomized study evaluating Rubraca versus chemotherapy in platinum-sensitive, partially platinum-sensitive and platinum-resistant patients with relapsed ovarian cancer and a BRCA mutation (inclusive of germline and/or somatic) who have received two or more prior lines of chemotherapy. The primary endpoint of the study is InvPFS, with a step down analysis from the efficacy population (if significant) to the ITT population. The efficacy population comprised the group of patients with a deleterious tumor BRCA mutation and excluded those with a BRCA reversion mutation as determined by a blood test developed by Guardant Health. Development of reversion mutations that restore BRCA protein function are associated with resistance to platinum-based chemotherapies and PARP inhibitors in BRCA-mutant cancers, and these occur more frequently in platinum-resistant vs platinum-sensitive patients (13% and 2% respectively in the ARIEL2 study).

Completion of ARIEL4 is a post-marketing commitment in the U.S. and EU.

349 women were enrolled in North and South America, Europe and Israel. The efficacy population (n=325) comprised the group of patients with a deleterious tumor BRCA mutation and excluded those with a BRCA reversion mutation. The rucaparib arm (n=220) successfully achieved statistical significance over the chemotherapy arm (n=105) for the primary endpoint of InvPFS with a hazard ratio of 0.639 (p=0.0010). The median PFS for the patients in the efficacy population treated with rucaparib was 7.4 months vs. 5.7 months among those who received chemotherapy.

In addition, in the ITT population (n=349), the rucaparib arm (n=233) successfully achieved statistical significance over the chemotherapy arm (n=116) for the primary endpoint of InvPFS with a hazard ratio of 0.665 (p=0.0017). The median PFS for the patients in the ITT population treated with rucaparib was 7.4 months vs. 5.7 months among those who received chemotherapy.

Patients with a BRCA reversion mutation represented 7 percent of patients enrolled in the study and as anticipated, InvPFS results for those patients showed limited benefit from Rubraca therapy.

An interim analysis of overall survival, a secondary endpoint in the study in which 51 percent of events have occurred in the ITT population, showed a trend toward an overall survival (OS) advantage in the chemotherapy arm, but was confounded by the high rate (64%) of per-protocol crossover to Rubraca following progression on chemotherapy. Importantly, an analysis of the ITT population of patients showed a trend toward an OS advantage for those patients who received Rubraca at any point in the trial versus those who did not.

The Company plans to provide an expanded description of the ARIEL4 results at a medical meeting in 2021.

Adverse events were consistent with the known safety profiles of Rubraca and chemotherapy. The most common (>5%) treatment-emergent grade 3/4 adverse events (TEAEs) among all patients treated with rucaparib (n=232) in the ARIEL4 study were anemia/decreased hemoglobin (22%), neutropenia/decreased absolute neutrophil count (10%), asthenia/fatigue (8%), thrombocytopenia/decreased platelets (8%), and increased ALT/AST (8%).

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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.

Most common adverse reactions in ARIEL3 (³ 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 (³ 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%).

To the extent that statements contained in this current report are not descriptions of historical facts regarding the Company, they are forward-looking statements reflecting the current beliefs and expectations of management. Examples of forward-looking statements contained in this current report include, among others, statements regarding our expectations for submission of regulatory filings, the timing and pace of commencement of and enrollment in our clinical trials, including those being planned or conducted in collaboration with partners, the potential results of such clinical trials, our expectations regarding the suitability of Rubraca, and our plans to develop Rubraca in additional indications and tumor types, and our expectations regarding the outcomes of early studies or trials supporting further development, both non-clinical and clinical. 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. The Company does not undertake to update or revise any forward-looking statements. A further description of risks and uncertainties can be found in the Company’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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