Clovis Oncology, Inc. (NASDAQ: CLVS) today announced the presentation of data from the TRITON3 Phase 3 trial in men with metastatic castration-resistant prostate cancer with BRCA or ATM mutations. The presentation titled, “TRITON3: A Phase 3 Study of Rucaparib vs. Physician’s Choice of Therapy in mCRPC Associated with Homologous Recombination Deficiency (HRD)” is being presented by Alan H. Bryce, MD, chair of the Division of Hematology and Medical Oncology at the Mayo Clinic and co-principal investigator of the TRITON3 trial during the session titled, “Novel Clinical Trial Updates” at the 29th Annual Prostate Cancer Foundation (PCF) Scientific Retreat.
The presentation is available at https://clovisoncology.com/pipeline/scientific-presentations/.
“We believe that the positive results from TRITON3 further demonstrate the important role that Rubraca may play as a treatment option for men with metastatic castration-resistant prostate cancer associated with homologous recombination deficiency. This is the first and only PARP inhibitor that has demonstrated superior radiographic PFS compared to a control arm containing docetaxel chemotherapy, which is today the standard of care for these patients,” said Patrick J. Mahaffy, President and CEO of Clovis Oncology. “We look forward to submitting additional data for presentation during a medical meeting in 2023.”
Earlier this month, the Company reported top-line data from the TRITON3 (NCT02975934) study evaluating Rubraca monotherapy versus chemotherapy or second-line second-generation androgen pathway inhibitor in patients with chemotherapy-naive mCRPC with mutations in BRCA or ATM achieved the primary endpoint of improved radiographic progression-free survival (rPFS) by independent radiology review (IRR).
About the TRITON3 Clinical Trial
TRITON3 (NCT02975934) is a Phase 3, multicenter, open-label, randomized trial of Rubraca in patients with chemotherapy-naïve mCRPC. Patients with a mutation in BRCA or ATM were randomized to Rubraca or the control group, which consisted of physician’s choice of docetaxel, abiraterone acetate, or enzalutamide. The primary objective was efficacy, as analyzed by independent radiology review (IRR) of radiographic progression-free survival (rPFS) in patients with mutations in BRCA1, BRCA2 or ATM. TRITON3 was designed as a Phase 3 trial to confirm and expand the efficacy data from TRITON2 in an earlier treatment setting against a relevant control arm.
About Prostate Cancer
The American Cancer Society estimates that approximately 268,000 men in the US will be diagnosed with prostate cancer in 2022, and the GLOBOCAN Cancer Fact Sheets estimated that approximately 473,000 men in Europe were diagnosed with prostate cancer in 2020. Castrate-resistant prostate cancer has a high likelihood of developing metastases. Metastatic castrate-resistant prostate cancer (mCRPC) is an incurable disease, usually associated with poor prognosis.i Approximately 43,000 men in the US were expected to be diagnosed with mCRPC in 2020.ii According to the National Cancer Institute, the five-year survival rate for mCRPC is approximately 30%. BRCA1, BRCA2 or ATM mutations have been detected in approximately 19% of patients with mCRPC according to articles published in JCO Precision Oncology in 2017 and in Clinical Cancer Research in 2021. These molecular markers may be used to select patients for treatment with a PARP inhibitor.iii
About Rubraca (rucaparib)
Rubraca 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 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 patients with a deleterious BRCA mutation (germline and/or somatic)-associated metastatic castration-resistant prostate cancer (mCRPC) who have been treated with androgen receptor-directed therapy and a taxane-based chemotherapy. This indication is approved under accelerated approval based on objective response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials.
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. In TRITON2, MDS/AML was not observed in patients with mCRPC (n=209) regardless of homologous recombination deficiency (HRD) mutation.
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. For males on Rubraca treatment who have female partners of reproductive potential or who are pregnant, effective contraception should be used during treatment and for 3 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 TRITON2 (≥ 20%; Grade 1-4) were fatigue/asthenia (62%), nausea (52%), anemia (43%), AST/ALT elevation (33%), decreased appetite (28%), rash (27%), constipation (27%), thrombocytopenia (25%), vomiting (22%), and diarrhea (20%).
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.
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).
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 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, including that of secondary endpoints such as overall survival, and the maturity of such data, 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.
i Sumanasuriya S. and Bono J., Treatment of Advanced Prostate Cancer—A Review of Current Therapies and Future Promise, Cold Spring Harb Perspect Med, 2018, June; 8(6); a030635.
ii Scher H. et al, Prevalence of Prostate Cancer Clinical States and Mortality in the United States: Estimates Using a Dynamic Progression Model, PLoS One, 2015; 10(10)
iii Congregado B., PARP Inhibitors: A New Horizon for Patients with Prostate Cancer, Biomedicines, 2022 Jun; 10 (6)