AstraZeneca and Merck announced positive results from the Phase 3 PROpel trial, in which LYNPARZA in combination with abiraterone and prednisone demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of radiographic progression-free survival (rPFS) versus abiraterone plus prednisone as a first-line treatment for men with metastatic castration-resistant prostate cancer (mCRPC) with or without homologous recombination repair (HRR) gene mutations. At a planned interim analysis, the Independent Data Monitoring Committee concluded that the trial met the primary endpoint of rPFS in men with mCRPC who had not received treatment in the first-line setting, including new hormonal agents (NHAs) or chemotherapy. The trial also showed a trend at this interim analysis towards improved overall survival (OS). However, the OS data are still immature, and the trial will continue to assess OS as a key secondary endpoint. The safety and tolerability were consistent with the known profiles of each medicine and will continue to be assessed. Globally, prostate cancer is the second most common cancer in men, with an estimated 1.4 million patients diagnosed worldwide in 2020. Approximately 10-20% of men with advanced prostate cancer are estimated to develop CRPC within five years, and at least 84% of these men may develop metastases at the time of CRPC diagnosis. The data will be presented at an upcoming medical meeting. PROpel is a randomized, double-blind, multicenter Phase 3 trial testing the efficacy, safety and tolerability of LYNPARZA versus placebo when given in addition to abiraterone in men with mCRPC who had not received prior chemotherapy or NHAs in the first-line setting. Patients in both treatment groups also received either prednisone or prednisolone (5 mg twice daily). The primary endpoint is rPFS, and secondary endpoints include OS and time to first subsequent anticancer therapy or death. The trial enrolled men with or without HRR gene mutations. They may have previously been treated with docetaxel at a prior stage of disease. The trial excluded men with prior treatment with abiraterone. Treatment with any other NHA must have been stopped one year or longer prior to randomization. Men must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 and be a candidate for abiraterone treatment with documented evidence of progressive disease. There are no contraindications for LYNPARZA. Myelodysplastic Syndrome/Acute Myeloid Leukemia (MDS/AML): Occurred in approximately 1.5% of patients exposed to LYNPARZA monotherapy, and the majority of events had a fatal outcome. The median duration of therapy in patients who developed MDS/AML was 2 years (range: 10 years). All of these patients had previous chemotherapy with platinum agents and/or other DNA-damaging agents, including radiotherapy. Do not start LYNPARZA until patients have recovered from hematological toxicity caused by previous chemotherapy (=Grade 1). Monitor complete blood count for cytopenia at baseline and monthly thereafter for clinically significant changes during treatment. For prolonged hematological toxicities, interrupt LYNPARZA and monitor blood count weekly until recovery. If the levels have not recovered to Grade 1 or less after 4 weeks, refer the patient to a hematologist for further investigations, including bone marrow analysis and blood sample for cytogenetics. Discontinue LYNPARZA if MDS/AML is confirmed. Pneumonitis: Occurred in 0.8% of patients exposed to LYNPARZA monotherapy, and some cases were fatal. If patients present with new or worsening respiratory symptoms such as dyspnea, cough, and fever, or a radiological abnormality occurs, interrupt LYNPARZA treatment and initiate prompt investigation. Discontinue LYNPARZA if pneumonitis is confirmed and treat patient appropriately. Embryo-Fetal Toxicity: Based on its mechanism of action and findings in animals, LYNPARZA can cause fetal harm. A pregnancy test is recommended for females of reproductive potential prior to initiating treatment. Females - Advise females of reproductive potential of the potential risk to a fetus and to use effective contraception during treatment and for 6 months following the last dose. Males - Advise male patients with female partners of reproductive potential or who are pregnant to use effective contraception during treatment and for 3 months following the last dose of LYNPARZA and to not donate sperm during this time. Venous Thromboembolic Events: Including pulmonary embolism, occurred in 7% of patients with metastatic castration-resistant prostate cancer who received LYNPARZA plus androgen deprivation therapy (ADT) compared to 3.1% of patients receiving enzalutamide or abiraterone plus ADT in the PROfound study. Patients receiving LYNPARZA and ADT had a 6% incidence of pulmonary embolism compared to 0.8% of patients treated with ADT plus either enzalutamide or abiraterone. Monitor patients for signs and symptoms of venous thrombosis and pulmonary embolism, and treat as medically appropriate, which may include long-term anticoagulation as clinically indicated.