3380 - Effectiveness and Safety of Relugolix in Patients With Advanced Prostate Cancer Receiving Radiation Therapy: 6-Month Subgroup Analysis of the OPTYX Study
Presenter(s)
D. E. Spratt1, T. B. Dorff2, B. Lowentritt3, A. E. Ross4, M. Cole5, A. Kavati6, C. Lickert5, Y. Zhong5, M. Ryan6, and R. R. Mckay7; 1University Hospitals Seidman Cancer Center, Case Western Reserve University, Cleveland, OH, 2City of Hope National Medical Center, Duarte, CA, 3Chesapeake Urology, Towson, MD, 4Northwestern University Feinberg School of Medicine, Chicago, IL, 5Sumitomo Pharma America, Inc., Marlborough, MA, 6Pfizer, Inc., New York, NY, 7University of California, San Diego, La Jolla, CA
Purpose/Objective(s): Limited data exist on use of relugolix, an oral androgen deprivation therapy approved in the US for the treatment of advanced prostate cancer (PC), with concomitant radiation therapy (RT) in real-world clinical practice. OPTYX (NCT05467176) is an ongoing multicenter, observational study of relugolix treatment in a real-world setting. We report effectiveness and safety data from baseline through 6 months in a subgroup of patients initiating RT with concurrent relugolix.
Materials/Methods: Men with PC were enrolled in OPTYX if they initiated relugolix =1 month prior to study enrollment and intended to remain on relugolix for =4 months. Testosterone suppression, serious adverse events (SAEs), and adherence (via Simplified Medication Adherence Questionnaire) were assessed in patients initiating RT concurrent with relugolix, defined as men starting a course of RT ±90 days of the first relugolix dose. All patients with =1 dose of relugolix and =6 months of data after enrollment were assessed. The study is ongoing, and data will be collected for a minimum of 2 years with no mandatory study visits required.
Results: In total, 999 patients were enrolled in OPTYX; 345 (34.5%) received RT concurrent with relugolix. RT was received within 90 days before and after initiating relugolix in 37 and 310 men, respectively (2 men received RT before and after). For men receiving RT and relugolix, median age was 70.0 years; 13.6% were Black, and 1.4% were Asian. At baseline, 71.3% men had local or locally advanced PC, 13.0% had metastatic PC, 12.5% had biochemical recurrence, and 0.9% had nonmetastatic castration-resistant PC. Types of RT included external beam RT (EBRT, 79.1%), brachytherapy (2.3%), both EBRT and brachytherapy (5.2%), or other (8.7%). Mean (SD) duration of relugolix therapy was 294.7 (159.3) days. Of patients with available testosterone data at 1 month (earliest timepoint assessed), 83.3% (55/66) achieved castrate testosterone levels (<50 ng/dL), and 51.5% (34/66) achieved profound castrate testosterone levels (<20 ng/dL). Of patients assessed at 6 months, 95.0% (95/100) achieved castrate testosterone levels, and 61.0% (61/100) achieved profound castrate testosterone levels. SAEs were reported in 2.3% (n=8) of patients. One patient experienced a cardiovascular-related SAE considered related to relugolix treatment. Patient adherence was high at 6 months, with 99.0% (192/194) of patients reporting taking relugolix at the appropriate time each day and 80.4% (156/194) reporting never forgetting to take relugolix.
Conclusion: In this 6-month subgroup analysis of the real-world OPTYX study, concurrent treatment with RT and relugolix was associated with testosterone suppression to castrate levels, low rates of SAEs, and high adherence at 6 months in patients with PC. This study is ongoing, and additional analyses are planned.