KEY TAKEAWAYS
- The phase II interventional study aimed to evaluate the combined efficacy of the relugolix + Apa in maintaining castrate T level.
- Pts with HR-LPC received a loading dose of relugolix followed by a standard dose of relugolix + apalutamide for 28 days. T levels were measured every 3 months.
- The study concluded that relugolix + Apa maintained castrate T levels and allowed T recovery within 30 days of discontinuation.
Androgen deprivation therapy (ADT) is a cornerstone treatment for prostate cancer (PC). Researchers aimed to determine the efficacy of the relugolix + apalutamide (Apa) combination in maintaining castrate testosterone (T) levels for 1 year.
Around 12 patients (pts) with HR-LPC received a loading dose of relugolix (360 mg) on Day -14, followed by the standard dose (120 mg/d) for 13 days. From Day 1, they were given relugolix + Apa (240 mg/d) for 28 days. The substudy concluded on Day 28, and pts continued with relugolix + Apa for 1 year in the main study. T levels (castrate level defined as < 50 ng/dL) were measured at baseline (Day -14), Day 1, Day 28, and every 3 months thereafter.
Of 12 pts, 1 withdrew, and another withdrew due to noncompliance but continued castration therapy. Among the 10 pts who completed therapy, 100% maintained castration during one year of concomitant therapy with relugolix + Apa. No dose modification of relugolix was needed. After one year of treatment, the median T level was 10.0 ng/dL. After treatment discontinuation, 8 out of 10 pts (80%) experienced T recovery (T ≥ 50 ng/dL) one month later. All 12 pts (100%) experienced treatment-emergent adverse events (TEAEs), consistent with the known safety profiles of each drug administered separately.
The study found that after 12 months of relugolix + Apa treatment, all pts maintained castrate T levels without dose changes. Almost all pts (except 2) had T recovery within 30 days after stopping therapy. The data supported long-term T suppression with standard doses of relugolix + Apa. Further T-level analysis will be reported later.
Source: https://meetings.asco.org/abstracts-presentations/223296
Clinical Trial: https://www.clinicaltrials.gov/study/NCT04523207
Gordon Brown, Laurence Belkoff, Jason Hafron, Pankaj Aggarwal, Rushikesh Potdar, Amitabha Bhaumik, Jennifer Phillips, Tracy McGowan, and Neal D. Shore. DOI: 10.1200/JCO.2023.41.16_suppl.e17094 Journal of Clinical Oncology 41, no. 16_suppl (June 01, 2023) e17094-e17094.
