A prospective, randomized, cross-over trial to assess patient preference for goserelin microsphere versus goserelin implant in prostate cancer: Interim results of the GOMIMP study.

130 Background: Androgen deprivation therapy (ADT), particularly gonadotropin-releasing hormone (GnRH) agonists like goserelin, remains a cornerstone in prostate cancer management. While the goserelin implant (Zoladex 3.6 mg) requires subcutaneous administration via a 16G needle (1.6 mm outer diameter) every 28 days, the goserelin microsphere formulation (LY01005 3.6 mg) is administered intramuscularly using a narrower 21G needle (0.8 mm outer diameter) at the same interval. Although phase III data (NCT04563936) confirmed comparable efficacy and safety between these formulations, patient preference remains unexplored. This GOMIMP study evaluates patient preference for the two formulations of goserelin. Methods: In this ongoing crossover trial (NCT06385847), 60 prostate cancer patients are randomized 1:1 to receive either goserelin implant (s.c., 3.6 mg every 28 days for 2 cycles) followed by goserelin microsphere (i.m., 3.6 mg every 28 days for 2 cycles) Arm 1, or vice versa Arm 2. The primary endpoint is patient preference assessed via questionnaire post-treatment. Secondary endpoints include preference rationale, injection tolerability (assessed via Visual Analogue Scale VAS), adverse events (AEs), and health-related quality of life (HRQoL). Results: Among 60 enrolled patients, 39 completed both treatment periods and were evaluable. No participants reported “no preference”. Goserelin microsphere was preferred by 35 (89.7%) patients versus 4 (10.3%) patients for the goserelin implant (p=0.0001). After adjusting for period effects via the Prescott test, the preference for goserelin microsphere remained statistically significant (p=0.0017). Patient preference for goserelin microsphere was mainly driven by less injection pain, easier injection, and better quality of life. Preference for goserelin implant was rare and the reasons were inconsistent. Overall, less injection pain (72%) and easier injection (18%) were the two predominant factors influencing patient preference. Goserelin microsphere showed significantly lower immediate injection pain (VAS) compared with goserelin implant (p<0.0001). For injection fear, “marked fear” was observed only at the first injection of goserelin implant (3 patients), whereas most patients receiving microsphere reported “no fear” in Arm 1 (90.5%) and Arm 2 (77.8%). Overall, injection fear was significantly lower for microsphere compared with implant (p<0.0001). In addition, no significant between-arm difference in FACIT-P fatigue, AEs matched known profiles. Conclusions: Interim findings demonstrate a strong patient preference for the goserelin microsphere formulation over the goserelin implant, primarily due to less injection pain and easier injection. Ongoing enrollment will further validate these results.