The impact of different formulations and dosing intervals of goserelin on testosterone suppression in patients with prostate cancer: A real-world observational study.

e17093 Background: The purpose of androgen deprivation therapy (ADT) is to reduce and stabilise serum testosterone. However, dosing nonadherence for various reasons may lead to insufficient testosterone suppression, thus affecting the outcome of patients with prostate cancer. The present study evaluated the differences in testosterone control by different dosage forms and dosing intervals of goserelin. Methods: This analysis was conducted in real-world clinics, focusing on patients diagnosed with prostate cancer who had initiated goserelin acetate extended-release microspheres for injection dosed every 4 weeks (dosing intervals of 28, 56, and 84 days) and goserelin acetate sustained-release depot dosed every 12 weeks (dosing intervals of 84, 168, and 252 days). We retrospectively analysed the testosterone testing intervals and results from a minimum of three testosterone tests collected within six months following the initial goserelin dosage. Results: The present study comprised a total of 60 prostate cancer patients, with 30 patients in each group. The study found no statistically significant difference in the efficacy of the two goserelin drugs in terms of testosterone control (≤50ng/dl and ≤20ng/dl). However, in real-world clinical settings, there are unavoidable delays in medication administration, the rate of delayed injections was lower in patients applying the 4-week dosage form than the 12-week dosage form (P = 0.035, χ2 = 4.444). The mean and dispersion of delayed injection days were found to be greater in patients in the implant 12-week dosage form group. The proportion of delayed medication for a period exceeding one week is even higher (56% vs. 10%). Additionally, within the same group, a trend towards a correlation between the level of testosterone de-escalation and delayed injection days was identified. The chi-square test revealed a statistically significant difference in the proportion of punctual or delayed injections for profound testosterone lowering (≤20ng/dl) (P = 0.004, χ2 = 10.060). The baseline patient profile and key findings can be found in Table 1. Conclusions: The study investigated the impact of varying formulation types and delayed goserelin injection on testosterone control. It is imperative to allocate greater resources to the development of effective follow-up strategies and to enhance the compliance of prostate cancer patients with androgen deprivation therapy. Goserelin acetate extended-release microspheres for injection dosed every 4 weeks Goserelin acetate sustained-release depot dosed every 12 weeks N 30 30 Median age (years) 72.5(50-91) 73.0(50-90) Median treatment cycles 7(3-12) 4(3-5) Median days of delayed injections 4(2-9) 14(7-35) Delayed injection rate %(n) 46.7%(14/30) 73.3%(22/30) testosterone ≤50ng/dl % 100% 100% testosterone ≤20ng/dl %(n) 66.7%(20/30) 60.0%(18/30)