A 6-month sustained-release formulation of triptorelin for locally advanced or metastatic prostate cancer: a real-world experience in Asia

Objective Long-acting triptorelin (LAT) (22.5 mg) is a gonadotropin-releasing hormone (GnRH) agonist used in men with prostate cancer. This study investigated the prescription pattern of LAT in a real-world setting and its efficacy. Patients & methods This was a retrospective review of patients in a tertiary center who were prescribed LAT for prostate cancer from January 2018 to March 2023 after the introduction of LAT in the territory. Demographic data were collected, and LAT prescription patterns were reviewed. These patterns included the indication and duration of prescription, testosterone suppression and characteristics of the primary prostate cancer. Results A total of 237 prostate cancer patients were prescribed LAT in the study period. The indications for LAT included metastatic prostate cancer (50.6%), neoadjuvant/adjuvant therapy for radiotherapy (28.7%) and neoadjuvant therapy for radical prostatectomy (5.1%). Among the cohort, 41.4% of the patients were receiving short-acting triptorelin (11.25 mg) before LAT initiation, 15.2% were receiving other GnRH agonists, and 15.6% were receiving GnRH antagonists. The median age at the first dose of LAT and the median treatment duration were 72 (53-94) years and 30 (6-72) months, respectively. During the study period, 92.0% of the patients did not receive another form of hormonal treatment other than LAT. A total of 121 (51.1%) patients had their testosterone level checked after LAT initiation. The median time interval of testosterone measurement after LAT initiation was 8 (1-47) months, with 98.3% of the patients having a testosterone level < 1.7 nmol/L and 92.6% having a level < 0.7 nmol/L. Among the cohort, 1 patient stopped LAT due to hot flashes and muscle weakness. Conclusion The LAT adherence rate was high in the setting of hormonal treatment for prostate cancer. Testosterone suppression was satisfactory after the initiation of LAT and was generally well tolerated.