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BACKGROUND: We compared patients' perceptions of post-injection burning and/or stinging following two 6-month GnRH formulations administered via different routes.
METHODS: This multicenter, crossover, open-label study enrolled adult men with advanced prostate cancer. Patients were randomized to receive one injection of triptorelin pamoate suspension (Trelstar^® 22.5mg) intramuscularly (IM) in the buttock or one injection of polymeric matrix leuprolide acetate (Eligard^® 45mg) subcutaneously (SC) in the abdomen. Six months later patients received the alternate treatment. After each injection, patients completed a Visual Analog Scale (VAS) questionnaire (range 0−100mm) 10−15 minutes post-injection, and adverse events (AEs) were assessed for 24 hours. VAS scores were analyzed using a repeated measures analysis of variance, adjusting for treatment, sequence, and period effects.
RESULTS: Of 118 patients randomized, 107 (mean age 74.0 +/− 9.7 yrs) completed the protocol. Adjusted mean scores for bother from injection site burning/stinging were 5.8mm for triptorelin IM and 23.9mm for leuprolide SC. The mean difference between treatments was 18.0mm (P<0.0001; 95% CI 12.6-23.5). Patients were significantly less bothered by post-injection burning/stinging with IM injection vs SC injection and reported significantly less discomfort (14.6mm, P=<0.0001) post-IM injection vs post-SC injection, as well as less bother from soreness (8.9mm, P=0.0001), redness (2.9mm, P=0.0302), itching (2.4mm, P=0.0052), and hardening (2.7mm, P=0.0386). No serious AEs were reported. No patients discontinued the study due to an AE.
CONCLUSIONS: Patients are significantly less bothered by post-injection site burning/stinging after triptorelin IM in the buttock than after leuprolide SC in the abdomen.