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Prostate Cancer Treatment and Research / Prostate Cancer Diagnosis and Treatment · Journal article
Frontiers in Pharmacology · August 18, 2026
Reinforces what was already believed, rather than introducing something new.
This retrospective analysis of 2,486 adverse event reports from FAERS (2004–2024) using disproportionality methods found that GnRH antagonists carry substantially higher risk of injection site reactions than GnRH agonists. The findings confirm a known safety distinction between the two drug classes and reveal different temporal onset patterns, but remain observational and subject to reporting bias inherent in spontaneous adverse event databases.
Retrospective pharmacovigilance analysis using disproportionality methods. All adverse event reports in FAERS involving GnRH antagonists or GnRH agonists for prostate cancer treatment between Q1 2004 and Q4 2024; no individual-level patient inclusion or exclusion criteria specified.. Intervention: GnRH antagonists (444 reports). Compared with: GnRH agonists (2,042 reports). n = 2,486. US Food and Drug Administration FAERS database (global reporting to FDA).
GnRH antagonists showed higher risk for injection site erythema (ROR = 16.07, 95% CI = 9.14–28.28; PRR = 14.33; χ² = 159.30) GnRH antagonists showed higher risk for injection site pain (ROR = 10.44, 95% CI = 6.53–16.71; PRR = 9.27; χ² = 140.27) GnRH antagonists showed higher risk for injection site swelling (ROR = 10.31, 95% CI = 5.58–19.05; PRR = 9.63; χ² = 82.72)
FAERS is a passive reporting system subject to underreporting, duplicate reporting, and reporter bias; absolute adverse event rates cannot be derived. Source does not report other serious adverse events (cardiovascular, metabolic) or comparative incidence in clinical practice; findings limited to reported injection site reactions.
Clinicians should be aware that GnRH antagonists carry substantially elevated risk of local injection site reactions (erythema, pain, swelling) compared with GnRH agonists. Injection site monitoring and patient counselling should be prioritized in the first month of antagonist therapy. These findings may inform shared decision-making and guide choice of agent based on injection tolerability profiles.
Pharmacovigilance analysis of 2,486 real-world adverse event reports confirming known safety differences between drug classes with clear disproportionality signals, but observational and hypothesis-generating rather than practice-changing in design.
As stated by the source record.
Quoted from the source exactly as published.
Clinicians should be aware that GnRH antagonists carry substantially elevated risk of local injection site reactions (erythema, pain, swelling) compared with GnRH agonists. Injection site monitoring and patient counselling should be prioritized in the first month of antagonist therapy. These findings may inform shared decision-making and guide choice of agent based on injection tolerability profiles.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
Purpose This study aimed to evaluate the safety profiles of gonadotropin-releasing hormone (GnRH) antagonists and agonists in the treatment of prostate cancer (PC). Methods A retrospective pharmacovigilance analysis was conducted using the US Food and Drug Administration Adverse Event Reporting System (FAERS) database from the first quarter of 2004 to the fourth quarter of 2024. Within-class direct comparison analyses between GnRH antagonists and GnRH agonists were performed using disproportionality methods, including the Reporting Odds Ratio (ROR) and Proportional Reporting Ratio (PRR). Further analyses on age stratification, combination therapy, and onset time of adverse events (AEs) were conducted to explore the safety differences between GnRH antagonists and agonists. Results A total of 2,486 reports were included in the study, comprising 444 reports for GnRH antagonists and 2,042 reports for GnRH agonists. GnRH antagonists showed higher risk for injection site reactions compared with GnRH agonists, with the strongest signals observed for injection site erythema (ROR = 16.07, 95% confidence interval [CI] = 9.14–28.28; PRR = 14.33; χ 2 = 159.30), injection site pain (ROR = 10.44, 95% CI = 6.53–16.71; PRR = 9.27; χ 2 = 140.27), and injection site swelling (ROR = 10.31, 95% CI = 5.58–19.05; PRR = 9.63; χ 2 = 82.72). Age-stratified analysis demonstrated that injection site reactions remained the predominant signals across age groups, while patients aged ≥65 years exhibited a broader spectrum of AE signals. Time-to-onset analysis revealed different temporal patterns between the two drug classes, with a higher proportion of GnRH antagonist-associated AEs occurring within 30 days after treatment initiation, whereas GnRH agonist-associated AEs were more frequently reported after 360 days. Concomitant medication subgroup analyses further identified distinct AE reporting patterns in specific treatment contexts. Conclusion This pharmacovigilance study identified distinct AE reporting patterns between GnRH antagonists and GnRH agonists in PC treatment. GnRH antagonists were primarily characterized by higher risk of local injection site reactions, whereas AE profiles varied according to patient age, treatment duration, and concomitant medication exposure.
Taken from the source record, never inferred. Follow any of these and new work involving them reaches your briefing.