Global regulatory variability in small-molecule inhibitor approvals: Differences in timelines, dosing, and pediatric indications across FDA, EMA, and PMDA

Purpose: Small-molecule inhibitors have transformed oncology in recent years. This study compared regulatory approvals of these agents across the United States Food and Drug Administration (FDA), the European Medicines Agency (EMA) and the Japanese Pharmaceuticals and Medical Devices Agency (PMDA), focusing on timelines, dosing recommendations, and pediatric labelling. Methods: A review of regulatory databases was conducted to identify small-molecule inhibitors approved for adult malignancies. Drug labels were compared to determine dosing concordance (Fully, Partially, or Non-Concordant), approval dates, and pediatric indications. Data extraction involved two independent reviewers. Results: Fifty-five inhibitors were approved by all three agencies. Adult dosing was Fully Concordant in 49 (89%), partially in 4 (7%), and Non-Concordant in 2 (4%). The median approval gap was 25 months (range: 1–88). FDA granted first approval for 85.5% of agents, followed by PMDA (12.7%) and EMA (1.8%). Among these 55 drugs, only 15 had pediatric indications (27%), 7 of them (46.7%) approved across all three regions. No complete divergence in pediatric dosing was observed, although minimum age thresholds varied. Discussion: Despite strong alignment in adult dosing, regulatory disparities in approval timelines and pediatric labelling persist, risking delays in therapy availability. More harmonized multinational trials and regulatory alignment could facilitate timely approvals while allowing for population-specific considerations in dosing and safety.