Therapeutic Window–Guided Regulatory Extrapolation: A Pharmacokinetic and Pharmacodynamic Framework for Deciding When Local Studies Are Necessary
Abstract
The global development of medicines increasingly contrasts with predominantly national regulatory requirements, often leading to duplicated studies and delayed access to effective therapies. While pharmacokinetic variability across populations is frequently invoked to justify local confirmatory trials, the clinical relevance of such variability depends on whether exposure differences meaningfully alter benefit–risk balance at approved doses. This review proposes a therapeutic window–guided framework integrating pharmacokinetic and pharmacodynamic principles to inform regulatory extrapolation decisions. Rather than treating ethnic sensitivity as a geographic attribute, variability should be assessed mechanistically: exposure shifts become clinically relevant only when they plausibly move patients outside established therapeutic boundaries. Using case-based analyses relevant to Mexican regulatory contexts—nifedipine, sildenafil, and vonoprazan—we illustrate how similar magnitudes of pharmacokinetic variability can carry different regulatory implications depending on exposure–response relationships and therapeutic window width. For drugs with shallow or plateaued exposure–response curves and broad functional therapeutic ranges, foreign efficacy data may be acceptable with targeted pharmacokinetic evaluation or labeling adjustments. Conversely, when mechanistic plausibility suggests clinically meaningful displacement of exposure, focused local studies may be warranted. This…
Read the paper
Related studies
- 2024 update in heart failure
- Vascular involvement in idiopathic pulmonary fibrosis
- A novel technique- subendometrial autologous platelet rich plasma injection in patients with unresponsive thin endometrium undergoing frozen-thawed embryo transfer: a prospective cohort study
- Does metformin prolong pregnancy in preterm pre-eclampsia? A study protocol for a South African, hospital-based double-blind, randomised, placebo-controlled trial
- Combined Pulmonary Fibrosis and Emphysema (CPFE): A "New" Smoking-Related Interstitial Lung Disease (ILD)
- Impact of an acute 1-month cannabidiol treatment on pain and inflammation after a long bone fracture: a triple-blind randomised, placebo-controlled, clinical trial protocol
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.