Integrated Summary of Safety and Efficacy Strategy (ISS and ISE) Across Heterogeneous Trial Populations in Oral Factor Xa Anticoagulant Development

An Integrated Summary of Safety (ISS) and Integrated Summary of Efficacy (ISE) do not simply restate the findings of each individual study report already filed in Module 5; they build the pooled, cross-study narrative that a reviewer actually reads first when forming an overall judgment of a development program, and a poorly integrated summary can leave a reviewer reconstructing that pooled picture manually from individual study reports, an outcome the ISS and ISE exist specifically to avoid (International Council for Harmonisation, 1996). This article addresses a representative oral factor Xa anticoagulant development program built around three studies with genuinely different designs: a pivotal efficacy trial in patients with a standard indication for anticoagulation, a supportive trial in a renal-impairment population using a dose-adjusted regimen, and a dedicated drug-drug interaction study evaluating concomitant antiplatelet therapy.The central challenge this program presents is one common to many drug categories but particularly pronounced in anticoagulant development: the renal-impairment study population received a reduced dose by design, meaning its safety and efficacy data cannot simply be pooled with the pivotal trial's standard-dose population without first addressing whether the two populations are measuring comparable things. This article examines how the ISS and ISE should be structured to present this heterogeneous evidence honestly, consistent with ICH E3 and FDA guidance on integrated summaries, rather than forcing a single pooled analysis that would misrepresent the underlying data.