When does broad consent expire? A temporal validity framework for biobank samples in induced pluripotent stem cell research.

Background: Induced pluripotent stem cell (iPSC) research increasingly draws on biobank samples collected years or decades earlier under broad consent for future unspecified use. We previously reported that the time elapsed between original sample collection and a proposed new use shaped whether community members and bioethicists regard the original broad consent as still sufficient, and identified this association as a novel finding, but we did not translate it into an operational standard. We address that gap in this paper. Methods: We conducted and analyzed key informant interviews with six Community Advisory Board (CAB) members and five bioethicists, and two focus group discussions with twenty community members, from a study of the YRI HapMap community in Ibadan, Nigeria. We coded the transcripts against two Results: Participants treated broad consent as durable but conditional rather than open-ended. Duration thresholds recurred across independent groups: renewal "at 5-year intervals," a fixed "time limit… like 20 years," and, at the permissive extreme, validity "to 50, 100 years." Duration and technological novelty operated jointly rather than separately; several participants tied renewal explicitly to technology "changing," and bioethicists distinguished elapsed time from the separate problem that the original consent language never contemplated iPSC-type uses. Anonymity of the original donors and continuity of the CAB shaped how participants resolved the two constraints, and several proposed the CAB as a surrogate re-authorizing body once individual re-contact was no longer feasible. We translate these findings into a four-state framework - presumptively valid, requires community reaffirmation, requires new authorization, and requires de novo consent - defined by elapsed-time bands crossed with a technology-novelty category. Conclusions: Elapsed time is not, by itself, an expiration date for broad consent. It is one input, alongside technological novelty and the persistence of trust infrastructure such as CAB continuity and community reporting, into a graded governance decision. The framework gives biobanks and research ethics committees a reproducible way to decide when broad consent for a sample collection still holds, when it needs reaffirmation, and when it does not.