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Over the past several years, the number of deviations and substantial amendments made to clinical trial protocols has increased notably, contributing to delays in drug development and rising costs for completing studies, a new analysis finds.

From 2018 through March 2020 — before the pandemic disrupted research and development work — the average number of amendments for Phase 1, 2 and 3 trial protocols was 2.4, 2.7 and 3.3, respectively. By comparison, the number of amendments for each of the three trial phases was 1.8, 2.2, and 2.3 from 2013 through 2015, according to the Tufts Center for the Study of Drug Development.


Looked at another way, during the most recent period, 59% of all Phase 1 trial protocols, 78% of all Phase 2 protocols, and 69% of all Phase 3 protocols had at least one substantial amendment, which was defined as a change affecting every investigative site. In each case, the number of amendments rose from the 2013 to 2015 period, although the greatest differences were seen in Phase 1 protocols.

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