Most Protocols Require Multiple Amendments

A recent study conducted by the Tufts Center for the Study of Drug Development (Tufts CSDD) found that more than half of all protocols require one or more amendments. Based on data from 3,410 protocols provided by 17 large and midsize pharmaceutical and biotechnology companies, Tufts CSDD found that completed protocols across all phases had an average of 2.5 amendments requiring 6.9 changes to the protocol per amendment. Later-stage Phase II and III protocols had a higher average number of amendments, 2.7 and 3.5 respectively. The most commonly cited causes of amendments included the availability of new safety information, requests from regulatory agencies to amend the study, and changes in the study strategy. Protocol design flaws and difficulties recruiting study volunteers were also cited as top causes. The study found that the incidence of amendments is associated with protocol complexity and duration. The mean number of amendments per protocol, for example, was positively and significantly correlated (p<.001) with the number of procedures per protocol, study length, and the number of investigative sites conducting that protocol.

—Tufts Center for the Study of Drug Development, http://csdd.tufts.edu.

Mean number of amendments per protocol. (Source: Tufts Center for the Study of Drug Development)