The allergic reactions that led to last month's recall of Omontys peginesatide from Affymax Inc. and Takeda Pharmaceutical Co. Ltd. are too rare to have been caught in premarket trials. Nevertheless, the episode probably will reinforce what is becoming a de facto two-speed system of U.S. approval. Timelines are getting shorter for targeted agents intended for use in well-defined populations, and longer for drugs intended for use in broad populations, especially those with therapeutic options.

FDA and Congress are proactively seeking ways to speed development and approval of drugs in the former category, including the new breakthrough designation and proposals for a limited-use pathway and expanded use of accelerated approval (see BioCentury, Dec. 3, 2012, & Jan. 28).