FDA’s drug center says it has been so overwhelmed with industry’s response to its new Breakthrough Therapy program that it is becoming difficult to promise an “all hands” commitment.

At a January FDA rare disease workshop in Silver Spring, MD, Richard Moscicki, a deputy director for the agency, said the number of such requests and designations has “exceeded expectations.” As of December, the program had received 121 requests and granted 34 designations, about one third for genetic diseases.

FDA managers have been somewhat disappointed by the number of designation requests for drugs that are late in the development phase; in some cases the marketing application has already been submitted.

“This is not the purpose of the program and requests should be early in development to allow us to work easily with those developing it,” he said.