Vertex Pharmaceuticals’s Kalydeco was approved to treat 33 rare gene mutations – up from 10 – without new additional data being generated in a first of its kind move the US Food and Drug Administration (FDA) attributed to the small patient populations for the additional indications.
“Many rare cystic fibrosis mutations have such small patient populations that clinical trial studies are not feasible,” director of the FDA’s Center for Drug Evaluation and Research Janet Woodcock said last week.
“This challenge led us to using an alternative approach based on precision medicine, which made it possible to identify certain gene mutations that are likely to respond to Kalydeco.”
When the additional mutations responded to Kalydeco in an in vitro cell-based model, researchers were able to extrapolate clinical benefit demonstrated in earlier clinical trials of other mutations, the Agency said.
The unconventional approval process was welcomed by Patrick Flume, director of the Medical University of South Carolina Cystic Fibrosis Center, who said in a statement: “CF treatment has advanced rapidly, but there is need for broader access to these important medicines and development of additional medicines remains urgent.
“The use of in vitro data to support this approval is an important step forward in making medicines like Kalydeco available to more patients, especially those with rare mutations.”
Based on this approval, Vertex has increased its guidance for 2017 product revenues of Kalydeco to a range of $740m to $770m, from $690m to $710m.