Fulcrum Therapeutics has announced that losmapimod has received orphan drug designation from the U.S. Food and Drug Administration. Losmapimod is currently in a Phase 2 clinical trial for facioscapulohumeral muscular dystrophy (FSHD). The drug qualified for this status because FSHD, with an estimated 20-40,000 affected individuals in the U.S., is considered a rare disease. (The FDA defines conditions that affect fewer than 200,000 people in the U.S. as rare diseases.)
What does this mean for patients?
The orphan designation grants the company seven years of market exclusivity following FDA approval (if received), exemption of FDA application fees, and tax credits for qualified clinical trials. This helps the bottom line and makes Fulcrum more attractive to investors. It’s good for patients indirectly, in that it helps the company from a business standpoint. But the orphan drug designation will not get losmapimod to patients any faster. The drug still needs to get through clinical trial(s) and the FDA approval process.
The true inflection point for patients would be if the FDA grants what is called an accelerated approval. This might be considered if the Phase 2 trial clearly shows that losmapimod reduces the activity of the gene DUX4. If the FDA accepts the argument that the drug is therefore likely to slow down disease progression, and that it has been shown to be safe, the agency might grant an accelerated approval on that basis.
The soonest that the FDA could consider an accelerated approval would be after the Phase 2 trial has been completed, a milestone that Fulcrum expects to reach in the third quarter of 2020. And there is no guarantee. The Phase 2 data might not support an approval, or the FDA might require a larger, Phase 3 trial. We will be following developments closely!