The RMAT designation was created through last year’s 21st Century Cures Act to give biopharma firms an expedited development pathway for cell and gene therapies.
The exact number of submissions since the programme began has not been disclosed, though according to regenerative medicine regulatory consultant Joyce Frey-Vasconcells it numbers over 20, with five companies publically announcing they have received the designation for one their products.
Winning the designation is largely due to the clinical evidence according to Frey-Vasconcells, who advised delegates at Biotech Week Boston "don’t apply for [fast-track designations] until you have clinical evidence. The clinical evidence content is the most important part of these applications.”
“You have to have a clinically significant endpoint most of them based on Phase II or Phase III endpoint,” she said, adding that developers also need to ensure sufficient subjects are involved in studies.
“Ten to fifteen is not significant, so if that’s what you have don’t even bother applying” she said.
Humacyte’s Humacyl (human acellular vessel), the first product to receive RMAT (at least publically) back in March, offered Phase II data based on 60 patients with end-stage renal disease. jCyte received the designation in May for its retinitis pigmentosa (RP) treatment, jCell, after submitting data for an ongoing Phase IIb trial studying 70 patients.
But Frey-Vasconcells said smaller numbers can be sufficient for some cell and gene therapies which due to their nature make finding large study populations problematic, so long as they show overwhelming results
Thus Mallinckrodt’s regenerative skin tissue product StrataGraft received designation in July after submitting a proposal with data based on a Phase I/II trial with 15 patients and a Phase II study using 20 subjects which looked at an alternative to autografting.
After submitting a request, Frey-Vasconcells told delegates the US FDA has 60 days to review before sending either a ‘Designation’ or ‘Non-Designation’ letter to the company.
The former grants RMAT designation for the product and explains how the FDA will work with the sponsor, while alerting them that the programme must continue to meet criteria.
The latter letter will state the reasons why the designation was denied, and will sometimes outline what is needed to be done for a new request.