The FDA has killed off Y-mAbs Therapeutics’ slim hopes of winning approval for 131I-omburtamab at the first time of asking. Weeks after its advisory committee roundly rejected the candidate, the agency has hit YmAbs with a complete response letter and discussed the need for an adequate and well-controlled trial of the rare pediatric cancer drug.
According to Y-mAbs, the FDA’s letter “includes a recommendation for meeting with the agency to discuss adequate and well-controlled trial design to demonstrate substantial evidence of effectiveness and a favorable benefit-risk profile.” The biotech is still assessing the implications of the rejection and its plans for omburtamab, but it is already talking up its resources beyond the candidate.
“We are excited about refining our focus primarily to drive growth from Danyelza and validate our SADA platform in the clinic, with the goal of bringing innovative solutions to patients and value to our shareholders,” Thomas Gad, interim CEO at Y-mAbs, said in a statement.
The reference to an “adequate and well-controlled trial design,” coupled to the points raised in the FDA’s briefing document and subsequent advisory committee, suggests omburtamab may lack a quick, cheap path to resubmission. Y-mAbs ended September with $114.5 million to its name, a sum it thinks will keep it going into mid-2024.
If Y-mAbs is to get the radioimmunotherapy to market, it will likely need to address the issues flagged at the advisory committee meeting, where experts noted “significant discrepancies between the external control and the treatment group” and called the numbers involved “unbelievably small.”
Shares in Y-mAbs fell 15% in premarket trading to $3.80. The stock traded around $15 in the run-up to the advisory committee but cratered as it became clear that the FDA and assembled experts took a dim view of the evidence presented to support approval in children with neuroblastoma.