After AdComm rejection, Mallinckrodt’s stannsoporfin gets stiff-armed at FDA

FDA
The structuring of the InfaCare deal means Mallinckrodt is insulated somewhat from the impact of the FDA rejection. (FDA)

The FDA has issued a complete response letter to Mallinckrodt’s jaundice drug stannsoporfin. Mallinckrodt plans to talk to the FDA in the coming months before deciding the fate of a drug it acquired in an $80 million buyout last year.

When Mallinckrodt wrapped up the buyout of InfaCare Pharmaceutical in September, stannsoporfin had a shot at winning approval on the strength of phase 2b data. The FDA agreed to consider a filing based on phase 2b trials in 2016, setting InfaCare and later Mallinckrodt on a path they hoped would lead to a 2018 approval.

Members of an FDA advisory committee poured cold water on those hopes earlier this year when they voted overwhelmingly against the approval of the drug. The negative vote reflected doubts about the benefits and neurodevelopmental safety of stannsoporfin.

Now, the FDA has sided with the advisory committee and issued a CRL. Mallinckrodt is yet to say much about the content of the CRL or its plans for stannsoporfin. The company is set to request to meet with the FDA to discuss potential paths forward in the coming months. Once Mallinckrodt has gotten the agency’s take, it will decide what to do with stannsoporfin.

The structuring of the InfaCare deal means Mallinckrodt is insulated somewhat from the impact of the FDA rejection. Mallinckrodt paid $80 million upfront to buy InfaCare, a paltry sum for a late-phase asset. The meat of the deal lay in $345 million in regulatory and sales milestones.

Depending on what the FDA wants to see in the next filing for approval of stannsoporfin, Mallinckrodt could walk away $80 million down, or commit further funds to try to push the program over the finish line at the second time of asking.