Citius Pharmaceuticals’ $40 million bet on a Dr. Reddy’s drug to replace the withdrawn cancer med Ontak has hit a snag in the U.S.
Late last week, the company said its application for Lymphir (denileukin diftitox) in relapsed or refractory cutaneous T-cell lymphoma (CTCL) had been rejected by the FDA. The regulator is requiring Citius to bolster its application with enhanced product testing and “additional controls agreed to with the FDA during the market application review,” the company said in a release.
Citius stressed that no issues pertaining to safety and efficacy of Lymphir’s clinical data package were flagged by the FDA. The regulator didn't raise any issues related to the drug's proposed prescribing information, either.
The company says it remains committed to working toward an approval.
Citius picked up its drug—a recombinant fusion protein combining the inteleukin-2 (IL-2) receptor binding domain with diphtheria toxin fragments—from Dr. Reddy’s back in Sept. 2021. Dr. Reddy’s had in turn paid Eisai in 2016 for the drug, which is meant to replace the Japanese pharma’s earlier cancer med Ontak. Ontak, approved in 2008, was pulled from the market in 2014 due to production issues related to bacterial expression and purification challenges.
Lymphir is a purer version of Ontak that's designed to address those manufacturing shortfalls. The drug is already approved in Japan.