Citius Pharmaceuticals hit with CRL from the FDA for reformulated non-Hodgkin lymphoma drug Lymphir

The FDA hit Citius Pharmaceuticals with a complete response letter (CRL) for its treatment of relapsed or refractory cutaneous T-cell lymphoma (CTCL), a rare form of non-Hodgkin lymphoma.

Leonard Mazur

The agency wants to see “enhanced product testing” and “additional controls” that the company agreed to with the FDA during the market application review of denileukin diftitox, marketed as Lymphir. Citius noted the CRL had nothing to do with safety, efficacy or the prescribing information.

“We appreciate the FDA’s expeditious review of our application,” Citius chairman and CEO Leonard Mazur said in a statement. “We intend to provide additional data and remain fully engaged with the FDA as we continue to work toward approval.”

New Jersey biopharma Citius licensed Lymphir, an IL-2-diphtheria toxin fusion protein, from Dr. Reddy’s Laboratories in 2021. Dr. Reddy’s had the exclusive license for the drug from Eisai. Lymphir is a reformulated drug of an older, previously-approved drug called Ontak for patients with persistent or recurrent CTCL. Ontak was approved in the US from 1999 to 2014 when it was voluntarily taken off of the market due to manufacturing issues.

The new formulation, according to Citius, has 15.2 times greater specific bioactivity. Results from a Phase III trial showed an objective response rate of 36.2% (25 out of 69 participants), the study’s primary endpoint.

When Citius first licensed the drug from Dr. Reddy’s, the last patient had been enrolled in a Phase III pivotal trial. Citius’ exclusive license rights include all markets except for Japan and certain parts of Asia.

Citius paid $40 million upfront to Dr. Reddy’s and promised another up to $110 million more in milestone payments related to CTCL approvals in the U.S. and other markets, along with additional indications of the drug.

Eisai will receive a $6 million development milestone payment upon initial approval and additional commercial milestone payments related to the achievement of net product sales thresholds.

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