Recently, Citius Pharmaceuticals faced a significant setback when the U.S. Food and Drug Administration (FDA) rejected their application for Lymphir (denileukin diftitox) in the treatment of relapsed or refractory cutaneous T-cell lymphoma (CTCL). The FDA’s decision came as a disappointment to the company, as they had invested considerable effort and resources in pursuing FDA approval for this promising drug. Citius Pharmaceuticals made a substantial investment of $40 million intending to replace the withdrawn Ontak with With Lymphir.
The regulatory authority’s rejection was not related to any concerns about the safety and efficacy of Lymphir’s clinical data package or the drug’s proposed prescribing information. Instead, the issues primarily revolved around the application and regulatory aspects of the drug’s submission. In response to the FDA’s decision, Citius Pharmaceuticals issued a statement explaining that the FDA requested the company to enhance product testing and implement “additional controls” that had been agreed upon during the market application review. These requirements are likely aimed at ensuring a comprehensive and rigorous evaluation of the drug’s safety and effectiveness before considering its approval.
Despite the setback, Citius Pharmaceuticals is determined to persevere in their pursuit of FDA approval for Lymphir. The drug, a recombinant fusion protein combining the inteleukin-2 (IL-2) receptor binding domain with diphtheria toxin fragments, was acquired from Dr. Reddy’s in September 2021. Dr. Reddy’s, in turn, had obtained the drug from Eisai in 2016 as a replacement for their previous cancer medication Ontak, which had to be withdrawn from the market in 2014 due to production challenges related to bacterial expression and purification.
In contrast to Ontak’s difficulties, Lymphir is positioned as a purer and more refined version of the drug. This makes it a promising alternative for treating CTCL, and its approval in Japan further validates its potential efficacy.
Despite this rejection, Citius Pharmaceuticals says recognizes the significance of gaining FDA approval for Lymphir in the U.S. market. As part of its strategy, the company says they are committed to working closely with the FDA to address the additional requirements and overcome any regulatory hurdles that may arise. This collaborative approach demonstrates their determination to bring Lymphir to patients in need of effective treatment for relapsed or refractory cutaneous T-cell lymphoma. Despite the current obstacles, Citius remains optimistic about the future prospects of Lymphir as a valuable addition to the arsenal of cancer-fighting medications.