Citius Resubmits BLA of Denileukin Diftitox for Relapsed or Refractory Cutaneous T-Cell Lymphoma

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Citius Pharmaceuticals announced today it has resubmitted the Biologics License Application (BLA) for denileukin diftitox (Lymphir) to the US Food and Drug Administration (FDA) for the treatment of adults with relapsed or refractory cutaneous T-cell lymphoma after at least one prior systemic therapy.¹

Acceptance of the BLA, accompanied by a Prescription Drug User Fee Act date, is anticipated within 30 days of the resubmission.

The IL-2-based immunotherapy is a recombinant fusion protein combining the IL-2 receptor binding domain with diphtheria toxin fragments. Diphtheria toxin fragments are able to inhibit protein synthesis as a result of the drug's ability to bind to IL-2 receptors on the cell surface.

The resubmission follows the issuance of a Complete Response Letter received by Citius from the FDA on July 28, 2023.²

"We appreciate the FDA's expeditious review of our application. We intend to provide additional data and remain fully engaged with the FDA as we continue to work toward approval," Leonard Mazur, chairman and CEO of Citius, had said at the time of the CRL's issuance last year.² "We remain confident in the potential of LYMPHIR to become an important addition to the treatment landscape for patients with relapsed or refractory CTCL and make a meaningful difference in their lives."

The FDA requested that Citius incorporate additional controls and enhanced product testing during market application review. There were, however, no safety or efficacy concerns noted in the CRL.

"Citius believes it has addressed enhanced product testing and additional manufacturing controls noted in the letter," according to today's news release.¹

Denileukin diftitox has previously been granted orphan drug designations from the FDA for peripheral T-cell lymphoma (PTCL) and CTCL in 2011 and 2013, respectively.

More recently, the drug received regulatory approval for both CTCL and PTCL in Japan in 2021, as well as a license to develop and commercialize denileukin diftitox in markets outside of Japan and some parts of Asia.

References

1. Citius Pharmaceuticals resubmits the Biologics License Application of Lymphir (denileukin diftitox) for the treatment of adults with relapsed or refractory cutaneous T-cell lymphoma. News release. PR Newswire. February 14, 2024. Accessed February 14, 2024. https://www.prnewswire.com/news-releases/citius-pharmaceuticals-resubmits-the-biologics-license-application-of-lymphir-denileukin-diftitox-for-the-treatment-of-adults-with-relapsed-or-refractory-cutaneous-t-cell-lymphoma-302061089.html
2. Citius Pharmaceuticals, Inc. receives a Complete Response Letter from the U.S. Food and Drug Administration (FDA) for Lymphir (denileukin diftitox) for the treatment of patients with relapsed or refractory cutaneous T-cell lymphoma. News release. PR Newswire. July 29, 2023. Accessed February 14, 2024. https://www.prnewswire.com/news-releases/citius-pharmaceuticals-inc-receives-a-complete-response-letter-from-the-us-food-and-drug-administration-fda-for-lymphir-denileukin-diftitox-for-the-treatment-of-patients-with-relapsed-or-refractory-cutaneous-t-cell-lympho-301888813.html