Citius Oncology, Inc., the oncology-focused subsidiary of Citius Pharmaceuticals, Inc., has announced the commercial launch of Lymphir (denileukin diftitox-cxdl). Lymphir is a novel IL-2 receptor-directed fusion protein approved by the US FDA for the treatment of adult patients with relapsed or refractory Stage I–III cutaneous T-cell lymphoma (CTCL) who have received at least one prior systemic therapy.

According to Leonard Mazur, chairman and CEO of Citius Oncology and Citius Pharmaceuticals, the launch of Lymphir marks a major milestone for the company. He highlighted its median time to response of 1.4 months, noting that the therapy may provide rapid relief from the severe and debilitating itching associated with CTCL. As the company’s first marketed product, Lymphir is the result of years of clinical development and commercial groundwork. Mazur noted that the drug enters a US market valued at over $400 million, with significant expansion potential through international access and future additional indications.

Lymphir received FDA approval based on results from Pivotal Study 302, which evaluated its efficacy and safety in patients with Stage I–III CTCL after at least one prior systemic therapy. The study showed an Objective Response Rate of 36.2%, and 84% of evaluable patients demonstrated a reduction in skin tumour burden. The therapy also showed meaningful improvement in severe pruritus, a major quality-of-life concern for these patients, with a rapid median time to response. Importantly, no cumulative toxicity was observed.

Dr. Myron Czuczman, executive vice president and chief medical officer of Citius Oncology and Citius Pharmaceuticals, emphasized that Lymphir is the only FDA-approved systemic therapy for CTCL in more than seven years. He noted its direct tumour-killing activity and ability to transiently deplete T-regulatory cells, providing a new approach to disease management without cumulative toxicity.

Lymphir is now available in the US through specialty distributors. The product has been assigned a permanent J-code (J9161), effective April 1, 2025, to support reimbursement and streamline claims processing. The launch is backed by medical education initiatives, payer access programs, and field engagement activities. Lymphir has also been included in the National Comprehensive Cancer Network (NCCN) Guidelines for CTCL with a Category 2A recommendation.

Globally, Citius Oncology holds exclusive rights to develop and commercialize Lymphir in all markets except India, Japan, and select Asian territories. The company recently signed a distribution agreement with Integris Pharma S.A. to initiate named-patient access programs across Greece, Cyprus, and parts of Southern Europe and the Balkans, marking the first step in its international expansion strategy.

To support clinicians and streamline access to therapy, Citius Oncology has developed extensive clinical, administrative, and educational materials available through a dedicated HCP portal. Resources include prescribing information, reimbursement support, and product ordering guidance, along with information on Citius Advantage, a patient assistance program designed to help reduce out-of-pocket costs through reimbursement support, prior authorization assistance, and coordination with specialty pharmacies.

Lymphir is a targeted immune therapy designed for relapsed or refractory CTCL (Stage I–III) after at least one prior systemic therapy. It is a recombinant fusion protein combining the IL-2 receptor binding domain with diphtheria toxin fragments. By binding to IL-2 receptors on tumour cells, the therapy delivers toxin fragments that inhibit protein synthesis and induce cell death. Lymphir has demonstrated both direct tumouricidal activity and the ability to deplete immunosuppressive regulatory T cells.

Regulatory approval for denileukin diftitox in Japan was granted in 2021 for both relapsed or refractory CTCL and peripheral T-cell lymphoma, and in the same year, Citius secured exclusive rights for global development and commercialization outside India, Japan, and parts of Asia. Lymphir was approved by the US FDA in August 2024.

CTCL is the most common form of cutaneous lymphoma, affecting T-cells that become cancerous and form skin lesions, significantly impacting patient quality of life due to chronic pain and severe pruritus. Mycosis Fungoides and Sézary Syndrome represent the majority of CTCL cases. While the disease may progress slowly, advanced tumour-stage CTCL carries a poor prognosis with potential spread to lymph nodes and internal organs. With no curative therapy available for advanced disease except allogeneic stem cell transplantation—an option limited to few patients—most individuals cycle through multiple treatments to manage progression.

Citius Oncology is focused on developing and commercializing targeted oncology therapies. Lymphir, its lead asset approved in August 2024, addresses a growing and underserved US market estimated to exceed $400 million. Its parent company, Citius Pharmaceuticals, is committed to advancing first-in-class critical care therapeutics.