LYMPHIR Launches in U.S., Bringing New Option for Stage 1 to 3 CTCL

The U.S. commercial launch of LYMPHIR (denileukin diftitox-cxdl), a novel cancer immunotherapy for adults with relapsed or refractory stage 1 to 3 cutaneous T-cell lymphoma (CTCL), offers a new treatment option for patients with limited alternatives, according to a news release from Citius Oncology, Inc.

LYMPHIR is an interleukin-2 (IL-2) receptor-directed fusion protein designed to target cancerous T-cells. It received U.S. Food and Drug Administration (FDA) approval for patients who have received at least one prior systemic therapy and was supported by data from the phase 3 Study 302.

The pivotal study evaluated efficacy and safety in patients with stage 1 to 3 CTCL, in which results showed an objective response rate (ORR) of 36.2%, with 84% of evaluable patients experiencing a reduction in skin tumor burden. The therapy also demonstrated significant relief of severe pruritus, a symptom that can greatly impact quality of life. LYMPHIR showed no evidence of cumulative toxicity, which may be advantageous for long-term disease management.

Leonard Mazur, chairman and CEO of Citius Oncology, emphasized the importance of this launch: “LYMPHIR is an important new treatment option for the CTCL community. With a median time to response of 1.4 months in the phase 3 trial, we believe LYMPHIR may offer rapid skin relief, among other benefits, to patients suffering from severe and debilitating itching common with the disease,” he said. “This is our first marketed product and the culmination of years of development work and commercial preparation. LYMPHIR addresses a clear clinical need in a disease with limited treatment options. Ultimately, we expect LYMPHIR to be a meaningful addition to the treatment paradigm for CTCL.”

Dr. Myron Czuczman, executive vice president and chief medical officer at Citius Oncology, highlighted LYMPHIR’s unique mechanism of action. “LYMPHIR’s direct tumoricidal activity and transient T-regulatory cell depletion offer a powerful new approach to disease control without cumulative toxicity. As such, LYMPHIR's clinical profile makes it a compelling treatment option for physicians and patients facing the burden of relapsed or refractory CTCL,” he said.

Notably, LYMPHIR is the only FDA-approved systemic therapy for CTCL in more than seven years, offering a meaningful addition to the treatment paradigm for patients with relapsed or refractory disease.

The Science Behind LYMPHIR: Precision Therapy for T-Cell Lymphoma

LYMPHIR is a recombinant fusion protein that combines the IL-2 receptor-binding domain with fragments of diphtheria toxin. Once the drug binds to IL-2 receptors on cancer cells, the toxin fragments enter the cell, inhibit protein synthesis and induce cell death. In addition to directly targeting tumor cells, LYMPHIR can deplete immunosuppressive regulatory T-cells (Tregs), further supporting immune-mediated antitumor activity.

What Patients Should Know About Safety, Side Effects and Precautions

LYMPHIR does carry potential risks, as the therapy includes a boxed warning for capillary leak syndrome (CLS). Patients may also experience visual impairment, infusion-related reactions, hepatotoxicity and embryo-fetal toxicity. Healthcare providers can regularly monitor for these effects and adjust therapy as needed.

Common side effects reported in clinical trials include nausea, fatigue, edema, musculoskeletal pain, rash and increased liver enzymes. Patients who are pregnant, breastfeeding or of reproductive potential should discuss risk mitigation and contraception with their healthcare team.

Why Do New Treatments Matter? Understanding CTCL

Cutaneous T-cell lymphoma is the most common type of cutaneous non-Hodgkin lymphoma. It occurs when T-cells, which play a key role in the immune system, become cancerous and form skin lesions. The disease can significantly reduce quality of life due to pain and severe itching. Mycosis Fungoides and Sézary Syndrome are the most prevalent forms of CTCL. While some forms of CTCL progress slowly, advanced disease can be highly malignant and spread to lymph nodes and internal organs.

Currently, there is no curative therapy for most patients, making access to new treatment options like LYMPHIR critical.

Reference

1. Citius Oncology Announces U.S. Commercial Launch of LYMPHIR™, a Novel Cancer Immunotherapy for Cutaneous T-Cell Lymphoma (CTCL), by Citius Oncology, Inc. News release; Dec. 1, 2025. https://www.citiusonc.com/news/news-details/2025/Citius-Oncology-Announces-U-S--Commercial-Launch-of-LYMPHIR-a-Novel-Cancer-Immunotherapy-for-Cutaneous-T-Cell-Lymphoma-CTCL/default.aspx

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