On August 8, the Food and Drug Administration (FDA) approved Lymphir (denileukin diftitox-cxdl), a new type of immunotherapy for cutaneous T-cell lymphoma (CTCL). It is indicated for adults with Stage I to III relapsed or refractory CTCL who have used at least one prior systemic therapy.

CTCL is a rare type of non-Hodgkin lymphoma. Mycosis fungoides and Sézary syndrome are the most common forms. In people with CTCL, T-cells become cancerous and give rise to skin lesions that can result in severe pain and itching. Stem cell transplants are the only curative therapy, but most patients are not eligible.

Lymphir, from Citius Pharmaceuticals, is the only systemic treatment for CTCL that targets the interleukin-2 (IL-2) receptor on malignant T-cells and Tregs, white blood cells involved in dampening immune response against cancer. It is a recombinant fusion protein that couples the IL-2 receptor binding site with diphtheria toxin fragments that kill malignant cells. Because it has a novel mechanism of action, it is likely to work against cancer that has become resistance to other types of treatment.

The approval was based on results from the Phase III Pivotal Study 302 (NCT01871727), which included 69 participants with relapsed or refractory (unresponsive) CTCL. They had to have tried at least one prior therapy, but the median number was four. All patients in this open-label trial received Lymphir via IV infusion daily for the first five days in a 21-day cycle. Treatment continued until they experienced disease progression or unacceptable toxicity. 

The overall response rate was 36%, including 9% with a complete response. The median time to response was 1.4 months, and about 70% of responders saw results after one or two treatment cycles. About half had a durable response lasting at least six months, and 20% were still responding at 12 months. Most patients (84%) experienced a reduction in skin tumors, and 32% reported reduced itching.

Treatment was generally safe with no cumulative toxicity. The Lymphir prescribing information includes warnings about capillary leak syndrome, visual impairment, infusion reactions and liver toxicity.

“Lymphir is the first therapeutic option in many years to offer hope of reducing skin disease, bringing us one step closer to filling the need for CTCL patients, particularly those that are not able to complete or continue prior therapies,” Francine Foss, MD, of Yale Cancer Center, said in a Citius press release.

Lymphir is expected to be available by the end of the year, according to the company announcement.

Click here for full prescribing information for Lymphir.

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