FDA Approves Lymphir for R/R Cutaneous T-Cell Lymphoma

The US Food and Drug Administration has approved denileukin diftitox-cxdl (Lymphir, Citius Pharmaceuticals) for adults with relapsed or refractory stage 1-3 cutaneous T-cell lymphoma after at least one prior systemic therapy.

The immunotherapy is a reformulation of denileukin diftitox (Ontak), initially approved in 1999 for certain patients with persistent or recurrent cutaneous T-cell lymphoma. In 2014, the original formulation was voluntarily withdrawn from the US market. Citius acquired rights to market a reformulated product outside of Asia in 2021. 

This is the first indication for Lymphir, which targets interleukin-2 receptors on malignant T cells.

This approval marks “a significant milestone” for patients with cutaneous T-cell lymphoma, a rare cancer, company CEO Leonard Mazur said in a press release announcing the approval. “The introduction of Lymphir, with its potential to rapidly reduce skin disease and control symptomatic itching without cumulative toxicity, is expected to expand the [cutaneous T-cell lymphoma] treatment landscape and grow the overall market, currently estimated to be $300-$400 million.” 

Approval was based on the single-arm, open-label 302 study in 69 patients who had a median of four prior anticancer therapies. Patients received 9 mcg/kg daily from day 1 through day 5 of 21-day cycles until disease progression or unacceptable toxicity.

The objective response rate was 36.2%, including complete responses in 8.7% of patients. Responses lasted 6 months or longer in 52% of patients. Over 80% of subjects had a decrease in skin tumor burden, and almost a third had clinically significant improvements in pruritus. 

Adverse events occurring in 20% or more of patients include increased transaminases, decreased albumin, decreased hemoglobin, nausea, edema, fatigue, musculoskeletal pain, rash, chills, constipation, pyrexia, and capillary leak syndrome.

Labelling carries a boxed warning of capillary leak syndrome. Other warnings include visual impairment, infusion reactions, hepatotoxicity, and embryo-fetal toxicity. Citius is under a postmarketing requirement to characterize the risk for visual impairment.

The company expects to launch the agent within 5 months.

M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape Medical News. Alex is also an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com.