Sun Pharma recently announced that the US Food and Drug Administration (FDA) approved an updated label for UNLOXCYT (cosibelimab-ipdl) for the treatment of adults with metastatic Cutaneous Squamous Cell Carcinoma (CSCC) or locally advanced CSCC who are not candidates for curative surgery or curative radiation. The updated label now incorporates long-term follow-up data from the pivotal CK-301-101 trial, a multicentre, multicohort, open-label study of 109 patients (31 with laCSCC; 78 with mCSCC), which showed patients receiving UNLOXCYT experienced durable clinical responses.

At least 50 percent of patients in the trial achieved the primary endpoint of objective response. In addition, 14 percent of mCSCC patients and 32 percent of laCSCC patients achieved stable disease. At the time of the follow-up analysis, the median duration of response had not been reached in either group. Many clinical trial participants achieved a rapid response; median time to response was 1.9 months (range: 1.6-16.9) and 3.6 months (range: 1.7-10.1) in mCSCC and laCSCC, respectively.

In the CK-301-101 pivotal trial, the most common adverse reactions (≥10 percent) were fatigue, musculoskeletal pain, rash, diarrhoea, hypothyroidism, constipation, nausea, headache, pruritus, edema, localised infection, and Urinary Tract Infection (UTI). Fifty three patients (24 percent) in this study experienced imARs (any grade), with a low incidence of high-grade events. Two patients (0.9 percent) experienced high-grade imARs; both were Grade 3 dermatologic imARs. There were no treatment-related deaths.

UNLOXCYT restores the adaptive immune response, enabling T cells to recognise cancer cells by inhibiting the binding of PD-L1 with PD-1 on T cells and B7.1 on antigen-presenting cells. UNLOXCYT also engages the innate immune system through an active fragment crystallizable (Fc) domain that binds to Natural Killer (NK) cells to induce Antibody-Dependent Cell-mediated Cytotoxicity (ADCC). UNLOXCYT also spares PD-L2, which may help preserve immune tolerance in non-tumour tissues, such as lung and liver, potentially limiting off-target effects and imARs.

"The longer-term results confirm that UNLOXCYT represents an advancement in the available treatment options for people living with aCSCC. As a company committed to addressing the unmet needs of the patient communities we support, these pivotal data highlight that more patients responded and maintained their responses to UNLOXCYT for longer than observed in the primary analysis. The updated label reinforces UNLOXCYT as an evolution in checkpoint inhibition," said Richard Ascroft, CEO, Sun Pharma North America.

UNLOXCYT was initially approved by the FDA in 2024. This updated label approval further underscores Sun Pharma's commitment to advancing data-driven innovation and expanding differentiated immunotherapy treatment options within its growing cutaneous oncology portfolio. With this updated label, Sun Pharma intends to commercially launch UNLOXCYT in early 2026.

"While there have been advances in aCSCC treatment, there still remains a significant unmet need for therapies that provide durable, long-term efficacy with acceptable tolerability. This is especially important in this aging population who are dealing with significant comorbidities. For many aCSCC patients who are over the age of 65 and dealing with comorbidities, UNLOXCYT provides an important, new treatment option that balances both efficacy and tolerability," said Emily Ruiz, MD, MPH, Associate Professor of Dermatology, Harvard Medical School, Academic Director, Micrographic Surgery Center, Brigham and Women's Hospital; Co-Founder, Skin Cancer Champions, and primary author on the long-term analysis publication.