The U.S. Food and Drug Administration (FDA) approved a label update for cosibelimab-ipdl (Unloxcyt, Sun Pharma) for the treatment of adults with metastatic cutaneous squamous cell carcinoma (mCSCC) or locally advanced (la) CSCC who are not candidates for curative surgery or curative radiation.
The updated label now incorporates long-term follow-up data from the CK-301-101 trial, a multicenter, multicohort, open-label study of 109 patients (31 with laCSCC; 78 with mCSCC), which showed patients receiving cosibelimab-ipdl experienced durable clinical responses.
With this updated label, Sun Pharma intends to commercially launch cosibelimab-ipdl in early 2026.
The long-term follow-up analysis demonstrated an improvement in the primary endpoint, objective response rate (ORR), including more complete responses compared with the primary analysis for both groups, with ≥50% of patients experiencing an objective response. In addition, 14% of mCSCC patients and 32% of laCSCC patients achieved stable disease.
The median duration of response (DOR) (secondary endpoint) improved with longer follow-up and was not reached in either the mCSCC or laCSCC cohorts at the time of analysis, highlighting the durability of responses. Many clinical trial participants achieved a rapid response; median time to response was 1.9 months and 3.6 months in mCSCC and laCSCC, respectively.
In the CK-301-101 trial, the most common adverse reactions (≥10%) were fatigue, musculoskeletal pain, rash, diarrhea, hypothyroidism, constipation, nausea, headache, pruritus, edema, localized infection, and urinary tract infection. Fifty three patients (24%) in this study experienced immune-mediated adverse reactions (imARs) of any grade, with a low incidence of high-grade events. Two patients (0.9%) experienced high-grade imARs; both were Grade 3 dermatologic imARs. There were no treatment-related deaths.
Experts React
“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,” says CK-301-101 Investigator Emily Ruiz, MD, MPH, Associate Professor of Dermatology at Harvard Medical School and Academic Director of the Micrographic Surgery Center at Brigham and Women’s Hospital in Boston, MA, in a news release. “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,” says Dr. Ruiz, who is also Co-founder of Skin Cancer Champions
“This label update reinforces the importance of therapeutic diversity in advanced CSCC,” adds David Miller, MD, PhD, Co-Director of the MMSC Multi-Disciplinary Clinic at Massachusetts General Hospital Cancer Center in Boston, MA. “Having access to a treatment option that works in a different way than other checkpoint inhibitors can only benefit patients who are fighting this disease and demand an efficacious treatment with acceptable tolerability.”
Cosibelimab-ipdl) is a programmed death ligand-1 (PD-L1)-blocking antibody that was initially approved by the FDA in 2024. The recommended dosage is 1,200mg as an intravenous infusion over 60 minutes every three weeks.
Following the FDA’s approval of the cosibelimab-ipdl label, Sun Pharma will continue to focus on ensuring all appropriate patients have access to cosibelimab-ipdl while engaging with pathway and guideline groups, such as the National Comprehensive Cancer Network, to consider this important treatment option for future updates.
