Sun Pharma’s UNLOXCYT™ (cosibelimab-ipdl) demonstrated durable efficacy in locally advanced cutaneous squamous cell carcinoma at ASCO 2026, with a 50% objective response rate and sustained benefit beyond 31 months, reinforcing its role as a tolerable immunotherapy option for older patients.
Written By: Shaik Yasmeen, PharmD
Reviewed By: Pharmacally Editorial Team
Sun Pharmaceutical Industries presented updated long-term results from the pivotal CK-301-101 trial (NCT03212404) of UNLOXCYT™ (cosibelimab-ipdl) in locally advanced cutaneous squamous cell carcinoma (laCSCC) at the 2026 ASCO Annual Meeting. In 64 treated patients, the objective response rate (ORR) was 50%, including 27% complete responses and 23% partial responses. At a median follow-up of 31 months, the median duration of response remained unreached, underscoring sustained benefit.
Patient Population and Treatment Exposure
The study cohort reflected real-world practice, with a median age of 77 years and 66% male. Patients received a median of 29 doses over 60 weeks. These data highlight clinically meaningful activity in an older population often burdened by comorbidities and limited treatment options.
Safety Profile
Safety findings were consistent with prior analyses. Treatment-emergent adverse events (TEAEs) occurred in 95% of patients, with 78% considered treatment-related. Grade ≥3 TEAEs were reported in 41% of patients, though only 11% were treatment-related. No treatment-related fatal events occurred. Immune-related adverse reactions were observed in 34% of patients, with only one Grade ≥3 case involving dermatologic toxicity. The most frequent adverse events were anemia and diarrhea (27% each).
Mechanistic Distinction
Cosibelimab is a PD-L1–targeting monoclonal antibody that restores antitumor immune activity. Investigators noted its potential to preserve PD-1/PD-L2 signaling while engaging innate immune mechanisms, a feature that may contribute to durable responses.
Clinical Implication
Rahul Ladwa, MBChB, FRACP, of Princess Alexandra Hospital and The University of Queensland, emphasized the high complete response rate and durability of benefit in a population with substantial unmet need.
Emily Ruiz, MD, MPH, of Harvard Medical School and Brigham and Women’s Hospital, highlighted the importance of tolerable regimens for older patients, noting cosibelimab’s distinct immunologic profile as a possible driver of sustained efficacy.
Regulatory and Competitive Landscape
UNLOXCYT is approved in the U.S. for adults with metastatic or locally advanced CSCC not amenable to curative surgery or radiation. While the pivotal trial used 800 mg every two weeks, the approved regimen is 1,200 mg every three weeks, supported by pharmacokinetic and pharmacodynamic modeling demonstrating equivalent exposure and PD-L1 receptor coverage.
Cosibelimab joins established PD-1 inhibitors such as cemiplimab and pembrolizumab in the advanced CSCC setting. The extended follow-up presented at ASCO 2026 positions UNLOXCYT as a durable and tolerable alternative, reinforcing its role in the evolving immunotherapy landscape.
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About the Writer
Shaik Yasmeen (LinkedIn) is a Pharm.D graduate with interests in clinical pharmacy, pharmacovigilance, and medical writing. She has gained experience through hospital clinical postings, patient case reviews, case presentations, and literature evaluation. Passionate about evidence-based healthcare, she is committed to creating accurate and engaging medical content while continuously expanding her professional knowledge.