Sun Pharmaceutical Industries Limited has secured a significant regulatory milestone after the U.S. Food and Drug Administration (FDA) approved an updated label for UNLOXCYT™ (cosibelimab-ipdl), the company’s innovative PD-L1 inhibitor for advanced cutaneous squamous cell carcinoma (aCSCC). The approval follows the submission of robust long-term follow-up data from the pivotal CK-301-101 clinical trial, which demonstrated improved clinical outcomes, greater durability of response, and a favorable safety profile across both metastatic and locally advanced patient groups.

This development marks another major step in Sun Pharma’s ongoing strategy to expand its presence in the global oncology and immunotherapy space. The company, now recognized as a leading global specialty generics manufacturer with an expanding innovative medicines portfolio, has emphasized that the updated label further validates UNLOXCYT’s differentiated mechanism of action and its long-term clinical value.

A Breakthrough in Checkpoint Inhibition for aCSCC

UNLOXCYT is the first and only PD-L1 immune checkpoint inhibitor approved specifically for aCSCC, a form of skin cancer that remains a significant clinical challenge, particularly among elderly patients and those with multiple comorbidities.

Traditional treatment options for advanced CSCC are limited, often resulting in poor long-term outcomes, reduced quality of life, and high morbidity. UNLOXCYT aims to fill this critical therapeutic gap by offering a biologically targeted and immunologically sophisticated approach.

The FDA’s decision to update the drug’s label was driven by compelling data from the CK-301-101 trial, a multicenter, multicohort, open-label study involving 109 patients with either metastatic (mCSCC) or locally advanced (laCSCC) disease.

Key Findings From the CK-301-101 Long-Term Analysis

The long-term follow-up demonstrated that UNLOXCYT delivers sustained clinical benefits, reinforcing its role as a transformative therapy for patients with advanced CSCC.

Objective Response Rate (Primary Endpoint)

The updated data showed:

• 50% ORR in metastatic CSCC patients (39 of 78 patients)

• 55% ORR in locally advanced CSCC (17 of 31 patients)

• Stronger complete responses in laCSCC (26%) compared with mCSCC (13%)

These figures indicate that at least half of all treated patients experienced clinically meaningful objective tumor responses, an important benchmark in a disease category with historically poor outcomes.

Durability of Response

Perhaps the most striking result is that median duration of response (DOR) was not reached (NR) in either cohort, even with median follow-up periods of 29.3 months (mCSCC) and 24.1 months (laCSCC).

• 85% of mCSCC responders maintained DOR ≥6 months

• 100% of laCSCC responders maintained DOR ≥6 months

• 67% of mCSCC responders maintained responses ≥12 months

• 88% of laCSCC responders maintained responses ≥12 months

These results underscore the durability of UNLOXCYT’s clinical effect, strengthening its position among next-generation immunotherapies.

Safety Profile: No New Risks Identified

The FDA confirmed that no changes were necessary to UNLOXCYT’s safety profile, further reassuring clinicians about its use in a population often burdened with comorbidities.

Adverse Reactions

The most common treatment-related reactions (≥10%) included:

• Fatigue

• Musculoskeletal pain

• Rash

• Diarrhea

• Hypothyroidism

• Constipation

• Nausea

• Pruritus

• Localized infections

• Urinary tract infection

Importantly, only 0.9% of patients experienced high-grade immune-mediated reactions, with no treatment-related deaths reported.

This low incidence of severe immune-mediated reactions reflects UNLOXCYT’s distinct mechanism that spares PD-L2, potentially preserving immune tolerance in non-tumor tissues.

A Mechanism Uniquely Positioned for Efficacy and Tolerability

UNLOXCYT operates through dual engagement of the adaptive and innate immune systems, setting it apart from other checkpoint inhibitors.

1. PD-L1 Blockade

By inhibiting PD-L1 binding with PD-1 and B7.1, the drug reactivates T-cell recognition of cancer cells.

2. Antibody-Dependent Cellular Cytotoxicity (ADCC)

The Fc domain actively binds natural killer (NK) cells, amplifying innate immune activity.

This dual mechanism, combined with PD-L2 sparing, positions UNLOXCYT as a refined and balanced immunotherapy offering strong efficacy with an acceptable safety profile.

Expert Reactions Highlight Clinical Significance

Healthcare leaders in oncology and dermatology have noted the significance of this updated label.

Richard Ascroft, CEO, Sun Pharma North America

He emphasized that long-term data shows patients not only responded well but maintained responses longer than earlier analyses suggested. He described the approval as proof of Sun Pharma’s commitment to data-driven innovation.

Dr. Emily Ruiz, Harvard Medical School

Dr. Ruiz highlighted the unmet needs in the aCSCC population, particularly among those over 65 with comorbidities. She noted that UNLOXCYT strikes a rare balance between efficacy and tolerability.

Dr. David Miller, Mass General Brigham Cancer Institute

He stressed the importance of therapeutic diversity in aCSCC care and welcomed UNLOXCYT’s differentiated immune approach, which may address critical gaps in current treatment pathways.

Disease Landscape: Why This Matters for CSCC Patients

CSCC is the second most common form of skin cancer in the U.S., with nearly 1 million diagnoses annually. Most cases remain localized, but:

• ~40,000 cases progress to advanced stages each year

• ~15,000 annual deaths occur due to aggressive disease progression

Advanced CSCC often leads to profound functional and cosmetic morbidity, particularly in the head and neck where tumors may infiltrate vital structures. With curative surgery or radiation often not feasible, effective systemic therapies like UNLOXCYT are critical.

Commercial Rollout and Future Plans

Sun Pharma confirmed that it plans to commercially launch UNLOXCYT in early 2026, leveraging its global specialty medicines network.

The company also intends to engage with key guideline-setting bodies such as the National Comprehensive Cancer Network® (NCCN®) to support the integration of UNLOXCYT into future clinical practice guidelines.

This aligns with Sun Pharma’s broader strategy to expand its footprint in advanced dermatology, onco-dermatology, and immunotherapy.

Strengthening Sun Pharma’s Global Innovation Portfolio

Sun Pharma, already the largest pharmaceutical company in India and a leading generics provider in the U.S. market, continues to strengthen its innovative therapeutics pipeline. Its dermatology, ophthalmology, and onco-dermatology portfolios now contribute roughly 20% of its revenue.

UNLOXCYT, recently recognized as a finalist for the 2025 Prix Galien USA Bridges Award, is emerging as one of the most promising assets in its growing immuno-oncology lineup.

Conclusion: A Significant Step Forward for aCSCC Treatment

The FDA’s approval of the updated UNLOXCYT label represents a major advancement for patients with advanced cutaneous squamous cell carcinoma. With strong long-term data, durable responses, and a favorable safety profile, UNLOXCYT stands out as a next-generation immunotherapy poised to transform outcomes for thousands of patients who previously had limited options.

For Sun Pharma, the decision reinforces its leadership in specialty medicine and fortifies its commitment to addressing unmet clinical needs through innovation.

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