Sun Pharmaceutical announced the US Food and Drug Administration (FDA) approved an updated label for UNLOXCYT (cosibelimab-ipdl) for the treatment of adults with metastatic 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 multicenter, 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% of patients in the trial achieved the primary endpoint of objective response. In addition, 14% of mCSCC patients and 32% 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%) were fatigue, musculoskeletal pain, rash, diarrhea, hypothyroidism, constipation, nausea, headache, pruritus, edema, localized infection, and urinary tract infection. 53 patients (24%) in this study experienced imARs (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.
UNLOXCYT restores the adaptive immune response, enabling T cells to recognize 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-tumor 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,” said Richard Ascroft, CEO, Sun Pharma North America. “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.”
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,” said Emily Ruiz, MD, MPH, Associate Professor of Dermatology, Harvard Medical School, Academic Director of the Micrographic Surgery Center at Brigham and Women’s Hospital, co-founder of Skin Cancer Champions, and primary author on the long-term analysis publication. “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.”
Key Clinical Data From Updated Analysis (CK-301-101 Study):
| Efficacy Endpoints | mCSCC
n=78 |
laCSCC
n=31 |
| Objective Response Rate (ORR) | ||
| ORR, n (%)
(95% CI) |
39 (50)
(38, 62) |
17 (55)
(36, 73) |
| Complete response, n (%) | 10 (13) | 8 (26) |
| Partial response, n (%) | 29 (37) | 9 (29) |
| Duration of Response (DOR)a | ||
| Number of responders | n=39 | n=17 |
| Median DOR in monthsb(range) | NR (1.4+, 45.3+) | NR (8.3, 31.3+) |
| Responders with observed DOR ≥ 6 months, n (%)c | 33 (85) | 17 (100) |
| Responders with observed DOR ≥ 12 months, n (%)c | 26 (67) | 15 (88) |
CI: confidence interval; NR: not reached; +: Denotes ongoing at last assessment.
a Median follow up time: mCSCC: 29.3 months; laCSCC: 24.1 months.
b Based on Kaplan-Meier estimate.
c The numerator includes the number of patients whose observed DOR reached at least the specified times of 6 or 12 months. Patients who did not have the opportunity to reach the specified timepoint were included in the denominator only.
Incidence of CSCC
CSCC is the second most common type of skin cancer in the United States, with approximately 1 million people diagnosed annually. While most cases are localized tumors amenable to curative resection, each year in the United States approximately 40,000 cases progress to an advanced stage and approximately 15,000 people die of this disease. These patients with advanced-stage disease face limited treatment options and remain a population with a high unmet need.
“This label update reinforces the importance of therapeutic diversity in advanced CSCC,” said Dr. David Miller, Co-Director, NMSC Multi-Disciplinary Clinic, Mass General Brigham Cancer Institute. “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.”
Following the FDA’s approval of the UNLOXCYT label, Sun Pharma will continue to focus on ensuring all appropriate patients have access to UNLOXCYT while engaging with pathway and guideline groups, such as the National Comprehensive Cancer Network (NCCN), to consider this important treatment option for future updates.
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