TOPLINE:

In an open-label trial of patients with metastatic or locally advanced cutaneous squamous cell carcinoma (cSCC), cosibelimab (Unloxcyt), a PD-L1 blocking monoclonal antibody, demonstrated durable objective response rates (ORRs) exceeding 50% and a low incidence of severe immune-related adverse events (irAEs) at more than 2 years of follow-up.

METHODOLOGY:

• Researchers conducted an open-label, multicenter, multicohort trial of 192 patients with cSCC: 78 with metastatic cSCC (mean age, 71.2 years; 75.6% men; 88.5% White) and 31 with locally advanced cSCC (mean age, 76.5 years; 61.3% men; 77.4% White) were included in the efficacy analysis.
• Patients received intravenous cosibelimab 800 mg every 2 weeks or 1200 mg every 3 weeks until disease progression or unacceptable toxicity.
• The primary endpoint was the ORR determined by an independent central review, with duration of response (DOR) and safety as secondary outcomes.
• Median follow-up duration was 29.3 months for the metastatic cSCC and 24.1 months for the locally advanced cSCC cohorts.

TAKEAWAY:

• The ORR was 50% in patients with metastatic disease and 54.8% in those with locally advanced disease, with complete response (CR) rates of 12.8% and 25.8%, respectively.
• The median duration of response was not reached; estimated 24-month response durability was 72.1% and 80.2% in metastatic and locally advanced disease cohorts.
• Treatment-emergent adverse events occurred in 94.3% of patients, with 32.8% experiencing serious events; irAEs were reported in 27.6% of patients, of which 3.6% were grade 3; there were no irAEs of grade 4 or above.
• Responses occurred regardless of PD-L1 expression: Among patients with metastatic disease, ORRs were 51% in those with PD-L1-positive tumors and 44% in those with PD-L1-negative tumors. Similarly, in the locally advanced cohort, response rates were 53% and 38%, respectively.

IN PRACTICE:

“In this pivotal study of patients with [metastatic] cSCC and [locally advanced] cSCC, cosibelimab was associated with robust and clinically meaningful ORRs ≥ 50% and CR rates, durable DORs, and a manageable safety profile with low rates of grade 3 irAEs and no grade ≥ 4 irAEs,” the study authors wrote. The results “provide additional support for the use of cosibelimab in these patients,” they added.

SOURCE:

The study was led by Emily S. Ruiz, MD, Department of Dermatology, Brigham and Women’s Hospital, Boston, and was published online on September 29 in the Journal of the American Academy of Dermatology.

LIMITATIONS:

The study limitations included its single-cohort design, short follow-up, limited biomarker analysis, and absence of pathologic confirmation of CR in externally visible target lesions.

DISCLOSURES:

The study was funded by Checkpoint Therapeutics. Ruiz disclosed serving as a consultant for Checkpoint Therapeutics, Feldan Therapeutics, Merck, Regeneron Pharmaceuticals, and Replimune. Three authors reported being employees and holding stocks in Checkpoint Therapeutics. Several authors reported receiving consulting fees, advisory fees, personal authors, and financial support from various pharmaceutical companies. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.