In Advanced Squamous Cell Carcinoma, Cosibelimab Led to Enduring Responses

Treatment with cosibelimab (CK-301) produced deep responses in patients with locally advanced or metastatic cutaneous squamous cell carcinoma (cSCC), according to a press release on long-term data from a phase 1 clinical trial (NCT03212404).¹

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As of the data cutoff of January 2023, cosibelimab elicited an objective response rate (ORR) of 55% (95% CI, 36%-73%) in a cohort of patients with locally advanced cSCC (n = 31) and 50% (95% CI, 39%-62%) in the metastatic cSCC cohort (n = 78). Additionally, the complete response (CR) rate in each respective cohort was 23% and 13%, and the partial response (PR) rate was 32% and 37%. Moreover, 82% and 69% of patients in each cohort had an ongoing response, and the median duration of response (DOR) was not reached in either cohort, respectively.

Across 247 patients who have received cosibelimab in all cohorts, 2% of patients had a severe immune-related adverse effect (IRAE), and less than 1% had IRAEs that led to treatment discontinuation.

Developers plan to present updated data from the study at a future medical conference.

“We are excited to see the substantial increases in the rate of patients experiencing a complete response of their cSCC tumors with further cosibelimab treatment in both our locally advanced and metastatic pivotal trials,” James Oliviero, president and chief executive officer at Checkpoint Therapeutics, said in the press release. “We believe cosibelimab’s favorable safety profile should position the product as the preferred immunotherapy of oncologists for the large number of patients [with high-risk cSCC], such as those with solid organ transplants or autoimmune disease, upon its potential launch early next year.”

In the open-label, multi-center phase 1 study, investigators are assessing the anti–PD-L1 antibody cosibelimab as a treatment for patients with cutaneous squamous cell carcinoma and other types of cancer including melanoma, renal cell carcinoma, urothelial carcinoma, and endometrial cancer. Patients received cosibelimab as part of 28-day cycles.

The study’s primary end points include dose-limiting toxicities, treatment-emergent AEs, and ORR per RECIST v1.1 criteria. Secondary end points include DOR, overall survival, and pharmacokinetics.

Patients 18 years and older with an ECOG performance status of 0 to 1 and at least 1 measurable lesion per RECIST v1.1 criteria were eligible for enrollment on the trial. Additional inclusion criteria included having adequate hematological, hepatic, and renal function as well as formalin fixed tumor tissue sample from a biopsy at the time of or after diagnosis of metastatic disease from a site not previously irradiated.

Those who received prior therapy with an anti–PD-L1, anti–PD-L2, anti–CD137, or anti–CTLA-4 antibody were not able to enroll on the study. Patients were also unsuitable for enrollment if they had interstitial lung disease, active or suspected autoimmune disease, or uncontrolled or significant cardiovascular disease.

The FDA accepted a biologics license application (BLA) for cosibelimab as a treatment for those with metastatic or locally advanced cSCC in January 2023.²

“If our BLA is approved in the coming months, based on its unique mechanism of action and compelling efficacy and safety profile, we believe cosibelimab, as a differentiated and possibly best-in-class treatment, has the potential to become the market leading immunotherapy for patients with cSCC,” Oliviero concluded.

References

1. Checkpoint Therapeutics announces cosibelimab longer-term results demonstrating substantial increases in complete response rates in advanced cutaneous squamous cell carcinoma. News release. Checkpoint Therapeutics, Inc. July 27, 2023. Accessed July 28, 2023. https://shorturl.at/cgrEH
2. Checkpoint Therapeutics submits biologics license application to FDA for cosibelimab as a treatment for patients with metastatic or locally advanced cutaneous squamous cell carcinoma. News release. Checkpoint Therapeutics, Inc. January 4, 2023. Accessed July 28, 2023. yhoo.it/3GqykPg

[This article was originally published by our sister brand, Cancer Network.]