Positive and clinically meaningful pivotal clinical results announced in 2022 in both metastatic and locally advanced indications

WALTHAM, MA, USA I January 04, 2023 I Checkpoint Therapeutics, Inc. (“Checkpoint”) (Nasdaq: CKPT), a clinical-stage immunotherapy and targeted oncology company, today announced the submission of a Biologics License Application (“BLA”) to the U.S. Food and Drug Administration (“FDA”) for the approval of cosibelimab, its investigational anti-PD-L1 antibody, as a treatment for patients with metastatic cutaneous squamous cell carcinoma (“cSCC”) or locally advanced cSCC who are not candidates for curative surgery or radiation.

“This is a major milestone for Checkpoint Therapeutics, representing our first submission of a marketing application for one of our investigational medications and furthering our evolution from a development-stage company to a fully integrated commercial organization to support the potential launch of cosibelimab,” said James Oliviero, President and Chief Executive Officer of Checkpoint. “cSCC is the second most common type of skin cancer in the United States. While most cases involve localized tumors amenable to curative resection, approximately 40,000 cases will become advanced, and an estimated 15,000 people will die from their disease each year. Based on its compelling and differentiated product profile and the positive data generated to date, we believe cosibelimab has the potential to be an important treatment option for patients. Importantly, we continue to plan for cosibelimab to be positioned, upon regulatory approval, as potentially the first and only price disruptive PD-1/PD-L1 inhibitor in the U.S. market.” Mr. Oliviero continued, “We want to thank the patients and their families, as well as the physicians and their research teams, who participated in our trial and contributed immensely to the advancement of cosibelimab.”

The BLA submission is based on positive efficacy and safety results from Checkpoint’s ongoing registration-enabling, multi-regional, multicohort clinical trial evaluating cosibelimab administered as fixed doses of either 800 mg every two weeks or 1200 mg every three weeks in patients with selected recurrent or metastatic cancers, including pivotal cohorts in metastatic and locally advanced cSCC.

In January 2022, Checkpoint announced that the metastatic cSCC cohort met its primary endpoint, with cosibelimab demonstrating a confirmed objective response rate (“ORR”) of 47.4% (95% CI: 36.0, 59.1) based on independent central review of 78 patients enrolled in the cohort using Response Evaluation Criteria in Solid Tumors version 1.1 (“RECIST 1.1”) criteria. In June 2022, Checkpoint announced positive interim results from its locally advanced cSCC cohort, with cosibelimab demonstrating a confirmed ORR of 54.8% (95% CI: 36.0, 72.7) based on independent central review of 31 patients enrolled in the cohort, exceeding a clinically meaningful lower bound of the 95% two-sided confidence interval of 25%. Based upon interactions with the FDA, the BLA submission includes both the metastatic and locally advanced cSCC indications.

About Cutaneous Squamous Cell Carcinoma
Cutaneous squamous cell carcinoma is the second most common type of skin cancer in the United States, with an estimated annual incidence of approximately 1 million cases according to the Skin Cancer Foundation. While most cases are localized tumors amenable to curative resection, approximately 40,000 cases will become advanced, and an estimated 15,000 people will die from their disease each year. In addition to being a life-threatening disease, cSCC causes significant functional morbidities and cosmetic deformities based on tumors commonly arising in the head and neck region and invading blood vessels, nerves and vital organs such as the eye or ear.

About Cosibelimab
Cosibelimab is a potential best-in-class, high affinity, fully-human monoclonal antibody of IgG1 subtype that directly binds to programmed death ligand-1 (“PD-L1”) and blocks the PD-L1 interaction with the programmed death receptor-1 (“PD-1”) and B7.1 receptors. Cosibelimab’s primary mechanism of action is based on the inhibition of the interaction between PD-L1 and its receptors PD-1 and B7.1, which removes the suppressive effects of PD-L1 on anti-tumor CD8+ T-cells to restore the cytotoxic T cell response. Cosibelimab is potentially differentiated from the currently marketed PD-1 and PD-L1 antibodies through sustained >99% target tumor occupancy to reactivate an antitumor immune response and the additional benefit of a functional Fc domain capable of inducing antibody-dependent cell-mediated cytotoxicity (“ADCC”) for potential enhanced efficacy in certain tumor types.

About Checkpoint Therapeutics

Checkpoint Therapeutics, Inc. (“Checkpoint”) is a clinical-stage immunotherapy and targeted oncology company focused on the acquisition, development and commercialization of novel treatments for patients with solid tumor cancers. Checkpoint is evaluating its lead antibody product candidate, cosibelimab, a potential best-in-class anti-PD-L1 antibody licensed from the Dana-Farber Cancer Institute, in an ongoing open-label, multi-regional, multicohort Phase 1 clinical trial in checkpoint therapy-naïve patients with selected recurrent or metastatic cancers, including cohorts in metastatic and locally advanced cutaneous squamous cell carcinoma (“cSCC”) intended to support one or more applications for marketing approval. Based on positive topline and interim results in metastatic and locally advanced cSCC, respectively, Checkpoint submitted a Biologics License Application for these indications in January 2023. Checkpoint is evaluating its lead small-molecule, targeted anti-cancer agent, olafertinib (formerly CK-101), a third-generation epidermal growth factor receptor (“EGFR”) inhibitor, as a potential new treatment for patients with EGFR mutation-positive non-small cell lung cancer. Checkpoint is headquartered in Waltham, MA and was founded by Fortress Biotech, Inc. (Nasdaq: FBIO). For more information, visit www.checkpointtx.com.

SOURCE: Checkpoint Therapeutics