Checkpoint Therapeutics announces interim results for anti-PD-L1 cosibelimab
Checkpoint Therapeutics announced that positive interim results for cosibelimab, a potentially differentiated high affinity anti-PD-L1 antibody with functional Fc domain, were presented on Saturday, September 28th, at the European Society for Medical Oncology Congress 2019 in Barcelona, Spain. The poster presentation provided updated interim efficacy and safety results from Checkpoint's ongoing multicenter Phase 1 clinical trial, including expansion cohorts in cutaneous squamous cell carcinoma and non-small cell lung cancer. Checkpoint continues to enroll CSCC patients to support an initial Biologics License Application submission for cosibelimab based on this ongoing clinical trial. The Phase 1, open-label, multicenter trial is evaluating the safety, efficacy and pharmacokinetics of cosibelimab in checkpoint therapy-naive patients with selected recurrent or metastatic cancers. Following dose escalation, the trial initiated multiple disease-specific expansion cohorts, including in CSCC and NSCLC, evaluating a fixed dose of 800 mg cosibelimab dosed intravenously every two weeks. As of August 5, 2019, 81 patients with diverse tumor types have been treated with cosibelimab. Sixty-eight patients were evaluable for efficacy at the time of data cutoff, having at least two tumor assessments or discontinued treatment prior. Key efficacy results were as follows: 50% objective response rate in CSCC patients per RECIST v1.1. One patient achieved a complete response and six patients achieved partial responses. All seven responses are confirmed and ongoing with the longest duration at 11.4 months at the time of analysis. 40% ORR in first-line NSCLC patients with high expression of PD-L1 per RECIST v1.1. Ten patients achieved partial responses. Nine of 10 responses are ongoing with the longest duration at 11 months at the time of analysis. Cosibelimab appeared to be safe and well-tolerated with a potentially favorable safety profile as compared to the currently available anti-PD-1 therapies. Treatment-related adverse events occurred in 48/81 patients, most commonly rash, fatigue, hypothyroidism, anemia, alanine aminotransferase increase, diarrhea, and infusion-related reaction. Treatment-related grade greater than or equal to3 AEs occurred in 5/81 patients, with only two patients discontinuing treatment due to a treatment-related AE.