Purple Biotech Ltd. announced the completion and data maturity of its Phase 1 dose escalation study of CM24, a first-in-class anti-CEACAM1 monoclonal antibody addressing multiple tumor types. In the dose escalation part of the study, 11 refractory, pancreatic ductal adenocarcinoma (PDAC) patients whose cancer progressed following two lines of prior therapies were treated with CM24 at 10, 15 and 20mg/kg once every two weeks (q2w) and nivolumab at 480mg once every four weeks (q4w). The investigational immunotherapy combination was well tolerated across all dose levels with no recorded Drug Limiting Toxicities (DLTs).

Grade 3 adverse events were reported in 6 of the patients and none was considered related to the study drugs. No Grade 4 or deaths were reported. Overall Survival (OS) data across all dose levels from this study with Purple’s chemo free CM24 in combination with nivolumab, demonstrated comparable OS rate in comparison to historical data of third line patients treated with chemotherapy, which demonstrate an OS median rate in a range of 3 to 4 months1.

Among the patients who demonstrated a response or disease control from the CM24 + nivolumab treatment, one third line patient has survived for 14.6 months. The patient had Microsatellite Stable (MSS) and PDL-1 IHC 2+ and 5% staining, features not expected to respond to immuno-oncology therapy. Based on the study’s safety, tolerability, efficacy, pharmacokinetic and pharmacodynamic data, the recommended Phase 2 dose of CM24 in combination with nivolumab was determined to be 20mg/kg.

The company believe that these encouraging and confirmed final results provide additional support to the rationale for conducting the already initiated Phase 2 randomized study of CM24 in combination with nivolumab and standard of care chemotherapy vs. standard of care chemotherapy alone, in the second line PDAC setting. This randomized Phase 2 study (NCT04731467) is being conducted as part of Purple Biotech's clinical collaboration with Bristol Myers Squibb.