Purple Biotech Ltd. announced positive interim data from its randomized, controlled, open label, multicenter Phase 2 study of CM24 in second-line metastatic pancreatic ductal adenocarcinoma (PDAC) presented at a late-breaking abstract poster presentation at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting. The Phase 2 study is evaluating CM24, a novel first-in-class multi-functional anti-CEACAM1 antibody, in combination with Bristol Myers Squibb?s immune checkpoint inhibitor nivolumab plus SoC chemotherapy in second-line PDAC patients versus SoC chemotherapy alone. CM24 is a humanized monoclonal antibody that blocks CEACAM1, an immune checkpoint protein responsible for tumor immune evasion and poor tumor response and/or resistance to immune checkpoint inhibitors.

The primary endpoint of the study is OS and the secondary endpoints include PFS, ORR and DCR. A Bayesian methodology was used to estimate the magnitude of effect of the experimental arm versus the SoC arm and the study is not powered for hypothesis testing. A total of 63 patients have been enrolled, across 18 centers in the U.S., Spain, and Israel in 2 parallel independent randomized study cohorts (total of 2 arms per cohort).

The experimental arms administered patients with CM24 plus nivolumab and a choice of one of two SoC chemotherapies for second-line PDAC, dependent on prior first line therapy regimen; either gemcitabine/nab-paclitaxel or liposomal irinotecan (Nal-IRI)/5-fluorouracil (5-FU) and leucovorin (LV) (Nal-IRI/5FU/LV), while the control arms administered either respective chemotherapy alone. CA19-9 as well as additional exploratory biomarkers are also being evaluated. Of the 63 patients enrolled, 32 were in the gemcitabine/nab-paclitaxel study (experimental and control) and 31 were in the Nal-IRI/5FU/LV study (experimental and control).

An analysis of the gemcitabine/nab-paclitaxel study will be performed when the data are sufficiently mature. Topline final data are expected by the end of 2024.