Sumitomo Dainippon Pharma Oncology has announced that the CanStem303C study evaluating the efficacy and safety of investigational agent napabucasin, when given in combination with FOLFIRI with or without bevacizumab in patients with previously treated metastatic colorectal cancer, failed to reach the primary endpoints of overall survival (OS).
Napabucasin in combination with FOLFIRI failed to show significant OS improvement in the general study population and in patients whose tumour was positive for the phosphorylated signal transducer and activator of transcription 3 (pSTAT3) biomarker.
"Patients with metastatic colorectal cancer have a high unmet medical need, and our hope was to develop a new treatment option for this population. We are disappointed with the results of this Phase 3 trial and would like to express gratitude to the trial participants, investigators and staff for their efforts and contributions to the study," said Patricia S Andrews, CEO and Global Head of Oncology, Sumitomo Dainippon Pharma Oncology (SDP Oncology). "SDP Oncology is committed to continuing our pursuit of advancing our pipeline to bring forward innovative treatments for patients with cancer."
The multi-centre, open-label, randomized Phase 3 CanStem303C study evaluated the efficacy and safety of napabucasin in approximately 1,250 patients with previously treated metastatic colorectal cancer. Patients were randomised 1:1 in the study. The study had two primary endpoints – overall survival in all randomized patients and overall survival in a subpopulation of patients whose tumour was positive for the pSTAT3 biomarker. Napabucasin at a dose of 240mg was administered orally, twice daily in combination with FOLFIRI with or without bevacizumab versus FOLFIRI with or without bevacizumab.
The most common adverse events, occurring in patients in the napabucasin combination arm, were consistent with previously published data and included diarrhoea, nausea, vomiting and abdominal pain.
Final data and analyses of this study will be published for the oncology community.