Evaluation of RBS2418 in Patients with Advanced, Metastatic, and Progressive Colorectal Cancer

RBS2418 is a specific immune modulator that works through the inhibition of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and is designed to lead to anti-tumor immunity by protecting endogenous 2'-3'-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) from hydrolysis and leading to the activation of antigen-presenting cells followed by T cell activation. The hypothesis is that RBS2418 versus placebo will be generally safe, well-tolerated, immunogenic, and will lead to anti-tumor responses in adult subjects for the treatment of advanced, metastatic, and progressive colorectal cancer (CRC).

In this Phase 2a study, subjects must have failed, been unable to tolerate, or declined to take known standard-of-care (SOC) therapies. Subjects must have measurable disease per RECIST 1.1, an Eastern Cooperative Oncology Group (ECOG) performance score of 0, 1 or 2, and predicted life expectancy of greater or equal to 3 months.

Up to approximately 150 subjects will be enrolled and will receive therapy as part of their respective treatment group. Subjects will receive study treatment of RBS2418 or Placebo to Match plus Best Supportive Care with a treatment period consisting of 21-day cycles up to two years or until there is progressive disease (PD), death, withdrawal, or study completion, whichever comes first.

Adverse events (AEs) will be monitored throughout the study and graded in severity according to the guidelines outlined in the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v5.0. AEs will be collected until up to 30 days after the end of treatment or until resolution, whichever comes first. Serious Adverse Events (SAEs) will be collected for 90 days after the end of treatment, or if the subject initiates new anti-cancer therapy, then 30 days after the end of treatment, whichever is earlier.