The study is composed of two arms, RXC004 monotherapy (Arm A) and RXC004 in combination with nivolumab (Arm B). 20 evaluable patients will be enrolled in Arm A and 20 eligible patients in Arm B.~The study initially opened with Arm A; Arm B will be opened once a recommended Phase II dose (RP2D) for RXC004 in combination with nivolumab is established in the phase I dose escalation study (NCT03447470).~Once Arm B is opened, patients who are eligible for both Arm A and Arm B will be randomised 2:1 to Arm B: Arm A in an open-label manner.~Patients in Arm A may be treated with RXC004 + nivolumab if they have progressive disease on the 8 week scan, as long as they are eligible for Arm B and have Sponsor approval.
This is a Phase II, open label, multicentre, multi-arm, study to evaluate the preliminary efficacy and safety of RXC004 as monotherapy and in combination with nivolumab in patients with Ring finger protein 43 (RNF43) or R-spondin (RSPO) aberrated, microsatellite stable (MSS), colorectal cancer (CRC), that have progressed following current standard of care treatment.