A Phase II Clinical Trial Comparing the Efficacy of RO7198457 Versus Watchful Waiting in Patients With ctDNA-positive, Resected Stage II (High Risk) and Stage III Colorectal Cancer

Must have received: adjuvant chemotherapy — post-surgery

The patient has started a standard of care AdCTx preferably within 8 weeks but no later than 10 weeks post-surgery and has completed at least 3 months of treatment of a 3- or a 6-month course of chemotherapy (including rest days). For the CLM Cohort: patient must have completed AdCTx with or without (neo-)adjuvant chemotherapy for up to 6 months in total or total intended amount determined by care providers per SoC. AdCTx must have started preferably within 8 weeks, but no later than 10 weeks, after hepatectomy. For the Biomarker Cohort: patient must have received at least one cycle of adjuvant chemotherapy per institutional standards.

Cannot have received: neo-adjuvant (radio)chemotherapy

Exception: Exception for the CLM Cohort: (neo-)adjuvant chemotherapy prior to curative-intent hepatectomy is accepted.

Prior therapy with any of the following: Neo-adjuvant (radio)chemotherapy prior to surgery.

Cannot have received: systemic immunosuppressive medication

Exception: low dose steroids defined as 10 mg oral prednisone (or equivalent)

Treatment with systemic immunosuppressive medication within 2 weeks prior to initiation of trial treatment or anticipation of need for systemic immunosuppressive medication during trial treatment, with the exception of low dose steroids defined as 10 mg oral prednisone (or equivalent).

Cannot have received: investigational drug

Current or recent (within the 28 days prior to randomization) treatment with another investigational drug.