Stopped: The trial is closing due to findings from a related study, prompting the sponsor to discontinue development and end this study.
Background: Metastatic colorectal cancer (mCRC) is cancer that has spread beyond the colon and rectum. Most people with mCRC die within 5 years. New immune-based treatments are making progress with some types of colon cancer. But these treatments do little for people with a type of cancer that is microsatellite stable (MSS). MSS is a specific cancer biomarker. Better treatments are needed. Objective: To test 2 drugs (tiragolumab and atezolizumab) combined with radiation therapy in people with MSS mCRC. Eligibility: People aged 18 years and older with MSS mCRC. Design: Participants will be screened. They will have a physical exam with blood tests. They will have imaging scans and a test of their heart function. They will provide a tissue sample from their tumor; if one is not already available, a new sample will be taken. Their ability to perform normal tasks will be assessed. Tiragolumab and atezolizumab are both administered through a tube attached to a needle inserted into a vein. Participants will receive both drugs on day 1 of 3-week treatment cycles. Each study visit should last about 8 hours. Participants will receive radiation therapy on days 1, 3, and 5 of cycle 1 only. Blood samples and rectal swabs will be collected on day 1 of every cycle. Imaging scans will be repeated every 9 weeks. Additional tumor samples may be taken during treatment. Treatment will continue for up to 2 years. Participants will have a follow-up visit 1 month after treatment ends. Follow-up visits will continue every 3 months for 1 more year.
Age range
18 Years – 120 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Confirm the recommended phase II dose (RP2D) of the combination therapy
Timeframe: Start of therapy through cycle 1 day 21
Determine the proportion of participants without progression after 9 weeks of the combination therapy
Timeframe: After 9 weeks of treatment