Testing the Combination of Anti-cancer Drugs Atezolizumab and Tiragolumab in People With Advanced Stage Rare Cancers, RARE3 Trial

This phase II trial tests how well atezolizumab works in combination with tiragolumab in treating patients with rare solid tumors that may have spread from where they first started to nearby tissue, lymph nodes, or distant parts of the body (advanced stage). Immunotherapy with monoclonal antibodies, such as atezolizumab and tiragolumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. The study biopsy takes small pieces of cancer tissue from a tumor. The purpose of these biopsies is to compare the body's immune response against the tumor before and after treatment with the study drugs. Blood samples will also be collected for the study. The researchers will use the samples to learn more about how atezolizumab and tiragolumab work and which patients in the future might be most likely to respond to atezolizumab and tiragolumab. Using atezolizumab in combination with tiragolumab may help to shrink tumors in patients diagnosed with advanced stage rare solid-tumor cancers.