Metastatic Alveolar Soft Part Sarcoma

This phase II trial tests whether atezolizumab in combination with selinexor works to shrink tumors in patients with alveolar soft part sarcoma and whether the study drugs are better than the usual approach in treating this type of cancer. The usual approach is defined as care most people get for alveolar soft part sarcoma if they are not part of a clinical study, which includes treatment with radiation, kinase inhibitor drugs, immunotherapy drugs, or chemotherapy drugs. Immunotherapy with monoclonal antibodies, such as atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Selinexor is in a class of medications called selective inhibitors of nuclear export (SINE). It works by blocking a protein called CRM1, which may help keep cancer cells from growing and may kill them. Giving atezolizumab in combination with selinexor may help shrink tumors and stabilize the cancer in patients with alveolar soft part sarcoma.

Background: A type of drug called monoclonal antibody immune checkpoint inhibitors are often used in cancer treatment. These drugs help the body s immune system fight cancer by blocking proteins that cause cancer cells to grow. One of these drugs (atezolizumab) is approved to treat certain cancers. Researchers want to find out if lower doses of this drug might provide the same benefit with fewer adverse effects. Objective: To test different doses and timing of atezolizumab for people with cancer. Eligibility: People aged 18 years and older with cancer that has spread locally or to other organs. They must be eligible for treatment with the study drug. Design: Participants will be screened. They will have blood tests and imaging scans. They will provide a sample of tissue from their tumor. Atezolizumab is administered through a tube attached to a needle inserted into a vein in the arm. Participants will take this drug alone or combined with other drugs prescribed for their care. The first 2 treatments will be done per the FDA recommended dose and schedule. Before administering the second dose of the study drug, researchers will check the level of the drug in the participant s blood. Depending on those results, their 3rd dose will be scheduled 2 to 6 weeks later. For the 3rd dose of the study drug, participants will switch to the FDA minimum dosage. Dosages of any other drugs will not change. Researchers will continue to test the levels of the drug in participants blood before each treatment for 16 weeks. After that, these levels will be tested every 3 months. Study treatment may last up to 2 years.