Dose Escalation/Expansion Study of Mavrostobart (PT199), an Anti-CD73 mAb, Administered Alone and in Combination With a PD-1 Inhibitor or Chemotherapy (the MORNINGSTAR Study)

This study is testing a new cancer drug called mavrostobart (PT199) — either alone or combined with another immunotherapy or chemotherapy — in people with advanced solid tumors. The drug is designed to help the immune system fight cancer by blocking a protein called CD73 that some tumors use to hide from the immune system. **You may be eligible if:** - You have advanced or metastatic solid tumors that have progressed on prior treatments - For the lung cancer group: you have non-small cell lung cancer (NSCLC) without certain genetic mutations, or advanced pancreatic cancer that has progressed on prior therapy - You have at least one measurable tumor that can be tracked on scans **You may NOT be eligible if:** - You have not received prior treatment for your cancer - Your tumor type does not match the specific groups being studied - Your overall health and organ function do not meet study requirements Talk to your doctor to see if this trial is right for you.