This study begins with a screening period that lasts about 28 days to see if a person can join. If eligible, participants will receive a study medicine called JANX014. This is a new immune based drug that is given through a vein at a clinic or hospital. The medicine may be given once every week, every two weeks, or every three weeks, depending on the study group and safety results. The study has two parts. In the first part, small groups receive different dose levels to find a safe amount of the medicine. In the second part, more people receive selected doses to learn more about safety and early effects. During the study, participants will have regular visits that include physical exams, blood and urine tests, heart tests, and imaging scans such as CT or PET scans. Some early treatment visits may require short hospital stays so doctors can watch closely. Participants may also check their temperature and blood pressure at home.