APX005M in Combination With Systemic Pembrolizumab in Patients With Metastatic Melanoma

Study Groups: If you are found to be eligible to take part in this study, you will be assigned to a study group based on when you join this study. Up to 4 groups of 3 participants will be enrolled in Part 1, and up to 20 participants will be enrolled in Part 2. If you are enrolled in Part 1, the dose of APX005M you receive will depend on when you join this study. The first group of participants will receive the lowest dose level of APX005M. Each new group will receive a higher dose of APX005M than the group before it, if no intolerable side effects were seen. This will continue until the highest tolerable dose of APX005M is found. If you are enrolled in Part 2, you will receive APX005M at the highest dose that was tolerated in Phase 1 All participants will receive the same dose level of pembrolizumab. Study Drug Administration: APX005M will be injected directly into 1 tumor every 3 weeks (Weeks 0, 3, 6, and 9) for up to 4 doses. The injections may be done with or without the help of a ultrasound, CT, and MRI. If the doctor thinks it is needed, you may need to stay in the hospital overnight or be monitored by a caregiver for 24 hours after you receive APX005M. You will receive pembrolizumab by vein 1 time every 3 weeks (Weeks 0, 3, 6, 9, and 12). The first dose of pembrolizumab will be given 1-2 days before or after your first dose of APX005M. You will be given a diary to write down any injection site reactions you may have. Study Visits: Within 1 week before your first APX005M injection: * You will have a physical exam. * You will have a punch biopsy or image-guided biopsy of a tumor to check the status of the disease. To collect a biopsy, the area of skin is numbed with anesthetic and a small cut is made to remove all or part of the affected tissue. To collect a punch biopsy, the area of skin is numbed with anesthetic and a small cut is made to remove all or part of the affected tissue. To perform an image-guided biopsy, a needle is inserted into the affected area using imaging such as CT or ultrasound to collect cells or tissue from an organ, lymph node, or suspected tumor mass. The doctor will use the imaging to guide the needle into the area. * Blood (about 4½ tablespoons) will be drawn to test your immune system. If you can become pregnant, blood (about 1 teaspoon) may be drawn for a pregnancy test or urine may be collected to test for pregnancy. * The tumors may be measured and photographed. On Day 1 of Cycle 1: * You will have a physical exam. * Blood (about 5½ tablespoons) will be drawn for routine tests and test your immune system. * The tumor may be measured and photographed. On Day 2 of Cycle 1: * Your vital signs (blood pressure, heart rate, temperature, and breathing rate) will be measured. * Blood (about 1 teaspoon) will be drawn for routine tests. * You will have a biopsy of one of the injected tumor sites within about 24 hours after the 1st injection to check the status of the disease. On Day 3 of Cycle 1: * Your vital signs will be measured. * Blood (about 5 tablespoons) will be drawn for routine tests and to test your immune system. On Days 8 and 15 of Cycle 1: * Your vital signs will be measured. * Blood (about 1½ teaspoons) will be drawn for routine tests. * Blood (about 4½ tablespoons) may be drawn to test your immune system (Day 8 only). On Day 1 of Cycle 2: * You will have a physical exam. * Blood (about 5½ tablespoons) will be drawn for routine tests and to test your immune system. On Days 8 and 15 of Cycle 2: * Your vital signs will be measured. * Blood (about 1½ teaspoons) will be drawn for routine tests. * Blood (about 4½ tablespoons) may be drawn to test your immune system (Day 8 only). On Day 1 of Cycle 3 (± 3 days): * Your vital signs will be measured. * You will have a physical exam. * You will have a biopsy of one of the injected tumors and one of the tumors for which you did not have an injection to check the status of the disease. * The tumors may be measured and photographed. * You will have CT, MRI/CT, and/or an ultrasound to check the status of the disease. * Blood (about 2½ teaspoons) will be drawn for routine tests. If you can become pregnant, a pregnancy test may be performed. Urine may be collected for the pregnancy test. * Blood (about 4½ tablespoons) will be drawn to test your immune system. On Day 1 of Cycle 4: * Your vital signs will be measured * You will have a physical exam. * Blood (about 2½ teaspoons) will be drawn for routine tests * Blood (about 4½ tablespoons) will be drawn to test your immune system. On Day 1 of Cycles 5-8: * Your vital signs will be measured. * You will have a physical exam. * Blood (about 1½ teaspoons) will be drawn for routine tests. On Day 1 of Cycles 5 and 8 ONLY (± 3 days): * Blood (about 1½ teaspoons) will be drawn for routine tests. * Blood (about 4½ tablespoons) will be drawn to test your immune system. * You may have a biopsy of one of the injected tumors and one of the tumors for which you did not have an injection to check the status of the disease (Cycle 5 only). * The tumors may be measured and photographed. * You will have CT, MRI/CT, and/or an ultrasound to check the status of the disease. Cycles beyond Cycle 8: °You will have CT, MRI/CT, and/or an ultrasound to check the status of the disease (every 3 months for up to 2 years). Length of Treatment: You will be on study for up to 2 years. You will be taken off study if the disease gets worse, if intolerable side effects occur, or if you are unable to follow study directions. If your doctor thinks it is in your benefit, you may continue to receive pembrolizumab as standard of care after you are off this study. Your doctor will describe this in more detail. Off-Study Visit: If you have to go off study early because the disease got worse or you had intolerable side effects: * Your vital signs will be measured. * You will have a physical exam. * Blood (about 1½ teaspoons) will be drawn for routine tests. * Blood (about 4½ tablespoons) will be drawn to test your immune system. Follow-Up: Within 2 weeks after your last study drug dose and every 8-12 weeks after that, you may have scans to check the status of the disease. Your doctor will decide what type of scans you will have. If you choose to seek care at another hospital, the study staff will call you every 3 months for up to 2 years after your last study drug dose. You will be asked how you are doing. The calls should last about 5 minutes.