Trial of TRX518 (Anti-GITR mAb) in Stage III or IV Malignant Melanoma or Other Solid Tumors

The following visits are required: Part A: * Screening visit: 1 to 2 appointments will be conducted to determine eligibility. All or most requirements can be determined from the patient's medical records. * Baseline visit: within 7 days of the planned study dosing day a baseline physical exam, blood tests and electrocardiogram will be obtained. * Dosing visit: 1 outpatient visit where TRX518 will be given IV over 1 hour followed by 4 hours of observation and some repeat blood tests. * Follow up visits: 5 outpatient visits following dosing at 1, 8 and 15 days and 3, 6, 12, and 18 weeks post dosing * Long term follow-up: 4 brief assessments by medical record review and/or telephone contact at 6, 12, 18, and 24 months post dosing. * The core study duration is 18 weeks. The follow-up study duration is 24 months. Parts B \& C: * Screening/Baseline visit: 1 appointment will be conducted to perform testing and evaluations for eligibility within 28 days of the first dosing day. * Dosing Visits: Each subject will receive IV doses of TRX518 once every other week (e.g., D1 and D15) in 28-day cycles * Follow up visits: When a patient stops treatment, they will enter the Follow-up Period and have an End of Treatment study visit approximately 30 days after the last dose of study drug. Subsequently, patients will have long-term follow-up approximately every 12 weeks until death or lost to follow up.