Study of Tebentafusp and Radioembolization in the Treatment of Metastatic Uveal Melanoma

Tebentafusp will be administered intravenously to participants at or within 28 days of their first Y-90 TARE procedure. This 28-day period includes the 14- to 28-day Y-90 TARE Recovery Period. For administrative purposes, one cycle of tebentafusp treatment is 28 days in length. Tebentafusp will be administered on a dose escalation schedule for Cycle 1 starting at 20 mcg on Day 1, increasing to 30 mcg on Day 8, and a final dose of 68 mcg on Day 15, which will be administered once per week until unacceptable toxicity develops, disease progression, or withdrawal of consent, whichever occurs first.

Participants will undergo radiographic and 99mTC-labeled macroaggregated albumin (99mTc-MAA) assessment for suitability prior to Y-90 absorbed glass microsphere treatment per institutional procedures. Y-90 trans-arterial radioembolization (TARE) is a standard of care treatment for intrahepatic metastases of uveal melanoma as indicated in the National Comprehensive Cancer Network (NCCN) consensus guidelines (NCCN Guidelines®, 2023). Y-90 absorbed glass microspheres will be administered at least one time prior to initiating Tebentafusp treatment. After the Y90-TARE procedure, participants will have a 14- to 28-day Y-90 TARE Recovery Period.