Table 1

Study inclusion and exclusion criteria

Inclusion Criteria	Exclusion Criteria	Arm assignments
≥18 years	Biotin supplement use	Intervention arm	sPD-L1 ≥1.7 ng/mL and available clinical capacity
Histological melanoma progressing despite immune checkpoint inhibitor	Pregnant or nursing	Intervention arm	sPD-L1 ≥1.7 ng/mL and available clinical capacity
Measurable disease		Standard of care arm	sPD-L1 <1.7 ng/mL or unavailable clinical capacity
ECOG ≤3
Ability to consent

Eligible patients for the study will be consenting adults with histologically confirmed melanoma receiving PD-(L)1 immunotherapy who are referred for stereotactic body radiation therapy. Patients who are receiving biotin supplements, pregnant or nursing are excluded. Patients with elevated sPD-L1 on registration will enter the intervention arm where clinical capacity is sufficient. Patients with low sPD-L1 or who enter the trial when clinical capacity is not available will enter the standard of care arm.
sPD-L1, soluble programmed death ligand 1.