In this phase II study (NCT03436563), pts with MSI-H metastatic solid tumors who had progressed on prior ICB were eligible. Pts received 1200 mg BA intravenously every 14 days. Dual inhibition of TGF-ß and PD-L1 by BA did not demonstrate significant anti-tumor activity in the majority of pts with MSI-H metastatic cancer who had progressed on prior ICB.