Star Rating for Biosimilars Act This bill requires the Centers for Medicare & Medicaid Services (CMS) to establish quality measures regarding biosimilar biological products under the five-star performance rating system for Medicare Advantage plans. The measures must assess the level of access that plans provide to covered biosimilars, including with respect to formularies, cost-sharing, and utilization management. The CMS must also incorporate such measures into similar rating systems for plans under the Medicare prescription drug benefit.