WASHINGTON — The Trump administration on Thursday boldly reversed an Obama-era policy that supporters said had helped lower prices for some costly drugs.

The policy centers on so-called biosimilar drugs, which are highly similar versions of biologic drugs manufactured in living cells or microorganisms. The Obama administration designed certain Medicare payments to encourage more price competition among those biosimilar drugs. Trump’s Centers for Medicare and Medicaid Services will reverse that policy beginning Jan. 1, 2018.