Biogen’s Costly, Unproven Drug Feared as Health Budget Buster

The approval of Biogen Inc.’s $56,000-a-year Alzheimer’s therapy creates an unprecedented challenge for the U.S. health system: a drug that many patients may get at a high price even though it may not slow their cognitive decline.

The U.S. has coped with costly, effective medicines for large populations, like those for hepatitis C, HIV and heart disease. And it has delivered therapies of less certain benefit for relatively rare diseases, such as some cancers or Duchenne muscular dystrophy.

Those drugs mainly provide solid, proven gains for patients. With Monday’s Food and Drug Administration clearance of Biogen and Eisai Co.’ ...