WASHINGTON — President Trump made an announcement Friday to tout one of his initiatives to lower drug prices. It left many questions unanswered.

All 50 states, Washington, D.C., and Puerto Rico will participate in the GENEROUS model, which is intended to give lower drug prices to Medicaid programs, Trump said.

Later on Friday, the Centers for Medicare and Medicaid Services said that 40 states and Puerto Rico had signed agreements to participate, while the others have applied. States have until the end of the month to sign agreements.