WASHINGTON – Senate Republicans blocked legislation Wednesday that would have allowed the federal government to negotiate Medicare drug prices, denying Democrats a victory on their 2006 election vow to lower prescription costs for senior citizens.

“This is not the end of the debate,” said Sen. Ron Wyden, D-Ore., a supporter of the bill. The vote was 55 to 42.

The Senate legislation would have allowed the government to directly negotiate with drug companies to secure lower prices for medications. But an independent Congressional Budget Office analysis found that the proposal would not result in cheaper drugs.

Sens. Olympia Snowe and Susan Collins, R-Maine, both voted in favor of the bill.