When will the blinders come off?

When Medicare began to cover drugs, the government in its wisdom put a clause in the legislation that prohibited the government from negotiating prices with the drug companies.  It made no sense then, it makes no sense now.

If we could negotiate drug prices as most advanced countries do, drugs from Medicare would cost less, perhaps as much as $25 billion a year.

We do require drug companies to negotiate prices in areas used by the VA, DOD and some hospitals.  Why can't we do the same with regard to Medicare?