The bipartisan coalition says the NIH and FDA have the power to license the drug to generic makers to produce more of the medication, and at a lower price.
Gilead Sciences prices the drug at $2340 per patient for wealthier countries.
It will charge U.S. patients with commercial insurance $3120 per patient, or $520 per vial.
In June, the government signed a deal with Gilead for 500,000 courses of the treatment.
However, a third of hospital pharmacy managers say they don't have enough of the drug.