A new government report says the United States spent $162 million getting Gilead’s COVID-19 drug remdesivir to market but opted against seeking government patents because Gilead invented the experimental medicine years earlier.

The drug sells for $3,120 for a five-day course of treatment for COVID 19. It brought in $2.8 billion in revenue for Gilead last year and the company expects to make a similar amount in 2020.

The Government Accountability Office documented government spending and its role in developing remdesivir — which won full Food and Drug Administration approval last year and is now sold under the brand name Veklury — at the request of Sen. Debbie Stabenow, D-Mich., and Rep. Carolyn Maloney, D-N.Y., chairperson of the House Committee on Oversight and Reform, after Gilead set its price.

Critics complained the cost was excessive for a pandemic-related drug developed with such a large government role. The GAO released its findings Wednesday.

Remdesivir was initially invented as a hepatitis C drug a decade ago but was shelved by Gilead. It then was tested again by the Centers for Disease Control and Prevention and the U.S. Army as an antiviral drug against other infectious diseases including Ebola. The drug fizzled against Ebola in a clinical trial in Africa but showed promise against coronaviruses.

The largest share of the $162 million was for clinical trials after the coronavirus outbreak began last year, when the National Institute of Allergy and Infectious Diseases sponsored a nationwide clinical trial, the GAO report said.

Remdesivir does not significantly prevent COVID-19 deaths, but it has shortened hospital stays to 11 days from 15, according to clinical trial findings.

“Federally supported remdesivir research conducted by CDC, DOD, NIH, and NIH-funded universities has not resulted in government patent rights, because, according to agency and university officials, federal contributions to the research did not generate new inventions,” the GAO report said.