FOSTER CITY (KPIX 5) — Truvada for PrEP is at the center of a tug of war between the Centers for Disease Control and Gilead Sciences. It’s an anti-retroviral designed to prevent HIV infection.

“PrEP is an absolutely essential tool in our effort to end new HIV infections. When someone is taking PrEP it reduces their risk of HIV infection by 99 percent,” said State Senator Scott Wiener (D – San Francisco).

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The CDC and the Department of Health and Human Services patented the drug in 2015. Gilead made $3 billion off it last year alone, but the U.S. hasn’t seen any money from the matter.

“We the people, it turns out, own technology that can end AIDS–the question is, what are we going to do with that?” said Peter Maybarduke, the Access to Medicines Director of Public Citizen.

In a statement to KPIX 5, Gilead said, “We believe the patents granted to the Department of Health and Human Services for Truvada for PrEP are not valid.”

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It’s not uncommon for the $31 billion in medical research from the National Institutes of Health to result in patents that are then offered as part of the public trust to companies for production.

“We tend to ask the companies to please commercialize these products and then insist on very few conditions, leading to the situation we have today where we’re being price gouged and people are not getting access to the treatment that they need,” said Maybarduke.

The list price for PrEp is $1600-$2000 per month. The same drug is as low as $6 dollars per month in other countries.

State Senator Wiener takes PrEP and says this fight once again sheds light on the stranglehold drug companies have.

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“The continued barriers to accessing PrEP, including the cost are very frustrating to me as someone who spent a lot of my life fighting HIV and trying to end new infections. I want everyone who needs PrEP to have access to it,” Wiener said.