Gilead Sciences is being sued by an AIDS advocacy group which claims the pharmaceutical giant halted development on an improved HIV drug because it feared cannibalizing the profits of an existing drug.

AIDS Healthcare Foundation, a Los Angeles nonprofit, accuses the Foster City-based drug company of purposefully delaying research on a less toxic drug to extend the patent expiration date for its drug tenofovir disoproxil (TDF) for another 14 years.

The Foundation accuses Gilead of keeping drug prices high while causing additional severe health problems millions of HIV patients.

Gilead Creates Blockbuster HIV Drug

The sordid story starts in 1997 when Gilead Sciences and UC San Francisco researchers discovered that a drug called tenofovir disoproxil, or TDF, could treat HIV. Gilead marketed the new drug under the name Viread.

Viread was approved by the US Food and Drug Administration (FDA) in 2001 and the patent for TDF was secured until 2018. The drug became a worldwide blockbuster, extending the lives of millions of HIV patients. Last year, Gilead made $11 billion in sales of Viread. Sales of Viread are projected to grow steadily to $21.5 million in 2020.

Viread Helps HIV, but Harms Kidneys and Bones

Although successful in blocking HIV’s proliferation, Viread’s benefits came at a high cost to AIDS patients. Patients developed kidney and bone problems, including chronic kidney disease, kidney failure, and bone loss. According to the LA Times, one patient who began taking Viread in his 40s was found to have bone loss equivalent to that of an 85-year-old woman.

Yet, during the honeymoon period shortly after Viread’s launch, Gilead improperly declared that Viread had “no toxicities” and was “extremely safe,” according to an FDA warning letter sent to the company in early 2002.

Gilead Researches a Less Toxic Alternative to Viread

In the meantime, while denying Viread’s dangers, Gilead began actively researching a less toxic variant of TDF in 2001. The new drug was called tenofovir alafenamide, or TAF, and it produced excellent results in animal studies.

TAF appeared to be better at penetrating cells which meant it could be just as effective as Viread at much lower doses, thereby greatly reducing its toxicity. Gilead published the animal studies on TAF in 2001.

Gilead Abruptly Halts Research on Promising New HIV Drug

Gilead Sciences began testing TAF on human patients in 2002, but the results of the study weren’t published at that time. Instead, the company went dark on TAF and, in 2004, it announced that it had stopped researching TAF altogether.

For the six years between 2004 and 2010, Gilead maintained radio silence on TAF, allowing its silence to be interpreted as a failure of the drug’s trials. However, behind the scenes, the pharma company was still applying for patents for TAF in 2004. Why would Gilead continue to pursue patents on a failed drug?

Release of Old Research Gives New Life to Gilead Patent

The answer to the patent question came in 2014 when Gilead Sciences finally released the results of its 2002 patient trials: TAF treated HIV effectively with less toxicity.

In 2015, the FDA approved the new drug, branded Genvoya. Gilead’s patent on tenofovir was extended because the pharma company claims that TAF is merely an altered version of the original drug, Viread. The patent extension for tenofovir now expires in 2032, meaning that Gilead has fourteen additional years to market tenofovir variants unopposed by generics.

Gilead Chose Profits Over Patient Health

If Gilead Sciences had released its 2002 research in 2003 instead of 2014, its patent on tenofovir would be due to expire in 2025 rather than 2032 – which leads one to the natural assumption that Gilead chose Genvoya’s release date based on maximized profits rather than how many human lives it could have helped in those seven intervening years.