TDF versus TAF: The Safer Alternative Design Argument

Trammell PC is currently investigating allegations of serious safety problems with the active ingredient in HIV drugs Truvada, Viread, Atripla, Complera, Stribild, and Truvada for PrEP.These medications work at least partly through an active ingredient called tenofovir disoproxil fumarate, or TDF for short.

TDF has been vitally important for people who are living with HIV—but over the years since TDF drugs have been approved, patients have consistently reported serious side effects. Scientists believe TDF reduces kidney function, causing a decline over time that could, for some patients, eventually lead to kidney failure. They also believe that TDF reduces bone density leading to conditions like tooth loss, tooth cracking, osteroporsis, osteopenia, and osteomalacia.

There’s an alternative to TDF that doesn’t have these serious bone and kidney side effects—TAF, or tenofovir alafenamide, the active ingredient in multiple HIV drugs. TAF was approved by the U.S. Food and Drug Administration fourteen years after TDF, even though the drugs are related and were both developed by drug manufacturer Gilead Sciences. In fact, multiple lawsuits have accused Gilead of deliberately delaying the introduction of TAF drugs in order to maximize its profit from TDF drugs. This blog post explains some of the differences.

Different Formulations

TDF was first FDA-approved for HIV treatment in 2001, and Truvada for PrEP was approved for the prevention of HIV transmission (PrEP) in 2012. It’s one of the most widely used HIV medications, according to the HIV magazine Poz. Prescription drugs that contain TDF, by itself or in combination with another drug, include:

  • Truvada
  • Viread
  • Atripla
  • Complera
  • Stribild

TAF was FDA-approved for HIV treatment in 2015, and for PrEP in 2019. Brand names of drugs that contain TAF include:

  • Vemlidy
  • Descovy
  • Biktarvy
  • Genvoya
  • Odefsey
  • Symtuza

Both TAF and TDF work by preventing HIV from reproducing, slowing its spread, and preventing transmission. Numerous studies have shown little difference in how effective they are against the virus.

However, because more TAF is absorbed by the body, it can be given to patients in much lower amounts, according to medical publication HCP Live. This smaller dose reduces kidney function and bone density side effects.

Accusations Against Drugmaker

Another important difference between TDF drugs and TAF drugs is that TDF lost its patent protection in 2017, whereas TAF remains under patent until 2022. Losing that protection means TAF drugs are currently much more expensive than TDF drugs, which now have generic alternatives.

Multiple lawsuits allege that Gilead, knowing this, gamed the U.S. drug patent system to maximize its profits. These lawsuits argue that Gilead knew TAF was safer as long ago as 2001 but deliberately didn’t ask regulators for approval of TAF until its TDF patent was close to expiring. In fact, they say the drugmaker made public statements suggesting TAF would not be brought to market, encouraging TDF usage, even as it continued to develop TAF. As a result, the lawsuits say, patients developed avoidable, serious health problems[1] as a side effect of TDF.

Currently, TDF lawsuits have been consolidated in a state coordinated proceedings in San Francisco County, California, and Trammell PC is actively litigating these cases.

Contact Trammell PC to Learn More About a TDF Lawsuit

At Trammell PC, we specialize in drug and device litigation. We have the expertise to handle the complex issues around a TDF lawsuit, and we handle cases across the United States. If you’d like to learn more, call us today at 1-800-405-1740 or contact us through our website.

[1] These problems include osteopenia, osteoporosis, osteomalacia, broken bones, kidney tubular dysfunction, lactic acidosis, Fanconi syndrome, acute kidney injury, chronic kidney disease, rental failure and more.

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