What is TDF (Viread)?

In 2001, the FDA approved Gilead’s TDF (also called “tenofovir DF”) for the treatment of HIV infection in adults. It is used in combination with other medications to keep the HIV virus under control. In 2008, the FDA approved it for use in patients with chronic hepatitis B infection, and in 2012, for the treatment of HIV in children over the age of two years. HIV (human immunodeficiency virus) is a virus that attacks the body’s immune system. Without treatment, it can destroy so many immune cells that the body can no longer mount a proper defense against infections and diseases. AIDS is the last stage of an HIV infection, in which the person has an extremely weak immune system that is no longer able to protect against infections and cancers. Though HIV cannot be cured yet, it can be controlled so that it doesn’t continue to multiply, allowing patients to live long, productive lives. Medications can also lower the risk that patients will infect others. Tenofovir DF belongs to a group of HIV drugs called “nucleoside reverse transcriptase inhibitors (NRTIs).” These drugs block the action of an HIV enzyme called “reverse transcriptase.” By doing so, they help keep the virus from multiplying, and reduce the amount of HIV in the body. In combination with other medications, TDF is used to help people with HIV to live longer, healthier lives. TDF does have a low bioavailability, which means that it’s not readily absorbed by the body. Higher doses are required, therefore, to be effective. Studies have linked high doses of TDF to an increased risk of kidney and bone problems. “Viread” was the first brand name TDF product Gilead sold, but they later combined it with other HIV drugs and sold it under other brands as well, including:

• Atripla
• Truvada
• Stribild
• Complera

Gilead Suppresses Research on Newer, Less-Toxic HIV Medication

According to the LA Times, scientists working for Gilead were aware early on that their drug could cause serious damage to the kidneys and bones. Even as Viread came onto the market in 2001, Gilead’s research and development team was working on a slightly different version of the drug called “tenofovir alafenamide fumarate (TAF),” which showed in animal studies to have a greater effect against HIV than TDF, with the potential to be far less toxic. Gilead even sent the drug to doctors for them to use in small clinical trials, where the drug performed well. Gilead suppressed the results of those studies, though, and even announced in 2004 that they were stopping research on TAF. Despite this claim, the company continued to apply for new patents on the drug. Whenever a pharmaceutical company releases a drug, they have only so many years to sell it while a patent protects it. Eventually, that patent runs out, and then generic manufacturers have access to the drug’s formula and can produce and sell the drug at a cheaper price. Therefore, drug companies generally try to make most of their profits before the patents run out. According to two TDF lawsuits filed in California, Gilead dragged their feet on revealing study results related to TAF in order to wait until TDF’s patent ran out. According to a press release from the AIDS Healthcare Foundation (AHF), the plaintiffs claim that Gilead “deliberately and maliciously suppressed from the market its alternate and newer formulation of the drug, TAF, in order to extend the patent life—and sales—of its existing medications that included TDF.” Indeed, several years after announcing they were stopping research on TAF, Gilead applied for FDA approval of new TAF medications. In November 2015, the FDA approved a new HIV drug named “Genvoya,” which consists of TAF in combination with three other medications. Other new TAF-combo medications would follow, including:

• Odefsey
• Descovy
• Biktarvy
• Vemlidy

The patent for TDF expired in 2018. Soon after the newer TAF-combo drugs came onto the market, Gilead raised prices for some of their TDF-based drugs, making them more expensive than the new ones.

Studies Show TDF & Viread Toxic to the Kidneys and Bones

Several scientific studies have shown that TDF is toxic to the kidneys, and can also negatively affect bone growth. Here is a glimpse at a few of them.

Kidney Disease

• In a 2010 review of 17 studies on TDF treatment, researchers concluded that TDF was associated with “a statistically significant loss of renal function.”
• In 2013, researchers published a study in which scientists noted the link between the drug and kidney disease, and recommended doctors “measure kidney function carefully and assess kidney disease risk before prescription.”
• In a 2017 study, researchers analyzed data from HIV patients taking TDF drugs, and found that TDF use was associated with chronic kidney disease, with longer exposures increasing the risk.
• In a 2018 study, researchers noted that TDF could impact kidney function, and that TDF toxicity could present as chronic kidney disease or Fanconi syndrome (disorder of kidney tubule function). They also recommended careful patient testing and monitoring and stated that TAF “appears to have less renal toxicity and is likely to replace TDF in future.”
• In another 2018 study, researchers tested TDF in patients with chronic hepatitis B, and noted that it decreased kidney function, adding that old age, diabetes, and prior kidney problems could increase rthe isk of TDF-linked kidney dysfunction.

Bone disease

• Researchers reported in a 2010 study that there was a strong correlation between treatment with TDF and loss of bone density, particularly in young children and adolescents. “These observations strongly suggest bone density is being affected during active bone growth and development, implicating a role for tenofovir in bone loss.”
• In a 2015 study, scientists found that HIV patients treated with alternative medications had significantly better outcomes related to kidney and bone health than those treated with TDF-containing medications.
• In a 2016 study, researchers found that TDF created a one to three percent greater bone mineral density loss in patients than other HIV drugs. The scientists concluded that because of these findings, TDF-containing treatments “may be gradually replaced with non-TDF containing regimens for the treatment of HIV infection, especially in those at higher risk for fragility fracture.”
• In a 2018 study, researchers stated that bone mineral density loss, a risk factor for osteoporosis, had been linked to HIV infection and treatment with TDF. They followed HIV-infected adults who had taken the drug for six months. One group received an alternate medication, while the other continued to take TDF. Results showed that those who switched medications had a significantly greater increase in total hip bone mineral density than participants who stayed on their TDF medications.

FDA Warns Gilead About Giving Patients Misleading Information

The FDA has issued two warning letters to Gilead concerning its marketing of TDF. The first one, sent in 2002, warned the company to stop making misleading and illegal statements when promoting Viread. Gilead representatives reportedly made statements at the Interscience Conference on Antimicrobial Agents and Chemotherapy that their drug had “no toxicities” and was “extremely safe” and “extremely well tolerated,” all statements that the FDA qualified as misleading. They also said that Viread was a “miracle drug,” even though its clinical benefits in HIV patients had not yet been determined at the time. The FDA sent another letter in 2003, requiring the company to retrain its sales representatives so that they would provide more accurate information at conferences and other events, particularly concerning TDF side effects. Specifically, the FDA referred to a Gilead representative who was making misleading statements during the 15^th National HIV/AIDS Update Conference in Miami, Florida. The representative reportedly stated that Viread was “more potent,” had “fewer side effects,” and was “safer” than other similar drugs. Despite these warnings, Gilead’s unbalanced promotional practices did lead to increased prescriptions and sales. In one 2009 lawsuit against the company, plaintiffs noted that domestic sales of Viread totaled $115.6 million and $59.4 million during the second and third quarters of 2003, respectively.

Types of Injuries Associated with TDF-Containing Medications Like Viread

Individuals taking TDF-containing medications may be at risk for the following conditions:

• Kidney damage and kidney failure
• Chronic kidney disease
• Acute kidney
• Fanconi syndrome (a disorder of kidney tubule function)
• Tubular dysfunction (tubular acidosis)
• Osteopenia
• Osteoporosis
• Bone fractures

Viread & TDF HIV Drugs Lawsuits

In 2016, the AHF filed a lawsuit against Gilead, claiming they delayed the development of TAF simply to extend the patents on their TDF medications. The AHF claimed that Gilead could have released TAF sooner, to the benefit of HIV patients, but instead put profits ahead of patients’ health. For nearly ten years, the company let patients take the more risky TDF, when they could have reduced the risk of kidney and bone disease by accelerating the development of TAF. In July 2016, the U.S. District Court for the Northern District of California granted Gilead’s motion to dismiss the case, but AHF has filed a petition for review by the Supreme Court of the United States. AHF President Michael Weinstein stated, “At the time of the 2016 ruling, AHF vowed that it would appeal to the Supreme Court, if necessary, to prevent Gilead from using a faulty patent process to game the system and garner more profits at the expense of patient health.” Meanwhile, other plaintiffs are filing TDF lawsuits in an effort to hold Gilead accountable for its actions. In May 2018, plaintiffs filed two new cases in the Superior Court of the State of California for the County of Los Angeles. The first was filed by two individuals living with HIV who took TDF and later suffered kidney and bone damage. The second is the class action lawsuit mentioned at the beginning of this article, also filed by two individuals who took TDF and suffered bone and kidney damage. If you or a loved one went through treatment with a TDF medication and then experienced serious side effects such as those listed above, you may be eligible to file a TDF lawsuit to recover damages. Chaffin Luhana is investigating these cases and will work to help you receive the compensation you deserve. Call today at 1-888-480-1123.