Descovy for PrEP

The most common adverse event is diarrhea, observed in up to 5% of individuals given Descovy in the large DISCOVER study that led the FDA to approve Descovy for PrEP. There was also nausea (4%) and headache, fatigue, and abdominal pain (2% each). If Descovy is discontinued abruptly in people with hepatitis B virus (HBV), flare-up of hepatitis may occur—talk to your provider before discontinuing. Check for hepatitis B before taking Descovy and vaccinate against it if appropriate. Drug resistance to HIV therapy may develop if people going on Descovy for PrEP unknowingly already have HIV, or if infection occurs after starting PrEP. However, drug resistance was rare in the extremely few individuals who acquired HIV during the DISCOVER trial (seven out of 2,670 persons on Descovy and 15 out of 2,665 on Truvada). All were in the Truvada arm and all were in those with baseline HIV infections. As with previous PrEP studies, DISCOVER found the effectiveness of Descovy for PrEP was related to drug adherence—taking Descovy for PrEP as prescribed. The TAF component in Descovy is associated with relatively decreased risk for toxicity to the kidneys and bones (such as decreases in estimated glomerular filtration rate, or eGFR, and bone mineral density, or BMD) when compared to TDF in Truvada. Kidney function (including creatinine clearance, or CrCl) should be monitored while taking Descovy for PrEP. Recommended monitoring also includes STI screening. When comparing TDF versus TAF, bone changes may be of greater concern for young people who are still growing their bone structure and older individuals who may be becoming frail. Kidney changes may be of greater concern for individuals who have pre-existing kidney problems or older individuals at risk for developing kidney problems. Stigma remains a significant concern of HIV prevention, especially PrEP.

Do not take with any other HIV or HBV drugs when using Descovy for PrEP. Avoid taking Descovy with drugs that negatively affect the kidneys, including chronic use or high doses of anti-inflammatory drugs for pain like Advil or Motrin (ibuprofen) and Aleve (naproxen). Descovy for PrEP can be used with the hepatitis C drugs Harvoni or Zepatier. Monitor for tenofovir toxicities if used with Epclusa. Descovy should not be taken with certain anticonvulsants (including carbamazepine, oxcarbazepine, phenobarbital, and phenytoin), rifabutin, rifampin, rifapentine, or St. John’s wort. Concentrations of tenofovir, FTC, and other substances that clear the body through the kidneys could be increased (along with risk of toxicity) by the aminoglycoside antibiotics and the antivirals acyclovir, cidofovir, ganciclovir, valacyclovir, and valganciclovir. Tell your provider or pharmacist about all medications, herbals, and supplements you are taking or thinking of taking, prescribed or not.

Descovy became the second FDA approved drug on the market for HIV prevention (called pre-exposure prophylaxis, or PrEP) in October 2019, with one important exception. The FDA specified that Descovy PrEP was not approved for individuals vulnerable to HIV through receptive vaginal sex. This is because the effectiveness of Descovy PrEP was not evaluated in this context. Studies with women and adolescent girls are underway. The tenofovir alafenamide (TAF) in Descovy and the tenofovir disoproxil fumarate (TDF) in Truvada (the first PrEP medication on the market) work differently in the body, raising questions for PrEP, but are both highly effective against the virus whether for treatment or prevention. In the meantime, Truvada, which is basically an earlier version of Descovy, is indicated for PrEP against HIV for all populations, including for use in receptive vaginal sex. Descovy for PrEP was only studied in men who have sex with men (MSM) and transgender women (5,387 MSM and 74 transwomen) in the DISCOVER study that brought Descovy PrEP to market. TAF has less of a negative effect on renal function and bone mineral density than TDF, but the long-term clinical significance of the changes seen with the two medications remains unknown. Medical providers, however, prefer TAF over TDF for certain patients who may be at higher risk for renal and bone toxicity (including youths and older individuals). There are considerations for using PrEP even with U=U (Undetectable equals Untransmittable). A guide to help providers bill for PrEP services is available at nastad.org/resource/billing-coding-guide-hiv-prevention. Two excellent websites for finding a PrEP provider are preplocator.org and aidsvu.org—although any provider can prescribe PrEP. For more information, go to cdc.gov/hiv/basics/prep.html.

Dr. Ross Slotten says:

“PrEP” stands for pre-exposure prophylaxis against HIV. It has become one of the two cornerstones of HIV eradication, the other being anti-HIV therapy itself. Public health authorities estimate that there are 1.2 million people at risk of HIV in the United States, but less than 100,000 people are taking PrEP. In healthy individuals at risk for HIV, Truvada and Descovy are very safe and the benefits far outweigh the risks. There are few long-term safety data for TAF-containing regimens, although 4 out of 10 patients in one study who were switched from TDF to TAF showed improvement in kidney function. People most at risk for side effects are those who are elderly, have a low body weight, have underlying kidney disease before starting medication or are diabetic, have uncontrolled high blood pressure, or are co-infected with hepatitis C. The bottom line is that for most people PrEP is safe, effective, and easy to take. Careful monitoring of kidney function will pick up problems before they become irreversible. Both drugs are well tolerated. If taken daily, they are 92–99% effective at preventing HIV. Both Truvada and Descovy take 7 days to become fully protective [for anal sex; 21 days for receptive vaginal sex]. It is therefore not recommended to skip doses or take the medication in an unconventional way, like one day before an unsafe sexual contact and a few days afterward, as some have advocated. I don’t believe there’s solid scientific evidence to back them up yet. If you want to stop PrEP, you should continue to take it for four weeks after the last [condomless] sexual contact. And neither drug protects against other sexually transmitted infections. In the pipeline are a good number of other possible PrEP candidates, including injectable agents, medication implants, vaginal rings embedded with a PrEP agent, etc.

Activist Bridgette Picou says:

Descovy recently got its approval for pre-exposure prophylaxis (PrEP) use on October 2019. Descovy uses tenofovir alafenamide, instead of tenofovir disoproxil fumarate like in Truvada. This means not only is less medication needed to be effective, it is a smaller pill as compared to Truvada. Also in comparison to Truvada it causes less loss of bone density and kidney toxicity. Descovy was only studied for the MSM and trans women populations. This excludes individuals at risk via receptive vaginal sex. This population will need to continue to use Truvada for PrEP. You need to take Descovy daily to ensure effectiveness. You will be monitored at three-month intervals including HIV and STI testing, and monitoring of your liver and kidney functions.