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). Check for hepatitis B virus (HBV) before taking Descovy and vaccinate against it if appropriate. If Descovy is discontinued abruptly in people with hepatitis B virus, flare-up of hepatitis may occur—talk to your provider before discontinuing. 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 daily 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 whose bone structure is still growing and for 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 of developing kidney problems. Stigma remains a significant concern of HIV prevention, especially PrEP. When taken for HIV treatment, tenofovir has been associated with weight gain; see Descovy page.

Do not take with any other HIV or HBV drugs (including Vemlidy, or TAF) 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 such as 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.

In December, DHHS perinatal guidelines added a new section on PrEP for periconception, antepartum, and postpartum periods. Descovy for PrEP was not approved for the prevention of HIV via receptive vaginal sex. This is because the effectiveness of Descovy for PrEP was not evaluated in this context. Studies with cisgender 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) absorb, distribute, and concentrate differently in the body, but both are highly effective against the virus whether for treatment or prevention.

In the meantime, Truvada, which is now available as a generic, is FDA approved 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 for 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 observed 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. Gilead Sciences helps patients work with their insurance, including pre-authorizations, as well as provides free PrEP to uninsured patients who are eligible and co-pay assistance up to $7,200 a year; contact the patient assistance hotline at (877) 505-6986, or go to gileadadvancingaccess.com. PrEP Facts: Rethinking HIV Prevention and Sex is a closed Facebook group for people interested in or currently on PrEP, and their allies.

Dr. Melanie Thompson: A head-to-head comparison of Descovy to Truvada in gay and bisexual men and transgender women showed that Descovy was not inferior to (or not worse than) Truvada for preventing HIV. The study did not include cis-gender women, transgender men, or people who inject drugs, and they are not included in the FDA approval for Descovy. A study is underway internationally to address efficacy and safety in cis-gender women.

Slightly lower rates of kidney side effects and decline in bone density were seen with Descovy, similar to results from HIV treatment studies. Also, as with treatment, HDL and LDL cholesterol and weight were slightly higher with Descovy than with Truvada. Weight gain was about 1 kg (2.2 lbs.) higher than with Truvada at 48 weeks. The long-term clinical impact of these findings is not clear.   

Initially, there was some misunderstanding about the study results, and some “spin” that Descovy was better than Truvada in preventing HIV. This is not true. And, especially for younger people without diseases that predispose them to kidney problems (diabetes, hypertension, for example), Truvada is safe and may be a preferable choice. TDF/FTC now is available off-patent and could impact cost.

Some people prefer the smaller pill size of Descovy.

Descovy has not been studied as intermittent treatment and is only approved when taken once daily.

Activist Bridgette Picou: Descovy serves dual roles as an HIV medication and an HIV prevention med. As pre-exposure prophylaxis, it prevents the transmission of HIV. Descovy is a smaller pill and requires less medication (TAF vs. TDF) than its predecessor, Truvada. This means less toxicity, sparing bone density and kidney health. This drug is not indicated as a prevention method for persons at risk for HIV who have vaginal intercourse. More study is needed for that. Descovy also does not prevent other sexually transmitted infections (STIs), so plan on regular monitoring of kidney health and STI testing while using Descovy. Do not skip doses as this increases chances of seroconversion.