FDA approves second drug to prevent HIV infection(PrEP).

The U.S. Food and Drug Administration today approved Descovy (emtricitabine 200 mg and tenofovir alafenamide 25 mg) in at-risk adults and adolescents weighing at least 35kg for HIV-1 pre-exposure prophylaxis (PrEP) to reduce the risk of HIV-1 infection from sex, excluding those who have receptive vaginal sex. Descovy is not indicated in individuals at risk of HIV-1 infection from receptive vaginal sex because the effectiveness in this population has not been evaluated.

PrEP, or pre-exposure prophylaxis, is an HIV prevention method in which people who do not have HIV take medicine on a daily basis to reduce their risk of getting HIV if they are exposed to the virus. Descovy for PrEP should be used as part of a comprehensive strategy, including adherence to daily administration and safer sex practices, including condoms, to reduce the risk of sexually acquired infections.


MECHANISM OF ACTION

TAF is a novel prodrug of tenofovir that is designed to deliver tenofovir to HIV-infected cells, including lymphocytes


DESCOVY contains TAF, which is part of the FTC/TAF backbone

In 2 trials of treatment-naive adults with HIV-1 infection, a 10-mg oral dose of TAF in FTC/TAF + EVG/COBI* resulted in >90% lower concentration of TFV in plasma as compared to a 300-mg oral dose of TDF in FTC/TDF + EVG/COBl

  • In a PK study, the unboosted 25 mg of TAF in DESCOVY was demonstrated to be bioequivalent to the COBI-boosted 10 mg of TAF in FTC/TAF + EVG/COBI
  • The concentration of TFV in plasma may differ if DESCOVY is paired with a boosted PI

  • TAF is metabolized to TFV by cathepsin A in PBMCs (including lymphocytes) and macrophages
  • TFV in the plasma is eliminated from the body through renal excretion

The safety and efficacy of Descovy for PrEP were evaluated in a randomized, double-blind multinational trial in 5,387 HIV-negative men and transgender women who have sex with men and were at risk of HIV-1 infection.

The trial compared once daily Descovy to Truvada (emtricitabine, tenofovir disoproxil fumarate, 200 mg/300 mg), a daily fixed dose combination of two drugs approved in 2012 to prevent the sexual acquisition of HIV; participants were followed for 48 to 96 weeks. The primary endpoint was the rate of HIV-1 infection in each group. The trial showed that Descovy was similar to Truvada in reducing the risk of acquiring HIV-1 infection. The most common adverse reaction in individuals without HIV who were taking Descovy for PrEP was diarrhea

Important Safety Information

BOXED WARNING: POST TREATMENT ACUTE EXACERBATION OF HEPATITIS B

  • DESCOVY® is not approved for the treatment of chronic hepatitis B virus (HBV) infection and the safety and efficacy of DESCOVY have not been established in patients coinfected with HIV-1 and HBV. Severe acute exacerbations of hepatitis B have been reported in patients who are coinfected with HIV-1 and HBV and have discontinued products containing emtricitabine (FTC) and/or tenofovir disoproxil fumarate (TDF), and may occur with discontinuation of DESCOVY. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in patients who are coinfected with HIV-1 and HBV and discontinue DESCOVY. If appropriate, initiation of anti-hepatitis B therapy may be warranted.

Warnings and precautions

  • Immune reconstitution syndrome, including the occurrence of autoimmune disorders with variable time to onset, has been reported.
  • New onset or worsening renal impairment: Cases of acute renal failure and Fanconi syndrome have been reported with the use of tenofovir prodrugs. In clinical trials of FTC and tenofovir alafenamide with elvitegravir and cobicistat, there have been no cases of Fanconi syndrome or proximal renal tubulopathy (PRT). Do not initiate DESCOVY in patients with estimated creatinine clearance (CrCl) <30 mL/min. Patients with impaired renal function and/or taking nephrotoxic agents (including NSAIDs) are at increased risk of renal-related adverse reactions. Discontinue DESCOVY in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome.
    Renal monitoring: In all patients, monitor CrCl, urine glucose, and urine protein prior to initiating and during therapy. In patients with chronic kidney disease, additionally monitor serum phosphorus.
  • Lactic acidosis and severe hepatomegaly with steatosis: Fatal cases have been reported with the use of nucleoside analogs, including FTC and TDF. Discontinue DESCOVY if clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity develop, including hepatomegaly and steatosis in the absence of marked transaminase elevations.

Adverse reactions

  • Most common adverse reaction (incidence ≥10%; all grades) in clinical studies was nausea (10%).

Drug interactions

  • Prescribing information: Consult the full prescribing information for DESCOVY for more information on potentially significant drug interactions, including clinical comments.
  • Metabolism: Drugs that inhibit P-gp can increase the concentrations of components of DESCOVY. Drugs that induce P-gp can decrease the concentrations of components of DESCOVY, which may lead to loss of efficacy and development of resistance.
  • Drugs affecting renal function: Coadministration of DESCOVY with drugs that reduce renal function or compete for active tubular secretion may increase concentrations of emtricitabine and tenofovir and the risk of adverse reactions.

Dosage and administration

  • Dosage: Patients who weigh ≥35 kg: 1 tablet taken orally once daily with or without food.
  • Renal impairment: Not recommended in patients with CrCl <30 mL/min.
  • Testing prior to initiation: Test patients for HBV infection and assess CrCl, urine glucose and urine protein.

Pregnancy and lactation

  • Pregnancy: There is insufficient human data on the use of DESCOVY during pregnancy. An Antiretroviral Pregnancy Registry (APR) has been established; available data from the APR for FTC shows no difference in the rates of birth defects compared with a US reference population.
  • Lactation: Women infected with HIV-1 should be instructed not to breastfeed, due to the potential for HIV-1 transmission.

Indication

DESCOVY is indicated in combination with other antiretroviral (ARV) agents for the treatment of HIV-1 infection in patients weighing at least 35 kg.

Limitations of Use:
DESCOVY is not indicated for use as pre-exposure prophylaxis (PrEP) to reduce the risk of acquiring HIV-1 infection.

Descovy was FDA approved in 2016 in combination with other antiretoviral drugs to treat HIV-1 infection in adults and pediatric patients. The FDA granted the approval of Descovy to Gilead Sciences Inc.

References:

  1. DESCOVY [package insert]. Foster City, CA: Gilead Sciences, Inc.; 2017.
  2. U.S. Department of Health and Human Services. Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV. https://aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf. Accessed October 17, 2017.