First New Flu Antiviral Approved in 20 Years

First New Flu Antiviral Approved in 20 Years

Baloxavir marboxil (XOFLUZA), a polymerase acidic (PA) endonuclease inhibitor, indicated for the treatment of acute uncomplicated influenza in patients 12 years of age and older who have been symptomatic for no more than 48 hours was recently approved by the FDA.  The recommended dose for patients ≥12 years old who weigh 40 kg to <80 kg is a single 40-mg dose; for those weighing ≥80 kg, a single 80-mg dose  is recommended.  Baloxavir joins the neuraminidase inhibitors; oral oseltamivir (Tamiflu, and generics) and inhaled zanamivir (Relenza) which are FDA-approved for treatment and prophylaxis of influenza. IV peramivir (Rapivab) is FDA-approved only for treatment of influenza.

The approval was based on two clinical trials.  In a double-blind, placebo- and active-controlled trial (CAPSTONE-1), 1436 patients with uncomplicated influenza were randomized to receive a single dose of baloxavir, a 5-day course of oseltamivir, or placebo. In patients with confirmed flu,  baloxavir reduced the duration of influenza symptoms by about 26.5 hours compared to placebo; however, time to  resolution of symptoms was similar to oseltamivir.    In the second trial, (CAPSTONE-2),  2184 patients ≥12 years old at increased risk of influenza complications (e.g., asthma, chronic lung disease, age ≥65 years) were randomized to receive baloxavir, oseltamivir, or placebo.  Similarily, time to resolution of symptoms was improved with baloxavir compared to placebo,  while time to symptom resolution was similar with baloxavir and oseltamivir.   Baloxovir was well tolerated, with nausea and vomiting reported as the most common adverse effects.


Read more about baloxavir here: FDA press release

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