First-in-Class Antiviral Approved for the Treatment of Influenza
by Dr. C.H. Weaver M.D.
The Food and Drug Administration (FDA) has approved Xofluza (baloxavir marboxil) for the treatment of acute uncomplicated influenza in patients aged ≥12 years old who have been symptomatic for no more than 48 hours. Xofluza is a single-dose oral medicine approved to treat the flu based on clinical trials results demonstrating that it significantly reduced the duration of flu symptoms.
What is Influenza?
Influenza or the “flu” is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. The influenza virus can cause mild to severe illness, and at times can lead to death. Compared with most other respiratory infections, such as the common cold, the flu often causes a more severe illness.
Each year, an estimated 3-11 percent of the U.S. population gets the flu, and it can be very serious, resulting in hospitalization or even death. Since 2010, the Centers for Disease Control and Prevention (CDC) estimates that the flu has resulted annually in 9.2 to 35.6 million illnesses, 140,000 to 900,000 hospitalizations and 12,000 to 80,000 deaths.
The flu vaccine remains the crucial first step in preparing for flu season and preventing illness, Xofluza is an important new treatment option for individuals who get sick.
Xofluza is a first-in-class, single-dose oral medicine designed to target influenza A and B viruses. The FDA approval was based on 2 randomized controlled clinical trials performed in 1832 patients who were assigned to receive Xofluza, placebo, or oseltamivir within 48 hours of experiencing "flu like" symptoms. The results of the study showed that patients who received Xofluza had a shorter time to symptom relief compared to patients who received placebo.The most common adverse reactions associated with therapy included diarrhea and bronchitis.
XOFLUZA was approved based on results from the Phase III CAPSTONE-1 study of a single dose of XOFLUZA compared with placebo or oseltamivir 75 mg, twice daily for five days, in otherwise healthy people with the flu, as well as results from a placebo-controlled Phase II study in otherwise healthy people with the flu. XOFLUZA significantly reduced the duration of flu symptoms compared to placebo, and demonstrated similar efficacy compared to oseltamivir. In clinical trials, XOFLUZA was safe and well-tolerated with a side effect profile similar to placebo. The CAPSTONE-1 and Phase II study results were recently published in the September 6, 2018 issue of the New England Journal of Medicine.