On December 19, the U.S. Food and Drug Administration approved Rapivab (peramivir) to treat influenza infection in adults.
Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. Flu infections can range from mild to severe and can sometimes lead to hospitalization and death. According to the Centers for Disease Control and Prevention (CDC), 5-20 percent of the American population gets the flu and more than 200,000 people are hospitalized from seasonal flu-related complications each year.
Rapivab is an inhibitor of influenza virus neuraminidase, an enzyme that releases viral particles from infected cells. Neuraminidase inhibitors are commonly used to treat flu infection. Rapivab is the first neuraminidase inhibitor approved for intravenous (IV) administration and is administered as a single IV dose. It is intended for patients 18 years and older who have acute uncomplicated influenza and have shown symptoms of flu for no more than two days.
“Rapivab is the third neuraminidase inhibitor approved by the FDA to treat flu infection, but the first approved as an IV formulation,” said Edward Cox, M.D., M.P.H, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research. “The availability of a single-dose, intravenous option for the treatment of acute uncomplicated flu allows health care professionals and patients to have a choice based on an individual patient’s needs.”
Other neuraminidase inhibitors approved by the FDA to treat flu include oseltamivir, administered orally, and zanamivir, which is inhaled. Older antiviral drugs for flu, amantadine and rimantadine, are no longer recommended by CDC because circulating influenza strains are resistant to these drugs.
Rapivab’s efficacy was established in 297 participants with confirmed influenza who were randomly assigned to receive Rapivab 300 milligrams (mg), Rapivab 600 mg or placebo. Overall, participants receiving Rapivab 600 mg had their combined influenza symptoms alleviated 21 hours sooner, on average, than those receiving placebo, which is consistent with other drugs in the same class. Those receiving Rapivab 600 mg also recovered to normal temperature approximately 12 hours sooner compared to placebo. Supportive trials confirmed these findings. However, efficacy could not be established in patients with serious influenza requiring hospitalization.
Common side effects seen in Rapivab-treated participants include diarrhea. Rare but serious side effects include serious skin or hypersensitivity reactions such as Stevens-Johnson syndrome and erythema multiforme. Patients with influenza may be at an increased risk of hallucinations, delirium and abnormal behavior early in their illness and should be monitored for abnormal behavior. These events have been reported with neuraminidase inhibitor drugs, but it is not clear that the drug caused the abnormal behavior.
Rapivab and other antiviral drugs used to treat flu are not substitutes for early, annual flu vaccination, as recommended by CDC’s Advisory Committee on Immunization Practices. CDC recommends all persons ages 6 months and older receive an annual flu vaccine.
Rapivab is manufactured by BioCryst Pharmaceuticals, based in Durham, North Carolina.