Single-dose flu pill wins FDA approval

U.S. approval of the first novel anti-flu pill in two decades has doctors cautiously optimistic about a simpler treatment for a virus that killed almost 200 American children last season.

The drug, which is to be marketed globally by Shionogi & Co. and Roche Holding, gained Food and Drug Administration approval just as the winter flu season begins. Developer Shionogi won approval for the treatment, called Xofluza, in Japan in February after studies showed the medication, known also by its chemical name baloxavir, relieved symptoms as quickly as Roche’s Tamiflu with faster antiviral activity.

Roche’s Genentech unit plans to launch Xofluza, for people age 12 and older, within a few weeks. It will cost $150 without insurance.

The need for only one dose is an advantage since patients don’t always take all their medicine, said Dr. Mark Eisner, Genentech’s head of development of infectious disease medicines.

The tablet gives doctors a new weapon, but studies reveal a tendency for viruses to develop reduced susceptibility to the new treatment. It’s not yet clear whether drug-evading germs are capable of spreading easily between people, causing potency to wane, Roche said. Lab tests indicate Xofluza also may have weaker activity against the typically less-common influenza B strain.

“A new antiviral against flu is of course welcome and is, at first blush, very attractive because it’s one dose,” said William Schaffner, professor of infectious diseases at Vanderbilt University School of Medicine in Nashville. “However, there are a couple of cautions, namely resistance seems to develop fairly readily, and the drug seems not to be as effective against influenza B strains,” he said in a phone interview Tuesday from the Centers for Disease Control and Prevention in Atlanta, where he sits on an immunization practices advisory panel.

The 2017-2018 Northern Hemisphere flu season was especially bad, leading to some 900,000 hospitalizations, including 183 pediatric deaths, in the U.S. alone.

Population-aging and the demand for flu immunizations, treatments and diagnoses will help push up the global influenza market 3 percent a year to reach $6.5 billion by 2022, BCC Research estimated in April. Shionogi will manufacture the drug in Japan, with the plan to transfer the manufacturing to Basel, Switzerland-based Roche, which has the rights to sell it everywhere except in Japan and Taiwan.

“Xofluza is an excellent drug,” said Atsushi Seki, an analyst with UBS in Tokyo. Still, its “commercial potential is moderate,” he said, noting concern among some investors the potential for drug-resistance represents a risk for sales, as does variation in the severity of flu seasons, which drives prescriptions. The past Southern Hemisphere winter flu season has been relatively mild.

It’s taken as a single dose, unlike Tamiflu, which is usually taken twice a day for five days. The simpler regimen eases concern that poor patient compliance could encourage drug-resistant viruses to emerge, and could ease the medication’s distribution during a pandemic.