Novel Flu Treatment Is Safe, Effective

AL-794, an orally active prodrug of ALS-033719, can safely spur significant antiviral activity, decreasing viral load, symptoms, and mucus weight in individuals with influenza, according to a new study.

To evaluate the antiviral activity of AL-794 as compared with placebo, the researchers analyzed the drug’s effect on participants aged 18 to 55 years with a body mass index of 18 to 30 kg/m².

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The otherwise healthy participants had been experimentally inoculated intranasally with influenza A/Perth/16/2009(H3N2) between November 2015 and May 2016.

The 61 participants were each randomly assigned to either AL-794, 50 mg; AL-794, 150 mg; or placebo twice daily for 5 days.

Participants treated with AL-794 had a reduction in influenza viral load and severity of influenza symptoms against influenza A/Perth/16/2009(H3N2).

While both doses of AL-794 had an antiviral effect as compared with placebo, the 150-mg regimen proved to be more potent than the 50-mg regimen—though equally as safe.

Among the 42 participants who met the definition for influenza virus infection, the mean peak viral load was 3.54 log₁₀ 50% tissue culture infectious doses (TCID₅₀)/mL for 50-mg AL-794 recipients, 2.77 log₁₀TCID₅₀/mL for 150-mg AL-794 recipients, and 3.72 log₁₀TCID₅₀/mL for placebo recipients.

The median time to virus nondetection was quicker among the 150-mg AL-794 group than among the 50-mg AL-794 group (75.3 hours vs 117.0 hours). The placebo group took 108.0 hours.

Consistent with the antiviral response, symptoms of influenza virus infection improved more quickly after treatment with 150 mg of AL-794, compared with 50 mg of AL-794 or placebo. 

Further, AL-794 was well tolerated, and no viral resistance to ALS-033719 was identified.

“Following oral administration of AL-794, significant dose-dependent antiviral activity was noted, with a greater decrease in viral load, symptoms, and mucus weight at the 150-mg dose, compared with the 50-mg dose, and no safety concerns for either dose or placebo,” the researchers concluded.

—Colleen Murphy

Reference:

Yogaratnam J, Rito J, Kakuda TN, et al. Antiviral activity, safety, and pharmacokinetics of AL-794, a novel oral influenza endonuclease inhibitor: results of an influenza human challenge study. J Infect Dis. 2019;219(2):177-185. https://doi.org/10.1093/infdis/jiy410.