An investigational, novel anti-influenza A virus inhibitor, ZSP1273 (Onradivir), demonstrated safety and reduced time to resolution of symptoms in a phase 2 trial by nearly a full day. The study’s results were published in The Lancet Infectious Diseases.
The investigators performed a double-blind, randomized, placebo-controlled study at 20 sites in China. Eligible participants for this phase 2 trial were adults between the ages of 18–65 years old who presented with influenza-like illness, screened by rapid antigen testing at the first visit at a clinic, had the presence of at least 1 moderate systemic and 1 respiratory symptom within 48 hours of symptom(s).
They decided to evaluate the participants self-assessed severity of 7 symptoms of influenza on a 4-point ordinal scale, as well as adverse events.
Within the study, 172 participants were randomized into different groups to receive either onradivir 200 mg twice per day (n=43); 400 mg of the therapy twice per day (n=43); 600 mg once per day (n=43), or a placebo (n=42).
“All three onradivir groups showed decreased median time to alleviate influenza symptoms (46·92 hours [IQR 24·00–81·38] in the 200 mg twice per day group, 54·87 hours [23·67–110·62] in the 400 mg twice per day group, and 40·05 hours [17·70–65·82] in the 600 mg once per day) compared with the placebo group (62·87 hours [36·40–113·25]),” the investigators wrote.
What You Need to Know
A study demonstrated that onradivir significantly reduced the time to resolution of influenza symptoms compared to the placebo group. All three dosage groups of onradivir showed a decrease in the median time to alleviate symptoms compared to the placebo, with the 600 mg once per day regimen showing the most significant reduction.
Onradivir exhibited a safety profile comparable to placebo. The most frequently reported side effect was diarrhea, experienced by a considerable portion of participants, but there were no serious adverse events reported.
The investigational antiviral demonstrated higher efficacy than placebo in ameliorating influenza symptoms and reducing viral load in adult patients with uncomplicated influenza infection.
They also said the median difference between the onradivir 600 mg once per day cohort and the placebo cohort was –22·82 hours (p=0·0330).
Prospective participants were excluded from the study if they were pregnant, allergic to onradivir, or had received any influenza antiviral therapy within 7 days before enrollment of the trial. There were no serious adverse events and the most frequently reported side effect was diarrhea, which was experienced in 71 of 171 participants overall (42%), and it ranged from 33–65% of the patients in onradivir-treated cohorts compared with 10% in the placebo group.
Onradivir is an oral antiviral tablet that was developed by the Chinese company, Zhongsheng Pharmaceutical.
"Onradivir showed a safety profile comparable to placebo, as well as higher efficacy than placebo in ameliorating influenza symptoms and lowering the viral load in adult patients with uncomplicated influenza infection, especially the onradivir 600 mg once per day regimen," the investigators concluded.
Reference
Yang Z., Li Z., et al. Safety and Efficacy of Onradivir in Adults with Acute Uncomplicated Influenza A Infection: a Multicentre, Double-Blind, Randomised, Placebo-Controlled, Phase 2 trial. The Lancet Infectious Diseases. February 5, 2024. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(23)00743-0/fulltext
