First RSV Antiviral Successfully Completes Phase 3 Study

Ark Biopharmaceutical recently announced the successful results of the multicenter AirFLO study with ziresovir, a novel small-molecule RSV fusion (F) protein inhibitor, in infants hospitalized with Respiratory Syncytial Virus (RSV). 

The phase 3 clinical trial met the primary endpoints of reduction in the signs-and-symptoms (S&S) score (p=0.002) and the key secondary endpoint of reduction in viral load (p=0.006) compared with placebo.

These results represent the first successful phase 3 study for an oral RSV antiviral drug globally.

As of April 11, 2022, there are neither effective vaccines nor treatments available that specifically target RSV.

“Every year, tens of thousands of young infants and children die from RSV infection, and we urgently need a safe and effective therapy,” commented Dr. Xin Ni, President of Beijing Children’s Hospital, Director of National Children’s Medical Center, and the leading investigator of the AirFLO study, in a press release issued on April 8, 2022.

In the AirFLO trial, ziresovir demonstrated a rapid onset of clinical effects, showing a 30% additional S&S score reduction compared with placebo (p=0.002) after two days.

In the study, patients under 6-month-old showed even more pronounced benefits, with 55% additional S&S score reduction compared with placebo (p<0.001).

Ziresovir also showed a significant antiviral effect, with the active drug group showing 77% additional viral load reduction compared with placebo (p=0.006) on day 5.

Statistically, significant viral load reductions were observed throughout the treatment period. 

Supported by the AirFLO results, the regulatory submission of ziresovir for market approval in China is planned for mid-2022.

Additional RSV antiviral and vaccine development news is posted at PrecisionVaccinations.com/RSV.

Note: The press statement was edited for clarity and manually curated for mobile readers.