Pardes Biosciences has reported interim results from the ongoing Phase I clinical trial of its oral antiviral drug candidate, PBI-0451, in healthy adult subjects.

An investigational direct-acting antiviral (DAA) inhibitor of the 3CL protease, PBI-0451 is under development to treat and prevent Covid-19 and associated ailments.

The drug is currently being analysed in a placebo-controlled, blinded, randomised, dose-escalation Phase I trial in New Zealand.

It enrolled healthy adult subjects to assess the safety, tolerability and pharmacokinetics of the single and multiple ascending doses of the antiviral.

Interim findings showed that PBI-0451 demonstrated to be well tolerated over a >20-fold single- and >14-fold multiple-total daily dosage.

In the trial, all treatment-emergent adverse events reported until 31 January 2022 were observed to be mild in nature and subsided without requiring intervention.

The pharmacokinetics of PBI-0451 in a drug-drug interaction arm was not significantly affected on co-administration with ritonavir, which is an inhibitor of P-glycoprotein/CYP450 3A.

Furthermore, a twice-a-day dose of PBI-0451 attained and retained PK exposures in multiple ascending dose arms.

Pardes noted that this indicates the drug’s potential to offer robust antiviral activity against the SARS-CoV-2 virus as well as its emerging variants.  

Additional dose cohorts and PK analysis in the trial are currently underway, which will aid in the selection of dose for the upcoming Phase II/III trial of PBI-0451.

The company plans to commence the Phase II/III trial this year on obtaining regulatory approval to assess PBI-0451 for treating Covid-19.

Pardes Biosciences CEO Uri Lopatin said: “We are highly encouraged by these initial Phase I observations, which support continued development of PBI-0451 as a potential stand-alone antiviral therapy for the treatment and prevention of SARS-CoV-2 infections. 

“We are excited to continue advancing our lead protease inhibitor PBI-0451 and bring our novel oral antiviral treatment one step closer to patients in need.”

The latest development comes after the US Food and Drug Administration granted clearance to Pardes’ Investigational New Drug application for PBI-0451 for Covid-19 treatment and prevention.