Once-a-Day Oral Pill to Treat and Prevent SARS-CoV-2 Infections Begins First-in-Human Study

An oral antiviral in development to treat and prevent SARS-CoV-2 infections has entered the first-in-human trial to explore the potential for dosing it as a once or twice-a-day pill.

Pardes Biosciences, Inc. (Berkeley, CA, USA) has initiated a Phase 1 clinical trial for evaluating its lead candidate, PBI-0451 which is being developed as a potential oral direct-acting antiviral to treat and prevent infections with SARS-CoV-2, the virus that causes COVID-19.


PBI-0451 works by inhibiting Viral Main Protease (Mpro), a highly conserved key protein in the virus required for its replication, thus blocking the virus’ ability to replicate. The highly conserved nature of Mpro across multiple coronaviruses, including emerging variants of concern such as Delta and Lambda, supports the potential for PBI-0451 to target both existing and future coronaviruses. In preclinical studies, PBI-0451 has been shown to inhibit replication of a broad range of coronaviruses including SARS-CoV-2 across multiple in-vitro models, and was well tolerated in clinically enabling toxicity studies.

To develop this candidate, the company leveraged structure-based drug design and its tunable, reversible covalent chemistry platform. The company envisions using its platform in the future to build novel drug candidates for the treatment of other diseases with high unmet medical need. The Phase 1 study will be a placebo-controlled, blinded, randomized, dose escalation study of PBI-0451 in healthy volunteers designed to evaluate the safety, tolerability, and pharmacokinetics of PBI-0451 after single and multiple ascending doses, and will also explore the drug-drug interaction potential of PBI-0451. This first-in-human study is designed to explore the potential for dosing PBI-0451 as a once or twice-a-day pill and is anticipated to enroll up to 110 healthy volunteers.

“We believe oral anti-viral therapies have the potential to address the significant global public health challenges of both COVID-19 as well as future pandemics,” said Uri A. Lopatin, M.D., Chief Executive Officer of Pardes Biosciences. “This trial marks a significant milestone in our efforts to develop PBI-0451 as a potential oral antiviral therapy for SARS-CoV-2, and we look forward to providing updates on our progress.”

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Pardes Biosciences, Inc.