Pfizer gets CDSCO panel nod to study PF-07321332 for COVID treatment

New Delhi: In a significant development, pharmaceutical major Pfizer has got a go ahead from the Subject Expert Committee (SEC) of the Central Drugs Standard Control Organization (CDSCO) to conduct a trial of oral antiviral clinical candidate PF-07321332/Ritonavir in the treatment of COVID 19.

The approval is subject to the condition that up to 100 volunteers from India be recruited for the study. In addition to this, the committee directed the firm to submit the final study data from the clinical Phase I study (FIH Study) to the CDSCO for review.

Further, the expert panel instructed that the firm should submit the completed non-clinical toxicological study data. 

This came after the drug-maker Pfizer presented the proposed amended-study protocol no. C4671002, Amendment 3 dated 03Aug2021 with justification in line with the earlier recommendation.

Ritonavir is an antiretroviral protease inhibitor that is widely used in combination with other protease inhibitors in the therapy and prevention of human immunodeficiency virus (HIV) infection and the acquired immunodeficiency syndrome (AIDS).

Protease inhibitors bind to a viral enzyme (called a protease), preventing the virus from replicating in the cell. Protease inhibitors have been effective at treating other viral pathogens such as HIV and hepatitis C virus, both alone and in combination with other antivirals.

Pfizer stated in a press release that already marketed viral protease inhibitors are not often linked with toxicity, and as a result, this class of medicines could potentially deliver well-tolerated COVID-19 therapy.

In March, Pfizer announced that the oral antiviral clinical candidate PF-07321332, a SARS-CoV2-3CL protease inhibitor, has demonstrated potent in vitro anti-viral activity against SARS-CoV-2, as well as activity against other coronaviruses, suggesting potential for use in the treatment of COVID-19 as well as potential use to address future coronavirus threats.

Furthermore, it added, "The Phase 1 trial is a randomized, double-blind, sponsor-open, placebo-controlled, single- and multiple-dose escalation study in healthy adults evaluating the safety, tolerability, and pharmacokinetics of PF-07321332."

Earlier, at the 178th SEC meeting to examine COVID-19 related proposals under the accelerated approval process, held on 26.08.2021 & 27.08.2021, the firm presented the proposal for Phase II/III clinical study protocol no. C4671002, Amendment 2, dated July 19, 2021, before the Subject Expert Committee (SEC) of the Central Drugs Standard Control Organization (CDSCO).

Responding to this, the committee opined that the proposal can be reviewed only after receiving complete pre-clinical toxicity data and clinical Phase I data with proposed IP.

Accordingly, at the 183rd SEC meeting held on September 16, 2021 at CDSCO, the firm presented the proposed amended-study protocol no. C4671002, Amendment 3, dated August 3, 2021, with justification.

After detailed deliberation, the Committee recommended the grant of permission to conduct the proposed clinical trial with the following conditions:

1) Up to 100 subjects from India should be recruited for the study.

2) The firm should submit the final study data from the clinical Phase I study (FIH Study) to the CDSCO for review.

3) The firm must submit the results of the non-clinical toxicological study.