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Paxlovid
Published
Product name
Paxlovid
Active ingredient
Nirmatrelvir/ritonavir
Submission type
New chemical entity
Decision
Approved for provisional registration
Decision date
Registration date
What this medicine was approved for
Paxlovid (nirmatrelvir/ritonavir) was approved for the following therapeutic use:
Paxlovid has provisional approval for the treatment of coronavirus disease 2019 (COVID 19) in adults 18 years of age and older, who do not require initiation of supplemental oxygen due to COVID 19 and are at increased risk of progression to hospitalisation or death (see Section 5.1 Pharmacodynamic properties, clinical trials).
The decision has been made on the basis of short term efficacy and safety data. Continued approval of this indication depends on the efficacy and safety data from ongoing clinical trials and post-market assessment.
How this medicine works
Nirmatrelvir is a peptidomimetic inhibitor of the Coronavirus disease (SARS-CoV-2) main protease (Mpro), also referred to as 3C-like protease (3CLpro) or nsp5 protease. Inhibition of SARS-CoV-2 Mpro renders the protein incapable of processing polyprotein precursors which leads to the prevention of viral replication. Nirmatrelvir was shown to be an inhibitor of SARS-CoV-2 Mpro (inhibitory constant (Ki)=3.1 nM, or total concentration of inhibitor needed to reach 50% inhibition (IC50)=19.2 nM) in a biochemical enzymatic assay. Nirmatrelvir was found to bind directly to the SARS-CoV-2 Mpro active site by X-radiation (X-ray) crystallography. Ritonavir inhibits the cytochrome P450, family 3, subfamily A (CYP3A)‑mediated metabolism of nirmatrelvir, thereby providing increased plasma concentrations of nirmatrelvir.
Why the TGA approved or did not approve this medicine
The decision was based on quality (chemistry and manufacturing), nonclinical (pharmacology and toxicology), clinical (pharmacology, safety and efficacy) and risk management plan information submitted by the sponsor. The benefit-risk profile of Paxlovid was considered favourable for the therapeutic use approved.
Sponsor