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PF-07820435 (pf-07820435)
PF-07820435 inhibits viral or cellular proteases to disrupt essential enzymatic processes required for viral replication or tumor cell survival.
PF-07820435 is a Pfizer-developed protease inhibitor initially investigated as an antiviral agent for COVID-19 treatment, designed to block the viral 3CL protease essential for SARS-CoV-2 replication. The compound was also explored in oncology as a potential cancer therapeutic targeting protease-dependent pathways in solid tumors. However, the program was discontinued, with the only documented clinical trial being a Phase 1 study in advanced solid tumors (non-small-cell lung cancer, melanoma) that was terminated after enrolling 9 patients. The drug never achieved regulatory approval or commercial launch, and no published clinical efficacy data or safety profile from human studies is publicly available. The discontinuation reflects either lack of clinical differentiation, safety concerns, or strategic portfolio prioritization by Pfizer in favor of alternative antiviral or oncology candidates.
At a glance
| Generic name | pf-07820435 |
|---|---|
| Sponsor | Pfizer Inc. |
| Drug class | Protease inhibitor |
| Target | SARS-CoV-2 3CL protease (main protease) and/or cellular proteases in oncology indications |
| Therapeutic area | Oncology |
| Phase | discontinued |
Mechanism of action
PF-07820435 was designed as a protease inhibitor with dual potential applications: as an antiviral agent targeting the SARS-CoV-2 3CL protease (main protease), which cleaves viral polyproteins essential for coronavirus replication, and as an oncology agent targeting protease-dependent pathways in cancer cells. In the viral context, blocking this protease prevents the maturation of viral proteins, thereby reducing viral load and halting infection progression. In the oncology context, protease inhibition may disrupt cellular signaling pathways critical for tumor growth and survival. The mechanism leverages the essential role of proteolytic processing in both viral lifecycle and malignant cell biology.
Approved indications
Pipeline indications
- Advanced solid tumors (non-small-cell lung cancer, melanoma) — Phase 1
Common side effects
Key clinical trials
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- PF-07820435 CI brief — competitive landscape report
- PF-07820435 updates RSS · CI watch RSS
- Pfizer Inc. portfolio CI