A PHASE 1 DOSE ESCALATION AND EXPANSION STUDY TO EVALUATE THE SAFETY, TOLERABILITY, PHARMACOKINETIC, PHARMACODYNAMIC, AND ANTITUMOR ACTIVITY OF PF-07260437 IN ADVANCED OR METASTATIC SOLID TUMORS

Number of Participants With Dose-Limiting Toxicities (DLTs) in Dose Escalation - Part 1

Time Frame: The first dose of the study intervention (C1D1) through Day 28 for participants without a priming dose or through Day 42 for participants with a priming dose.

Any of the following treatment-related adverse events (AEs) occurring during the DLT observation period were classified as DLTs: Hematological DLTs: neutropenia Grade (G) 4, febrile neutropenia, ≥G3 for \>7d (days), G3 with infection; thrombocytopenia G4, G3 with bleeding or requiring platelet transfusion; anemia G4, G3 requiring blood transfusion. Non-hematologic: hepatic toxicity; ≥G3 fatigue for ≥5d, ≥G3 nausea/vomiting or diarrhea for ≥3d, ≥G3 cytokine release syndrome (CRS) of any duration/QTcF prolongation/anaphylaxis, G5 AE without clear reason; immune-related (ir)AE: ≥G4 irAEs/colitis, G3/4 non-infectious pneumonitis, G2 pneumonitis not resolved to ≤G1 within 3d of the initiation of max supportive care. Severity of AEs were graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, with the exception of CRS, which were graded according to the American Society for Transplantation and Cellular Therapy (ASTCT) CRS Consensus Grading for CRS.

Number of Participants With Treatment Emergent Adverse Events (TEAEs) - Part 1

Time Frame: Baseline (Day 1 of dosing ) through 4 week follow-up, up to 35.1 weeks

An AE was any untoward medical occurrence in a participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. TEAE was defined as any AE that occurred from first dose of study intervention to either last dose of study treatment + 90 days, start of new anti-cancer therapy, or completion in study as determined by disposition, whichever was earliest. A serious AE (SAE) was defined as any untoward medical occurrence that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, persistent disability/incapacity, or was a congenital anomaly/birth defect. AEs were graded by the investigator according to CTCAE v5.0.

Number of Participants With Clinically Significant Laboratory Abnormalities - Part 1

Time Frame: Baseline through up to 35.1 weeks

Laboratory parameters included: hematology (hemoglobin, hematocrit, red blood cell, platelet and white blood cell count, neutrophils, eosinophils, monocytes, basophils and lymphocytes), chemistry (blood urea nitrogen, creatinine, sodium, potassium, aspartate aminotransferase, alanine aminotransferase, total bilirubin, alkaline phosphatase, albumin, total protein and serum pregnancy test \[for all female participants\]) and urine (urine pregnancy test \[for all female participants\]). Clinical significance of laboratory parameters was determined at the investigator's discretion.