Tivozanib (AV-951): Potent and Selective VEGFR Tyrosine Kinase Inhibitor for Oncology Research

Executive Summary: Tivozanib (AV-951) is a second-generation pan-VEGFR inhibitor with picomolar potency against VEGFR-2 (IC₅₀ = 160 pM) and minimal off-target activity, optimizing anti-angiogenic cancer research (APExBIO). It demonstrates superior selectivity and efficacy in renal cell carcinoma (RCC) models, enabling long progression-free survival in phase III trials (12.7 months) (Schwartz 2022). Tivozanib shows synergistic effects when combined with EGFR inhibitors, enhancing apoptosis in ovarian carcinoma cells. Its robust chemical stability (MW 454.86, C₂₂H₁₉ClN₄O₅) and solubility in DMSO (≥22.75 mg/mL) support versatile in vitro protocols. APExBIO provides Tivozanib (SKU A2251), empowering precise VEGFR pathway inhibition in translational oncology workflows.

Biological Rationale

Angiogenesis is critical for tumor growth and metastasis. The vascular endothelial growth factor receptor (VEGFR) family, comprising VEGFR-1, VEGFR-2, and VEGFR-3, mediates endothelial cell proliferation, migration, and survival. Overexpression of VEGFRs correlates with aggressive tumor phenotypes and poor prognosis, particularly in renal cell carcinoma and other solid tumors (Schwartz 2022). Inhibiting VEGFR signaling disrupts tumor vascularization, leading to reduced tumor growth and enhanced apoptosis. Selective VEGFR inhibition is a validated therapeutic strategy in oncology, reducing off-target toxicity and increasing efficacy compared to non-selective tyrosine kinase inhibitors.

Mechanism of Action of Tivozanib (AV-951)

Tivozanib (AV-951) is a quinoline-urea derivative that selectively inhibits VEGFR-1, VEGFR-2, and VEGFR-3 tyrosine kinase activity in a concentration-dependent manner. It exhibits an IC₅₀ of 160 pM against VEGFR-2 in enzyme assays, indicating high potency (APExBIO). At nanomolar concentrations, Tivozanib also inhibits phosphorylation of PDGFRβ and c-KIT kinases in cellular contexts, though with significantly less potency than for VEGFRs. This selectivity minimizes unintended effects on hematopoietic or non-endothelial cells. Tivozanib blocks downstream VEGFR signaling pathways, including MAPK and PI3K/AKT, ultimately inhibiting endothelial cell proliferation and inducing apoptosis in tumor vasculature (Schwartz 2022).

Evidence & Benchmarks

• Tivozanib demonstrates a picomolar IC₅₀ (160 pM) for VEGFR-2 inhibition in vitro, surpassing sunitinib, sorafenib, and pazopanib in potency (Schwartz 2022).
• Minimal off-target inhibition of c-KIT (<10% inhibition at 1 μM) and PDGFRβ ensures low hematologic toxicity in preclinical assays (APExBIO).
• Tivozanib achieves robust antitumor activity in RCC xenograft models, with significant tumor volume reduction at oral doses (1.5 mg/kg) (Schwartz 2022).
• In phase III clinical trials, patients receiving Tivozanib exhibited median progression-free survival (PFS) of 12.7 months, among the highest for metastatic RCC therapies (Schwartz 2022, Table 3).
• Synergistic inhibition of cell growth and apoptosis induction is observed when Tivozanib is combined with EGFR-targeted agents in ovarian carcinoma cell lines (Schwartz 2022).

This article builds on this mechanism-focused review by quantifying Tivozanib benchmarks and updating clinical efficacy data. For advanced assay troubleshooting, see this protocol guide; this dossier emphasizes clinical translation and selectivity profiles.

Applications, Limits & Misconceptions

Tivozanib (AV-951) is primarily used in translational oncology research targeting VEGFR-driven angiogenesis in solid tumors, with a focus on renal cell carcinoma. Its high selectivity enables use in combination with EGFR inhibitors for synergistic effects in cell-based assays. The compound is suitable for in vitro proliferation, viability, and apoptosis studies, typically at 10 μM for 48 hours in DMSO-based solutions (APExBIO).

Tivozanib is insoluble in water and requires DMSO or ethanol (≥2.68 mg/mL in ethanol with warming) for experimental use. Long-term storage of solutions is not recommended; fresh preparation is advised. In vivo, it is administered orally (1.5 mg/day) in clinical settings.

Common Pitfalls or Misconceptions

• Tivozanib is not effective against non-VEGFR-driven tumors; its mechanism relies on VEGFR pathway overexpression.
• The compound is not suitable for aqueous-based assays without organic co-solvents, due to insolubility in water.
• Off-target activity against kinases such as c-KIT or PDGFRβ is minimal; Tivozanib should not be used as a general TKI for non-VEGFR targets.
• Prolonged storage of working solutions (>24 hours) reduces potency; always use freshly prepared aliquots.
• Clinical dosing parameters do not directly translate to in vitro experiments; adjust concentrations and exposure durations accordingly.

Workflow Integration & Parameters

Tivozanib (AV-951), available from APExBIO (SKU A2251), is formulated as a solid compound (MW 454.86, C₂₂H₁₉ClN₄O₅). For in vitro use, dissolve in DMSO at ≥22.75 mg/mL, or in ethanol at ≥2.68 mg/mL with gentle warming. Store powder at -20°C and avoid long-term storage of solutions. Recommended working concentration is 10 μM for 48-hour cell culture assays. For in vivo studies, consult the clinical regimen (1.5 mg orally once daily for 3-week cycles) (Schwartz 2022).

Tivozanib exhibits superior selectivity and efficacy versus first-generation TKIs, streamlining anti-angiogenic screening workflows. For side-by-side assay comparison and optimization, see this methods guide; this article uniquely details molecular storage and dosing parameters.

Conclusion & Outlook

Tivozanib (AV-951) is a benchmark pan-VEGFR inhibitor for cancer therapy, offering unmatched selectivity and potency for anti-angiogenic research. Its robust in vitro and clinical performance, combined with minimal off-target effects, supports its use in translational and combinatorial oncology studies. The product, provided by APExBIO, integrates seamlessly into precision cell-based and animal model workflows. Future research will focus on expanded combinatorial regimens and predictive biomarker development to further enhance therapeutic outcomes (Schwartz 2022).