A 62-year-old woman with metastatic renal cell carcinoma (clear cell type) who progressed on sunitinib after 8 months of treatment is now being considered for second-line therapy. What is the preferred drug of choice for this patient?

Explanation

## Second-Line Therapy After TKI Failure in Metastatic RCC **Key Point:** Axitinib is the preferred second-line TKI for patients with metastatic RCC who have progressed on first-line VEGFR-targeted therapy (sunitinib, pazopanib, or bevacizumab). ### Mechanism of Action Axitinib is a potent, selective VEGFR inhibitor with: - High selectivity for VEGFR-1, VEGFR-2, and VEGFR-3 - Rapid oral absorption and short half-life (~2.5 hours) - Continuous daily dosing (5 mg BD, titrated up to 10 mg BD) Its selectivity for VEGFR over other kinases may confer activity in TKI-resistant disease. ### Second-Line TKI Sequencing | Agent | Setting | Mechanism | Key Evidence | Status | |-------|---------|-----------|--------------|--------| | **Axitinib** | Post-VEGFR-TKI progression | Selective VEGFR inhibitor | AXIS trial: superior PFS vs sorafenib | **Preferred second-line** | | **Sorafenib** | Post-sunitinib/pazopanib | Multi-targeted TKI | SHARP trial (older); less efficacy | Older standard; less preferred | | **Pazopanib** | Post-sunitinib | Multi-targeted TKI | Can be used if prior TKI was different | Alternative | | **Bevacizumab + IFN-α** | First-line or salvage | Anti-VEGF + immunotherapy | AVOREN trial | Rarely used second-line now | **High-Yield:** The landmark AXIS trial (2011) demonstrated that axitinib significantly improved progression-free survival (6.7 months vs 4.7 months) compared to sorafenib in patients with prior sunitinib or bevacizumab failure, establishing axitinib as the preferred second-line agent. ### Clinical Pearl Axitinib's rapid pharmacokinetics and VEGFR selectivity allow for dose escalation in individual patients based on tolerability and response. This personalized dosing approach (starting at 5 mg BD and titrating to 10 mg BD) may improve efficacy in TKI-resistant disease. ### Rationale for Axitinib Over Sorafenib - Superior PFS in head-to-head AXIS trial - Better tolerability profile in many patients - Selective VEGFR inhibition may overcome resistance mechanisms - Shorter half-life allows rapid dose adjustment [cite:Harrison 21e Ch 347]