Phase III AXIS trial for second-line metastatic renal cell carcinoma (mRCC): Effect of prior first-line treatment duration and axitinib dose titration on axitinib efficacy.

Abstract

354 Background: Axitinib is a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors (VEGFRs) 1, 2, and 3. In the phase 3 AXIS trial of axitinib vs sorafenib for second-line mRCC, axitinib significantly prolonged median progression-free survival (mPFS) (6.7 vs 4.7 months; hazard ratio 0.665; P<0.0001). Here, we evaluated the effect of prior sunitinib treatment duration and axitinib dose titration on subsequent axitinib efficacy. Methods: Eligible patients had clear-cell mRCC; measurable RECIST-defined progressive disease after 1 prior first-line systemic therapy; and Eastern Cooperative Oncology performance status (PS) 0/1. Patients were stratified by PS and prior therapy, and randomized 1:1 to either axitinib, at a starting dose of 5 mg twice daily (BID), or sorafenib, 400 mg BID. Patients without toxicity >grade 2 and BP <150/90 mmHg without antihypertensive medication for >2 weeks were eligible to increase axitinib dose to 7 mg BID and then to 10 mg BID. Results: The mPFS for patients receiving at least one total daily axitinib dose >10 mg (dose-titrated group; n=132) was 6.6 months [95% CI 4.7–8.3] and 8.3 months [95% CI 6.0–10.2] for patients receiving axitinib ≤10 mg (n=227). A total of 194 patients (53.7%) in the axitinib arm and 195 patients (53.9%) in the sorafenib arm had prior sunitinib treatment. The mPFS for patients with duration of prior sunitinib treatment ≥6 months and <6 months were 4.8 months [95% CI 4.5–6.5] and 4.6 months [95% CI 2.8–8.3] for axitinib patients; and 4.6 months [95% CI 2.9–4.9] and 2.9 months [95% CI 2.8–4.6), for sorafenib patients. The mPFS for duration of prior sunitinib ≥9 months and <9 months were 6.3 months [95% CI 4.6–6.7] and 4.5 months [95% CI 2.8–6.4] for axitinib patients; and 4.6 months [95% CI 2.8–4.9] and 2.9 months [95% CI 2.8–4.7]) for sorafenib patients. Conclusions: Duration of prior sunitinib ≥9 months may be associated with a longer PFS on second-line VEGFR tyrosine kinase inhibitors. Both axitinib dose-increased and non-increased patients had longer PFS compared with the sorafenib arm.