Axitinib in first-line for patients with metastatic papillary renal cell carcinoma: Results of the multicentre, open-label, single-arm, phase II AXIPAP trial.

INTRODUCTION

Papillary renal cell carcinoma (PRCC) represents 10%-15% of renal carcinomas. No standard treatments exist for metastatic PRCC (mPRCC) patients. Axitinib is indicated as second-line treatment in metastatic clear cell renal carcinoma, and we aim to assess the efficacy of this vascular endothelial growth factor receptor inhibitor in front line for mPRCC.

METHODS

This French multicentre phase II study AXIPAP enrolled untreated mPRCC patients, with measurable disease, Eastern Cooperative Oncology Group performance status ≤ 1 and adequate organ functions. PRCC had to be confirmed by histology expert central review. Axitinib was administered orally 5 mg twice daily. Primary end-point was progression-free rate at 24 weeks (24w-PFR) by central review.

RESULTS

Fifty-six patients were screened, and 44 included (13 type 1, 30 type 2 and 1 non-specified). The median follow-up was 32.0 (13.1-39.9) months. The 24w-PFR was 45.2% (95% confidence interval [CI], 32.6% to +∞), the objective response rate was 28.6% (95% CI, 15.7%-44.6%) (type 1: 7.7%; type 2: 35.7%). The overall median progression free survival was 6.6 months (95% CI, 5.5-9.2), 6.7 months (95% CI, 5.5-9.2) and 6.2 months (95% CI, 5.4-9.2) for type 1 and 2, respectively. Median overall survival was 18.9 months (95% CI, 12.8-not reached). Adverse events were as expected; grade 3-4 treatment-related adverse events were rare except hypertension (27%).

CONCLUSIONS

Axitinib demonstrated encouraging efficacy in mPRCC patients, especially in type 2 PRCC. Toxicity was manageable. Axitinib appears as an interesting option for first-line treatment and to be worth further investigation in combination with immunotherapy in these patients. Expert pathology review should be recommended in this setting.

CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02489695.