The majority of renal cell carcinomas (RCCs) are a subtype called clear cell RCC. Most drugs have been developed to treat this subtype of RCC, leaving people with other metastatic RCC subtypes with an unmet need for an effective treatment in the first-line. Papillary RCC (pRCC) represents 10-15% of renal cell carcinomas, and is not an insignificant subtype. Currently, there is no standard treatment for people with metastatic pRCC, and few trials have been conducted. Trials with sunitinib, everolimus and savolitinib had disappointing response rates.
The results from a phase 2 clinical trial to assess the safety and efficacy of axinitib as a first-line treatment for patients with pRCC were published in the European Journal of Cancer recently. In this trial, the vascular endothelial growth factor (VEGF) inhibitor, axitinib, was investigated as a potential treatment for metastatic pRCC in the first-line. Axitinib is currently available as a second-line treatment for metastatic RCC.
Forty-four patients with type 1 (12 patients), type 2 (30 patients), or mixed/undetermined (2 patients) pRCC were treated with axitinib in the study. The objective response rate was 28.6%, and the median progression-free survival was 6.6 months. The median overall survival was 18.9 months. The safety profile of axitinib was as expected from previous studies.
In conclusion, axitinib shows encouraging efficacy in people with metastatic pRCC, especially in type 2 pRCC. Axitinib toxicity was manageable and as expected from previous clinical trials. Further clinical trials are needed to evaluate the promising efficacy of axitinib for the first-line treatment of patients with metastatic pRCC.