Axitinib treatment among patients with mRCC in a U.S. community oncology setting: A retrospective study of 135 patients.

Abstract

569 Background: We have previously reported differences in a variety of outcome measures between clinical trial and real world use of several therapies for advanced renal cell carcinoma (RCC) (Vogelzang NJ, et al. Clin Genitourin Cancer, 2015, Hutson TE et al. Lancet Oncol, 2013, Motzer RJ, et al. NEJM, 2013). In an attempt to better understand the real-world use of axitinib in patients (pts) with metastatic RCC (mRCC) after one prior systemic therapy, a retrospective study was conducted using the US Oncology’s (USON) iKnowMed electronic health records database and medical record review data. Methods: Eligibility criteria were: pts with mRCC ≥ 18 years of age at first diagnosis, treated with VEGFR-TKIs or immunotherapy including IL-2 and IFN as first line of therapy (LOT), received second or third line axitinib between 1/1/2012 and 10/31/2014, with ≥ 2 visits within the USON. LOT was defined based on treatment sequence. Dosing analysis included duration of therapy, dose change, and reasons for discontinuation. Results: 135 pts met eligibility criteria. The most common prior therapies were sunitinib (48.5%) and pazopanib (48.5%) for pts with axitinib as 2nd LOT (n=68), and everolimus (55.2%), temsirolimus (19.4%), and pazopanib (14.9%) for pts with axitinib as 3rdLOT (n=67). 80.7% (109) of pts started axitinib at 5mg BID, and 68.9% remained at this dose. 17.8% had a dose increase mainly due to physician’s choice and 13.3% a dose decrease mainly due to toxicity. The median duration of therapy was 4.57 months (mean 6.32, SD 5.91, range 0.03-35.49). Axitinib was discontinued in 91 (67.4%) pts, and the most common reasons for discontinuation were disease progression (39.3%) and toxicity (17.0%). Conclusions: In the community oncology setting, axitinib was commonly used in the 2nd and 3rd line setting for pts with mRCC. The usage pattern appears to be consistent with published NCCN guideline recommendations. Surprisingly and in contrast to our experience with other agents for RCC, dose changes were less common and duration of therapy was consistent with the pivotal clinical trial results. These findings suggest ease of use among community oncologists and patient tolerance are key features of axitinib.