A new modified sunitinib schedule for metastatic renal cell cancer (mRCC): A pilot study

471 Background: Oral sunitinib administration at 50 mg daily given for 4 weeks followed by 2 weeks off treatment (4+2 schedule) is a standard first line for mRCC treatment. About 20% of patients had to discontinue treatment permanently and 50% of patients are forced to reduce the doses due to adverse events [Motzer RJ, J Clin Oncol. 2009]. A meta-analysis showed that increase exposure to sunitinib is associated with improved clinical outcome [Houk BE, Cancer Chemother Pharmacol. 2010]. Methods: This is a pilot study in which consecutive mRCC patients admitted to our hospital who had at least a grade 2 toxicity with sunitinib, were switched to a modified schedule maintaining the same dose-intensity of 4+2 schedule: starting on Monday, 1 tablet (50 mg) a day for 5 consecutive days a week for 5 weeks and 1 tablet per day on days 1, 3 and 5 in the sixth week (28 tablets in 6 weeks), until disease progression. Primary end points were toxicity changes assessment and schedule feasibility, secondary end point was overall progression free survival (PFS). Results: Eight nephrectomized patient were enrolled: 6 males; median age 61; 37% good, 50% intermediate and 13% poor MSKCC risk; 3 patient pretreated; 6 clear cell histologies, 1 papillary and 1 undifferentiated histotypes. Median time from start therapy to switch was 7.4 months (range 1.4-16.1). Treatment delays and dose reductions were reduced from 50% to 25% and from 37% to 12% of patients respectively. The table shows the toxicity changes: there were no new toxicities. PFS was 16.3 months (CI 95% 5.6-23.4). Conclusions: This new modified schedule requires and deserves further studies. [Table: see text]