Differences in adverse event profiles between everolimus and temsirolimus and the risk factors for non-infectious pneumonitis in advanced renal cell carcinoma

Background There have been few reports of the differences in safety between the mammalian target of rapamycin inhibitors, everolimus and temsirolimus. The purpose of this study is to compare the adverse event profiles of both agents and to estimate the risk factors for non-infectious pneumonitis in patients with advanced renal cell carcinoma on the basis of our real-world clinical experience. Methods Data from 218 consecutive patients that received either everolimus or temsirolimus for advanced renal cell carcinoma at five Japanese centers were retrospectively analyzed. Chi-squared test and univariate and multivariate logistic regression analyses were performed to investigate the differences in adverse event profiles and the risk factors associated with non-infectious pneumonitis, respectively. Results A total of 196 patients were evaluable. In the everolimus group compared with temsirolimus, stomatitis (56 vs 30 %, p < 0.001) and non-infectious pneumonitis (38 vs 22 %, p = 0.018) were more frequently observed, and asthenia (11 vs 23 %, p = 0.027), rash (20 vs 36 %, p = 0.018), and fatigue (33 vs 48 %, p = 0.032) occurred less frequently in all grades. On multivariate analysis, male gender (odds ratio 3.65; 95 % confidence interval 1.44-9.26, p = 0.007) and everolimus treatment (odds ratio 2.00; 95 % confidence interval 1.01-3.96, p = 0.046) were significantly associated with development of non-infectious pneumonitis. Conclusion Our findings suggest that adverse event profiles may differ between everolimus and temsirolimus and that non-infectious pneumonitis may occur more frequently in patients treated with everolimus than temsirolimus. Further investigations are needed to confirm these results.