404 Background: Treatment options for metastatic renal cell carcinoma (mRCC) have increased. Complete remission is, however, rarely seen and patients are treated with multiple sequential therapies. We assessed clinical activity of sorafenib rechallenge after progressing on other therapies. Methods: Patients with mRCC who received a second course of sorafenib therapy after failure of prior sorafenib and other agents were retrospectively identified. RECIST-defined objective response rate and progression-free survival (PFS) and toxicity were analyzed. Results: Fourteen patients with mRCC who were retreated with sorafenib were identified and twelve patients were assessable for this study. 92% were male. Median age at first systemic therapy was 63 years. Prior nephrectomy was performed in 92% of patients. 42% of patients had favorable or intermediate risk, 17% poor, and the rest not available per MSKCC criteria. Eighty-three percent of patients were treated with other agents before initial sorafenib therapy, including 75% interferon-alpha (IFN-alpha), 50% interleukin-2 (IL-2), and 17% sunitinib. First sorafenib therapy began a median of 9.0 months after the diagnosis of mRCC and produced a clinical benefit (PR + SD) rate of 75% and a median PFS of 5.0 months. 67% of patients discontinued initial sorafenib for disease progression and 33% for adverse events. Interval between discontinuation of initial sorafenib and rechallenge was a median of 7.6 months. During the intervening period, 50% of patients were treated with sunitinib, 33% with everolimus, 25% with VEGFR1 vaccine, and others. Clinical benefit rate of 67% and a median PFS of 4.3 months were obtained on sorafenib rechallenge. There was no significant difference in outcome to sorafenib rechallenge based on duration between sorafenib treatments or number or type of intervening treatments. No new severe toxicity was observed during rechallenge. Conclusions: Sorafenib rechallenge has potential to achieve clinical benefits, is well-tolerated, and may be considered after multiple sequential therapies in select mRCC patients. No significant financial relationships to disclose.
Changes in tumor oxygen state after sorafenib therapy evaluated by 18F-fluoromisonidazole hypoxia imaging of renal cell carcinoma xenografts
