816PDCLINICAL ACTIVITY OF SUNITINIB RECHALLENGE IN METASTATIC RENAL CELL CARCINOMA (MRCC) – RESULTS OF THE RESUME STUDY

Abstract Aim: Sunitinib is a front-line standard of care in mRCC patients. Several studies have shown that a 2nd line with a TKI after sunitinib progression is an effective treatment in mRCC. We assessed the efficacy and tolerability of a sunitinib rechallenge in 3rd line or more after progression with other therapies. Methods: All mRCC patients (pts) initiating a sunitinib rechallenge in 3rd line or more between January 2006 and May 2013 in the 18 French participating centres were enrolled. Patient characteristics, disease characteristics, tolerability, treatment modalities and outcomes of all therapeutic lines (sunitinib in 1st line, treatment received before rechallenge, sunitinib rechallenge) where retrospectively and/or prospectively recorded. All of these data come from a partial analysis on available data in May 2014 and will be updated with the final analysis (August 2014) at the ESMO congress. Results: Fifty pts treated with sunitinib rechallenge have been analysed. Seventy four percent of pts were male, mean age at diagnosis was 59.3 years, 98% had a clear cell mRCC, ECOG PS was 0-1 in 92.6% pts and 96% had had a prior radical nephrectomy. Ninety six percent of pts had favourable or intermediate risk per MSKCC criteria in 1st line. Sunitinib was started at 50mg 4/2 in 87.5% and 34.7% pts in 1st line and at rechallenge, respectively and at 37.5mg 4/2 in 10.4% and 53.1%. Sunitinib in 1st line produced an ORR of 52.1%, and a median PFS of 18.4 months [CI95%, 12.4 – 23.7]. Most pts (83.3%) discontinued initial sunitinib for disease progression. Rechallenge began a median of 15 months after discontinuation of initial sunitinib treatment. The majority of pts (63.3%) received sunitinib rechallenge in 4th line and 20.4%, 12.2%, 4.1% received sunitinib in 3rd, 5th, 6th line respectively. Treatments received in between were: 82.6% TKI, 97.8% mTOR and both 80.4%. Upon sunitinib rechallenge, 17.1% of pts achieved a partial response with a median PFS of 7.6 months [95%CI, 4.4-9.7]. The overall survival was 61.9 months [95%CI, 55.5 – 74.5]. Substantial new toxicity or significantly increased severity of prior toxicity was not observed during rechallenge. Conclusions: These data show that sunitinib rechallenge has potential benefits and is tolerated in mRCC patients. They suggest that disease progression on initial sunitinib is not associated with absolute resistance to therapy. Disclosure: S. Oudard: Consultant or AdvisoryRole; Entity: Sanofi, Novartis, Roche,