Obermannová, Radka

668 Background: Ramucirumab is a human IgG1 monoclonal antibody antagonist of VEGFR-2. Overall survival (OS) and progression-free survival (PFS) in 2nd line FOLFIRI based treatment for metastatic colorectal cancer (mCRC) were improved with RAM therapy versus PBO in the RAISE trial. Recent work suggests mCRC primary tumor location is both prognostic and predictive; with improved OS and therapy-specific sensitivity observed in left (L)- vs right (R)-sided tumors. Given these findings, the RAISE trial data was subjected to post-hoc analysis to determine if sidedness influenced RAM efficacy. Methods: Primary tumor site was obtained. L-CRC was defined as the splenic flexure, descending and sigmoid colon, and rectum, while R-CRC included transverse, ascending colon and cecum. OS/PFS in L and R subgroups were analyzed via Kaplan-Meier method and unstratified log-rank test (treatments within subgroup), unstratified Cox proportional hazards model (estimate hazard ratio [HR] and 95% CI), and Wald test (treatment-by-subgroup interaction). Results: Tumor location was available for 1012/1072 (94%) patients, 699 L- and 313 R-CRC. Baseline characteristics were balanced between arms. RAM treatment enhanced L-CRC median OS by 2.5 mo (median 14.5 vs 12.0 mo) with a HR (95% CI) = 0.807 (0.675, 0.965), P = 0.019; compared to a 1.1 mo increase in median OS in R-CRC vs PBO (12.7 vs 11.6) with a HR (95% CI) = 0.971 (0.750, 1.258), P = 0.823; and, RAM enhanced L-CRC median PFS by 1.6 mo (6.0 vs 4.4 mo) and HR (95% CI) = 0.776 (0.664, 0.906), P = 0.001 compared to a 1.1 mo increase in median PFS R-CRC vs PBO (5.6 vs 4.5) with a HR (95% CI) = 0.855 (0.674, 1.084), P = 0.197. The treatment-by-subgroup interaction for both OS and PFS was not significant ( P = 0.276, 0.578, respectively). Conclusions: Despite L-CRC patients having longer OS/PFS and a seemingly stronger RAM treatment effect than R-CRC, the non-significant interaction test cannot verify sidedness as being predictive of RAM efficacy. The current study confirms ramucirumab benefits mCRC patients regardless primary tumor location. Clinical trial information: NCT01183780.

512 Background: Angiogenesis is an important therapeutic target in CRC; VEGF plays a key role in angiogenesis. RAM is a human IgG1 monoclonal antibody that targets the extracellular domain of VEGFR-2. The RAISE study evaluated the efficacy and safety of adding RAM to standard second-line treatment FOLFIRI. Methods: Eligible pts with mCRC who progressed on or after first-line combination therapy with bev, ox, and fp, had an ECOG PS of 0 or 1, and adequate organ function were randomized 1:1 (stratified by region, KRAS mutation status, and time to progressive disease [PD] after beginning first-line treatment) to receive RAM (8 mg/kg IV) plus FOLFIRI or PBO plus FOLFIRI every 2 weeks until PD, unacceptable toxicity, or death. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and safety. Planned sample size of 1,050 pts ensured 85% power to demonstrate statistical significance at an overall two-sided alpha of 0.05, assuming a hazard ratio (HR) of 0.8. Results: Between Dec 2010 and Aug 2013, 1,072 eligible pts were randomized (RAM 536; PBO 536). Baseline pt characteristics were similar between treatment arms. The OS HR was 0.84 (95% CI: 0.73, 0.98; log-rank p=0.0219). Median OS was 13.3months (m) for RAM vs 11.7m for PBO. The PFS HR was 0.79 (95% CI: 0.70, 0.90; log-rank p = 0.0005). Median PFS with RAM was 5.7m and 4.5m for PBO. ORR was 13.4% RAM; 12.5% PBO (p = 0.6336). Subgroup results were consistent with the OS and PFS results. Grade ≥3 adverse events (AEs) occurring in >5% of pts in RAM+FOLFIRI were: neutropenia (RAM 38.4% vs PBO 23.3% ), hypertension (11.2% vs 2.8%), diarrhea (10.8% vs 9.7%), and fatigue (11.5% vs 7.8%). Conclusions: RAISE met its primary end-point, demonstrating a statistically significant improvement in OS for RAM and FOLFIRI vs PBO and FOLFIRI in second-line mCRC pts. Benefits were similar across important clinical subgroups and no unexpected AEs were identified. Clinical trial information: NCT01183780.