Citations

569 Background: BBI-608 is an oral first-in-class cancer stemness inhibitor that blocks STAT3-mediated transcription of cancer stemness genes. Potent anti-CSC activity was observed in vitro and in vivo,in mono and combination therapy. In phase I studies, BBI-608 was generally well tolerated with encouraging signs of anti-tumor activity. Methods: A phase Ib open label, multi-center study in pts with advanced CRC was undertaken to confirm the RP2D of BBI-608 in combination with FOLFIRI with or without BEV. BBI-608 was administered at 240 mg BID in combination with FOLFIRI (5-FU 400 mg/m2 bolus with 2400 mg/m2, irinotecan 180 mg/m2, and leucovorin 400 mg/m2infusion) with or without BEV 5 mg/kg, administered bi-weekly until progression of disease, unacceptable toxicity, or other discontinuation criterion was met. Results: 18 heavily pretreated pts with an average of > 3 prior lines of therapy of which 10 pts (56%) previously progressed on FOLFIRI were enrolled. Of the 17 pts evaluable for response, 8 pts received FOLFIRI and 9 pts received FOLFIRI with BEV in combination with BBI-608. Most common adverse events included grade 1 and 2 diarrhea, abdominal pain, nausea, vomiting and anorexia. No dose limiting toxicity or new adverse events were seen, and the safety profile was similar to that of each regimen as monotherapy. Grade 3 events related to protocol therapy included diarrhea occurring in 3 pts, fatigue in 2 pts and dehydration in 1 pt. All events resolved after dose reduction and/or start of anti-diarrheal medications. No significant pharmacokinetic interactions were observed. Disease control (PR+SD) was observed in 16 of 17 evaluable pts (94%) with 2 PR (per RECIST 1.1 criteria: 44% and 33% regression) and 14 SD (of which 13 (93%) had tumor regression < 25%). In the evaluable pts, median progression free survival was 5.54 months. Of 17 pts, 7 (41%) had prolonged SD of > 6 months. Conclusions: This phase Ib study confirmed that BBI-608 at 240 mg bid can be safely combined with FOLFIRI with and without BEV, and shows encouraging anti-tumor activity in heavily pretreated CRC pts, even in pts with prior progression on FOLFIRI-based therapy. Clinical trial information: NCT02024607.

497 Background: As activating RAS mutations have been shown to predict lack of benefit from anti-EGFR therapies in advanced CRC, NCCN guidelines recommend testing for KRAS exon 2 and non-exon 2 mutations; however, these alterations are thought to explain only a subset of de novo resistance to targeted therapy. In a large set of CRC assayed with comprehensive genomic profiling (CGP) in the course of clinical care, we assessed the frequency of less common KRAS short insertions that may predict failure of anti-EGFR therapy. Methods: 4,422 CRC cases were assayed with CGP performed on hybridization-captured, adaptor ligation based libraries to a mean coverage depth of > 650X for at least 236 cancer-related genes plus 47 introns from 19 genes frequently rearranged in cancer. All classes of genomic alterations (GA) were identified, including base pair substitutions, insertions/deletions, copy number alterations, and rearrangements. Pertinent available prior molecular testing results and clinical history was reviewed for selected cases. Results: Out of 4,422 CRC cases analyzed, KRAS short variants were identified in 50.9% of cases. A majority of cases contained a KRAS alteration at either codon G12 (35.5%) or G13 (9.1%), while alterations at codons Q61 or A146 were identified in 2.2% and 3.1% of cases, respectively. KRAS insertions were identified in 8 ( < 0.5%) cases. All KRAS insertions identified fell within codons 9-13, and 6/8 cases harbored V9_G10 insertions. Out of 6 patients with prior KRAS testing results available, 5 (83%) were negative by previous testing. Conclusions: CGP identifies KRAS insertions within or adjacent to hotspot regions in CRC cases which have previously tested negative for KRAS mutations. Given the importance of KRAS alterations in predicting lack of response to anti-EGFR therapies in CRC, accurate detection of these alterations in the course of clinical care is essential for effective treatment. CGP offers the possibility of identifying KRAS insertions that may impact efficacy of anti-EGFR targeted therapy and should be considered when previous focused testing for KRAS mutations is negative.

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.

LBA385 Background: Regorafenib (BAY 73-4506) is an oral multikinase inhibitor of a broad range of angiogenic, oncogenic, and stromal kinases. The phase III CORRECT trial was conducted to evaluate efficacy and safety of regorafenib in pts with mCRC who had progressed after all approved standard therapies. Methods: Enrollment criteria included documented mCRC and progression during or ≤3 months after last standard therapy. Pts were randomized 2:1 to receive regorafenib (160 mg od po, 3 weeks on/1 week off) plus BSC, or placebo (PL) plus BSC. Pts continued on treatment until progression, death, or unacceptable toxicity. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), overall response rate (ORR), disease control rate (DCR), safety, and quality of life. Results: From May 2010 to March 2011, 760 pts were randomized (regorafenib: 505; PL: 255). Baseline characteristics were balanced between two arms. Preliminary results are available from a pre-planned formal interim analysis. The estimated hazard ratio (HR) for OS was 0.773 (95% CI: 0.635, 0.941; 1-sided p=0.0051). Median OS was 6.4 mos (95% CI: 5.9, 7.3) for regorafenib and 5.0 mos (95% CI: 4.4, 5.8) for PL. The estimated HR for PFS was 0.493 (95% CI: 0.418, 0.581; 1-sided p < 0.000001). Median PFS was 1.9 mos (95% CI: 1.88, 2.17) for regorafenib and 1.7 mos (95% CI: 1.68, 1.74) for PL. ORR was 1.6% for regorafenib and 0.4% for PL. DCR was 44% for regorafenib and 15% for PL (p < 0.000001). Since the prespecified OS efficacy boundary was crossed (nominal α: 0.0093), the Data Monitoring Committee recommended to unblind the study and pts on PL were allowed to cross over to regorafenib. The most frequent grade 3+ AEs in the regorafenib arm were hand-foot skin reaction (17%), fatigue (15%), diarrhea (8%), hyperbilirubinemia (8%), and hypertension (7%). Updated results will be presented. Conclusions: Statistically significant benefit in OS and PFS was observed for regorafenib over PL in pts with mCRC who have failed all approved standard therapies. No new or unexpected safety signal was found.

535 Background: Prior ARIES analyses showed that BV-treated mCRC patients (pts) receiving chemotherapy (CT)/biologics + BV within 2 months (mo) after 1st progressive disease (PD) had longer post-progression survival (PPS) than pts receiving only CT/biologics. The present analysis evaluated whether this effect of BV was consistent when used with common 2L CT regimens— irinotecan- (iri-) and oxaliplatin- (ox-) based—in mCRC pts exposed to 1L BV in ARIES. Methods: ARIES enrolled mCRC pts receiving 1L CT + BV. No tx regimens or assessments were protocol specified. This analysis evaluated 1L BV-treated mCRC pts who had PD, survived ≥2 mo after PD, and received 2L iri- or ox-based tx. PPS was estimated by Kaplan-Meier methods. Cox regression was used to estimate hazard ratios (HRs), while adjusting for covariates (eg, 1L time to progression). Results: Of 1550 1L pts in ARIES, 1074 had 1st PD and survived ≥2 mo after PD. Of these 1074, 390 and 114 received 2L iri- and ox-based tx, respectively, ± BV ( table ). Baseline characteristics were generally similar between groups. The incidence of targeted adverse events (TAEs) was as expected and similar between the BV and No BV groups over time. In pts receiving 2L iri- or ox-based CT tx, PPS in BV-treated pts was longer compared to those not on BV. Analyses may be limited by small pt numbers in some groups. Conclusions: Consistent with prior ARIES analyses, the continued use of BV after 1st PD was associated with prolonged PPS regardless of the 2L CT backbone used. [Table: see text]