Höchster, Howard S.

4016 Background: No standard treatment options are available for patients with advanced BC who fail gemcitabine/platinum therapy. The rationale for evaluation of trametinib was based on the presence of MAPK alterations and on earlier promising results with other MEK inhibitors in BC. Methods: Pts with histologically proven BC who progressed on gemcitabine/platinum were randomized to trametinib (2mg qd) (Arm A) vs infusional 5FU at 2400 mg/m2 over 46 hours or capecitabine (1000 mg/m2PO days 1-14 BID) (Arm B). Patients were stratified by planned chemotherapy 5FU/LV vs capecitabine; and disease site: cholangiocarcinoma vs gallbladder. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS) and response rate (RR). 80 eligible patients (40 for each arm) were needed to detect an improvement in median OS from 5 months to 8.25 months (1.65 HR). A planned interim futility analysis of objective response was performed on the first 14 pts registered to the trametinib arm. Results: The study was stopped early based on the lack of measurable response in the trametinib arm. 53 pts were randomized (27 pts in Arm A vs 26 pts in Arm B). Median age was 62 years and the primary sites of tumor were cholangiocarcinoma (77%) and gallbladder (23%). Median OS was 4.3 months (95% CI 3.1-5.1) for Arm A, and 8.0 months (95% CI 3.2-14.6) for Arm B with a HR of 2.02 (95% CI 1.01-4.03, p=0.05). The median PFS was 1.3 months (95% CI 1.2-1.5) for arm A and 2.8 months (95% CI 1.4-6.9) for arm B with a HR of 2.95 (95% CI 1.38-6.30, p=0.01). Overall RR was 8% (95% CI 0%, 19%) in Arm A vs 10% (95% CI 0%, 23%) in Arm B (p>0.99), and 8% vs 45% had stable disease. Eight pts in Arm A experienced treatment-related ≥ grade 3 toxicities, including one death due to vomiting/dehydration. Seven pts in Arm B experienced treatment-related grade 3 toxicities; no higher grade toxicities were reported. Conclusions: To our knowledge, this is the first prospective randomized study of a targeted agent versus chemotherapy for the second line treatment of BC. In this unselected population, the lack of response to trametinib resulted in early closure. The PFS and OS for trametinib were inferior to 5FU. Clinical trial information: 02042443.

3559 Background: A Phase 3 clinical trial (RECOURSE) showed that trifluridine/tipiracil (FTD/TPI) was effective in the treatment of refractory metastatic colorectal cancer (mCRC) treated with standard chemotherapy and targeted-therapy drugs (Mayer et al. N Engl J Med 2015;372:1909-19). An expanded-access program (EAP) was started to provide access to FTD/TPI for patients with mCRC with similar eligibility and to further assess the safety of FTD/TPI in a “real-world” setting in US patients. Methods: Patients aged ≥18 years with refractory mCRC resistant to ≥2 regimens of standard chemotherapy with appropriate biologics and an Eastern Cooperative Oncology Group performance status of 0 or 1 were enrolled to this open-label EAP. Patients received FTD/TPI 35 mg/m2twice daily for 5 days followed by 2 days’ rest repeated twice followed by 14 days’ rest over a 28-day treatment cycle until drug discontinuation. Sites reported duration of therapy, discontinuation due to disease progression, and adverse events (AEs) for each patient. Results: 549 patients were enrolled; 53.2% were male. Median duration of FTD/TPI therapy was 9.7 weeks, which was similar to US patients from RECOURSE (8.9). 10.2% of patients died during the study period, 9.7% due to disease progression. 76.1% of patients discontinued treatment due to disease progression and 4% discontinued due to AEs. Drug-related clinically significant AEs (all grades) are summarized in the table. Conclusions: Patients with refractory mCRC in this EAP had a similar exposure duration to that reported in US patients from RECOURSE, with no unexpected safety concerns. While gastrointestinal toxicity was lower in this population, this may be due to reporting of “significant” events. The clinical profile of FTD/TPI is confirmed in this larger, non-randomized “real-world” experience. Sponsorship: Taiho Oncology, Inc. Editorial Assistance: Complete HealthVizion. Clinical trial information: NCT02286492. [Table: see text]

3511 Background: CALGB 80405 was a randomized Ph3 trial showing no OS or PFS difference in mCRC pts treated with Bevacizumab (BV) or Cetuximab (Cet) in the first line. A Nanostring platform was used to determine the CMS classification of 392 KRAS wt (codon 12 and 13) primary tumors and correlated it with OS and PFS in patients enrolled in 80405. Methods: CMS for 392 of 431tumors were defined using a custom CRC Nanostring panel (39 CMS classification not possible). Stratified Cox proportional hazard model was used to evaluate the effect of CMS classification stratified by prior radiation, prior chemotherapy, adjusting for age, sex, race, primary in place, liver met only, and sidedness. Results: We found CMS1 (14%), CMS2 (47%), CMS3 (2%), CMS4 (29%), NonConsensus (8%). Results are shown in Table 1. Patients with CMS1 who received BV had significantly longer OS than those who received Cet (HR 0.47, 95% CI [0.24, 0.92]). Patients with CMS2 who received BV tended to have shorter OS than those who received Cet (HR 1.41, CI [0.95, 2.08]). Conclusions: Our data suggest that CMS is associated with OS and PFS in first line therapy in mCRC patients. Preliminary data suggest that certain CMS may be associated with efficacy of Bev and Cet based chemotherapy. CMS classification should be explored as a stratification factor in future trials. Support: U10CA180821, U10CA180830, U10CA180882 Clinical trial information: NCT00265850. [Table: see text]

3504 Background: CALGB 80405 was a randomized phase III trial that found no difference in OS in first-line mCRC pts treated with either bevacizumab (Bev) or cetuximab (Cet). Primary tumor DNA from 361 pts, including KRAS mutant (mut) pts, has been profiled for somatic gene mutations/ML/MSI to discover molecular markers of OS. Methods: Mutations in 11 genes were determined by PCR, MSI by microsatellite analysis, and ML by next-generation sequencing (FoundationOne). Cox proportional hazard models are used, stratified by prior XRT and +/- adjuvant chemotherapy; adjusted by age, race, gender, synchronous vs. metachronous, liver metastases, sidedness, all RAS. Results: BRAF: Mut pts had shorter OS than wild-type (wt) pts (HR 1.92, 95% CI 1.34,2.75; p<0.001); HR 1.65 (1.09,2.50) after adjusting for sidedness (p 0.022). In mut pts longer OS is observed in Bev arm vs. Cet arm (p 0.041); in wt pts no arm difference is observed (p 0.291, table). MSI: OS does not differ between MSI-H and MSI-S pts (HR 0.78 [0.40, 1.52], p 0.450). In MSI-H pts longer OS is observed in Bev arm vs. Cet arm (p 0.002); in MSI-S pts no difference is observed (p 0.305, table). ML: Hypermutated MSI-H pts are excluded. In a subset of 205 pts, pts with ML>5 (N=93) have longer OS than pts with ML≤5 (N=112) (HR 0.65 [0.42,1.00], p 0.048). In Bev arm higher ML confers longer OS than lower ML (HR 0.85 [0.80,0.96], p 0.004); in Cet arm no difference is observed (HR 0.99 [0.90,1.09], p 0.862). Conclusions: BRAF is a strong negative prognostic factor in mCRC, even when sidedness is taken into account. ML is a novel marker for further evaluation. The effect of Bev and Cet in either BRAF mut or MSI-H pts should be tested in larger datasets. Updated results from more screened samples will be presented. [Table: see text]

3503 Background: 80405 found no OS or Progression Free Survival (PFS) difference when bevacizumab (BV) or cetuximab (Cet) was added to 1st-line FOLFOX or FOLFIRI in All RAS wild type (wt) mCRC pts. There was a significant 1° side by biologic interaction (P int: OS = 0.008, PFS = 0.001) favoring pts with left-sided (L) 1°. Analyses of 1° tumors beyond All RAS includes Consensus Molecular Subtype (CMS), BRAF and MSI. (CMS results - see Lenz et al; BRAF -see Innocenti et al) We asked whether 1° tumor location - L vs right (R) - is an independent prognostic marker when these other molecular features are considered. Methods: We used a Cox proportional hazard model stratified by prior XRT and +/- adjuvant chemo; adjusted for age, gender, synchronous vs metachronous, CMS, MSI and BRAF status. Pts with transverse (T) tumors were excluded in this analysis. Results: Sidedness was determined in 782 pts (L - 472; R - 256; T -54). Molecular data from 728 pts (with L - and R-sided 1°s) was available as follows: KRAS -- 291, NRAS -393, BRAF - 393, MSI - 378, CMS - 533. L vs R mOS: 32.9 v 19.6 months (mo) (p < 0.0001). See Table for OS results in All RAS / BRAF wt and BRAF mutant (mut) pts. Sidedness (R vs L) is an independent prognostic marker even after adjusting for all these molecular features: HR = 1.392 (1.032, 1.878), p = 0.031. Conclusions: Primary tumor location is an independent prognostic factor when adjusted for age, gender, synchronous/metachronous, CMS, MSI and BRAF status. We are exploring clinical variables such as tumor burden, metastatic sites and measurability of disease in an attempt to explain the impact of sidedness. Support: U10CA188021, U10CA180882. Eli Lilly and Co, Genentech/Roche, Pfizer, Sanofi. Clinical trial information: NCT002655850. [Table: see text]

Purpose Treatment options for neuroendocrine tumors (NETs) remain limited. This trial assessed the progression-free survival (PFS) of bevacizumab or interferon alfa-2b (IFN-α-2b) added to octreotide among patients with advanced NETs. Patients and Methods Southwest Oncology Group (SWOG) S0518, a phase III study conducted in a US cooperative group system, enrolled patients with advanced grades 1 and 2 NETs with progressive disease or other poor prognostic features. Patients were randomly assigned to treatment with octreotide LAR 20 mg every 21 days with either bevacizumab 15 mg/kg every 21 days or 5 million units of IFN-α-2b three times per week. The primary end point was centrally assessed PFS. This trial is registered with ClinicalTrials.gov as NCT00569127. Results A total of 427 patients was enrolled, of whom 214 were allocated to bevacizumab and 213 to IFN-α-2b. The median PFS by central review was 16.6 months (95% CI, 12.9 to 19.6 months) in the bevacizumab arm and was 15.4 months (95% CI, 9.6 to 18.6 months) in the IFN arm (hazard ratio [HR], 0.93; 95% CI, 0.73 to 1.18; P = .55). By site review, the median PFS times were 15.4 months (95% CI, 12.6 to 17.2 months) for bevacizumab and 10.6 months (95% CI, 8.5 to 14.4 months) for interferon (HR, 0.90; 95% CI, 0.72 to 1.12; P = .33). Time to treatment failure was longer with bevacizumab than with IFN (HR, 0.72; 95% CI, 0.58 to 0.89; P = .003). Confirmed radiologic response rates were 12% (95% CI, 8% to 18%) for bevacizumab and 4% (95% CI, 2% to 8%) for IFN. Common adverse events with bevacizumab and octreotide included hypertension (32%), proteinuria (9%), and fatigue (7%); with IFN and octreotide, they included fatigue (27%), neutropenia (12%), and nausea (6%). Conclusion No significant differences in PFS were observed between the bevacizumab and IFN arms, which suggests that these agents have similar antitumor activity among patients with advanced NETs.

659 Background: Regular physical activity (PA) is associated with reduced risk of recurrence and mortality in non-metastatic colorectal cancer. Its influence on patients with metastatic colorectal cancer (mCRC) is largely unexplored. Methods: 1231 patients participating in CALGB 80405 (first-line phase III chemotherapy trial for mCRC) completed questionnaires that included self-report on PA at time of chemotherapy initiation and total metabolic equivalent task (MET)-hours/week were determined based on responses. The primary endpoint of the clinical trial and this companion study was overall survival (OS), with progression-free survival (PFS) as a secondary endpoint. To minimize confounding by poor and rapidly declining health, we excluded patients who experienced progression or died within 60 days of activity assessment and adjusted for known prognostic factors, comorbid illness, and weight loss over the previous six months. Results: Compared with patients engaged in less than three MET-hours/week of PA, patients engaged in 18 or more MET-hours/week experienced an adjusted hazard ratio for OS of 0.81 (95% CI 0.67 to 0.98, P for trend 0.03) and for PFS of 0.84 (95% CI 0.71 to 1.00, P for trend 0.03). Greater nonvigorous PA and walking duration were both associated with improved OS ( P for trend 0.01 and 0.04, respectively). Conclusions: In mCRC patients from CALGB 80405, greater total PA was associated with improved PFS and OS, while greater walking duration and non-vigorous PA were associated with reduced risk of all-cause mortality. Support: U10CA180821, U10CA180882. ClinicalTrials.gov ID: NCT00265850 [Table: see text]

1 Background: To determine whether changing chemotherapy (CT) during pre-op chemoradiation (CRT) based on response to induction CT by 18F-fluoro-deoxyglucose PET imaging can lead to improved pathologic complete response (pCR) in patients (pts) with resectable esophageal and gastroesophageal junction (GEJ) adenocarcinomas. Methods: 257 eligible pts were enrolled, underwent baseline PET scan, and were randomized to one of 2 induction CT arms: Modified FOLFOX-6 (oxaliplatin, leucovorin, 5-FU), days 1, 15, 29 or Carboplatin/Paclitaxel (CP), days 1, 8, 22, 29. Repeat PET was performed days 36-42; change in max standardized uptake value (SUV) from baseline was assessed. PET non-responders (≤35% decrease in SUV – PET-NR) crossed over to alternative CT regimen during CRT (50.4Gy/28 fractions). PET responders (>35% decrease in SUV – PET-R) continued on same CT during CRT. Pts underwent surgery 6 wks post-CRT. Pts evaluable if had surgery, disease progression (PD), death due to disease, were unresectable or had adverse event (AE). Primary endpoint was pCR in PET-NR who crossed over to alternative CT (expected 5% under H0 to 20% under Ha). Results: Pre-audit PET response data after induction CT and pCR rates after CRT and surgery are shown in the table. For PET-NR who crossed over to alternative CT during CRT, pCR was 15.6%; 95% CI (0.08, 0.26). Conclusions: Efficacy criteria were met for an improvement in pCR rates among pts who were PET-NR after induction CT and received alternative CT during CRT for esophageal and GEJ adenoca. Pts receiving induction and concurrent CP had an unexpectedly low pCR. Support: U10CA180821, U10CA180882 Clinical trial information: NCT01333033. [Table: see text]