Richard M. Goldberg

3604 Background: Limited research has investigated the role of variation in the host genome as a determinant of colon carcinoma (CC) outcomes, including toxicity due to therapeutic agents. We examined the relationship between germline genetic factors and treatment-associated serious adverse events (SAEs) in a population of CC patients in which treatment was standardized and follow-up for outcomes was uniformly conducted. Methods: Using existing biospecimens from CC patients with resected stage III disease in a phase III randomized trial of FOLFOX adjuvant chemotherapy with and without cetuximab (NCCTG N0147), genome-wide genotyping arrays were conducted for 2200 patients for a total of ~20 million single nucleotide polymorphisms (SNPs). Using logistic regression models we assessed SNP-specific associations with SAEs, utilizing a discovery-based approach to search the genome in an unbiased manner. Detailed information on SAEs was collected using the Common Toxicity Criteria for Adverse Events (CTCAE, v3.0). Analyses evaluating associations with specific classes of common grade ≥3 SAEs were performed, including gastrointestinal toxicities, neutropenia, and paresthesias. A threshold of P < 5x10^-8was used to denote genome-wide significance. Results: Among patients who received FOLFOX, several SNPs on chr 15 near the ANP32A gene and on chr 2 near the CD207 gene were statistically significantly associated with grade ≥3 neuropathy. The strongest SNP-specific associations in these regions were in the range of odds ratio (OR) = 1.3, P = 2.8×10⁻¹⁰ and OR = 1.5, P = 2.7×10⁻¹⁰, respectively. Conclusions: Findings from this genome-wide analysis demonstrate the potential importance of germline genetic variation in influencing CC patients’ experience of specific toxicities to FOLFOX regimens. These results highlight two genomic regions of potential interest for understanding the biological mechanism for such toxicities, although further evaluation and replication is needed. Support: U10CA180821, U10CA180882, U10CA180820, U10CA180863, U10CA180888, CCSRI 021039, R01CA176272, Eli Lilly & Co, Pfizer, Sanofi. Clinical trial information: NCT00079274 .

3535 Background: CRC is known to be a heterogeneous disease. This study quantifies within pt heterogeneity in early lesion change rate (LCR) in the era of targeted agents compared to chemo alone and its potential impact on survival. Methods: Pts with 2-10 lesions measured at baseline were included. For each lesion, the early LCR was defined as the change in size (shrinking or growing) from baseline to 12 weeks on treatment. Within pt heterogeneity in early LCR among lesions was estimated by standard deviation (STD). A larger value of STD indicates larger variation of LCR per pt. Stratified multivariate Cox models were used to assess the associations between LCR STD with overall survival (OS). Adjusted hazard ratios (HR_adj) and 95% confidence intervals (CIs) are reported. Results: Data were available on 9,092 mCRC pts (median age 61; 60% male, 55% ECOG PS 0; 61% 2+ metastatic sites) enrolled in 16 1^st-line randomized trials, with 44%, 42%, and 10% of pts received chemo alone, + a VEGF inhibitor (VEGFi) or an EGFR inhibitor (EGFRi), respectively. LCR heterogeneity is the highest among pts received EGFRi but lowest among pts received VEGFi (Table). Overall, higher heterogeneity is associated with worst OS (HR_adj1.22, 95% CI (1.16, 1.27)). The effect is most pronounced in pts received VEGFi (interaction p=0.0012). Conclusions: There was heterogeneity observed in lesion size changes within pts. Its magnitude varies across treatment approaches, and was associated with poor survival. This preliminary result reveals the great potentials to define novel response endpoint and refine treatment decision-making by incorporating heterogeneities in lesion changes. [Table: see text]

3516 Background: Epidemiological data suggest a protective effect of vitamin D on CC risk. However, association of serum vitamin D level with clinical outcome in pts with surgically resected CC remains unknown. We analyzed total circulating 25-hydroxyvitamin D [25(OH)D)] with clinical outcome in pts with resected stage III CC treated with FOLFOX +/- cetuximab in a phase III trial. Methods: Association of pre-treatment level of plasma 25(OH)D with disease-free survival (DFS) and time-to-recurrence (TTR) was analyzed with 25(OH)D as a continuous variable by a relative risk model with splines and as a binary variable (vitamin D deficient [interaction=0.044). There were no statistically significant associations with DFS/TTR for either continuous 25(OH)D level (DFS, p=0.22; TTR, p=0.26) nor for vitamin D deficiency (DFS, adjusted hazard ratio [HR_adj]=1.01, 95% CI, 0.74-1.38; p_adj=0.94; TTR, HR_adj=1.00; CI, 0.72-1.38; p_adj=0.99. A comparison of the highest vs lowest tertile showed a significant association between the highest 25(OH)D level and better outcomes in men (DFS, HR_adj.=0.18, CI, 0.04-0.76, p_adj=0.020; TTR, HR_adj.=0.12, CI, 0.02-0.64, p_adj=0.014), but not in women (DFS, p_interaction=0.039; TTR, p_interaction=0.033). Conclusions: Nearly one-half of pts in the clinical trial cohort were vitamin D deficient with lowest 25(OH)D levels found in women and blacks. While vitamin D deficiency was not associated with adverse outcome, high levels of vitamin D in men, but not women, were associated with longer survival. Support: U10CA180821, U10CA180882, U10CA180820, U10CA180863, U10CA180888, U10CA077202, CCSRI 021039. ClinicalTrials.gov Identifier: NCT00079274.

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]

3518 Background: High levels of TILs are associated with favorable prognosis in some solid tumors. We examined TIL levels in CC subtyped using mutations in KRAS or BRAF oncogenes as well as DNA mismatch repair (MMR) status, and examined association with patient (pt) prognosis. Methods: Stage III CC (N=2293) from a randomized trial of adjuvant FOLFOX + cetuximab (NCCTG N0147) were analyzed for TILs; dichotomized as high (> 4 TILs per HPF) vs low at light microscopy. We determined the association of TILs with clinicopathological features, mutations in KRAS exon 2 or BRAF(V600E), MMR status, and DFS by multivariate Cox regression analyses. Results: Higher TIL densities were found in tumors with wild-type (wt) vs mutated (mut) KRAS (p=.038) or BRAF (p<.0001). Among tumors with mut BRAF^V600E or mut KRAS, high vs low TILs were found in 19.2% and 9.5%, respectively. In tumors with mut BRAF, high TILs were detected in 31.2% of dMMR vs 9.5% of pMMR cancers (p<.0001). TILs were increased 3.6-fold in dMMR vs proficient (p) MMR tumors (p<.0001). Also associated with high vs low TILs were female vs male (p=.011), white vs non-white (p=.008), proximal vs distal (p<.0001), lower T stage (p=.004), fewer positive/examined nodes (p=.015), and high vs low grade (p=.0001). High vs low TILs were associated with better DFS overall [HR=0.76 (0.57-1.01), p=0.047], and among tumors with wt KRAS [HR= 0.61 (0.41-.89), p=.006] or wt KRAS and BRAF [HR= 0.56 (0.34-.92), p=.013]. TILs were not prognostic in tumors with mut KRAS (p=.71; TIL*KRAS interaction p= 0.097) or mut BRAF (p=.18). High vs low TILs were associated with favorable DFS in pt tumors with dMMR [HR= 0.55 (.30-1.01), p=.045], but not pMMR (p=.301; interaction p=0.17]. No significant differences were found by treatment arm. Conclusions: Significantly lower TILs are found in tumors with mut vs wt KRAS or BRAF suggesting reduced immunogenicity. Among tumors with wt, but not mut, KRAS and BRAF, high vs low TILs were associated with better survival. TILs were increased 3.6-fold in dMMR vs pMMR, and favorably prognostic within dMMR pts. These results for wt tumors and those with dMMR suggest that immune activation improves survival outcomes.

3600 Background: The identification of biomarkers that can predict patient survival after recurrence (SAR) of cancer is important to guide clinical decision-making. We determined the association of molecular markers in the primary tumor with SAR in patients with stage III colon carcinomas treated with adjuvant FOLFOX-based chemotherapy in two clinical trials. Methods: In randomized trials of adjuvant FOLFOX ± cetuximab (NCCTG N0147) or FOLFOX + bevacizumab (NSABP C-08), we determined the association of somatic BRAF^V600E and KRAS exon 2 mutations and DNA mismatch repair (MMR) status in colon adenocarcinomas with patient SAR. Cox models were utilized and adjusted for clinicopathological features and time-to-recurrence data. The interaction effect of the anatomic site of the primary tumor on the impact of biomarkers on SAR was determined. Results: Among patients with colon cancer recurrence [N0147 (N = 871); C-08 (N = 524)], those with tumors harboring mutant BRAF^V600E had significantly worse SAR compared to those with non-mutated BRAF and KRAS genes [HR 2.45 (95% CI, 1.85-3.25, P_adjusted < .0001]. Mutant BRAF^V600E was also associated with significantly poorer outcome for tumors with proficient (p) DNA mismatch repair (pMMR) [HR 2.64 (95% CI, 1.96-3.57), P_adjusted < .0001] and with deficient (d) MMR [HR 2.70 (95% CI, 1.23-5.93), P_adjusted = .014]. Significant interactions were found for MMR (P = .027) and KRAS (P = .014) status by primary tumor site for SAR, with significantly better SAR for dMMR tumors of the proximal vs distal colon [HR 0.57 (95% CI, 0.39-0.81), P_adjusted = .023], and significantly worse SAR for mutant KRAS tumors of the distal colon [codon Conclusions: Patients whose tumors harbored BRAF^V600E mutations and were dMMR or pMMR had significantly shorter SAR. The significant adverse impact of KRAS mutations on SAR was limited to patients with distal cancers, indicating that KRAS should be interpreted by primary tumor site. These molecular markers may, therefore, inform patient management and treatment decisions at the time of tumor recurrence. Clinical trial number: NCCTG NO147, NCT00079274; NSABP C-08, NCT00096278

666 Background: Early tumor shrinkage (ETS; ≥20% decrease from baseline) and early objective tumor response (EOTR; CR/PR by RECIST) are associated with improved PFS/OS to a similar extent than best overall response (BOR), confirmed response (ConfR) and non-progression rate (NPR; CR/PR/SD by RECIST) at the individual level in first-line mCRC (ASCO 2014, abstr 3538/3578). We assessed these RBEs at the trial level. Methods: Data were available on 12,185 pts enrolled in a total of 17 randomized trials of chemotherapy (CT) alone or with targeted agents (TAs). ETS, EOTR and NPR were assessed at 6/8/9 and 12 weeks (wks), whereas BOR and ConfR were ascertained within 26 wks from randomization. Association between treatment effects on RBEs and on PFS/OS was assessed by coefficients of determination (R², adjusted for estimation errors) using a copula model). Results: None of the RBEs had consistently strong correlations with PFS or OS (Table). The number of trials was insufficient to obtain reliable estimates for antiangiogenics and anti-EGFR separately. Conclusions: Despite their individual-level associations with PFS and OS, RBEs do not appear to be surrogate endpoints in first-line mCRC, given their poor predictive ability. [Table: see text]

710 Background: In the CORRECT phase III trial (NCT01103323), the multikinase inhibitor REG significantly improved overall survival (OS) and PFS vs placebo in patients with mCRC who had disease progression after other standard therapies (HR for OS: 0.77; 1-sided p =0.0052; Grothey 2013). A post-hoc exploratory subgroup analysis was conducted to evaluate patients in the REG treatment group who had a PFS longer than 4 months (long-PFS) defined as patients who progressed, died, or discontinued treatment for other reasons after 4 months. Methods: Of the505 patients randomized to REG in CORRECT, 98 (19.4%) were classified as having a long-PFS benefit. Baseline characteristics, safety, and dosing parameters were analyzed descriptively. Results: The long-PFS subpopulation was representative of the overall study population (Table). Long-PFS patients received a median of 6 cycles of REG (1-12), 92% received ≥5 cycles, and 20% had > 8 cycles. Overall 34% of patients had dose reductions and 87% had dose interruptions. The actual mean daily dose was 139 mg and the mean percent of the planned dose was 81%. Adverse events (AE) of any grade were experienced by all long-PFS patients, and the most common grade ≥3 AEs were hand-foot skin reaction (20%), hypertension (17%), diarrhea (17%), and fatigue (16%). Conclusions: A subset of 98 (19.4%) patients treated with REG in the CORRECT study had a PFS > 4 months, confirming the clinical benefit and tolerability of REG as a treatment option for patients with mCRC. Prospective validation of these findings in conjunction with biomarker analysis from real-life clinical experience is needed. Clinical trial information: NCT01103323. [Table: see text]

508 Background: Severe adverse events (AEs) to 5-fluorouracil (5-FU) constitute a major dilemma in CC treatment. We recently demonstrated that specific deleterious DPYD variants in the coding region were highly predictive of grade >3 (G3+) AEs in stage III CC pts receiving adjuvant 5-FU based combination chemotherapy [Lee et al. JNCI. In press]. Other studies have suggested potential associations between AEs and non-coding DPYD variants: a novel haplotype (HapB3) containing three intronic variants (c.483+18 G>A, c.680+139 G>A, and c.959-51 T>C), one synonymous variant (c.1236 G>A, E412E), and a deep intronic variant (c.1129-5923 C>G) that affects pre-mRNA splicing. However, these studies included a diversity of cancer types, stages and treatments. The findings require further evaluation in a refined population. Methods: A total of 2,134 Caucasian stage III CC pts without DPYD*2A, D949V, and I560S variants from NCCTG N0147 trial who received adjuvant FOLFOX or FOLFIRI +/- cetuximab were genotyped by multiplexed single-base extension assays on the Sequenom MassARRAY. G3+ AEs were recorded (CTCAE v3) and classified as common to 5-FU treatment (5FU-AEs). Logistic regressions were used to assess the univariate and multivariate associations. Results: Analyzed pts displayed the following characteristics: 54.3% male, median age 59 [19-85], proficient MMR 87.5%, PS-0 76.5%, + irinotecan 8.5%, and + cetuximab 46.5%. Pts carrying c.1129-5923 C>G were significantly associated with higher risk of G3+ 5FU-AEs (Odds Ratio [OR]=1.539, 95% confidence interval [CI]=1.001 – 2.367, p=0.049). Only marginal association was observed for one of the HapB3 variants, c.1236 G>A (p=0.058). A linearly increasing risk of G3+ 5FU-AEs was identified for HapB3, comparing pts with no, one or >1 variant present (unadjusted OR=1.539, 95% CI=1.001 – 2.367, p=0.041; adjusted OR=1.198, 95% CI=0.998-1.437, p=0.052). Conclusions: In the largest study to date, c.1129-5923 C>G and HapB3 were predictive of 5FU-AE risk in stage III CC patients without DPYD*2A, D949V, and I560S variants receiving 5-FU-based combination chemotherapy.

Colorectal cancer remains one of the most common causes of cancer death in the US, with approximately a quarter of patients presenting with metastatic disease at the time of diagnosis. Recent...