Gramont, Aimery de

4029 Background: The clearance of 5-FU differs significantly between men (M) and women (W). Adjuvant chemotherapy (CT) for CRC has a higher toxicity in W. The impact of sex on efficacy and toxicity in first-line trials of metastatic CRC (mCRC) is unknown. Methods: We analyzed patient (pt) and tumor characteristics, toxicities (nausea (AE1), vomiting (AE2), diarrhea, neutropenia (AE3)) and efficacy (overall survival (OS), progression-free survival (PFS)) according to sex in the following treatment groups: A: CT alone, B: CT + bevacizumab, C: CT + EGFR-antibodies, with subgroup analyses in the CT alone group for single-agent, doublets and triplets, as well as irinotecan- and oxaliplatin-based regimens. Pts from trials with treatments still used today and all relevant data available were eligible. OS and PFS were assessed using Kaplan-Meier and Cox models adjusted for primary tumor location and performance status (PS). Results: We included 28 trials with 18.399 pts (11.352 M and 7.047 W). W were younger (61 vs. 63 years), had more often a PS of 1 (49 vs 45%), BRAF mutations (10 vs. 7%), right-sided tumors (42 vs. 35%) and less often rectal tumors (26 vs. 32%). Significant differences in toxicity are reported in table. Rates of diarrhea were similar. There was no sex disparity in OS in the predefined subgroups except for pts receiving triplets where OS was better in M (HRadj=1.39 (1.05 - 1.85)). Median (interquartile range) OS in months for M and W was 16.7 (9.2-27.4) and 16.2 (8.9-27.2) in group 1, 21.9 (12.7-37.5) and 22.3 (12.9 – 39.0) in group 2, and 26.8 (14.6-45.3) and 24.8 (12.3-49.2) in group 3. HRsadj (W vs M) (95% CI), p values for OS were 1.02 (0.96-1.09), .557, 0.92 (0.83-1.03), .142, 0.99 (0.85-1.14), .866. Conclusions: M and W with mCRC differ significantly regarding patient and tumor characteristics. The significant higher toxicity in W does not translate in a higher treatment efficacy. Apart from known sex differences in pharmacokinetics of 5-FU, differences in pharmacodynamics must be postulated. [Table: see text]

Abstract Background Carcinoembryonic antigen (CEA) levels are used in conjunction with imaging to monitor response to systemic therapy in metastatic colorectal cancer (mCRC). We sought to identify a threshold for CEA change from baseline to predict progressive disease (PD) in mCRC patients receiving first-line therapy. Methods Patients from trials collected in the ARCAD database were included if baseline CEA was at least 10 ng/mL and repeat CEA was available within 14 days of first restaging scan. Optimal cutoffs for CEA change were identified by receiver operating characteristic analysis. Prediction performance of cutoffs was evaluated by sensitivity, specificity, and negative predictive value. Analyses were conducted by treatment class: chemotherapy alone, chemotherapy with anti-VEGF antibody, and chemotherapy with anti-EGFR antibody. Results A total of 2643 mCRC patients treated with systemic therapy were included. Median percent change of CEA from baseline to first restaging for patients with complete response, partial response, or stable disease (non-PD) and PD was −53.1% and +23.6% for chemotherapy alone (n = 957) and −71.7% and −45.3% for chemotherapy with anti-VEGF antibody (n = 1355). The optimal area under the curve cutoff for differentiating PD from non-PD on first restaging was −7.5% for chemotherapy alone and −62.0% for chemotherapy with anti-VEGF antibody; chemotherapy alone, adjusted odds ratio = 6.51 (95% CI = 3.31 to 12.83, P < .001), chemotherapy with anti-VEGF antibody, adjusted odds ratio = 3.45 (95% CI = 1.93 to 6.18, P < .001). A 99% negative predictive value clinical cutoff for prediction of non-PD would avoid CT scan at first restaging in 21.0% of chemotherapy alone and 16.2% of chemotherapy with anti-VEGF antibody–treated patients. Among patients with stable disease on first restaging, those with decreased CEA from baseline had statistically significantly improved progression-free and overall survival. Conclusions Change in CEA from baseline to first restaging can accurately predict non-progression and correlates with long-term outcomes in patients receiving systemic chemotherapy.

3533 Background: PFS has previously been established as a surrogate for OS based on IPD from first-line mCRC trials conducted before 1999. As mCRC treatment (trt) has advanced in the last decade and OS has increased from 1 to 2 years, this surrogacy required re-examination. Methods: IPD from 16,762 pts, median age 62, 62% male, 53% ECOG PS 0 were available from 22 1st line mCRC studies conducted from 1997-2006; 12 tested targeted (anti-angiogenic and/or anti-EGFR) regimens. The relationship between PFS (first event of progression or death) and OS was evaluated at patient-, trt-arm-, and trial-levels using correlation (corr.) coefficients and R2 (closer to 1 the better) from weighted least square (WLS) regression of arm-specific survival rates and trial-specific hazard ratios (HRs), estimated using Cox and Copula bivariate models. The concordance of significance (CoS) of the treatment effects (TEs) on both endpoints was calculated. Results: 44% pts received a targeted regimen. Median PFS was 8 and OS was18 months. The corr. between PFS and OS was modest at all three levels with low CoS in TE comparisons (see Table). Analyses limited to trials testing targeted trts, non-strategy trials, or superiority trials did not improve surrogacy. Conclusions: In modern mCRC trials, where survival post-first progression exceeds time to first progression, PFS TEs do not reliably predict TEs on OS. Nonetheless, until alternative endpoints of clinical benefit can be validated, PFS remains a relevant primary endpoint for 1st line mCRC trials, as our data demonstrate that the ability for any agent to produce an OS benefit from a single line of therapy is challenging. [Table: see text]

3520 Background: EOTR has been suggested as a potential surrogate for overall survival (OS) in patients (pts) with mCRC and allows early assessment of treatment efficacy, facilitating adaptive trial design. We assessed at the individual patient level, the correlation between EOTR (complete or partial response) at 6, 8 and 12 weeks (wk), OS and progression free survival (PFS) in pts with mCRC treated with 1stline chemotherapy with or without a targeted agent as a first step in a surrogacy demonstration. Methods: IPD from 13,949 pts enrolled on 15 randomized Phase III trials in 1st line mCRC were used; 8 trials included targeted (anti-angiogenic and anti-EGFR) agents. EOTR prognostic value was assessed by landmark analyses using Cox models stratified by treatment assignment. P-values <0.01 were considered statistically significant to account for multiple comparisons. Results: Of 13,949 pts, 11,987 had sufficient response data to be included in the analysis. Median OS was 21.7 months (mo) in pts with an EOTR vs. 16.5 mo without EOTR at 6 wk (p<.0001, Hazard Ratio [HR] 0.64, 95% confidence interval [CI] 0.58-0.70, c statistic [c] 0.55). HRs were similar whether pts were treated with targeted therapies (p<.0001, HR 0.68, 95% CI 0.58-0.80, x 0.54) or non-targeted therapies (p<.0001, HR 0.61, 95% CI 0.55-0.69, x 0.55). Median PFS was 8.4 mo in pts with EOTR at 6 wk vs. 7.0 mo in pts without EOTR (p<.0001, HR 0.79, 95% CI 0.73-0.85). EOTR at 8 and 12 wks were also significantly associated with longer OS and PFS. The prognostic value of EOTR at 6, 8 and 12 wks remained significant (p<0.0001) after adjusting for age, gender, performance statusand location of metastatic disease (lung or liver). Overall tumor response (to 26 wk) however provided superior OS prediction (p<.0001, HR 0.51, 95% CI, 0.47-0.56, CS 0.61) vs. EOTR. Conclusions: Early response measured at 6, 8 or 12 wk after starting 1st line treatment was a strong and independent predictor of both OS and PFS in patient with mCRC and warrants further consideration as a potential endpoint for future trials, particularly randomized phase II trials.

3517 Background: The combination of oxaliplatin, fluorouracil, and leucovorin is effective in many patients with colon cancer treated in either the advanced or adjuvant disease setting. To better identify the risks & benefits of this regimen for elderly patients we compared safety & efficacy data for the FOLFOX4 regimen (oxaliplatin plus fluorouracil/leucovorin administered bimonthly) in patients over & under 70 years of age. Methods: We conducted a retrospective analysis of 3742 patients (614 aged ≥ 70) with colorectal cancer enrolled in four clinical trials using the same FOLFOX4 regimen as adjuvant therapy, or as first- or second-line therapy in advanced disease. Endpoints included grade ≥ 3 adverse events, response rate (RR) (in studies of advanced disease), progression (metastatic)/relapse free (adjuvant) survival (P/RFS), overall survival (OS), and dose intensity. Results: Age ≥ 70 was associated with slightly higher rates of neutropenia and thrombocytopenia but no other grade ≥ 3 adverse events (see table). There was no difference in 60-day mortality (1.1% vs 2.3%, p=0.20). We observed no significant difference in any measure of therapeutic impact of FOLFOX based on age, including P/RFS, OS, response rate, or dose intensity (see table). Conclusions: The FOLFOX4 regimen maintains its efficacy/safety ratio in elderly patients with colorectal cancer, and was administered per protocol at similar drug doses compared to the younger patients enrolled on these trials. Age alone should not be a factor limiting the use of FOLFOX4 provided patients are carefully evaluated and monitored. This analysis was supported by Sanofi-Aventis [Table: see text] [Table: see text]

89 Background: Monitoring of adverse events (AE) is crucial in clinical trials. Maximum grade per patient (pt) is commonly used but better metrics are needed to aid describing and comparing AE profiles. Methods: We developed and evaluated 2 longitudinal AE summary metrics. 1) Onset time of max grade refers to whether a pt has max grade within pre-specified timeframes for an AE, e.g. onset can be defined as “early” (max grade before the 6th cy) or “late” (≥ 6th cy). 2) Adverse effect load (AEL) is a longitudinal score of worst grade possible excluding death over the entire treatment for an AE. Higher AEL means worst overall experience of AE. We applied these metrics to real trial data. Pts were from 6 mCRC trials included in ARCAD database and received Irinotecan-based (n = 1,119) or Oxaliplatin-based (n = 1,230) treatments that did not include biologicals. AEs were diarrhea, nausea/vomiting, neutropenia/leukopenia, and neuropathy. We used linear model to AEL and logistic model to the other metrics, adjusting for age, sex, and number of metastases. Results: For nausea/vomiting, pts in Oxali-based chemo showed a higher AEL compared to patients in Iri-based (mean (M) [standard deviation (SD)] = 0.04 [0.06] vs. 0.02 [0.04]; p < 0.001) even though less pts had gr ≥ 3 (10.4% vs. 16.2%, resp.; p < 0.001), suggesting a lower-grade but persistent nausea/vomiting for Oxali-based. Among pts with diarrhea max gr 2, pts in Iri-based had higher AEL than with Oxali-based (M [SD] = 0.11 [0.11] vs. 0.08 [0.09]; p = 0.008), indicating more persistent diarrhea for Iri-based trts even among pts with same max grade. For neutropenia/leukopenia, pts in Oxali-based trts experienced higher AEL (M [SD] = 0.09 [0.13] vs. 0.05 [0.11], p < 0.001), and more pts in Oxali-based trts had gr ≥ 3 (70.1% vs. 64.4%; p = 0.002), suggesting that pts in Oxali-based trts experienced worst overall and max grade neutropenia/leukopenia compared to pts in Iri-based. Conclusions: To improve toxicity assessment in clinical trials, AEL and onset time of max grade are new measures that describe the evolution of adverse events over time. Further validation is warranted.

6 Background: Rates and survival outcomes for second-line therapy for mCRC for OA vs. YA are poorly understood. Methods: Pts with available subsequent treatment data after progression from 10 1st line trials were included. Associations between key clinical/disease characteristics, time to initial progression (TTiP) and rate of receipt of second-line therapy were evaluated. Time to progression (TTP) and overall survival (OS) were compared between OA and YA who were enrolled on second-line trials by Cox regression, adjusting for age, sex, ECOG PS, number of metastatic sites, presence of metastasis in lung/liver/peritoneum. Results: OA comprised 16.4% of first-line trials. OA and ECOG PS >0 were less likely to receive second-line therapy than YA. Odds of receiving second-line therapy decreased by 11% for each additional decade of life in multivariate analysis (p=0.0117). OA enrolled in second-line trials experience similar mTTP and mOS as YA (5.1 vs. 5.2mos; 11.6 vs 12.4mos, respectively). Conclusions: OA are less likely to receive 2nd line therapy for mCRC. We did not observe a statistical difference in survival outcomes for OA vs. YA following second-line therapy. Further study is needed to examine unmeasured factors, including comorbidity and functional status given observed inferior outcomes among adults with ECOG PS >0, and consideration given to inclusion of geriatric assessment to select OA likely to benefit from 2nd line therapy for mCRC. [Table: see text]

188 Background: Unplanned subgroup analyses from several studies have suggested primary tumor sidedness (PTS) as a potential prognostic and predictive parameter in metastatic colorectal cancer (mCRC). We aimed to investigate the prognostic and predictive impact of PTS on outcomes. Methods: PTS data of 7,828 mCRC patients (pts) from 10 first-line randomized trials in the ARCAD database were pooled. PTS was defined as right-sided (RS) or left-sided (LS) if tumor arose from the cecum to the hepatic flexure or from the splenic flexure to the rectum, respectively; transverse colon cancers were not included. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier and Cox models adjusting for age, sex, performance status (PS), prior radiation/chemo, and stratified by treatment arm. Predictive value was tested by interaction term between PTS and treatment (anti-EGFR plus chemotherapy vs. chemotherapy alone). Results: Compared to RS pts (2407, 31%), LS pts (5421, 69%) had better OS (median: 21.6 v 16.8 mos; HRadj: 0.73, 95% CI 0.69-0.78, P < .001) and PFS (median 8.4 v 7.2 mos; HRadj: 0.81, 95% CI 0.76-0.86, P < .001). Results were consistent among subgroups defined by age, sex, PS, metastatic sites and chemo backbone (irinotecan- and oxaliplatin-based). Interaction between PTS and KRAS mutation was significant (Pinteraction< .001): LS is associated with better prognosis only among KRAS wild-type (wt) (HRadj: OS 0.62, 95% CI, 0.55-0.70; PFS 0.71, 95% CI 0.63-0.80), but not among KRAS mutated pts. Among KRAS wt pts, survival benefit from anti-EGFR was observed for LS, but not for RS (table). Conclusions: The prognostic value of PTS is restricted to the KRAS wt population. PTS is predictive of anti-EGFR efficacy, with a significant improvement of survival for LS mCRC pts. These results suggest treatment stratification in mCRC studies by both PTS and KRAS status. [Table: see text]

3539 Background: Previous studies suggest a possible gender-specific response to Bev in mCRC, showing a benefit in males, while the effect in females is less significant. Therefore, we evaluated response to Bev according to gender. Methods: Data from 3369 mCRC patients enrolled on 4 first-line randomized trials testing Bev (2000-2007) were pooled. Association between gender and progression-free survival (PFS)/overall survival (OS) was evaluated by stratified Cox regression model, adjusted for potential confounders. Predictive value was evaluated by interaction (inter.) effect between gender and treatment. In a pre-planned secondary analysis, analyses were stratified using an age cut-point of 60 years (commonly used in breast cancer trials) to evaluate the possible role of menopausal-related effects. Results: OS was not statistically different between males and females (median OS [mOS], 18.8 vs. 17.6 months [mo], adjusted hazard ratio [HRadj], 0.93, 95% confidence interval [CI], 0.84-1.03, p, 0.15) in the overall population. Bev was associated with an improved mOS in males and females, with a 2.3 and 0.6 mo benefit, respectively, as well as an improved PFS. There was no statistically significant interaction effect between gender and treatment (see table). Further stratified by age (< vs. ≥ 60 years), Bev resulted in improved PFS and OS in both genders, at all ages, except for the effect in young females which did not reach statistical significance (see table). Conclusions: Our results confirmed the mOS benefit from addition of Bev to first-line chemotherapy in mCRC in both genders, although the benefit in females was < 1 month. For females under the age of 60, there are uncertainties for mOS benefit from addition of Bev and further evaluation is needed. [Table: see text]