Sargent, Daniel J.

4008 Background: To explore and inform 3 critical issues facing trialists and practicing oncologists testing adjuvant therapy (AT) for stage II and III colon cancer: 1) The nature and duration of AT benefit, 2) detailed information on survival and recurrence (rec) rates, including long-term event rates (> 10 years (yrs)), and 3) adequacy of statistical models for power and sample size calculations based on a disease-free survival (DFS) endpoint. Methods: The dataset assembled by the Adjuvant Colon Cancer Endpoints (ACCENT) Group, a collection of individual pt data from 18 trials and over 20,800 pts testing 5-FU based AT for pts with stage II and III colon cancer, was analyzed. Results: 1) Significant DFS benefit from AT were manifest in the first two years post randomization; after 2 years DFS rates in the AT and control groups were not significantly different. Significant Overall Survival (OS) benefit of AT was consistent over the 8 year follow-up period. 2) After 5 yrs, rec rates were <1.5%/yr, and after 8 yrs, < 0.5%/yr. 3) For DFS, a Weibull model provided superior model fit compared to the standard exponential model. In the range of Weibull values seen in trials in the dataset, however, the use of the Weibull model did not meaningfully impact power and sample size (<2% impact on power for the same sample size), assuming a constant effect of AT on DFS. Additionally, modeling a non-constant AT effect (as observed for DFS) had a similar negligible impact on statistical power compared to the standard exponential model, for the same sample size. Conclusions: AT provides significant benefit for DFS, primarily within the first 2 years, translating into long-term OS benefit. Long term follow-up for rec yields few events. Despite some increased complexity, existing methods remain appropriate for power and sample size determination for the DFS endpoint, pending further confirmation. No significant financial relationships to disclose.

PURPOSE The microsatellite instability (MSI) or deficient mismatch repair (dMMR) phenotype is usually regarded as a single biologic entity, given the absence of comparative analyses regarding prognosis and response to chemotherapy between sporadic and familial dMMR cancers. PATIENTS AND METHODS Patients with stage III colon cancers were randomly assigned to FOLFOX (leucovorin, fluorouracil, and oxaliplatin) with or without cetuximab in 2 large adjuvant phase III trials (N = 5,577). Among patients with MSI and KRAS exon 2 wild-type (WT) tumors, the prognostic and predictive impacts of sporadic versus familial dMMR cancers and BRAF V600E mutational status were determined. Multivariable Cox proportional hazards models were used to assess disease-free survival (DFS) by treatment arm, adjusting for age, sex, tumor grade, Eastern Cooperative Oncology Group performance status, pT/pN stage, and primary tumor location. RESULTS Among patients with MSI status with complete data for dMMR mechanism analysis (n = 354), 255 (72%) had sporadic ( BRAF mutation and/or MLH1 methylation) and 99 (28%) had familial tumors ( BRAF WT and unmethylated MLH1 or loss of MSH2/MSH6/PMS2 protein expression). A large proportion of dMMR sporadic tumors were mutated for BRAF (n = 200). In patients treated with FOLFOX, DFS did not differ statistically by dMMR mechanism, whereas in patients treated with FOLFOX plus cetuximab, those with sporadic tumors had worse DFS than those with familial cancers (multivariable hazard ratio, 2.69; 95% CI, 1.02 to 7.08; P = .04). Considering the predictive utility, the interaction between treatment and dMMR mechanism was significant ( P = .03). Furthermore, a nonsignificant trend toward a deleterious effect of adding cetuximab to FOLFOX was observed in patients with BRAF-mutant but not BRAF WT tumors. CONCLUSION The addition of cetuximab to adjuvant FOLFOX was associated with shorter DFS in patients with sporadic dMMR colon cancer. Additional studies are needed to validate these results in metastatic disease.

Abstract Background: Patients (pts) with DLBCL who receive first-line anthracycline based immunochemotherapy and remain in remission at 2 years have excellent outcomes with overall survival (OS) in one study that was comparable to the age and sex matched general population in cohorts from the US and France (Maurer et al, JCO 2014). To evaluate whether these findings are robust and generalizable, we assessed OS stratified by progression-free survival at 24 months (PFS24) using individual patient data from pts with DLBCL enrolled in 14 multi-center, international randomized clinical trials as part of the SEAL consortium. Methods: Central data alignment was performed by the SEAL statistics and data center. All enrolled patients treated with rituximab-containing anthracycline-based immunochemotherapy as part of initial induction therapy were included in this analysis using an intent-to-treat approach. PFS was defined as time from initiation of first-line therapy to progression or death. PFS24 was defined as being alive and progression-free 24 months (731 days) after initiation of therapy. Overall survival from PFS24 was defined as time from achieving PFS24 until death due to any cause. OS was compared to each patient's age-, sex-, and country- matched general population using expected survival and standardized mortality ratios (SMR). Country-level population rate tables were obtained from www.mortality.org where available. A per-study average rate table was used when country information was unavailable. OS beyond 9 years from treatment initiation was only available the time of analysis from two trials (13% of cohort) and thus follow-up from PFS24 was restricted to the first 7 years after PFS24 for this analysis. Results: Fourteen studies with 7975 patients were included in the SEAL database. 5853 (73%) received rituximab as part of induction therapy and used in this analysis. Median age was 62 years (range 18-92) with 56% >60 years, 54% were male, 57% had elevated LDH, 63% had stage III/IV disease, 13% had ECOG PS 2-4, and IPI was 0-1 in 36%, 2 in 25%, 3 in 23%, and 4-5 in 16%. At a median follow-up of 4.4 years, 1337 (23%) had disease progression, 1489 patients (25%) had died, and 5101 patients were evaluable for PFS24. 1423 (28%) of evaluable patients failed to achieve PFS24. These patients had poor outcomes after progression with median OS of 7.2 months (95% CI 6.8-8.1), 5-year OS of 19%, and SMR of 32.1 (95% CI: 30.0-34.4). Outcome was excellent (median unreached) in the 3678 patients who were progression-free at 24 months, with subsequent OS after achieving PFS24 approaching the age and sex matched general population (Figure). The observed vs. expected OS at 3, 5, and 7 years after achieving PFS24 was 93.1% vs. 94.4%, 87.6% vs. 89.5%, and 80.0% vs. 83.7%, respectively, the SMR was 1.22 (95% CI: 1.09-1.37). In subset analyses examining pts achieving PFS24, adverse prognostic characteristics at baseline (elevated LDH, advanced stage, ECOG PS 2-4, high IPI) were associated with greater decrement in OS from the general population based expected survival (Table). Conclusions: PFS24 from the start of initial therapy stratifies DLBCL pts into populations with distinct outcomes. DLBCL pts treated with rituximab containing anthracycline-based immunotherapy on large randomized clinical trials who are alive without progression at 24 months from start of initial therapy have excellent outcomes with survival that is marginally lower but clinically indistinguishable from the age-, sex-, and country-matched background population for at least 7 years after achieving PFS24. Further follow-up time will be needed to assess any long-term impact of late relapse and survivorship issues in this population. Table Table. Figure Figure. Disclosures Shi: Mayo Clinic: Employment. Cunningham:Amgen: Research Funding; Astra-Zeneca: Research Funding; Bayer: Research Funding; Celgene: Research Funding; Merrimack: Research Funding; Medimmune: Research Funding. Seymour:AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Speakers Bureau; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Jaeger:Roche: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Haioun:Sandoz: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ghesquieres:Mundipharma: Consultancy; Roche France: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Merli:Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Teva Pharmaceuticals Industries: Membership on an entity's Board of Directors or advisory committees. Herbrecht:Servier: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Cell Therapeutics, Inc: Membership on an entity's Board of Directors or advisory committees. Flament:Celgene: Employment, Equity Ownership. Fu:Celgene: Employment, Equity Ownership. Flowers:Gilead: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Acerta: Research Funding; ECOG: Research Funding; Mayo Clinic: Research Funding; Pharmacyclics, LLC, an AbbVie Company: Research Funding; Millenium/Takeda: Research Funding; Infinity: Research Funding; TG Therapeutics: Research Funding; Genentech: Consultancy, Research Funding; NIH: Research Funding; AbbVie: Research Funding. Ou:Mayo Clinic: Employment. Sargent:Celgene: Research Funding. Coiffier:MorphoSys: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Abstract Background OSis the gold standard primary efficacy endpoint for evaluating treatment strategies for DLBCL. Because current standard of care first-line regimens with rituximab plus chemotherapy produce median OS > 8 years, an endpoint assessed earlier would accelerate the evaluation of new therapies and potentially allow patients (pts) to more rapidly benefit from study results. The SEAL group formally evaluated PFS as a surrogate endpoint for OS in first-line therapy for DLBCL. Methods Through a systematic literature search and input from lymphoma experts on the SEAL committee, we identified multicenter, randomized controlled clinical trials that evaluated active treatment and enrolled at least 100 pts with previously untreated DLBCL or aggressive non Hodgkin lymphoma by WHO/REAL classification, published after January 1, 1995. Studies which enrolled only early stage (I or II) pts and studies that could not provide individual pt data (IPD) were excluded from surrogacy analysis. Potential surrogate candidates for OS included: 1) PFS, defined as the time from initiation of induction treatment to progressive disease, relapse or death due to any cause, and 2) PFS rate at 24 months after initiation of induction treatment (PFS24). These endpoints were derived consistently for all studies based on IPD. Surrogacy was evaluated by the correlation between surrogate candidates and OS. Pt-level correlation was measured by the rank correlation coefficient (ρ) and global odds ratio for PFS and PFS24, respectively, estimated by the Copula model. Trial-level correlation was evaluated by the correlation between trial-specific treatment effects on surrogate candidates and OS with two commonly used trial-level R2s: R2WLS (Sargent et al JCO 2005) and R2Copula (Burzykowski et al J R Stat Soc C 2001 and Burzykowski et al J R Stat Soc A 2004). For the R2 measures, a value closer to 1 indicates a stronger correlation. We pre-specified that if either trial-level R2 was >=0.80 and its 95% confidence interval (CI) excluded 0.60, the candidate would meet criteria for surrogacy. Results Thirteen of 14 studies collected to date in the SEAL database met all inclusion criteria. IPD for 7507 pts (median age 63 years, 54% male, 46% ECOG performance status 0, 8% IPI 0, 50% IPI 1-2, 64% stage III/IV, median follow-up time of 52 months) were analyzed. Among 13 studies, one tested maintenance treatment only and two tested both induction and maintenance regimens. One study included four treatment arms. Thus at the trial level, 17 two-arm comparisons were formed: 14 comparisons comparing induction regimens and 3 comparing maintenance; 15 comparisons involved rituximab. Longer PFS was highly correlated with longer OS at the pt level (ρ= 0.85, 95% CI 0.84-0.86), as was PFS24 (Global odds ratio = 61.1, 95% CI 52.6-69.6). The Table shows trial-level correlations, and the Figure shows trial-level association between estimated treatment effects (log(HR) [hazard ratio]) on PFS and OS. The trial-level correlation between PFS and OS was strong and met the pre-specified surrogacy criteria, with R2WLS of 0.83 (95% CI 0.58-0.94) and R2Copula of 0.85 (95% CI 0.72-0.99). Sensitivity analyses including only comparisons including rituximab or only induction regimens showed consistent results. The overall trial-level correlation between PFS24 and OS was reduced slightly, with R2WLS of 0.77 (95% CI 0.49-0.92) and R2Copula of 0.78 (95% CI 0.59-0.96). Performance of PFS24 was improved when restricting analysis to only including induction studies (see table). Conclusion This large IPD pooled-analysis demonstrates that PFS duration met the pre-specified criteria as a robust surrogate endpoint for OS, and can be considered as a surrogate endpoint for OS for frontline DLBCL trials evaluating immunochemotherapy. The earlier endpoint of PFS24 showed promise as a potential surrogate and further validation is warranted. Figure Figure. Disclosures Shi: Mayo Clinic: Employment. Flowers:Millenium/Takeda: Research Funding; TG Therapeutics: Research Funding; Pharmacyclics, LLC, an AbbVie Company: Research Funding; Gilead: Consultancy, Research Funding; NIH: Research Funding; Mayo Clinic: Research Funding; ECOG: Research Funding; Acerta: Research Funding; Infinity: Research Funding; AbbVie: Research Funding; Roche: Consultancy, Research Funding; Genentech: Consultancy, Research Funding. Ou:Mayo Clinic: Employment. Cunningham:Merrimack: Research Funding; Celgene: Research Funding; Bayer: Research Funding; Astra-Zeneca: Research Funding; Amgen: Research Funding; Medimmune: Research Funding. Pfreundschuh:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Spectrum: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Seymour:AbbVie Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Jaeger:Roche: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Haioun:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sandoz: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ghesquieres:Mundipharma: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche France: Research Funding. Merli:Teva Pharmaceuticals Industries: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Herbrecht:Cell Therapeutics, Inc: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees. Flament:Celgene: Employment, Equity Ownership. Fu:Celgene: Employment, Equity Ownership. Coiffier:MorphoSys: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees. Sargent:Celgene: Research Funding.

Abstract Background: Limited data exist to describe the clinical features and outcomes for elderly pts with FL. The FLASH group performed a prospectively planned pooled analysis of IPD from first-line RCTs and examined associations between age (<= 70 vs. > 70 years), clinical characteristics and FL outcomes. Methods: We identified 18 randomized controlled multicenter clinical trials in the FLASH database which enrolled elderly pts (> 70 yrs). From these 18 studies, 5922 previously untreated FL pts were included for this analysis. Complete response (CR) at 24 and 30 months were defined as whether the pt achieved and remains in CR at 24 months and 30 months after initiation of induction treatment. PFS24 is defined as proportion of pts progression-free and alive at 24 months post-randomization. Time to progression (TTP) and overall survival (OS) were defined as time from randomization to the date of progression (censoring for death without progression) and date of death due to any cause, respectively. Progression-free survival (PFS) was defined as time from randomization to the date of progression or death, due to any cause, whichever comes first. Non-lymphoma death was defined as death without prior progression. Early disease outcomes, i.e. CR24, CR30, and PFS24 were primary outcomes; secondary outcomes were TTP, OS, and PFS. For time-to-event outcomes, Kaplan-Meier method and log-rank test were used for univariate estimation and comparison; stratified Cox proportional hazard modeling was used for multivariable analyses. Cumulative incidence methods were used to model PFS while treating disease progression as the primary event of interest and non-lymphoma death as a competing risk. For binary outcomes, multivariable logistic regression was used to estimate the association between age groups and outcomes. Variable adjusted in the regression models are FLIPI score without the age component, ECOG performance status (>= 2 vs < 2), and rituximab use. Results: Among 5922 previously untreated FL pts from 18 RCTs, 63% (n = 3728) were <= 60, 28% (n = 1652) 61-70, and 9% (n = 542) > 70 yrs. Pts age > 70 (vs. <= 70) more commonly had elevated LDH (42% vs 36%, p = 0.02), hemoglobin < 12 g/dL (27% vs 19%, p < 0.0001), ECOG PS >= 2 (8.8% vs 5.0%, p = 0.0004), and elevated β2-microglobulin (68% vs 49%, p < 0.001), less often had > 4 lymph nodes involved (54% vs 65%, p < 0.001), and had similar FLIPI scores without age component (p = 0.17). There were no significant differences between groups in: Ann Arbor stage (94% vs 95% stage III/IV) or rituximab use (62% vs 58%). Median survival follow-up was 5.6 yrs. Pts > 70 yrs did not differ from pts <= 70 in rates of CR24 (27% vs 30%, p=0.32), CR30 (29% vs 31%, p=0.55) or PFS24 (63% vs. 67%, p=0.10). Median TTP was 3.8 and 4.0 years for pts > 70 and <= 70, respectively (HR=1.08, 95% CI 0.96-1.23, p=0.20). With a median OS of 14.6 years for all pts, median OS was 7.4 and 15.7 years for pts > 70 and <= 70, respectively (HR=2.35, 95% CI=2.03-2.73, p<0.001). PFS was statistically significantly different but clinically similar at median 3.1 and 3.8 years for pts > 70 and <= 70, respectively (HR=1.26, 95% CI =1.12-1.41, p<0.001). Further investigation showed the difference in PFS was due to higher incidence of non-lymphoma death in pts > 70 with no difference in disease progression (Figure). In regression models, adjusting for rituximab use, ECOG PS >= 2, and FLIPI score without the age component, age > 70 was a significant predictor of OS and PFS (due to higher incidence of non-lymphoma death), but not PFS24, CR24 or CR30 (Table). Conclusions: FL pts > 70 yrs treated on trials have similar early disease outcomes to younger patients. There is no disease-specific outcome difference between age groups. Age alone should not disqualify patients from standard treatments or RCTs. Disclosures Flowers: Genentech: Consultancy, Research Funding; NIH: Research Funding; Mayo Clinic: Research Funding; TG Therapeutics: Research Funding; Millenium/Takeda: Research Funding; ECOG: Research Funding; Acerta: Research Funding; Pharmacyclics, LLC, an AbbVie Company: Research Funding; Roche: Consultancy, Research Funding; AbbVie: Research Funding; Infinity: Research Funding; Gilead: Consultancy, Research Funding. Ou:Mayo Clinic: Employment. Shi:Mayo Clinic: Employment. Hochster:Genentech: Consultancy, Other: Consultancy fees for advisory boards for GI cancer and bevacizumab with amounts within Yale University de minims guidelines. Brice:Roche: Honoraria; Takeda Pharmaceuticals International Co.: Honoraria, Research Funding; Bristol Myers-Squibb: Honoraria; Gilead: Honoraria; Seattle Genetics: Research Funding. Hiddemann:Roche: Other: Grants; Roche: Membership on an entity's Board of Directors or advisory committees; Genentech: Other: Grants. Marcus:Takeda: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau. Kimby:Abbvie: Consultancy, Honoraria; Jansen: Consultancy, Honoraria; Celgene: Honoraria; Baxalta: Consultancy; Gilead: Honoraria. Herold:Gilead: Other: Personal fees from member advisory board; Celgene: Honoraria; Genentech: Other: Grants; Roche: Honoraria, Other: Grants. De Bedout:Celgene: Employment. Nielsen:Hoffmann-La Roche: Employment. Morschhauser:Roche: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria; Janssen: Honoraria. Rummel:Mundipharma GmbH: Other: Personal fees, Research Funding; Roche Pharma AG: Other: Personal fees, Research Funding. Vitolo:Gilead: Other: Honoraria for lectures; Takeda: Other: Honoraria for lectures; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Honoraria for lectures; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Honoraria for lectures. Salles:Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Gilead: Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Roche/Genentech: Consultancy, Honoraria, Research Funding; Mundipharma: Honoraria. Sargent:Celgene: Research Funding.

3583 Background: The Microsatellite instability (MSI) or deficient mismatch repair (dMMR) phenotype is usually taken as a single biological entity whereas no data are available concerning prognosis and response to chemotherapy between sporadic and familial dMMR cases. Methods: Resected KRAS exon 2 wild-type (WT) tumor stage III colon cancers (N = 4596) from patients (pts) randomly assigned to FOLFOX +/- cetuximab in two adjuvant large phase III trials were prospectively analyzed for MSI status and dMMR mechanism (sporadic vs familial). Stratified Cox models were used to assess prognostic and predictive values of dMMR mechanism by treatment arms, adjusting for age, gender, tumor grade, ECOG PS, pT/pN stage and primary tumor location. Results: Among dMMR patients with complete data for dMMR mechanism analysis (N = 354), there were 255 (72%) sporadic ( BRAF mutated or WT with MLH1 methylation) and 99 (28%) familial (loss of MSH2 or MSH6, or loss MLH1 with BRAF WT and unmethylated MLH1) cases. A large proportion of dMMR sporadic cases were mutated for BRAF (n = 200; 80%). In pts treated with FOLFOX, the disease-free survival (DFS) was not statistically different by dMMR mechanism, while for pts treated with FOLFOX + cetuximab, the sporadic cases did worse than familial cases (DFS; adjusted (adj) HR, 2.69; 95% CI, 1.02-7.08; P= 0.04). Considering the predictive value, a deleterious effect of adding cetuximab to FOLFOX was observed in sporadic (DFS; adjHR, 1.68; 95% CI, 1.01-2.79; P= 0.04) but not in familial dMMR pts (interaction P value regarding treatment effect = 0.03). Furthermore, a non-significant trend to a deleterious effect of adding cetuximab to FOLFOX was observed in BRAF mutant (DFS; adjHR, 1.66; 95% CI, 0.95-2.92; P= 0.07) but not in BRAF WT pts. Conclusions: The addition of cetuximab to FOLFOX was associated with reduced DFS in patients with sporadic dMMR cases. Further studies including the methylator phenotype (CIMP) analysis are needed to validate these results. Clinical trial information: NCT00265811 and NCT00079274.