Tabernero, Josep

TPS3634 Background: Vascular endothelial growth factor (VEGF) and the VEGF receptor-2 (VEGFR-2) regulate angiogenesis and are overexpressed in CRC. RAM is a fully human IgG1 monoclonal antibody that inhibits binding of VEGF ligands to VEGFR-2 and inhibits VEGFR-2 activation and signaling. In a preclinical study, antiangiogenic and antitumor effects were observed when DC101, an antibody that targets murine VEGFR-2, was administered to mice bearing human colon cancer xenografts. Antitumor activity for RAM has been demonstrated in a Ph I study in pts with solid tumors over a wide range of RAM dose levels and in a Ph II study with RAM + mFOLFOX-6 as 1st-line therapy in pts with mCRC. Methods: This ongoing, randomized, double-blind, placebo-controlled Ph III study includes mCRC pts with measurable or nonmeasurable disease and ECOG performance status of 0-1 who have experienced disease progression during or within 6 months following 1st-line therapy with BEV, OXALI, and any FP. Randomization is stratified by geographic region, KRAS status, and time to progression after initiation of 1st-line therapy. Pts are randomized 1:1 to either RAM 8 mg/kg or PL every 14 days. Pts in both arms receive FOLFIRI (irinotecan: 180 mg/m2, folinic acid: 400 mg/m2, 5-fluorouracil: 400 mg/m2 bolus followed by 2400 mg/m2 continuous infusion over 46-48 hours). The primary endpoint is overall survival (OS). The sample-size estimate assumes 85% power to detect at least a 2.5-month median OS difference (HR = 0.8) between treatment arms with a 1-sided alpha of 0.025. Secondary endpoints include progression-free survival, tumor response, safety, pharmacokinetics, immunogenicity, and correlations between biomarkers and clinical outcome. CRC tissue and blood collection is mandatory for biomarker analyses. As of 05 January 2012, 238 of 1050 planned pts have been enrolled from 100 sites in North America, South America, Europe, Asia, and Australia.

3502 Background: Regorafenib (REG) is an oral multi-kinase inhibitor. The CORRECT trial was conducted to evaluate REG in patients (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 best supportive care plus either REG (160 mg od po, 3 wks on/1 wk off) or placebo (PL). The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), overall response rate, disease control rate, safety and quality of life (QoL). Efficacy analyses across prespecified subgroups were evaluated using univariate Cox regression. Results: 760 pts were randomized (REG: 505; PL: 255). The OS primary endpoint was met at a preplanned interim analysis. OS and PFS were significantly improved in REG arm compared to PL arm: hazard ratio (HR) for OS 0.77 (95% CI 0.64-0.94, 1-sided p=0.0052), median OS 6.4 vs 5.0 mos; HR for PFS 0.49 (95% CI 0.42-0.58, 1-sided p<0.000001), median PFS 1.9 vs 1.7 mos. Comparable OS and PFS benefits were observed in exploratory subgroup analyses by region, age, time from diagnosis of mCRC to randomization, prior lines of treatment, and KRAS status (shown in table). The most common grade 3+ AEs related to REG were hand-foot skin reaction (16.6%), fatigue (9.6%), hypertension (7.2%), diarrhea (7.2%) and rash/desquamation (5.8%). QoL data will be presented. Conclusions: REG demonstrated statistically significant improvement in OS and PFS over PL, as well as comparable efficacy benefits across pt subgroups analyzed. [Table: see text]

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 Purpose: To review key aspects of the design and conduct of early clinical trials (ECT) of immunotherapy agents. Experimental Design: The Methodology for the Development of Innovative Cancer Therapies Task Force 2019 included experts from academia, nonprofit organizations, industry, and regulatory agencies. The review focus was on methodology for ECTs testing immune-oncology therapies (IO) used in combination with other IO or chemotherapy. Results: Although early successes have been seen, the landscape continues to be very dynamic, and there are ongoing concerns regarding the capacity to test all new drugs and combinations in clinical trials. Conclusions: Optimization of drug development methodology is required, taking into account early, late, and lower grade intolerable toxicities, novel response patterns, as well as pharmacodynamic data.

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]

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.

3520 Background: Duration of adjuvant FOLFOX or CAPOX for stage III CC is being guided by pt stratification into low (T1-3N1) and high (T4 or N2) risk groups based on the IDEA study. We determined the relative contributions of clinical and molecular features for prediction of time-to-recurrence (TTR) and survival after recurrence (SAR) within each risk group. Methods: Stage III CC (N=5,430) from 2 trials of adjuvant FOLFOX ± cetuximab with similar outcome by study arm [NCCTG N0147 (Alliance), PETACC-8] were used. Tumors were analyzed for mismatch repair (dMMR vs pMMR), mutations in KRAS (exon 2) and BRAFV600E. Median pt follow-up was 83.4 months. Relative contributions to predicting outcome were assessed using χ2 (Harrell’s rms) based on multivariable (MV) Cox models. Results: N (50.8%) and T (31.8%) stage were the top two contributors to prediction of TTR which supports risk grouping. High risk (n=2566) vs low risk (n=2774) pts had poorer TTR (HR 2.7, 95% CI, 2.4-3.0) and SAR [HR 1.6 (1.4-1.9)], both p<.0001. TTR: KRAS contributed the most to predicting TTR among high (58.6%) and low (51.1%) risk pts (Table). Contribution of MMR (16%) to predicting TTR was limited to low risk pts. Contribution of BRAFV600E to TTR was nearly 3-fold increased in high vs low risk pts. SAR: BRAFV600E contributed the most to predicting SAR, especially in high vs low risk pts (2-fold increase). Tumor sidedness and performance status (PS) were key contributors to SAR, but not TTR. MV associations: TTR: low risk, KRAS [HR 1.7 (1.4-2.3], MMR [HR 0.55 (.35-.87), gender (M/F) [HR 1.3 (1.0-1.5)], all p<.04]; high risk: BRAF [HR 1.3 (1.1-1.7)], sidedness (R vs L) [HR 1.14 (1.0-1.3)], KRAS [HR 1.4 (1.2-1.6)], all p<.04]. SAR: BRAF, sidedness, PS (all p<.05). Conclusions: KRAS mutation was the strongest predictor of shorter TTR in both risk groups whereas BRAFV600E was the primary driver of SAR, especially in high risk pts. Support: U10CA180821, U10CA180882, U24CA196171; BMS, Pfizer, Sanofi. NCT00079274.[Table: see text]