ASCO 2010 Biomarker-driven Treatment in Stage II Colon Cancer: When to Hold and When to Fold

– Overview of adjuvant clinical trials in stage II colon cancer - results, challenges, and confusion. -Al B. Benson, III, MD – Prognostic and predictive molecular biomarkers in stage II colon cancer current evidence and future perspective. -Sabine Tejpar, MD, PhD – Biomarker-driven treatment decisions in stage II colon cancer – making sense of what we know. - Neal J. Meropol, MD

Overview of Adjuvant Clinical Trials in Stage II Colon Cancer - Results, Challenges, and Confusion Al B. Benson III, MD, FACP Professor of Medicine Associate Director for Clinical Investigations Robert H. Lurie Comprehensive Cancer Center of Northwestern University

Trends in Oncology Care Evidence-based practice/guidelines Risk assessment – Pathology – Markers Comparative Effectiveness Research (CER)

Archie Chocrane identified three concepts related to the evaluation of a medical technology – efficacy, effectiveness, and efficiency: – Efficacy is the extent to which an intervention does more good than harm under ideal circumstances (i.e., in circumstances designed to maximize the effect of the intervention and eliminate confounding factors). (“Can it work?”) – Effectiveness is the extent to which an intervention does more good than harm when provided to real-world patients by physicians practicing in ordinary clinical settings. (“Does it work in practice?”) – Efficiency measures the effect of an intervention in relation to the resources it consumes. (“Is it worth it?”)

Comparative Effectiveness Individual factors contribute to differences in clinical outcomes – Race or ethnic diversity – Co-morbidities – Drug-drug interactions – Tumor heterogeneity – Tumor genetics – Host genetics

Recurrence Risk & Treatment Benefit Markers Currently Used for Stage II Colon Cancer Recurrence Risk Bowel obstruction or perforation T-Stage # of nodes assessed Tumor grade Lymphatic/vascular invasion Margin status Treatment Benefit None According to current guidelines*: Unlike in breast cancer, there are no molecular markers established in clinical practice for stage II colon cancer No markers in stage II colon cancer identify patients with disproportionately high or low benefit from chemotherapy According to current guidelines*: Unlike in breast cancer, there are no molecular markers established in clinical practice for stage II colon cancer No markers in stage II colon cancer identify patients with disproportionately high or low benefit from chemotherapy * NCCN Clinical Practice Guidelines for Oncology: Colon Cancer v ASCO Recommendations on Adjuvant Chemotherapy for Stage II Colon Cancer, JCO, 2004.

CategorySEER TNRelative survival, 5-year (%) SETNM stage, 6 th ed TNM stage, 7 th ed Observed survival, 5-year (%) SE T1N II T2N II T3N IIA T4aN IIB T4bN IIBIIC T1-2N1a IIIA T1-2N1b IIIA T1-2N2a IIICIIIA/IIIB T3N1a IIIB T4aN1a IIIB Colon Cancer: Expanded Changes in AJCC Substaging for Stage II and III Based on Expanded SEER Data (con’t) AJCC 7 th edition

Colon Cancer: Expanded Changes in AJCC Substaging for Stage II and III Based on Expanded SEER Data (con’t) CategorySEER TNRelative survival, 5-year (%) SETNM stage, 6 th ed TNM stage, 7 th ed Observed survival, 5-year (%) SE T3N1b IIIB T1-2N2b IIICIIIB T4aN1b IIIB T3N2a IIICIIIB T4aN2a IIIC T3N2b IIIC T4bN1a IIIBIIIC T4bN1b IIIBIIIC T4bN2a IIIC T4aN2b IIIC T4bN2b IIIC AJCC 7 th edition

Observed survival rates for 28,491 cases with adenocarcinoma of the colon AJCC 7 th edition

Prognostic Factors in Colorectal Cancer COLLEGE OF AMERICAN PATHOLOGISTS CONSENSUS Category I path-local extent of tumor = pT path-nodes = pN blood or lymphatic invasion post-op residual tumor = R (e.g., + margin) post-op  CEA Category IIA tumor grade radial margin status residual tumor s/p neoadjuvant tx

Estimates of 5 Year DFS (%) with Surgery Plus Adjuvant Therapy NodalT stageLow GradeHigh Grade Status S +AT S +AT 0 nodes T T T1-T nodes T T T1-T > 5 nodes T T Adapted from Cill et al.. J Clin Oncol 22 :1801, 2004

Existing Tools for Selecting Stage II Patients for Treatment Are Inadequate Guidelines: presence of any existing risk marker categorizes patients into “higher risk” vs “standard risk” groups – No further discrimination for “standard risk” (the majority) – Not individualized or quantitative In the absence of established predictive markers, treatment decisions today are based on the expectation that higher risk stage II colon cancer patients derive larger absolute benefit with adjuvant chemotherapy NCCN Clinical Practice Guidelines for Oncology: Colon Cancer v ASCO Recommendations on Adjuvant Chemotherapy for Stage II Colon Cancer, JCO, 2004.

Clinical Background The 5 year overall survival rate for patients with stage II colon cancer is between 75% and 80% Defining a specific high risk group of patients with stage II disease that may benefit from adjuvant chemotherapy remains a challenge Retrospective analysis of molecular prognostic factors suggest that there may be subsets of patients with stage II disease who are at higher risk of recurrence Prognostic markers to identify these patients have not been validated in prospective trials Treatment options are evolving – Role of biologics in adjuvant therapy

INT %65%75%LDLV/LEV 63%60%77%LEV 66%63%75%HDLV 67%63%77%LDLV All Stages 5-yr OS Stage III 5- yr OS Stage II 5- yr OS Proc ASCO 17:982, 1998

Multivariate Analysis for LN Negative Patients: INT-0089 CSS= cause-specific survival

Cohort Definition 3444 resected Stage II colon cancer patients “Usual” Risk Stage II 3151 T3N0 tumor No obstruction No perforation High Risk Stage II 293 T4N0 tumor Obstruction Perforation

International Multicentre Pooled Analysis of Colon Cancer Trials (IMPACT) Investigators Gruppo Interdisciplinare Valutazione Interventi Oncologia (GIVIO) National Cancer Institute Canada Clinical Trials Group (NCIC-CTG) Fondation Francaise de Cancerologie Digestive (FFCD) North Central Cancer Treatment Group (NCCTG) University of Siena

Survival by Receipt of Chemotherapy IMPACT B2 vs. SEER-Medicare SEER-Medicare IMPACT

Deficient Mismatch Repair as a Predictive Marker for Lack of Benefit from 5-FU based Chemotherapy in Adjuvant Colon Cancer DJ Sargent, S Marsoni, SN Thibodeau, R Labianca, SR Hamilton, V Torri, G Monges, C Ribic, A Grothey, S Gallinger ASCO 2008

Pooled data (N=1027) TrialTreatmentN% Stage II % dMMR FU/LEV11730%14% INT 00355FU/LEV21550%18% FU/LV6619%12% GIVIO5FU/LV18352%16% FFCD5FU/LV15466%19% NCIC5FU/LV29261%15% Total102752%16%

DFS by MMR status, pooled data HR: 0.79 ( ) p=0.30 HR: 0.51 ( ) p=0.009 Treated (N=512)Untreated (N=515) dMMR 70% pMMR 67% 5 yr DFS dMMR 80% pMMR 56% 5 yr DFS

DFS in pMMR patients, Pooled data HR: 0.84 ( ) p=0.38 HR: 0.64 ( ) p=0.001 Stage II (N=428)Stage III (N=434) Untreated 72% Treated 77% Untreated 41% Treated 58% 5 yr DFS

QUASAR: 5FU/LV Chemotherapy Benefit in the 1,436 Evaluable Stage II Colon Cancer Patients Kerr et al., ASCO 2009, #4000 RFI (recurrence-free interval) DFS (disease-free survival) OS (Overall Survival)

QUASAR RESULTS: Recurrence Score, T Stage, and MMR Deficiency are Key Independent Predictors of Recurrence in Stage II Colon Cancer Multivariate Analysis

Figueredo et al, JCO 22(16), 2004

Approximate Number of Patients Needed to Detect a Realistic Treatment Benefit* Dukes’ B Dukes’ C No. of No. of Survival ARR Patients Survival ARR Patients At 3 years 85% 2.5% 8,000 65% 5.2% 3,400 At 4 years 80% 3.3% 5,800 58% 6.0% 2,800 At 5 years 75% 4.0% 4,700 50% 6.6% 2,400 Abbreviation: ARR = absolute risk reduction For 90% power of detecting the treatment benefit using two-tailed significance tests at the 5% level, assuming the true relative risk reduction is 18% for both Dukes’ B and Dukes’ C. Buyse, Piedbois, 2001

Recent Adjuvant Colon Cancer Trials X-ACT MOSAIC NSABP C-07 C89803 PETACC 3 ACCORD-02 NSABP C-08 N0147

Disease-free Survival: Stage II and Stage III Patients Data cut-off: June 2006 HR [95% CI] p-value Stage II 0.84 [0.62–1.14] Stage III 0.78 [0.65–0.93] FOLFOX4 stage II LV5FU2 stage II FOLFOX4 stage III LV5FU2 stage III Months Probability % 7.5% p=0.258 p=0.005

Disease-free Survival: High-risk Stage II Patients Disease-free survival (months) FOLFOX4 n=286 LV5FU2 n=290 Probability year 5-year FOLFOX4 85.4% 82.1% LV5FU2 80.4% 74.9% HR [95% CI]: 0.74 [0.52–1.06] High-risk stage II- defined as at least one of the following: T4, tumor perforation, bowel obstruction, poorly differentiated tumor, venous invasion, <10 lymph nodes examined; Data cut-off: June % Exploratory analysis

Stratification: Stage II vs. III Center RANDOMIZATIONRANDOMIZATION Day 1Day 2 FA 200 mg/m 2 5-FU bolus 400 mg/m 2 5-FU CI 600 mg/m 2 Day 1Day 2 Irinotecan 180 mg/m 2 LV5FU2 as above F IF Repeat q 2 weeks for 12 Cycles PETACC-3 (V307) VanCutsem PASCO 2005 abstract #8

Efficacy Data for Treated Patients Randomly Assigned to the LV5FU2 Regimen ParameterLV5FU2Irinotecan + LV5FU2 Relapse-free survival (stage III), risk adjusted 3 year year HR % CI0.73 to 0.96 P.009 Disease-free survival (stage II) 3 year year HR % CI0.61 to 1.08 P.158 ParameterLV5FU2Irinotecan + LV5FU2 Disease-free survival (stage II and III combined) 3 year year HR % CI0.79 to 1.00 P.045 Overall survival (stage III) 3 year year P.094 Overall survival (stage II) 3 year year P.344 Journal of Clinical Oncology, Vol 27, No 19 (July 1), 2009: pp

Kuebler, J. P. et al. J Clin Oncol; 25: Fig 1. National Surgical Adjuvant Breast and Bowel Project Protocol C-07 Consolidated Standards of Reporting Trials diagram

Kuebler, J. P. et al. J Clin Oncol; 25: Fig 3. Treatment hazard ratio and 95% CI for disease-free survival according to patient subsets defined by baseline prognostic factors significant in multivariate analysis

Kuebler, J. P. et al. J Clin Oncol; 25: Fig 2. Kaplan-Meier estimates of disease-free survival by treatment

NSABP C-08 Stage ll + lll mFF6 + B mFF6 Randomize Strat: # Pos. N

Ev 3yDFS mFF6+B mFF HR 0.89 P 0.15 NSABP C-08 DFS % Yrs

NSABP C-08 HR

Ev 3yDFS mFF6+B mFF HR 0.82 P 0.35 DFS Stage II Δ 2.7 Ev 3yDFS mFF6+B mFF HR 0.90 P 0.25 DFS Stage III Δ 1.8 NSABP C-08

AVANT BO17920 Stage ll + lll FF4 + B FF4 Randomize Strat: # Pos. N Xelox + B 12 ’04- 5 ‘07 N=3450

E5202 Trial Schema Low-Risk Patients MSS or MSI-L with retention of 18q alleles MSI-H Arm A: mFOLFOX6 q2w × 12 Arm B: mFOLFOX6 + bevacizumab* q2w × 12 Arm C: Observation only High-Risk Patients MSS/18q LOH or MSI-L/18q LOH are RANDOMIZED MSI-L = low-level microsatellite instability MSI-H = high-level microsatellite instability *Bevacizumab continued for an additional 6 months Stratify: Disease stage (IIA or IIB) Microsatellite stability (stable vs MSI) 18q LOH