A Quantitative Multi-Gene RT-PCR Assay for Prediction of Recurrence in Stage II Colon Cancer (CC): Selection of the Genes in 4 Large Studies and Results of the Independent, Prospectively-Designed QUASAR Validation Study

Kerr D et al.ASCO 2009; Abstract 4000. (Oral Presentation)

Study Goals

Develop and validate a multi-gene expression assay that improves treatment decisions for patients with stage II colon cancer, and…

– provides individualized assessment of recurrence risk following surgery

– identifies patients with differential 5FU/LV benefit

– provides clinical value in the context of other measures such as T-stage and MMR/MSI

– is optimized for fixed, paraffin-embedded colon tumor tissue

Colon Cancer Technical Feasibility

Selection of Final Gene List & Algorithm

Clinical Validation Study: Stage II Colon Cancer

QUASAR (n=1,436)

Test Prognosis and Treatment Benefit

Assay Development and Validation

Standardization and Validation of Analytical Methods

Development StudiesSurgery Alone

NSABP C-01/C-02 (n=270)

Cleveland Clinic (n=765)

Development Studies Surgery + 5FU/LV

NSABP C-04 (n=308)

NSABP C-06 (n=508)

Modeling and Analytical Performance

48 Recurrence and 66 Treatment Benefit Genes Significant Across Development Studies

Assessment of 761 Candidate Genes in 1,851 Patients in the Development Studies to Yield Final

Pre-specified Assay for Validation in QUASAR

RECURRENCE SCORE®

(0-100)

TREATMENT SCORE

(0-100)

7 Recurrence Genes 6 Treatment Benefit Genes 5 Reference Genes

FINAL ASSAY

Parent QUASAR studyn=3,239

Patients with collected blocksn=2,197 (68%)

Confirmed stage II colon cancern=1,490 (69%)

Final evaluable populationn=1,436 (711 surgery alone,

725 surgery + chemo)

54 excluded (3.6%):29 synchronous tumors8 insufficient tissue7 identifier queries6 RNA quality/quantity4 ineligible histology

707 cases stage III and rectal cancer

QUASAR: Evaluable Stage II Colon Cancer Patients

Is there a significant relationship between the risk of recurrence and the pre-specified continuous Recurrence Score in patients with stage II colon cancer randomly assigned to surgery alone?

STROMALFAP

INHBABGN

CELL CYCLEKi-67

C-MYCMYBL2

REFERENCEATP5EGPX1PGK1UBB

VDAC2

GADD45B

RECURRENCE SCORE

Calculated from Tumor Gene Expression

QUASAR: Pre-Specified Primary Endpoint — Recurrence Risk

5040

QUASAR Results: Continuous RS Predicts Recurrence in Stage II CC (N = 711) Following Surgery

Source: With permission from Kerr D et al. ASCO 2009; Abstract 4000.

3-yearrecurrence

rate

Recurrence Score

p = 0.004

0 10 20 30 60 70

0%

5%

10%

15%

20%

25%

30%

35%

Kaplan-Meier Estimates (95% CI) of Recurrence Risk at 3 years

QUASAR Results: Recurrence Risk in Pre-Specified Recurrence Risk

Groups (n = 711)

Source: With permission from Kerr D et al. ASCO 2009; Abstract 4000.

Recurrence Risk Group

Range of RS

Proportion of patients

Low <30 43.7%

Intermediate 30-40 30.7%

High ≥41 25.6% 22% (16%-29%) 18% (13%-24%) 12% (9% -16%)

Years

Recurrence Risk Group

HighIntermediate

Low

ProportionEvent Free

0.0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 4 5

Results: Clinical/Pathologic Covariates and Recurrence

Source: Kerr D et al. ASCO 2009; Abstract 4000.

Variable Categories HR P value

MMR 13% deficient vs 87% proficient 0.32 <0.001

T stage 15% T4 vs 85% T3 1.83 0.005

Tumor grade 29% High vs 71% Low 0.62 0.026

No. nodes examined 62% <12 vs 38% >12 1.47 0.040

LVI 13% Present vs 87% Absent 1.40 0.175

RS per 25 units Continuous 1.61 0.008

Prespecified Multivariate Analysis: Patients Who Underwent Surgery Alone (n=605)

RS, T Stage and MMR Deficiency:Key Independent Predictors of

Recurrence in Stage II CC

Source: With permission from Kerr D et al. ASCO 2009; Abstract 4000.

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

0 10 20 30 40 50 60 70

Recurrence Score

3-yearrecurrence

rate

MMR deficient (11% of Stage II patients)

T4 stage (13% of Stage II patients)

T3 and MMR proficient (76% of Stage II patients)

Treatment Score Prediction of 5FU/LV Benefit

Treatment Score by treatment interaction was not significant for RFS (p = 0.19), DFS (p = 0.12) or OS (p = 0.15)

"The proportional benefits of chemotherapy were maintained across the recurrence score prognostic categories. Therefore if you had a high chance of the tumor recurring as predicted by the Recurrence Score, the absolute benefits of chemotherapy would be somewhat higher.”

Source: Kerr D et al. ASCO 2009; Abstract 4000.

Editor: Overall, QUASAR demonstrated that chemo resulted in fewer recurrences — HR = 0.78 (0.67-0.91; p = 0.001)**Lancet 2007; 370: 2020-29

Editor: Overall, QUASAR demonstrated that chemo resulted in fewer recurrences — HR = 0.78 (0.67-0.91; p = 0.001)**Lancet 2007; 370: 2020-29

Source: Kerr D et al. ASCO 2009; Abstract 4000.

Key Conclusions

First demonstration that a prospectively-defined gene expression assay can independently predict recurrence in stage II CC following surgery– Recurrence Score (RS) provides independent value

beyond available prognostic factors RS provides individualized assessment of recurrence risk

– Greatest clinical utility when used in conjunction with T stage and Mismatch Repair (MMR/MSI), particularly for the majority of patients for whom those markers are uninformative (~70% of patients)

The continuous Treatment Score (TS) did not predict a differential benefit from 5FU/LV