Blood Based Screening

Transcription

1 Plenary Session 4 CRC screening: The best modality is... Blood Based Screening Molnár, Béla M.D., PhD 2nd Dept. of Medicine Semmelweis Budapest Hungary

2 There is no controversy: screening saves lives Irrefutable evidence in very large trials gfobt screening reduces incidence and mortality FIT screening trial data limited based on performance considered more effective than gfobt Flexible sigmoidoscopy reduces incidence and mortality Colonoscopy trials ongoing considered to reduce incidence and mortality

3 What is the controversy? Despite the irrefutable evidence for both a mortality and incidence benefit, and (in the US) despite having guidelines and screening methods in place participation in screening programs remains suboptimal

4 Although the potential exists to prevent CRC and reduce the risk of dying from this disease... CRC screening remains largely underutilized. American Cancer Society. Facts and Figures

5 Why? and What else? The reasons are multitude and include financial and cultural elements Amongst these, the sample collection (stool tests) or bowel prep methods are frequently cited as intrinsic barriers to participation A simple blood test in the menu of screening choices can help increase participation in screening programs.

6 A Simple Blood Based CRC Screening Test

7 Will a blood test improve participation? Colon Cancer Alliance US Survey Availability of a blood test would increase screening participation Huntsman Cancer Center Focus Group Study Amongst non-screened, majority would prefer a blood test Berlin Adherence Study >80% of colonoscopy refusers took Epi procolon

8 What is the potential impact of a blood test like Epi procolon? Theoretical Screening Population: 1,000,000, CRC Prevalence: 0.5%, Total Cancers = 5000 Modality Participa tion Sensitivi ty # Patients tested # Cancers # Detected % of Total Cancers FOBT / FIT 12% 70% 120, % Colonoscopy 53% 95% 530,000 2,650 2, % Totals 65% 650,000 3,250 2, % Missed 35% 350,000 1,750 Blood based test Epi procolon 80% 70% 280,000 1, % Combined 93% 930,000 4,650 3, %

9 Fundamentals of a reliable blood test Biomarker(s) or bioprocess (es), ~100% related to cancer development Released or taking place continously in/to blood Stability and lifetime in blood is expected upto 8 hours or more Quantifiable Automatable Financially reasonable

10 CRC Biomarkers as blood test Proteins markers of oncofetal transition, inflammation related Nucleic Acids RNA DNA mirnas in development and testing Mutated sequences : frequency and penetration is low (10-50%) Methylated sequences

11 CRC Biomarkers : Methylated DNA Sequences Tissue Frequency and penetration is almost 100% at a right CpG island of a right gene Plasma circulating free DNA quantity is disease related stabile, disease and tissue specific sequences methylated DNA is resistant to DNAses

12 SEPTIN9 protein expression is in correlation with methylation and RNA epression in the N-Ad-Dyspl-CRC sequence

13 2nd Department 2nd of Department Internal of Medicine, Internal Medicine, Semmelweis University Septin RNA levels in CRC laser microdissected samples Stroma 1. Cutting of the tissue compartments by focused laser ray 2. Removal of the samples from slide 3. RNA and DNA isolation from the cells 4. Affymetrix whole genomic microarray analysis array (> transcripts) 2,8 2,75 2,7 2,65 2,6 2,55 2,5 2,45 2,4 2,35 2,3 2,25 2,8 2,75 2,7 2,65 2,6 2,55 2,5 2,45 2,4 2,35 2,3 2, Epithelium

14 Septin 9 multi CpG island bisulfite sequencing of promoters

15 Bisulfite sequencing of SEPTIN9 CpG islands in splicing variants

16 Septin 9 methylation in CRC tissue Healthy biopsy SEPT9/ACTB ratio Adenoma biopsy SEPT9/ACTB ratio Cancer biopsy SEPT9/ACTB ratio PMR for m SEPT9 in tissue PMR >1% found in NED 7.7% (1/13) Adenoma 100% (10/10) CRC biopsies 100% (16/16) PMR = percent methylation reference

17 Septin9: a Marker for CRC Detection Epi procolon detects methylated Septin9 in blood by real-time PCR The presence of methylated Septin9 is highly correlated with the occurrence of colorectal cancer

18 Clinical Studies: PRESEPT (NCT ) 7940 average risk subjects enrolled at 32 sites Plasma collected prior to bowel prep. Optical colonoscopy was the reference standard Plasma samples masked and tested at external labs FIT Comparison (NCT ) 301 valid subjects enrolled at 61 US sites 199 prospectively enrolled, 102 screen detected cases Optical colonoscopy was the reference standard Plasma samples masked and tested at external lab

19 Clinical Performance Academic PRESEPT Study February 2010 Prospective study pivotal clinical trial for FDA submission December 2011 FIT Comparison Study Samples (from 7940) 1510 (all cancers, stratified sampling of other classes) 1544 (all cancers, advanced adenomas, stratified sampling of other classes) 301 Sensitivity 51%/67% 1 68% 73% Specificity 91%/88% 1 80% 82% Assay / Kit Septin9 prototype assay Epi procolon Epi procolon 1 Duplicate vs. triplicate testing

20 Clinical Data Comparison of Epi procolon and FIT 337 subjects enrolled at 61 sites in US 301 valid in study 290 subjects with valid results for both FIT and Epi procolon 97 patients with Colon Cancer 193 patients with no evidence of disease, small polyps or advanced adenomas

21 Enrolled N=337 In Study N=301 Excluded N=36 Not CRC A.A. N=3 Screen Detected Cases N=102 Prospective Collection N=199 Stool n=2 Blood n=3 CRC Total N=99 CRC N=2 A.A. N=26 S.P. N=77 N.E.D. N=94 Stool n=95 Blood n=99 Stool n=2 Blood n=2 Stool n=25 Blood n=26 Stool n=75 Blood n=77 Stool n= 91 Blood n= 94

22 Sensitivity Results paired samples Sensitivity (n) 95% CI FIT Sensitivity 68.0 % (66/97) 58.2% % Epi procolon Sensitivity 72.2 % (70/97) 62.5% % Conclusion: Septin9 is not inferior to FIT (10% margin - statistically significant)

23 Specificity Results paired samples Specificity (n) 95% CI FIT Specificity 97.4 % (188/193) 94.1% % Epi procolon Specificity 80.8 % (156/193) 74.7% % Conclusion: Septin9 non-inferiority to FIT not proven (20% margin - not statistically significant)

24 Comparison Summary Epi procolon sensitivity (72.2%) non-inferior to OC FIT-chek (68.0%) for cancer detection Epi procolon specificity (80.8%) lower than OC FIT-check (97.4%) and not statistically non-inferior Additional Observations Both tests detected cancers with equal sensitivity in the right and left colon

25 Summary Methylated DNA in plasma can be used for screening based on rationals and facts The metseptin9 blood test has been validated in the average risk screening population The test has a sensitivity for cancer detection that is better than tests with proven incidence and mortality reduction (gfobt) The test is not inferior to FIT for cancer detection The test provides an option that may be accepted by people who reject other modalities

26 Choice improves participation What gets lost with a single test only strategy: ADHERENCE TO ANY CRC SCREENING IS SUPERIOR TO NO SCREENING AT ALL. Young P et al. Colonoscopy for colorectal cancer screening, 2013.