Despite advances in treatment of bowel cancer, it remains the second most common cause of cancer death in the Western world. Use of drugs or nutritional supplements (chemoprevention) is an attractive strategy for prevention of bowel cancer in combination with other modalities such as population screening and endoscopic surveillance, particularly if the chemoprevention agent is safe, well tolerated and cost effective. This webinar describes existing evidence that omega-3 fatty acids have activity against bowel cancer. Recent completed and ongoing clinical trials of EPA for primary prevention of bowel cancer and prevention of metastatic disease are described. Current thinking about how omega-3 fatty acids might work against bowel cancer are also explained.

1. EPA for prevention and treatment
of bowel cancer
Professor Mark Hull
Leeds Institute of Biomedical & Clinical Sciences
University of Leeds and Leeds Teaching Hospitals

2. Bowel (colorectal) cancer
• Third most common cancer in men and women
• Second commonest cause of cancer-related death
• Treatment is sub-optimal and aggressive
– Bowel surgery
– Chemotherapy
– Radiotherapy
• But………..bowel cancer is preventable

3. Natural history of colorectal cancer
CRC liver
metastasis
adenocarcinoma
(cancer)adenoma (polyp)
benign malignant
5-10 years 0-5 years

4. 1o CRC prevention strategies
• Screening (stool testing, endoscopy)
• Surveillance
• Lifestyle/behaviour modification
– weight
– diet
– alcohol
– smoking
– awareness/early diagnosis
• Chemoprevention

5. Cancer chemoprevention
‘The use of natural or synthetic chemical
agents to reverse, suppress, or prevent
carcinogenic progression to invasive cancer’
Sporn 1976

6. The ideal CRC chemoprevention agent
• Effective
– Colorectal cancer
– Other malignancies
– Other conditions (improved life-expectancy)
• Safe and well tolerated
• Easy to use
• Inexpensive

7. Candidate CRC chemoprevention agents
• omega-3 fatty acids
• aspirin
• other anti-inflammatories eg. ibuprofen
• statins
• metformin
• calcium ± vitamin D
• folate

8. Drug re-purposing
• The application of known drugs to a new disease
• Advantages
– Well–established with excellent safety profile
– Effectiveness against more than one condition
– Inexpensive (off-patent)
• Disadvantages
– Clinical testing can outstrip understanding of MOA
– Off-patent (regulatory problems)

9. Aspirin goes ‘prime-time’

10. Colorectal cancer (CRC) prevention
CRC liver
metastasis
adenocarcinoma
(cancer)adenoma (polyp)
benign malignant
1o and 2o chemoprevention 3o chemoprevention
seAFOod Trial The EMT2 Trial
aspirin

11. Omega-3 fatty acids (O3FAs)
• Found in highest quantities in oily fish (salmon or mackerel)
• Two main long-chain O3FAs – EPA and DHA
• 2 g daily dose = eating 10-12 portions of oily fish per week
• ‘nutraceuticals’
– Concentrated (80-90%) EPA, DHA or EPA/DHA mix
– Encapsulated
– 2 g possible in 4-5 capsules
– Minor gastrointestinal side-effects only (approx 5%)
• Large amount of experimental evidence that O3FAs have anti-
cancer activity

12. Evidence that dietary O3FA intake
reduces CRC risk is not convincing
• “Limited, but suggestive, evidence that
dietary fish intake reduces CRC risk”
• 35 cohort studies
• Approx. 50% have reported decreased risk
• >50 case-control studies
• Meta-analysis of cohort studies
• RR for CRC 0.98 (0.88-1.09) in relation to
O3FA intake
2nd Expert report WCRF/AICR 2007 and WCRF/AICR CUP 2011
Br J Nutr 2012;108:1550-6

13. Strong pre-clinical evidence that O3FAs
have CRC chemopreventative efficacy
• Chemical carcinogenesis models (15 rat/2 mouse)
– 4-20% (v/w) fish oil in chow
– 20-50% reduction in tumour incidence
– 30-70% reduction in aberrant crypt focus/tumour multiplicity
• ApcMin/+ and ApcD716 mouse models
– 1-12% (v/w) fish oil in chow
– 40-80% reduction in adenoma multiplicity
• Usually EPA/DHA mix
• EPA = DHA
– 6 single w-3 PUFA studies
– 1 direct comparison (ApcMin/+)
Gut 2012;61:135-49

14. Human biomarker studies of O3FA therapy
Gut 2012;61:135-149
Study
(author/year)
Design
Patient group
N ω-3 PUFA daily dose Treatment
Duration
Primary
outcome
Mucosal PUFA
content
Results
Anti 1992 R, DB, PC
‘sporadic’ adenoma
24 7.7 g FO1 12 wk PI ↑EPA & ↓AA 62% ↓PI
Bartoli 1993 R, DB, PC
‘sporadic’ adenoma
40 2.5-7.7 g FO1 30 days PI Dose dependent
↑EPA/DHA & ↓AA
Dose dependent 40-70%↓ PI
Bartram 1993 DB crossover trial
Healthy volunteer
12 4.4 g FO2 4wk +4 wk PI ω-3 PUFA
ω-6 PUFA↓( NS)
16%↓ PI & 35%↓ mucosal
PGE2
Anti 1994 R, DB, PC
‘sporadic’ adenoma
60 2.5-7.7 g FO1 30 days PI Dose dependent
↑EPA/DHA & ↓AA
Dose independent
50-70%↓ PI
Huang 1996 R, DB, PC
Dukes A/B CRC or
severely dysplastic
polyp
27 7.2 g FO3 6 months PI ↑EPA/DHA & ↓AA 71%↓PI (only in patients with
high baseline PI)
Gee 1999 R, PC, single blind
Awaiting CRC surgery
51 2.4 g FO4 7-21 days pre-
and 8-12 wk
post- surgery
PI ↑EPA/DHA
↑ ω-3 : ω-6 ratio
No effect on PI at surgery or
12wk post-op
Cheng 2003 R, C, open label
Previous CRC/adenoma
41 Dietary advice +/-
500 mg FO5
2 years PI/AI Not assessed PI↔, 50%↑AI, 50%↑ Bax,
COX2 ↔
Courtney 2007 R, single blind
‘sporadic’ adenoma
30 EPA 2 g as FFA 3 months PI/AI ↑EPA/DHA & ↓AA 20%↓PI
7x↑ AI
West 2009 R, DB, PC
‘sporadic’ adenoma
152 EPA 1 g or2 g as FFA 6 months PI/AI ↑EPA/DHA & ↓AA 13%↓PI
57%↑ AI (NS)
FO1 = 54%EPA/46% DHA as ethyl esters
FO2 = 48%EPA/44%DHA, as triglycerides
FO3= 55%EPA/30%DHA/15% other ω-3 PUFAs
FO4 = 58% EPA/42%DHA
FO5= 20%EPA/80%DHA

15. -25
-20
-15
-10
-5
0
5
10
15
P = 0.0122
9.7 [-2.6; 22.0]
-12.6 [-24.7; -0.6]
-22.4 [-39.6; -5.1]
Δ No. of
polyps (%)
Net changePlacebo EPA-FFA
EPA is chemopreventive in humans
Gut 2010;59:918-25
• double-blind randomised placebo-controlled trial of EPA 2g daily
• 58 patients with familial adenomatous polyposis undergoing surveillance

16. The seAFOod (Systematic Evaluation of Aspirin and
Fish Oil) polyp prevention trial

17. • Double-blind randomised placebo-controlled trial
• 2 x 2 factorial design
– EPA 2 g daily (either FFA or TG)
– aspirin EC 300 mg daily
• treatment for 12 months
• NHS Bowel Cancer Screening Programme patients
• Multiple polyp patients needing repeat colonoscopy at 1 year
• No alteration of routine clinical practice
• Tissue biobank
• 51 sites in England
• 550/755 (73%) recruited – recruitment end June 2016
• Results available end of 2017
seAFOod Polyp Prevention Trial
placebo
placebo
placebo
EPA 2g
aspirin 300mg
placebo
aspirin 300mg
EPA 2g

18. Different formulations of EPA
• 99% EPA-FFA 500 mg gastro-resistant capsules
• 90% EPA-TG 574 mg soft-gel capsules (Igennus)
• EPA-FFA dose equivalence
– 5 capsules 90% EPA-TG = 4 capsules 99% EPA-FFA
– differences
• no gastro-resistant coating
• small amount of AA
• Trial biobank to compare EPA bioavailability
– RBCs, plasma, rectal mucosa
• So far…………no difference in adverse events or dropout

19. Pre-clinical evidence of EPA activity against CRC liver
metastasis
EPA
DHA
AA
DPA
0
2
4
6
8
10
12
%PUFAcontent
CONTROL 2.5% EPA-FFA 5% EPA-FFA
0
1
2
3
4
5
Liverweight(g)
P<0.05
0
2000
4000
6000
8000
0
200
400
600
800
TissuePGE2(pg/mg)
TissuePGE3(pg/mg)
CONTROL 2.5% EPA-FFA 5% EPA-FFA
Br J Pharmacol 2012;166:1724-37
P=0.04
0
20
40
60
80
100
%BrdU-positivecells
CONTROL 2.5% EPA-FFA 5% EPA-FFA
CONTROL 2.5% EPA-FFA 5% EPA-FFA

20. • A Phase II randomised double-blind placebo controlled trial of EPA 2 g
daily in patients awaiting liver resection for liver metastasis
• ‘window trial’ - variable treatment period before surgery
• Trial designed to test
• Safety and tolerability
• Markers of tumour growth after surgical removal
• Incorporation of EPA into tumour tissue
• Survival after the trial had finished
The EPA for Metastasis Trial (EMT)
Gut 2014;63:1760-1768
O v e ra ll s u rv iv a l
M o n th s
Percentsurvival
0 6 1 2 1 8 2 4 3 0 3 6 4 2
0
2 5
5 0
7 5
1 0 0
P la c e b o
E P A
No. at risk
EPA 41 41 40 40 32 13 1
Placebo 42 42 38 32 26 15 5
p = 0 .0 9 8 5

21. Tumour fatty acid levels
PUFA Placebo (n=37)a EPA-FFA (n=37)a % difference
from placebo
P value
EPA (C20:5w3) 1.30% (±0.10) 1.82% (±0.11) +40% 0.0008
DPA (C22:5w3) 1.25% (±0.08) 1.76% (±0.09) +41% <0.0001
DHA (C22:6w3) 2.89% (±0.12) 2.56%(±0.11) -11% 0.0465
AA (C20:4w6) 12.82% (±0.53) 12.03% (±0.45) -6% 0.2579
AA:EPA ratio 11.35 (±0.72) 7.58 (±0.53) -33% <0.0001
EPA
%
0
1
2
3
4
EPA-FFAplacebo
DPA
0
1
2
3
4
5
EPA-FFAplacebo
AA
%
0
5
10
15
20
25
EPA-FFAplacebo
%
Gut 2014;63:1760-1768

22. • Compatible with tissue plasma membrane incorporation
• Rapid incorporation (2-3 weeks) but prolonged ‘washout’
over 3-4 months
• Is it explained by O3FA exposure during the critical peri-
operative period?
• Decreased tumour growth and/or anti-cachexia mechanism?
Prolonged effect of short-term
EPA-FFA therapy

23. • A Phase III randomised double-blind placebo controlled trial of EPA 2 g
daily in patients awaiting surgery for liver metastasis
• treatment started before surgery then continuing for minimum 2 yr FU
• Trial designed to test whether EPA provides survival benefit (30%
improvement)
• 450 participants
• 8 sites with high-volume liver surgery units
• Leeds and Sheffield expected to contribute at least one third of patients
• Measurement of EPA incorporation in patient samples
• Start Oct 2015 – recruitment start Oct 2016
• Results due 2020
The EMT2 trial

24. • RCT evidence that EPA has chemoprevention activity
• seAFOod Trial will determine whether EPA ‘works’ in large
number of patients at risk of future CRC
• Hint that EPA provides benefit in advanced CRC patients
• EMT2 trial in patients with CRC liver metastasis just opening
• Many open questions
– Optimal dose and timing?
– Is it tissue EPA incorporation that matters?
– EPA, DHA or both?
– How does EPA have anti-cancer activity?
EPA for prevention and treatment
of CRC

25. Acknowledgements
(in no particular order!)
• patients
• Co-Investigators
• Collaborators
• Trial staff
• funders