Optimal Selenium for Bowel Polyps (OSCAR)

NCT04952129 | Completed Phase 1

• 1 other identifier: OSCAR
• Study Type: interventional
• Target: 56
• Locations: 1 country
• Sites: 2

Brief Summary

New Zealand (NZ) has high bowel cancer rates, which the Bowel Screening Programme aims to reduce by early detection of bowel cancer and its precursor, adenomas (polyps). Bowel cancer and adenoma rates are higher in countries like NZ with low intake of the essential trace mineral selenium. Overseas, trials of selenium supplements reduced adenoma recurrence in people with low blood selenium, but not with high levels (where adding selenium increased health risks). Laboratory research explained this, and found certain types of selenium are safer and more effective. The optimal type and dose of selenium to use in NZ cancer prevention trials is not known. The goal of this clinical trial is to find out how to achieve the optimal amount of body selenium in people who have had a high risk bowel adenoma removed. The main questions it aims to answer are:

• what dose of selenium taken by mouth will maximise levels of the main selenium protein in blood;
• whether one type of organic selenium is better than the other at increasing blood levels of this selenium protein;
• whether a larger dose of selenium is needed in people who start with lower blood selenium levels; Participants will take one selenium capsule a day for 6 weeks then two capsules a day for 6 weeks. Each participant will have blood tests at baseline, then blood tests and evaluation of side effects at 6 weeks and 12 weeks. Researchers will compare these results in the participants taking each type of selenium (selenomethionine or methylselenocysteine).

Conditions

Colorectal Adenoma

Keywords

selenium; colorectal adenoma; selenomethionine; methylselenocysteine; selenoprotein P

Outcome Measures

Primary Outcomes (3)

• Plasma SEPP1 concentration 1

  To determine whether 50 micrograms/day of selenium for 6 weeks significantly increases plasma SEPP1 from baseline.

  At 6 weeks

• Plasma SEPP1 concentration 2

  To determine whether the change in plasma SEPP1 from baseline is greater with selenium 100 micrograms/day than 50 micrograms/day only when baseline plasma selenium is below the median value for the trial population.

  At 6 and 12 weeks

• Plasma SEPP1 concentration 3

  To determine whether the change in plasma SEPP1 from baseline is not different between methylselenocysteine and selenomethionine at each dose.

  At 6 and 12 weeks

Secondary Outcomes (4)

• Plasma selenium

  At 6 and 12 weeks

• Treatment-emergent adverse effects

  At all time points

• White blood cell DNA damage

  At 6 and 12 weeks

• Recruitment

  At baseline

Study Arms (2)

Selenomethionine

EXPERIMENTAL

50 micrograms of selenium as Selenomethionine per oral capsule. Dosage: One capsule a day for 6 weeks, followed by two capsules per day for 6 weeks.

Drug: Selenomethionine

Methylselenocysteine

EXPERIMENTAL

50 micrograms of selenium as Methylselenocysteine per oral capsule. Dosage: One capsule a day for 6 weeks, followed by two capsules per day for 6 weeks.

Drug: Methylselenocysteine

Interventions

Selenomethionine DRUG

Seleno-amino acid

Also known as: L-selenomethionine

Selenomethionine

Methylselenocysteine DRUG

Seleno-amino acid

Also known as: Se-methyl-selenocysteine

Methylselenocysteine

Eligibility Criteria

• Age: 60 Years - 74 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Participants will have all of the following:
• pathologically-confirmed advanced adenoma (defined as any one of \>/= 10mm diameter, \>/= 3 adenomas, high-grade dysplasia, tubulovillous or villous adenoma) 5 diagnosed at first colonoscopy in the National bowel screening programme within the previous 6 months;
• no residual colorectal adenomas;
• next colonoscopy planned within 5 years;
• willing and able to comply with all trial requirements, including treatment and assessments;
• signed written, informed consent.

You may not qualify if:

• Participants will have none of the following:
• currently taking selenium supplements (including in multivitamins) or within the last 6 weeks;
• previous history of colorectal adenoma, colorectal cancer or familial colorectal cancer syndrome;
• other significant cancers within the last 5 years;
• concurrent medical conditions that, in the opinion of the investigators, would compromise either participant safety or the integrity of the data (e.g., malabsorption);
• male participants with a female partner of childbearing potential or pregnant, and unwilling to remain abstinent or use effective contraception (including barrier contraception with a pregnant partner).

Sponsors & Collaborators

• University of Auckland, New Zealand: lead
• Cancer Trials New Zealand: collaborator
• Counties Manukau Health: collaborator
• Waikato Hospital: collaborator

Study Sites (2)

Waikato DHB

Hamilton, Waikato Region, 3240, New Zealand

Location

Counties Manukau DHB

Auckland, 2025, New Zealand

Location

MeSH Terms

Interventions

Selenomethionine; Selenium; selenomethylselenocysteine

Intervention Hierarchy (Ancestors)

Organoselenium Compounds; Organic Chemicals; Methionine; Amino Acids, Sulfur; Sulfur Compounds; Amino Acids; Amino Acids, Peptides, and Proteins; Chalcogens; Elements; Inorganic Chemicals; Minerals

Study Officials

• Michael Jameson, PhD

  University of Auckland, New Zealand

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: June 14, 2021
• First Posted: July 7, 2021
• Study Start: May 6, 2022
• Primary Completion: December 11, 2023
• Study Completion: December 11, 2023
• Last Updated: January 22, 2025

Record last verified: 2025-01

Data Sharing

• IPD Sharing: Will not share

Locations

NZ (2)