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Examining a Novel Gastrointestinal Intervention to Negate Environmental Toxicants (ENGINE)

NCT ID: NCT07226440

Last Updated: 2025-11-10

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Clinical Phase

PHASE1/PHASE2

Total Enrollment

40 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-12-31

Study Completion Date

2028-11-30

Brief Summary

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This randomized, placebo-controlled crossover trial will test the feasibility and acceptability of using colesevelam in male firefighters with high per- and polyfluoroalkyl substances (PFAS) exposure. This trial will also explore whether colesevelam lowers blood PFAS levels and urine environmental toxicant and mold mycotoxin levels.

Detailed Description

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Firefighters experience elevated exposure to per- and polyfluoroalkyl substances (PFAS) through firefighting foams, turnout gear, and dust in fire stations. PFAS persist in the body due to their long biological half-lives, leading to bioaccumulation and raising concern for adverse effects on hormone regulation, immune function, reproduction, and cancer risk. Despite growing awareness, there are no approved treatment options to reduce PFAS levels in humans. Bile acid sequestrants, such as colesevelam, bind bile acids in the gastrointestinal tract and may interrupt enterohepatic recirculation of PFAS, thereby enhancing elimination. Observational studies and one small randomized trial suggest that bile acid sequestrants can meaningfully reduce PFAS levels. This trial will evaluate the feasibility, adherence, and acceptability of colesevelam in male firefighters with elevated PFAS, while exploring its effects on serum PFAS concentrations and urine environmental toxicant and mold mycotoxin levels.

Conditions

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Toxicant Exposure Firefighter Occupational Exposure to Chemicals

Keywords

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Per- and polyfluoroalkyl substances PFAS Firefighters Occupational exposure Bile acid sequestrants Colesevelam

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

This is a randomized, double-blind, placebo-controlled, crossover trial with a 2-week washout between treatment periods. Participants are assigned to one of two sequences: colesevelam followed by placebo, or placebo followed by colesevelam.
Primary Study Purpose

TREATMENT

Blinding Strategy

TRIPLE

Participants Investigators Outcome Assessors
All study staff will be masked. The only unmasked individuals will be the pharmacists dispensing in the medication/placebo.

Study Groups

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Colesevelam first

Participants randomized to this arm will receive colesevelam, taking 3 tablets twice daily for 12 weeks, followed by a 2-week washout period, and then 12 weeks of matching placebo tablets taken on the same schedule. Both the study drug and the placebo will be provided in identical-appearing bottles to maintain blinding.

Group Type ACTIVE_COMPARATOR

Colesevelam

Intervention Type DRUG

We will provide Colesevelam in 625-mg tablets. Participants will take 3 tablets orally, twice daily (total daily dose 3.75 g) for 12 weeks.

Placebo

Intervention Type DRUG

Matching inert oral tablets designed to mimic colesevelam 625 mg tablets in size, shape, and color, but containing no active pharmaceutical ingredient. Participants will take 3 orally, twice per day for 12 weeks.

Placebo first

Participants randomized to this arm will receive placebo tablets, taking 3 tablets twice daily for 12 weeks, followed by a 2-week washout period, and then 12 weeks of colesevelam (3 tablets twice daily). Both the study drug and the placebo will be provided in identical-appearing bottles to maintain blinding.

Group Type PLACEBO_COMPARATOR

Colesevelam

Intervention Type DRUG

We will provide Colesevelam in 625-mg tablets. Participants will take 3 tablets orally, twice daily (total daily dose 3.75 g) for 12 weeks.

Placebo

Intervention Type DRUG

Matching inert oral tablets designed to mimic colesevelam 625 mg tablets in size, shape, and color, but containing no active pharmaceutical ingredient. Participants will take 3 orally, twice per day for 12 weeks.

Interventions

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Colesevelam

We will provide Colesevelam in 625-mg tablets. Participants will take 3 tablets orally, twice daily (total daily dose 3.75 g) for 12 weeks.

Intervention Type DRUG

Placebo

Matching inert oral tablets designed to mimic colesevelam 625 mg tablets in size, shape, and color, but containing no active pharmaceutical ingredient. Participants will take 3 orally, twice per day for 12 weeks.

Intervention Type DRUG

Other Intervention Names

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Welchol Inert oral tablets

Eligibility Criteria

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Inclusion Criteria

* Male firefighter
* California resident
* Age 18-64
* Full-time, active-duty (fire suppression and/or arson investigation) firefighter for the past 10 consecutive years
* English-speaking
* Access to a reliable internet connection
* Willing to attend 3 in-person study visits in the San Francisco Bay Area over about 6.5 months
* Willing to receive weekly text message reminders to complete online surveys
* Willing to complete a mail-based, at-home finger-prick blood test
* Willing to take 3 tablets (each tablet about the size of a multivitamin) orally twice daily for a total of 6 months
* Evaluated by study team to have an elevated risk of PFAS exposure

Exclusion Criteria

* Gastroparesis or other severe gastrointestinal motility disorders
* Bowel obstruction
* History of major gastrointestinal tract surgery
* Dysphagia or difficulty swallowing (due to tablet size)
* History of hypertriglyceridemia (triglycerides exceeding 500 mg/dL)
* History of hypertriglyceridemia-induced pancreatitis
* Type 1 or 2 diabetes
* History of fat-soluble vitamin deficiencies i.e., vitamins A, D, E, or K
* Phenylketonuria
* History of known bleeding/clotting disorders
* Medications or treatments that may impact the excretion of PFAS, such as activated charcoal, other bile acid sequestrants, chelation therapies, etc.
* More than one blood or plasma donation in the past 12 months and/or unalterable plans to donate blood or plasma during the study participation period
* Use of clomiphene, testosterone, human chorionic gonadotropin, anabolic steroids, anastrozole or any other substances that may impact testosterone levels in males
Minimum Eligible Age

18 Years

Maximum Eligible Age

64 Years

Eligible Sex

MALE

Accepts Healthy Volunteers

No

Sponsors

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University of California, San Francisco

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Ashley E Mason, PhD

Role: PRINCIPAL_INVESTIGATOR

University of California San Francisco, Osher Center for Integrative Health

Leena Pandya, ND

Role: PRINCIPAL_INVESTIGATOR

University of California San Francisco, Osher Center for Integrative Health

Sarah Fisher, MS

Role: STUDY_DIRECTOR

University of California San Francisco, Osher Center for Integrative Health

Locations

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UCSF Osher Center for Integrative Health

San Francisco, California, United States

Site Status

Countries

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United States

Central Contacts

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Ashley Mason, PhD

Role: CONTACT

Phone: 415-514-6820

Email: [email protected]

Leena Pandya, ND

Role: CONTACT

Phone: 415-502-1619

Email: [email protected]

References

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Johnson JD, Gibson SJ, Ober RE. Cholestyramine-enhanced fecal elimination of carbon-14 in rats after administration of ammonium [14C]perfluorooctanoate or potassium [14C]perfluorooctanesulfonate. Fundam Appl Toxicol. 1984 Dec;4(6):972-6. doi: 10.1016/0272-0590(84)90235-5.

Reference Type BACKGROUND
PMID: 6519377 (View on PubMed)

Mazumder NU, Hossain MT, Jahura FT, Girase A, Hall AS, Lu J, Ormond RB. Firefighters' exposure to per-and polyfluoroalkyl substances (PFAS) as an occupational hazard: A review. Front Mater. 2023;10:10.3389/fmats.2023.1143411. doi: 10.3389/fmats.2023.1143411. Epub 2023 Mar 23.

Reference Type BACKGROUND
PMID: 38074949 (View on PubMed)

Young AS, Sparer-Fine EH, Pickard HM, Sunderland EM, Peaslee GF, Allen JG. Per- and polyfluoroalkyl substances (PFAS) and total fluorine in fire station dust. J Expo Sci Environ Epidemiol. 2021 Sep;31(5):930-942. doi: 10.1038/s41370-021-00288-7. Epub 2021 Feb 5.

Reference Type BACKGROUND
PMID: 33542478 (View on PubMed)

Lucas K, Gaines LGT, Paris-Davila T, Nylander-French LA. Occupational exposure and serum levels of per- and polyfluoroalkyl substances (PFAS): A review. Am J Ind Med. 2023 May;66(5):379-392. doi: 10.1002/ajim.23454. Epub 2022 Dec 27.

Reference Type BACKGROUND
PMID: 36573587 (View on PubMed)

Moller JJ, Lyngberg AC, Hammer PEC, Flachs EM, Mortensen OS, Jensen TK, Jurgens G, Andersson A, Soja AMB, Lindhardt M. Substantial decrease of PFAS with anion exchange resin treatment - A clinical cross-over trial. Environ Int. 2024 Mar;185:108497. doi: 10.1016/j.envint.2024.108497. Epub 2024 Feb 13.

Reference Type BACKGROUND
PMID: 38367552 (View on PubMed)

Ducatman A, Luster M, Fletcher T. Perfluoroalkyl substance excretion: Effects of organic anion-inhibiting and resin-binding drugs in a community setting. Environ Toxicol Pharmacol. 2021 Jul;85:103650. doi: 10.1016/j.etap.2021.103650. Epub 2021 Apr 2.

Reference Type BACKGROUND
PMID: 33819618 (View on PubMed)

Seyyedsalehi MS, Boffetta P. Per- and Poly-fluoroalkyl Substances (PFAS) Exposure and Risk of Kidney, Liver, and Testicular Cancers: A Systematic Review and Meta-Analysis. Med Lav. 2023 Oct 24;114(5):e2023040. doi: 10.23749/mdl.v114i5.15065.

Reference Type BACKGROUND
PMID: 37878255 (View on PubMed)

Other Identifiers

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ENGINE-01

Identifier Type: -

Identifier Source: org_study_id