Recruiting

Phase 1

Phase 2

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

Sponsor:

UCLA

Code:

NCT07226440

Conditions

Toxicant Exposure

Firefighter

Occupational Exposure to Chemicals

Eligibility Criteria

Sex: Male

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Colesevelam

Placebo

Study Details

Brief summary:

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.

Conditions

Toxicant Exposure

Firefighter

Occupational Exposure to Chemicals

Study ID

NCT07226440

Start date

Mar 1, 2026

Status verified date

Apr, 2026

Completion date

Dec, 2028

Anticipated

Primary completion date

Dec, 2028

Anticipated

Eligibility Criteria

Sex: Male

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

Male firefighter, active or retired
California resident
Age 18 or older
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 (e.g., duration of firefighting service, prior NASEM-7 result greater than or equal to 10 ng/mL)

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.
Unalterable plans to donate blood or plasma during the study participation period

Study Design

Enrollment

50 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

active comparator: 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.

placebo comparator: 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.

Interventions

Colesevelam

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

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.

Primary outcome measure

Retention [ Time Frame: Enrollment to Week 27 ]
Adherence to study drug [ Time Frame: Enrollment to Week 27 ]
Adherence to placebo [ Time Frame: Enrollment to Week 27 ]
Acceptability [ Time Frame: Week 27 ]
Likability [ Time Frame: Week 27 ]

Central Contacts and Locations

Central contacts

Ashley Mason, PhD

415-514-6820 enginestudy@ucsf.edu

Leena Pandya, ND

415-502-1619 leena.pandya@ucsf.edu

Locations

UCSF Osher Center for Integrative Health

Recruiting

San Francisco, California, United States, 94115

Contacts

Leena Pandya, ND

enginestudy@ucsf.edu

Principal Investigator:

Ashley E Mason, PhD

More Information

Sponsor

University of California, San Francisco

Last update posted

Apr 24, 2026

Last verified

Apr, 2026

Keywords

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

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of California, San Francisco on 2026-04-24.