Impact of Rifabutin on the Pharmacokinetics of Elexacaftor/Tezacaftor/Ivacaftor

NCT ID: NCT04840862

Last Updated: 2024-08-09

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

COMPLETED

Clinical Phase

PHASE4

Total Enrollment

6 participants

Study Classification

INTERVENTIONAL

Study Start Date

2022-05-09

Study Completion Date

2024-05-30

Brief Summary

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This is a prospective, single-center, fixed-sequence, nonrandomized, open-label study in healthy adults to investigate the impact of rifabutin on the pharmacokinetics of trikafta.

Detailed Description

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Trikafta (Elexacaftor \[ELX\], Tezacaftor \[TEZ\], Ivacaftor\[IVA\]) is contraindicated with concomitant use of strong inducers as co-administration of rifampin decreased the area-under-the concentration time curve (AUC) of IVA by 89%, creating a therapeutic challenge to the treatment of non-tuberculosis mycobacteria (NTM) infection in people with cystic fibrosis (CF). While rifabutin also induces CYP3A4 activity, its effects appear to be more moderate when compared with rifampin. Therefore, we hypothesize that rifabutin can be co-administered with an adjusted dose of ELX/TEZ/IVA in patients being treated for NTM pulmonary disease.

Conditions

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Drug Drug Interaction

Study Design

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Allocation Method

NA

Intervention Model

SINGLE_GROUP

A single group of subjects will receive a single dose of trikafta (orange tablet) in period 1. After washout period greater or equal to 2 days, subjects will receive 300 mg/d of rifabutin on day 1 through 17 and a single dose of trikafta (orange tablet) on day 15 in period 2.
Primary Study Purpose

OTHER

Blinding Strategy

NONE

Study Groups

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rifabutin

Rifabutin PO \[two 150mg capsules\] ; Trikafta PO \[one orange tablet containing ELX 100mg, TEZ 50mg, and IVA 75mg\]

Group Type EXPERIMENTAL

Trikafta [orange tablet containing ELX 100mg, TEZ 50mg, and IVA 75mg]

Intervention Type DRUG

Subjects will receive a single dose of trikafta (orange tablet) on day 1 of period 1 and on day 15 of period 2.

Rifabutin 300mg

Intervention Type DRUG

After washout period greater or equal to 2 days, subjects will receive 300 mg/d of rifabutin on days 1 through 17 of period 2.

Interventions

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Trikafta [orange tablet containing ELX 100mg, TEZ 50mg, and IVA 75mg]

Subjects will receive a single dose of trikafta (orange tablet) on day 1 of period 1 and on day 15 of period 2.

Intervention Type DRUG

Rifabutin 300mg

After washout period greater or equal to 2 days, subjects will receive 300 mg/d of rifabutin on days 1 through 17 of period 2.

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Able and willing to sign informed consent prior to any study-related activities.
* Male or female participants between 18 and 65 years of age inclusive.
* Healthy subjects as determined by no clinically significant deviation from normal in medical history, physical examination findings, and clinical laboratory test results
* Body mass index (BMI) of 17.5 to 30.5 kg/m2, inclusive; and a total body weight \>50kg (110 lbs).
* Willing to stop using any herbal or natural health products for 2 weeks prior to and during the study including: Grapefruit, grapefruit juice, St. John's Wort.
* Participant must use a reliable method of birth control while they are participating in the study; for instance an intrauterine device (IUD), condom with spermicidal gel or foam, diaphragm with spermicidal gel or foam, vasectomy, tubal ligation, hysterectomy or abstinence or female must be post-menopausal for at least one year.

Exclusion Criteria

* Female subjects of childbearing potential with positive urine pregnancy test at screening.
* Female subjects who are breastfeeding.
* Use of CYP3A modulators (e.g., rifampicin, phenobarbital, carbamazepine, phenytoin, azole drugs, telithromycin, clarithromycin, erythromycin)
* Any significant acute or chronic medical illness that might confound the results of the study or pose an additional risk in administrating study drugs to the subject, as determined by the investigator.
* Any condition that could affect drug absorption (eg, gastrectomy, pancreatitis).
* Any major surgery within 4 weeks of study drug administration.
* Blood donation of approximately 1 pint (500 mL) within 56 days before study drug administration.
* Known hypersensitivity to rifamycins
* Patients with hepatic impairment (Child-Pugh Class B or C) and/or with history of hepatobiliary disease or liver function test elevations.
* Renal insufficiency (eGFR \< 60 mL/min)
* History of uveitis and/or current eye or vision problems with the exception of corrective lenses.
* Contact lens use during study drug administration.
Minimum Eligible Age

18 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University of Southern California

OTHER

Sponsor Role lead

Responsible Party

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Paul Beringer

Professor of Clinical Pharmacy

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Adupa P Rao, M.D.

Role: STUDY_DIRECTOR

Keck Medicine of USC

Locations

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University of Southern California

Los Angeles, California, United States

Site Status

Countries

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United States

References

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Sanders M, Hong E, Chung PS, Rao AP, Cohn W, Beringer P. Evaluation of the drug interaction between rifabutin and elexacaftor/tezacaftor/ivacaftor (ETI). J Cyst Fibros. 2025 Sep 15:S1569-1993(25)01581-4. doi: 10.1016/j.jcf.2025.09.002. Online ahead of print.

Reference Type DERIVED
PMID: 40957819 (View on PubMed)

Other Identifiers

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HS-21-00315

Identifier Type: -

Identifier Source: org_study_id

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