An Open-Label Drug-Drug Interaction Study of Telotristat Etiprate and Fexofenadine in Healthy Subjects

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the effects of steady-state telotristat ethyl on the pharmacokinetics (PK) of single-dose fexofenadine in healthy subjects.

Official Title
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A Phase 1, Open-label, Single-center, 2-period, Single Sequence Drug-drug Interaction Study to Evaluate the Effects of Multiple-dose Telotristat Etiprate on the Pharmacokinetics of Single-dose Fexofenadine, a Sensitive P Glycoprotein Substrate, in Healthy Male and Female Subjects

Conditions
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Drug Interactions

Intervention / Treatment
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* Drug: Fexofenadine
* Drug: Telotristat etiprate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adult subjects aged ≥18 to ≤55 years of age at screening Body mass index ≥18.0 to ≤32.0 kg/m^2 Acceptable vital signs at Screening: Systolic blood pressure = 90-140 mm Hg, Diastolic blood pressure = 50-90 mm Hg, Heart rate = 40-100 beats per minute Willingness to adhere to the restrictions outlined in the protocol Able to comprehend and sign the Informed Consent Form Exclusion Criteria: Presence of any clinically significant physical, laboratory, or ECG finding that may interfere with the study in the opinion of the Investigator Use of any medications, herbal tea, energy drink, herbal products, or supplements within 14 days of Day 1 Receipt of any investigational agent or study drug within 30 days or 5 half-lives prior to Screening Receipt of any protein- or antibody-based therapeutic agent within 3 months of Screening Prior exposure to telotristat etiprate Use of tobacco, smoking cessation products, or nicotine products within 3 months prior to Screening History of major surgery within 6 months prior to Screening History of any GI surgery that may induce malabsorption History of any serious adverse reaction or hypersensitivity to any component of fexofenadine History of renal disease, or significantly abnormal glomerular filtration rate (<90 mL/min as calculated using the Cockcroft-Gault equation) at Screening History of hepatic disease, or significantly abnormal liver function tests at Screening History of any clinically significant psychiatric, renal, hepatic, pancreatic, cardiovascular, neurological, endocrinologic, hematological, or GI abnormality History of any active infection within 14 days prior to first dosing History of alcohol or substance abuse within 2 years prior to Screening Positive hepatitis panel (including hepatitis B surface antigen and hepatitis C virus antibody) or positive human immunodeficiency virus antibody screens Concurrent conditions that could interfere with safety and/or tolerability measurements Donation or loss of >500 mL of blood or blood product within 3 months prior to Screening Women who are breastfeeding or are planning to become pregnant during the study Positive serum pregnancy test (females only) Positive urine screen for selected drugs of abuse and cotinine Consumption of alcohol within 48 hours prior to study start Consumption of caffeine- and/or xanthine-containing products within 72 hours of study start Consumption of grapefruit, Seville oranges, and grapefruit- or Seville orange-containing products within 72 hours prior to study start Unable or unwilling to communicate or cooperate with the Investigator for any reason Use of any drugs or substances that are known to be substrates, inducers, or inhibitors of CYP3A4 within 30 days prior to the first dose

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: All subjects<br>All subjects will receive a single oral dose of fexofenadine on Day 1 while fasting. Days 2 to 5 will be Washout days. On Day 6, subjects will begin a 5 day telotristat etiprate regimen. On Day 10 subjects will be given the morning telotristat etiprate dose concomitantly with a single dose of fexofenadine while fasting. | Drug: Fexofenadine<br>* All subjects will receive 180 mg fexofenadine<br>Drug: Telotristat etiprate<br>* All subjects will receive 500 mg (2 X 250 mg tablets) telotristat etiprate tablets three times daily<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fexofenadine plasma concentration in combination with steady state telotristat etiprate |  | Day 10 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of treatment emergent adverse events |  | 14 days |