A Study to Evaluate Vonoprazan Concentrations in Breast Milk of Healthy Lactating Women Receiving Vonoprazan 20 mg Once Daily or Vonoprazan 20 mg Twice Daily

Phase 1

Completed

Conditions: Erosive Esophagitis
Heartburn
Symptomatic Nonerosive Gasroesophageal Reflux Disease
Helicobacter Pylori Infection

Interventions: Drug: Vonoprazan

Registration Number: NCT06391177

Lead Sponsor: Phathom Pharmaceuticals, Inc.

Brief Summary: The primary objective is to determine the pharmacokinetics (PK) of vonoprazan in breast milk of healthy lactating women who have received vonoprazan administered once daily or vonoprazan 20 mg administered twice daily for 4 consecutive days.

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: Female

Target Recruitment: 15

Inclusion Criteria

The participant is a healthy lactating woman at least 18 years of age at the time of signing the informed consent form (ICF).
The participant has delivered a normal term infant (at least 37 weeks gestation) and has been breastfeeding or actively pumping breast milk for at least 4 weeks postpartum prior to the first dose.
The participant is willing to not breastfeed or otherwise use her breast milk during administration of vonoprazan and until at least 5 days after the last dose of the study drug.
The participant has confirmed that her breastfed infant is able to feed from a bottle.
The participant agrees to collect all breast milk from pre-dose to 24 hours after the morning dose administration on Day 4, using an electric pump.
The participant is considered by the investigator to be in good general health as determined by medical history, clinical laboratory test results, vital sign measurements, 12-lead ECG results, and physical examination findings at Screening.
Participants of childbearing potential must use an acceptable method of birth control (ie, diaphragm with spermicide, intrauterine device, condom with foam or vaginal spermicide, oral contraceptives, or abstinence) or be surgically sterile (ie, hysterectomy, bilateral tubal ligation, or bilateral oophorectomy). All participants must have a negative pregnancy test at Screening and before the first dose of study drug (Baseline).
The participant agrees to comply with all protocol requirements.
The participant is able to provide written informed consent.

Exclusion Criteria

The participant has a positive pregnancy test at Screening or Baseline, is planning to become pregnant before, during, or within 4 weeks after participating in this study, or intends to donate ova during this time period, or is of childbearing potential and not using an effective contraceptive method.
The participant has a history of breast implants, breast augmentation, or breast reduction surgery that significantly impacts breastfeeding or collection of milk from one or both breasts.
The participant has signs or symptoms of mastitis or other condition that would prevent the collection of milk from one or both breasts.
The participant has undergone prior esophageal and/or gastrointestinal surgeries that may affect study drug absorption.
The participant has undergone surgery (other than cesarean section) within 30 days before the first dose of study drug.
The participant has a positive test result for hepatitis B surface antigen, hepatitis C virus antibody, or human immunodeficiency virus types 1 or 2 antibodies at Screening.
The participant has any other clinically significant findings on physical examination, clinical laboratory abnormalities, or ECG results that preclude participation in the study, as deemed by the investigator.
The participant has used any prescription (excluding hormonal birth control) and/or over-the-counter medications (including cytochrome P450 3A4 inducers), including herbal or nutritional supplements, within 14 days before the first dose of study drug, and/or is expected to require any such medication during the course of the study until end of the Treatment Period. Use of multivitamins and acetaminophen (up to 2 g per day) is permissible.
The participant has consumed grapefruit and/or grapefruit juice, Seville orange, or Seville orange-containing products (eg, marmalade) within 7 days before the first dose of study drug and/or is expected to be unable to abstain through the study.
The participant is a smoker or has used nicotine or nicotine-containing products (eg, snuff, nicotine patch, nicotine chewing gum, mock cigarettes, or inhalers) within 6 months before the first dose of study drug.
The participant has a history of alcohol abuse or drug dependency within 12 months before the first dose of study drug.
The participant has a positive test result for drugs of abuse, alcohol, or cotinine (indicating active current smoking) at Screening, Baseline, or Day 4 (Check-in).
The participant is involved in strenuous activity or contact sports within 24 hours before the first dose of study drug and during the study.
The participant has a history of relevant drug and/or food allergies (ie, any significant food allergy that could preclude a standard diet in the clinical research unit).
The participant has received study drug in another investigational study (including vonoprazan) within 30 days prior to start of the Screening Period.
The participant has a history of hypersensitivity or allergies to vonoprazan or any of its formulation excipients (D-mannitol, microcrystalline cellulose, hydroxypropyl cellulose, fumaric acid, ascorbic acid, croscarmellose sodium, magnesium stearate, hypromellose, polyethylene glycol 8000, titanium dioxide, or ferric oxide red).
In the opinion of the investigator, the participant is not suitable for entry into the study.

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Vonoprazan 20 mg Once Daily	Vonoprazan	Participants will be administered once-daily doses of vonoprazan 20 mg for 4 consecutive days (Days 1 through 4).
Vonoprazan 20 mg Twice Daily	Vonoprazan	Participants will be administered twice-daily doses of vonoprazan 20 mg for 4 consecutive days (Days 1 through 4).

Primary Outcome Measures

Name	Time	Method
Area Under Drug Concentration-time Curve From Time 0 to 24 Hours (AUC0-24) Following the Morning Dose of Vonoprazan in Breast Milk	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	AUC from time 0 to 24 hours post-dose, calculated as: the sum of the product of the concentration of the interval and the width of the interval.
Maximum Drug Concentration (Cmax) of Vonoprazan in Breast Milk	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	Maximum observed concentration after dosing.
Minimum Drug Concentration (Cmin) of Vonoprazan in Breast Milk	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	Minimum observed concentration after dosing.
Average Drug Concentration (Cavg) of Vonoprazan in Breast Milk	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	Average concentration, calculated as: AUC0-24/tau (tau=the difference between the end time of the last interval and dosing time).
Time to Cmax (Tmax) of Vonoprazan in Breast Milk	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	Time to maximum observed concentration (actual midpoint of the interval in which Cmax was observed).

Secondary Outcome Measures

Name	Time	Method
Total Amount of Vonoprazan Excreted in Breast Milk	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	Total amount of drug excreted in breast milk over 24 hours; calculated as the sum of drug concentration × expressed milk volume in each collection interval over 24-hour period.
Percentage of Vonoprazan Excreted in Breast Milk Relative to the Total Dose Received	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	Total amount of drug excreted over 24 hours relative to total dose administered; calculated as the sum of (total amount of drug excreted in each collection interval / total dose received over 24-hour period) \* 100.
Estimated Infant Daily Dose of Vonoprazan	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	Estimated weight adjusted daily dose consumed by the infant through breast milk; calculated as total amount of drug excreted over 24-hour period / weight of infant. Calculation used the nominal infant weight of 6.0 kg which is the approximate 50th percentile for a 3-month old infant.
Estimated Relative Infant Dose to the Total Maternal Dose Received of Vonoprazan	Pre-dose on Day 4, and at regularly scheduled intervals through 24 hours after the morning dosing (0-4 hours, 4-8 hours, 8-12 hours, 12-18 hours, and 18-24 hours).	Percentage of daily infant dose relative to the daily maternal dose; calculated as (daily infant dose / daily maternal dose) \* 100.