NCT05343364

A Study to Evaluate the Pharmacokinetics, Pharmacodynamics and Safety of Vonoprazan in Adolescents With Symptomatic Gastroesophageal Reflux Disease

Completed Phase 1 Results posted Last updated 23 April 2025

What this trial tests

Phase 1 trial testing Vonoprazan in Gastroesophageal Reflux in 24 participants. Completed in 13 June 2023.

Timeline

9 May 2022

Primary endpoint
30 May 2023

13 June 2023

Quick facts

Lead sponsor	Phathom Pharmaceuticals, Inc.
Phase	Phase 1
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	none
Primary purpose	basic science
Enrollment	24
Start date	9 May 2022
Primary completion	30 May 2023
Estimated completion	13 June 2023
Sites	10 locations across United States

Drugs / interventions tested

• Vonoprazan — full drug profile →

Conditions studied

• Gastroesophageal Reflux — all drugs for Gastroesophageal Reflux →

Sponsor

Phathom Pharmaceuticals, Inc. — full company profile →

Who can join

Adults 12 to 17, any sex, with Gastroesophageal Reflux. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Maximum Observed Drug Concentration at Steady State (Cmax-ss) of Vonoprazan Primary · Blood samples were collected predose, once between 0.5 and 2 hours, and once between 2.5 and 4 hours post-dose on Days 7 and 14

Plasma pharmacokinetic (PK) parameters were estimated using a non-linear mixed effects model and were determined from the concentration-time data for all evaluable participants. Actual sampling times, rather than scheduled or nominal sampling times, were used in all computations using sampling time.

Group	Value	95% CI
Vonoprazan 10 mg QD	13.4	6.57 – 25.6
Vonoprazan 20 mg QD	26.7	13.1 – 49.1

Area Under the Plasma Concentration-time Curve During the Dosing Interval τ (AUCτ) of Vonoprazan Primary · Blood samples were collected predose, once between 0.5 and 2 hours, and once between 2.5 and 4 hours post-dose on Days 7 and 14

PK parameters were estimated using a non-linear mixed effects model and were determined from the concentration-time data for all evaluable participants. Actual sampling times, rather than scheduled or nominal sampling times, were used in all computations using sampling time.

Group	Value	95% CI
Vonoprazan 10 mg QD	94.6	56.0 – 165
Vonoprazan 20 mg QD	208	95.6 – 381

Apparent Oral Clearance (CL/F) of Vonoprazan Primary · Blood samples were collected predose, once between 0.5 and 2 hours, and once between 2.5 and 4 hours post-dose on Days 7 and 14

PK parameters were estimated using a non-linear mixed effects model and were determined from the concentration-time data for all evaluable participants. Actual sampling times, rather than scheduled or nominal sampling times, were used in all computations using sampling time.

Group	Value	95% CI
Vonoprazan 10 mg QD	124	60.5 – 179
Vonoprazan 20 mg QD	117	52.5 – 209

Apparent Central Volume of Distribution (Vc/F) of Vonoprazan Primary · Blood samples were collected predose, once between 0.5 and 2 hours, and once between 2.5 and 4 hours post-dose on Days 7 and 14

PK parameters were estimated using a non-linear mixed effects model and were determined from the concentration-time data for all evaluable participants. Actual sampling times, rather than scheduled or nominal sampling times, were used in all computations using sampling time.

Group	Value	95% CI
Vonoprazan 10 mg QD	686	314 – 1280
Vonoprazan 20 mg QD	704	311 – 1110

Number of Participants Experiencing Adverse Events (AEs) Secondary · Up to Day 28

AE: any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a drug. Treatment-emergent adverse event (TEAE): any AE that occurred after the first dose of study drug or at baseline that worsens in either intensity or frequency after the first dose of study drug. Serious AE: any AE for which the following occurred: death, was life threatening, hopsitalization or prolongation of hospitalization, persistent or significant disability/incapacity, a congenital anomaly/birth defect, or the AE was deemed an important medical event. Related AE: any AE that follo

Any TEAEs

Group	Value	95% CI
Vonoprazan 10 mg QD	4
Vonoprazan 20 mg QD	1

Any Serious TEAEs

Group	Value	95% CI
Vonoprazan 10 mg QD	0
Vonoprazan 20 mg QD	0

Any Study Drug-related TEAEs

Group	Value	95% CI
Vonoprazan 10 mg QD	0
Vonoprazan 20 mg QD	0

Any Serious Study Drug-related TEAEs

Group	Value	95% CI
Vonoprazan 10 mg QD	0
Vonoprazan 20 mg QD	0

Any TEAE Leading to Treatment Discontinuation

Group	Value	95% CI
Vonoprazan 10 mg QD	0
Vonoprazan 20 mg QD	0

Any TEAE Leading to Study Discontinuation

Group	Value	95% CI
Vonoprazan 10 mg QD	0
Vonoprazan 20 mg QD	0

Any AEs Leading to Death

Group	Value	95% CI
Vonoprazan 10 mg QD	0
Vonoprazan 20 mg QD	0

Adverse events — posted to ClinicalTrials.gov

Time frame: Up to Day 28. Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Vonoprazan 10 mg QD

Serious: 0/12 (0%)

Deaths: 0/12

Vonoprazan 20 mg QD

Serious: 0/12 (0%)

Deaths: 0/12

Other adverse events (6 terms — click to expand)

Reaction	System	Vonoprazan 10 mg QD	Vonoprazan 20 mg QD
Cellulitis	Infections and infestations	—	—
Enterocolitis infectious	Infections and infestations	—	—
Gastrooesophageal reflux disease	Gastrointestinal disorders	—	—
Back pain	Musculoskeletal and connective tissue disorders	—	—
Migraine	Nervous system disorders	—	—
Anxiety	Psychiatric disorders	—	—

Data from ClinicalTrials.gov NCT05343364 adverse events section.

Sponsor's own description

The primary objective of this study is to evaluate the pharmacokinetic profile of vonoprazan in adolescent participants with symptomatic gastroesophageal reflux disease (GERD).

Publications & conference data

2 peer-reviewed publications reference this trial (live from Europe PMC):

1. The pharmacokinetics and safety of vonoprazan in adolescents and children with gastroesophageal reflux disease.
   Mulford DJ, Gremse DA, Chang YM, Leifke E, et al · · 2026 · PMID 41721637 · DOI 10.1002/jpn3.70368
2. Abstract
   · 2024