Medical Information Only. Always consult your healthcare provider before enrolling in any clinical trial.

NCT03591094 · ClinicalTrials.gov registry record · Phase 2

Study Assessing PTI-428 Safety, Tolerability, Pharmacokinetics and Effect in Subjects With Cystic Fibrosis

A Phase 2 study, sponsored by Proteostasis Therapeutics.

Completed
Registry status
Phase 2
Development phase
40
Enrollment target

NCT03591094: Completed Phase 2 study, sponsored by Proteostasis Therapeutics.

NCT03591094 is a Phase 2 study that has completed, run by Proteostasis Therapeutics. The registered enrollment target is 40 participants, below the 133-participant average among 30,622 other Phase 2 trials with a reported enrollment target (70% lower). According to ClinicalTrials.gov, the official US trial registry.

View on ClinicalTrials.gov ↗

View your shortlist →

The verdict

NCT03591094, a Phase 2 study, has completed, sponsored by Proteostasis Therapeutics.

COMPLETED
Registry status
Phase 2
Development phase
40 participants
Enrollment target

Study Summary

The study population is comprised of adult subjects with cystic fibrosis (CF) who are homozygous for the F508del mutation and are currently receiving background treatment with tezacaftor/ivacaftor for a minimum of 1 month prior to Day 1. The planned sample size is approximately 40 subjects. 20 subjects will be assigned to PTI-428 dose level 1 or placebo and 20 subjects will be assigned to PTI-428 dose level 2 or placebo. At each dose level, subjects will be randomized at a 3:1 randomization ratio. Subjects will receive once daily oral doses of PTI-428 or placebo for 28 days, while the subjects continue to receive background treatment with tezacaftor/ivacaftor per product label. The study drug administration period will be followed by a 14-day safety follow-up period.

Primary Outcome

Safety and tolerability will be assessed by adverse events (AEs), safety labs, electrocardiograms (ECGs), physical examinations and vital signs.

Interventions

  • DRUG Placebo
  • DRUG PTI-428

Trial Details

FieldValue
Enrollment Target 40 participants
Start Date 2018-08-21
Est. Completion 2019-02-18
Phase Phase 2
Proteostasis Therapeutics

5 total trials

What the finished NCT03591094 record still lists

NCT03591094 is an interventional study that assigns participants to a tested intervention. The registry caps enrollment at 40 participants, a relatively small participant target, below the 133-participant average among 30,622 other Phase 2 trials with a reported enrollment target (70% lower).

The record links to 0 conditions, and to 2 interventions - of which Placebo is the first listed.

NCT03591094 does not publish any study locations in the registry export this page uses.

Frequently Asked Questions

What is clinical trial NCT03591094 about?

NCT03591094 is a clinical study titled "Study Assessing PTI-428 Safety, Tolerability, Pharmacokinetics and Effect in Subjects With Cystic Fibrosis". The study population is comprised of adult subjects with cystic fibrosis (CF) who are homozygous for the F508del mutation and are currently receiving background treatment with tezacaftor/ivacaftor for a minimum of 1 month prior to Day 1. The planned sample size is approximately 40 subjects. 20 subje...

What is the current status of trial NCT03591094?

This trial is currently completed. It is a Phase 2 study. The enrollment target is 40 participants. The study started on 2018-08-21. Estimated completion is 2019-02-18.

What interventions are being tested in trial NCT03591094?

The interventions under investigation include: Placebo (DRUG), PTI-428 (DRUG).

Who is sponsoring clinical trial NCT03591094?

This trial is sponsored by Proteostasis Therapeutics, which has 5 total clinical trials registered on ClinicalTrials.gov.

How this trial's enrollment target compares

Where NCT03591094's enrollment target sits among peer trials

40 1362nd of 2000 higher than 542 of 2,000 other Phase 2 trials

participants (enrollment target), bucketed by value

Each bar is a band; taller bars hold more other Phase 2 trials. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.

Source ClinicalTrials.gov registry export · 2026-08-08

Nationwide trials with similar profiles

Cross-condition peers matched on enrollment target and registry start date, not the same-condition list above.

Similar enrollment target

  • NCT01306019 · 40 participants · Phase 1

    Lentiviral Gene Transfer for Treatment of Children Older Than Two Years of Age With X-Linked Severe Combined Immunodeficiency (XSCID)

  • NCT01608152 · 40 participants

    Development of a Video Game for the Improvement of Outcomes in Stem Cell Transplant Survivors

  • NCT01668082 · 40 participants · NA

    An Investigation of Brain Tumor Metabolism in Patients Undergoing Surgical Resection

  • NCT02015013 · 40 participants · Phase 2

    Hematopoietic Stem Cell Mobilization in Idiopathic CD4 Lymphocytopenia Patients and Healthy Controls for the Study of T Cell Maturation and Trafficking in Murine Models

Similar registry start date

  • NCT05962346 · started 2026-12 · NA

    Fetal Endoscopic Tracheal Occlusion for Congenital Diaphragmatic Hernia

  • NCT07125183 · started 2026-12 · Phase 2

    Study on Efficacy and Tolerability of Weekly Doxorubicin in Elderly Patients With Advanced or Metastatic Leiomyosarcoma

  • NCT07292298 · started 2026-11 · Phase 2

    Phase 2 Single-Arm Rectal Cancer Brachytherapy for Patients With Low-Lying Residual Adenocarcinoma After Total Neoadjuvant Therapy to Improve Organ Preservation Rates

  • NCT04263285 · started 2026-10 · NA

    Treatment of Depression Post-SCI

Source: ClinicalTrials.gov NCT03591094, the US trial registry maintained by the National Library of Medicine. NCT03591094 (small enrollment · none site footprint · completed) retrieved and formatted by PlainTrial, see methodology.