A Healthy Volunteer Study Evaluating the the Safety, Tolerability, and Pharmacokinetics of RT234

September 16, 2025 updated by: Respira Therapeutics, Inc.

A Phase 1, Two-Part, Single-Center, Open-Label, Randomized, Cross-Over, Single Ascending Doses (SAD), Followed by a Multiple Ascending Doses (MAD) Safety and Pharmacokinetic Study of RT234 in Healthy Subjects

The objective of this two part study was to demonstrate safety, tolerability, and pharmacokinetics of RT234 in healthy volunteers.

This study is also known as Vardenafil Inhaled for Pulmonary Arterial Hypertension PRN Phase 1 (VIPAH-PRN 1) study

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This study was designed to evaluate safety and tolerability and to characterize the PK profiles of single and repeated doses of inhaled vardenafil as RT234. In addition, vardenafil PK after single 0.6 mg doses of RT234 was compared to that following administration of a single 20 mg dose of oral vardenafil tablets.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
31

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Australia
    • Victoria
      • Prahran, Victoria, Australia, 3004
        • Nucleus Network, Burnet Institute

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 41 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Healthy male or female, 18 to 45 years of age (inclusive at time of informed consent)
  2. Normal heart, lung, kidney, and liver function based on physical examination
  3. Systolic blood pressure of 100-145 mmHg, diastolic blood pressure of 50-90 mmHg, and a resting heart rate of 40-100 bpm at Screening
  4. A body mass index (BMI) of ≤18 to ≥30 kg/m2 at Screening
  5. Must be a non-smoker or ex-smoker with less than a 5-pack year history of smoking (including the use of electronic cigarettes) and have ceased smoking ≥1 year prior to Screening; or a social smoker (defined as less than 10 cigarettes in the previous 12 months)

Exclusion Criteria:

  1. Has serum transaminase (i.e., alanine aminotransferase [ALT], aspartate aminotransferase [AST], or gamma-glutamyl transferase [GGT]) levels greater than three times the upper level of normal
  2. Abnormal orthostatic vital signs (at screening) defined as a decrease of ≥20 mmHg in systolic blood pressure and/or a decrease of ≥10 mmHg in diastolic blood pressure and/or >25 bpm increase in heart rate within 3 minutes of standing, or with symptoms of light-headedness, dizziness, or fainting upon standing.
  3. History of hypotension including fainting, syncope, orthostatic hypotension, and/or vasovagal reactions
  4. History of retinitis pigmentosa
  5. Vision loss due to non-arteritic anterior ischemic optic neuropathy (NAION) or other optic perfusion impairment
  6. History of priapism or anatomical deformation of the penis
  7. History of sudden sensorineural hearing loss (SSHL), need for hearing aids, and/or other documented hearing loss
  8. A corrected QT interval using Fridericia's formula (QTcF) >450 msec

  9. Has evidence of significant obstructive lung disease on spirometry. Subjects with any of the following criteria will be excluded:

    1. FEV1 <60% (predicted) (pre-bronchodilators); or
    2. FEV1/FVC <65% (pre-bronchodilators)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: RT234 0.2 mg, Single Ascending Dose (SAD)
Part 1, SAD Cohort 1A
Combination product: Drug: RT234 - vardenafil inhalation powder; Device: RS01 dry powder inhaler (RS01 DPI)
RT234 is a drug/device combination product composed of vardenafil hydrochloride as the drug constituent and will utilize RS01 DPI device.
Other Names:
  • vardenafil inhalation powder
Experimental: RT234 0.6 mg followed by oral vardenafil 20mg on day 3, SAD
Part 1, SAD Cohort 2A1
Combination product: Drug: RT234 - vardenafil inhalation powder; Device: RS01 dry powder inhaler (RS01 DPI)
RT234 is a drug/device combination product composed of vardenafil hydrochloride as the drug constituent and will utilize RS01 DPI device.
Other Names:
  • vardenafil inhalation powder
Drug: Vardenafil Oral Tablet
20 mg oral vardenafil tablet.
Other Names:
  • Levitra
Experimental: Oral vardenafil 20mg followed by RT234 0.6 mg on day 3, SAD
Part 1, SAD Cohort 2A2
Combination product: Drug: RT234 - vardenafil inhalation powder; Device: RS01 dry powder inhaler (RS01 DPI)
RT234 is a drug/device combination product composed of vardenafil hydrochloride as the drug constituent and will utilize RS01 DPI device.
Other Names:
  • vardenafil inhalation powder
Drug: Vardenafil Oral Tablet
20 mg oral vardenafil tablet.
Other Names:
  • Levitra
Experimental: RT234 1.2 mg, SAD
Part 1, SAD Cohort 3A
Combination product: Drug: RT234 - vardenafil inhalation powder; Device: RS01 dry powder inhaler (RS01 DPI)
RT234 is a drug/device combination product composed of vardenafil hydrochloride as the drug constituent and will utilize RS01 DPI device.
Other Names:
  • vardenafil inhalation powder
Experimental: RT234 2.4 mg, SAD
Part 1, SAD Cohort 4A
Combination product: Drug: RT234 - vardenafil inhalation powder; Device: RS01 dry powder inhaler (RS01 DPI)
RT234 is a drug/device combination product composed of vardenafil hydrochloride as the drug constituent and will utilize RS01 DPI device.
Other Names:
  • vardenafil inhalation powder
Experimental: RT234 2.4 mg, Multiple Ascending Dose (MAD)
Part 2, MAD Cohort 1B
Combination product: Drug: RT234 - vardenafil inhalation powder; Device: RS01 dry powder inhaler (RS01 DPI)
RT234 is a drug/device combination product composed of vardenafil hydrochloride as the drug constituent and will utilize RS01 DPI device.
Other Names:
  • vardenafil inhalation powder

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Number of participants with treatment related adverse events as assessed by CTCAE v5.0
Time Frame: Up to to 10 days
Adverse events reported by participants and those observed by the investigator in relation to laboratory tests, vital signs, ECGs, medications used to treat adverse events, and physical examinations were analyzed.
Up to to 10 days

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Peak plasma concentration (Cmax)
Time Frame: Up to 10 days
Cmax was measured for 4 single doses of oral vardenafil.
Up to 10 days
Time to reach maximum concentration (Tmax)
Time Frame: Up to 10 days
Tmax was measured for 4 single doses of oral vardenafil.
Up to 10 days
Area under the curve (AUC)
Time Frame: Up to 10 days
AUC was measured for 4 single doses of RT234
Up to 10 days
Half life (t1/2)
Time Frame: Up to 10 days
t1/2 was measured for 4 single doses of RT234
Up to 10 days
Terminal elimination rate constant (Kel)
Time Frame: Up to 10 days
Kel was measured for 4 single doses of RT234
Up to 10 days
Total body clearance (CL/F)
Time Frame: Up to 10 days
CL/F was measured for 4 single doses of RT234
Up to 10 days
Total volume of distribution at the terminal phase
Time Frame: Up to 10 days
measured for 4 single doses of RT234
Up to 10 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Respira Therapeutics, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Donna Jarlenski, MS, Respira Therapeutics

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 31, 2018

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 4, 2019

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 4, 2019

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 4, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 2, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 5, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 22, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 16, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • RT234-CL101
  • ACTRN12618001077257 (Registry Identifier: Australian New Zealand Clinical Trials Registry (ANZCTR))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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