Evaluating the Early Bactericidal Activity, Safety and Tolerability of Nebulised RESP301 in Adults With Tuberculosis

June 25, 2025 updated by: Thirty Respiratory Limited

A Phase 2 Study to Evaluate the Early Bactericidal Activity, Safety and Tolerability of Nebulised RESP301 in Adults With Newly Diagnosed, Rifampicin Susceptible Pulmonary Tuberculosis

A Phase 2, Single-Centre, Open-Label, Parallel Control Arm, Randomised Clinical Study to Evaluate the Early Bactericidal Activity (EBA), Safety and Tolerability of Nebulised RESP301 in Adults with Newly Diagnosed, Rifampicin Susceptible Pulmonary Tuberculosis

Study Overview

Status

Status

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

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

A total of approximately 15 participants will be recruited per treatment arm (total of approximately 75 participants in the study). Control arm participants will be split across sequential stages stages 1 and 2, with no stratification.

Stage 1: To determine the EBA of

  • Treatment Arm 1 (Active; n = 15) - inhaled RESP301 6 ml dosed via nebulisation administered three times daily over 14 days
  • Treatment Arm 2 (Control; n= 5) - HRZE taken orally once daily

On completion of Stage 1, recruitment will be paused and an interim analysis performed to determine whether the study should proceed to Stage 2.

Stage 2: To determine the EBA of

  • Treatment Arm 2 (Control; n= 10) - HRZE taken orally once daily
  • Treatment Arm 3 (Active; n = 15) - inhaled RESP301 6 ml dosed via nebulisation administered once daily over 14 days
  • Treatment Arm 4 (Active; n = 15) - inhaled RESP301 6 ml dosed via nebulisation administered twice daily over 14 days
  • Treatment Arm 5 (Active; n = 15) - inhaled RESP301 6 ml dosed via nebulisation administered three times daily in combination with HRZE taken orally once daily over 14 days

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.
20

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 2

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • South Africa
    • Bellville
      • Cape Town, Bellville, South Africa, 7531
        • TASK Clinical Research Centre

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Provide written, informed consent prior to all study-related procedures and agree to undergo all study procedures
  • Body weight (in light clothing and with no shoes) between 40 and 90 kg, inclusive
  • Newly diagnosed pulmonary TB
  • Rifampicin susceptible pulmonary TB as determined by molecular testing
  • Ability to produce an adequate volume of sputum as estimated from a pre-treatment overnight sputum collection sample (estimated 10 ml or more)
  • Spirometry performed during screening with a FEV1 of ≥ 40%
  • Be of non-childbearing potential or willing to use effective methods of contraception

Exclusion Criteria:

  • HIV positive AND CD4 < 350 cells/mm3 OR are receiving antiviral therapy (ART)
  • Methaemoglobin saturation (SpMet) >3%
  • Female participant who is pregnant or breast-feeding
  • Participants planning to conceive a child within the anticipated period of study participation and for at least 90 days after the last dose of IMP in the study
  • Participation in other clinical studies with investigational agents within 8 weeks prior to screening
  • Treatment received for this episode of TB with any drug active against M.tb
  • Treatment with immunosuppressive medications such as TNF-alpha inhibitors within 2 weeks prior to screening, or systemic corticosteroids for more than 7 days within 2 weeks prior to screening.
  • Treatment with nitric oxide and other nitric oxide donor agents, phosphodiesterase inhibitors and lung surfactant drugs, within 30 days prior to screening

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: Single

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: 1 (Active)
Inhaled RESP301 6ml via nebulisation three times daily
Drug: RESP301
Nitric Oxide agent
Active Comparator: 2 (Control)
HRZE taken orally once daily
Drug: HRZE
isoniazid 75 mg (H), rifampicin 150 mg (R), pyrazinamide 400 mg (Z), ethambutol 275 mg (E)
Experimental: 3 (Active)
Inhaled RESP301 6 ml via nebulisation once daily
Drug: RESP301
Nitric Oxide agent
Experimental: 4 (Active)
Inhaled RESP301 6 ml via nebulisation twice daily
Drug: RESP301
Nitric Oxide agent
Experimental: 5 (Active)
Inhaled RESP301 6 ml via nebulisation three times daily plus HRZE taken orally once dialy
Drug: RESP301
Nitric Oxide agent
Drug: HRZE
isoniazid 75 mg (H), rifampicin 150 mg (R), pyrazinamide 400 mg (Z), ethambutol 275 mg (E)

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
Early Bactericidal Activity (EBA) of Inhaled RESP301 Measured as Time to Positivity (TTP)
Time Frame: 0-2, 0-7, 0-14, 0-15 and 14-15 days
Overnight sputum collection from which viable mycobacteria in the sample is quantified as TTP Observed EBA for 0-2, 0-7, 0-14, 0-15 and 14-15 days in TTP (hours) for treatment in each of the treatment groups
0-2, 0-7, 0-14, 0-15 and 14-15 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
Early Bactericidal Activity (EBA) of Inhaled RESP301 Measured as Colony Forming Units (CFU)
Time Frame: 0-2, 0-7, 0-14, 0-15 and 14-15 days
Overnight sputum collection from which viable mycobacteria in the sample is quantified as CFU Observed EBA for 0-2, 0-7, 0-14, 0-15 and 14-15 days in CFU (Log10 CFU/mL) for treatment in each of the treatment groups
0-2, 0-7, 0-14, 0-15 and 14-15 days
Safety and Tolerability of Inhaled RESP301 Measured as Number of Treatment Emergent Adverse Events (TEAEs)
Time Frame: Stage 1: Dosing period 14 days + Follow-up period 14 days. Stage 2: Participants did not enter the treatment phase due to early study termination
Incidence of Treatment Emergent Adverse Events (TEAEs) will be presented by severity, drug relatedness, seriousness, leading to early withdrawal and leading to death.
Stage 1: Dosing period 14 days + Follow-up period 14 days. Stage 2: Participants did not enter the treatment phase due to early study termination

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.
Thirty Respiratory Limited

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.
September 27, 2023

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.
July 24, 2024

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.
March 6, 2025

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).
August 21, 2023

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.
September 11, 2023

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.
September 18, 2023

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.
July 15, 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.
June 25, 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.
June 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.
  • RESP30X-EBA

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

IPD is confidential until the CSR is published

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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