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

NCT06041919 | Terminated Phase 2 Results DMC

• 1 other identifier: RESP30X-EBA
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

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

Conditions

Rifampicin Susceptible Pulmonary Tuberculosis

Keywords

Early Bactericidal Activity (EBA)

Outcome Measures

Primary Outcomes (1)

• Early Bactericidal Activity (EBA) of Inhaled RESP301 Measured as Time to Positivity (TTP)

  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 Outcomes (2)

• Early Bactericidal Activity (EBA) of Inhaled RESP301 Measured as Colony Forming Units (CFU)

  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)

  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

Study Arms (5)

1 (Active)

EXPERIMENTAL

Inhaled RESP301 6ml via nebulisation three times daily

Drug: RESP301

2 (Control)

ACTIVE COMPARATOR

HRZE taken orally once daily

Drug: HRZE

3 (Active)

EXPERIMENTAL

Inhaled RESP301 6 ml via nebulisation once daily

Drug: RESP301

4 (Active)

EXPERIMENTAL

Inhaled RESP301 6 ml via nebulisation twice daily

Drug: RESP301

5 (Active)

EXPERIMENTAL

Inhaled RESP301 6 ml via nebulisation three times daily plus HRZE taken orally once dialy

Drug: RESP301; Drug: HRZE

Interventions

RESP301 DRUG

Nitric Oxide agent

1 (Active); 3 (Active); 4 (Active); 5 (Active)

HRZE DRUG

isoniazid 75 mg (H), rifampicin 150 mg (R), pyrazinamide 400 mg (Z), ethambutol 275 mg (E)

2 (Control); 5 (Active)

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Thirty Respiratory Limited: lead

Study Sites (1)

TASK Clinical Research Centre

Cape Town, Bellville, 7531, South Africa

Location

Results Point of Contact

• Title: Inva Hoti
• Organization: Thirty Respiratory Ltd

Inva.Hoti@30.technology

+44 (0) 1235 431200

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Microbiology staff will be blinded to treatment allocation.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Parallel control arm, randomised clinical study in two sequential stages, with no stratification

Study Record Dates

• First Submitted: August 21, 2023
• First Posted: September 18, 2023
• Study Start: September 27, 2023
• Primary Completion: July 24, 2024
• Study Completion: March 6, 2025
• Last Updated: July 15, 2025
• Results First Posted: July 15, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will not share

Locations

ZA (1)