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Updated May 2026 · ClinicalTrials.gov

RECRUITINGPhase 2INTERVENTIONAL

High vs. Standard Dose Rifampicin for Effusive Tuberculous Pericarditis

IMPI-3 - A Randomized Controlled Trial of High vs. Standard Dose Rifampicin for Effusive Tuberculous Pericarditis

High vs. Standard Dose Rifampicin for Effusive Tuberculous Pericarditis (NCT04521803) is a Phase 2 interventional studying Tuberculous Pericarditis and HIV Status, sponsored by University of Cape Town. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

Important: This information is not medical advice. Talk to your doctor about whether a clinical trial is right for you.

About This Trial

The investigators hypothesise that high dose RIF (RIF35) will increase pericardial fluid RIF exposure and so enhance mycobacterial clearance, compared to standard of care dosing (RIF10). This Phase 2b randomized, placebo-controlled, double-blinded trial will evaluate the efficacy and safety of RIF 35mg/kg compared 10mg/kg, added to standard first-line ATT, for the treatment of PCTB.

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Tuberculous Pericarditis and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 60 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Tuberculous Pericarditis subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: 1. Aged \>18 years 2. Suspected PCTB with confirmed pericardial effusion on echocardiography (i.e., echo free space of ≥1 cm anterior to the right ventricle in diastole) 3. Consent to study participation including testing for HIV-1 (if HIV status is unknown) 4. Microbiologically detected Mtb in PCF or diagnosis of probable PCTB. Probable PCTB (in the absence of a positive pericardial fluid culture) will be defined as per Mayosi et al.4: 1. Evidence of pericarditis with microbiologic confirmation of Mtb- infection elsewhere in the body and/or 2. Exudative, lymphocyte predominant effusion with elevated adenosine deaminase (≥35 U/L) 5. Participant will undergo pericardiocentesis (as per clinical indication) 6. Within 5 days of ATT initiation Who Should NOT Join This Trial: 1. Glomerular filtration rate \<30ml/min or renal failure requiring dialysis 2. Rifampin-resistant TB 3. Severe concurrent opportunistic infection 4. Contraindication to placement of intra-pericardial catheter 5. Failed pericardiocentesis procedure and/or failure of placement of intra-pericardial catheter 6. Any disease or condition in which the use of the standard anti-TB drugs (or any of their components) are contraindicated. This includes, but is not limited to, allergy to any TB drug or their components. 7. In females: a positive urine pregnancy test result 8. Confirmed autoimmune disorders (e.g. systemic lupus erythematosus) Additional Exclusions for Gadolinium contrasted CMR 1. Any implanted devices that are not MR compatible (e.g. pacemaker, defibrillators, cerebral aneurysm clips, cochlear implants etc.) 2. Claustrophobia 3. Gadolinium allergy 4. Inability to lie on a flat surface for prolonged periods of time (e.g. severe congestive cardiac failure) 5. Breastfeeding Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language
Inclusion Criteria: 1. Aged \>18 years 2. Suspected PCTB with confirmed pericardial effusion on echocardiography (i.e., echo free space of ≥1 cm anterior to the right ventricle in diastole) 3. Consent to study participation including testing for HIV-1 (if HIV status is unknown) 4. Microbiologically detected Mtb in PCF or diagnosis of probable PCTB. Probable PCTB (in the absence of a positive pericardial fluid culture) will be defined as per Mayosi et al.4: 1. Evidence of pericarditis with microbiologic confirmation of Mtb- infection elsewhere in the body and/or 2. Exudative, lymphocyte predominant effusion with elevated adenosine deaminase (≥35 U/L) 5. Participant will undergo pericardiocentesis (as per clinical indication) 6. Within 5 days of ATT initiation Exclusion Criteria: 1. Glomerular filtration rate \<30ml/min or renal failure requiring dialysis 2. Rifampin-resistant TB 3. Severe concurrent opportunistic infection 4. Contraindication to placement of intra-pericardial catheter 5. Failed pericardiocentesis procedure and/or failure of placement of intra-pericardial catheter 6. Any disease or condition in which the use of the standard anti-TB drugs (or any of their components) are contraindicated. This includes, but is not limited to, allergy to any TB drug or their components. 7. In females: a positive urine pregnancy test result 8. Confirmed autoimmune disorders (e.g. systemic lupus erythematosus) Additional Exclusions for Gadolinium contrasted CMR 1. Any implanted devices that are not MR compatible (e.g. pacemaker, defibrillators, cerebral aneurysm clips, cochlear implants etc.) 2. Claustrophobia 3. Gadolinium allergy 4. Inability to lie on a flat surface for prolonged periods of time (e.g. severe congestive cardiac failure) 5. Breastfeeding

Treatments Being Tested

DRUG

high dose Rifampicin (RIF)

Simulations were performed to determine the dose of RIF required to achieve the most equitable drug exposures across the weight range, 30 to 100 kg. Demographic data of a reference cohort of TB patients (n = 1225), with or without HIV-1 coinfection, recruited in clinical trials conducted in West Africa and South Africa were used for the simulations35-38. An additional 12 250 virtual patients were generated using the weight and height distributions of the 1225 patients to increase the number of patients with a weight close to the boundaries of the weight range. Parameter estimates of the population PK model for RIF were used to simulate (100 replicates) RIF exposures22. Four dosing scenarios were evaluated using the weight-band based dosing with 4-drug FDC tablets and extra RIF tablets with each tablet containing 150 mg or 600 mg RIF. The FDC tablets were assumed to have 20% reduced bioavailability based on data from a clinical trial where the same formulation was used

Locations (2)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Nelson Mandela Academic Hospital
Mthatha, Eastern Cape, South Africa
Groote Schuur Hospital
Cape Town, Western Cape, South Africa

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT04521803), the sponsor (University of Cape Town), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT04521803 clinical trial studying?

The investigators hypothesise that high dose RIF (RIF35) will increase pericardial fluid RIF exposure and so enhance mycobacterial clearance, compared to standard of care dosing (RIF10). This Phase 2b randomized, placebo-controlled, double-blinded trial will evaluate the efficacy and safety of RIF 35mg/kg compared 10mg/kg, added to standard first-line ATT, for the treatment of PCTB. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT04521803?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT04521803?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT04521803. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT04521803. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.