CLINICAL TRIALS PROFILE FOR RIFABUTIN

All Clinical Trials for rifabutin

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00000826 ↗	Effect of Fluconazole, Clarithromycin, and Rifabutin on the Pharmacokinetics of Sulfamethoxazole-Trimethoprim and Dapsone and Their Hydroxylamine Metabolites	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	Phase 1	1969-12-31	To determine the effects of fluconazole and either rifabutin or clarithromycin, alone and in combination, on the pharmacokinetics of first sulfamethoxazole-trimethoprim and then dapsone in HIV-infected patients. Although prophylaxis for more than one opportunistic infection is emerging as a common clinical practice in patients with advanced HIV disease, little is known about possible adverse drug interactions. The need exists to define pharmacokinetics and pharmacodynamic adverse interactions of the many combination prophylactic regimens that may be prescribed.
NCT00000877 ↗	Study of How Indinavir (an Anti-HIV Drug) and Rifabutin (a Drug Used to Treat MAC, an HIV-Associated Disease) Interact in HIV-Positive and HIV-Negative Adults	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	Phase 1	1969-12-31	The purpose of this study is to evaluate the safety of giving indinavir and rifabutin at the same time (simultaneously) vs 4 hours apart (staggered) to HIV-positive and HIV-negative adults. It is important to determine which medications for HIV-associated diseases, such as Mycobacterium avium complex (MAC) disease, can be given safely and effectively with anti-HIV drugs. Indinavir and rifabutin have been given simultaneously in the past with good results. This study seeks to examine if staggering the doses will make the 2 drugs more effective. HIV-negative volunteers are used in this study to examine the effect of rifabutin on indinavir and the effect of staggered rifabutin doses. The effect of rifabutin on the drug activity of indinavir is evaluated in HIV-positive patients.
NCT00001023 ↗	The Safety and Effectiveness of Rifabutin, Combined With Clarithromycin or Azithromycin, in HIV-Infected Patients	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	N/A	1969-12-31	PER 03/10/94 AMENDMENT: PART B. To determine whether there is an effect on plasma drug levels of azithromycin and rifabutin as measured by changes in the plasma concentration-time curve (AUC) when these drugs are taken concomitantly. ORIGINAL PRIMARY: To gain preliminary information about the safety and tolerance of clarithromycin and azithromycin in combination with rifabutin (three potential agents against Mycobacterium avium-intracellulare) in HIV-infected patients with CD4 counts < 200 cells/mm3. ORIGINAL SECONDARY: To determine whether there is an effect on the pharmacokinetics of the macrolide antibiotics or rifabutin when these drugs are taken concomitantly. To monitor the effect of rifabutin therapy on dapsone serum levels in patients taking dapsone for PCP prophylaxis. To monitor the effect of macrolide/rifabutin combination therapies on AZT or ddI serum levels. Two new macrolide antibiotics, clarithromycin and azithromycin, and rifabutin (a rifamycin derivative) have all demonstrated in vitro and in vivo activity against Mycobacterium avium-intracellulare, a common systemic bacterial infection complicating AIDS. Further information is needed, however, regarding the clinical and pharmacokinetic interaction of these drugs used in combination.
NCT00001030 ↗	The Safety and Effectiveness of Clarithromycin and Rifabutin Used Alone or in Combination to Prevent Mycobacterium Avium Complex (MAC) or Disseminated MAC Disease in HIV-Infected Patients	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	Phase 3	1969-12-31	To compare the efficacy and safety of clarithromycin alone versus rifabutin alone versus the two drugs in combination for the prevention or delay of Mycobacterium avium Complex (MAC) bacteremia or disseminated MAC disease. To compare other parameters such as survival, toxicity, and quality of life among the three treatment arms. To obtain information on the incidence and clinical grade of targeted gynecologic conditions. Persons with advanced stages of HIV are considered to be at particular risk for developing disseminated MAC disease. The development of an effective regimen for the prevention of disseminated MAC disease may be of substantial benefit in altering the morbidity and possibly the mortality associated with this disease and its treatment.
NCT00001039 ↗	Evaluation of Treatment for Mycobacterium Avium Complex (MAC) Infection in HIV-Infected Patients	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	Phase 2	1969-12-31	To assess the feasibility of using culture and staining techniques to quantify tissue Mycobacterium avium Complex (MAC) burden in bone marrow. To correlate and compare changes in MAC bone marrow burden with quantitative MAC blood culture results at baseline and after 4 and 8 weeks of treatment. MAC is easiest to detect in the blood, although doctors generally believe that MAC in blood is just "spill-over" from infection of other parts of the body. Traditionally, studies of potential treatments for MAC focus only on MAC changes in the blood. This study compares MAC changes in blood to those in bone marrow, which is another tissue where MAC is often found.
NCT00001047 ↗	Study of Four Different Treatment Approaches for Patients Who Have Mycobacterium Avium Complex Disease (MAC) Plus AIDS	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	Phase 3	1969-12-31	To compare the safety and efficacy of two doses of clarithromycin in combination with ethambutol and either rifabutin or clofazimine for the treatment of disseminated Mycobacterium avium Complex (MAC) disease in AIDS patients. Recommendations have been issued for AIDS patients with disseminated MAC to be treated with at least two antimycobacterial agents and for every regimen to include a macrolide (clarithromycin or azithromycin). However, the optimal treatment for disseminated MAC remains unknown.
NCT00001058 ↗	A Comparison of Three Drug Combinations Containing Clarithromycin in the Treatment of Mycobacterium Avium Complex (MAC) Disease in Patients With AIDS	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	Phase 2	1969-12-31	To compare the efficacy and safety of clarithromycin combined with rifabutin, ethambutol, or both in the treatment of disseminated Mycobacterium avium Complex (MAC) disease in persons with AIDS, including individuals who have or have not received prior MAC prophylaxis. It is believed that effective therapy for MAC disease in patients with AIDS requires combinations of two or more antimycobacterial agents in order to overcome drug resistance and the unfavorable influence of the profound immunosuppression associated with AIDS. Data suggest that clarithromycin may have substantial activity in two- or three-drug combination regimens with clofazimine, rifamycin derivatives, ethambutol, or the 4-quinolones.

Clinical Trial Conditions for rifabutin

Condition Name

Condition Name for rifabutin
Intervention	Trials
HIV Infections	31
Tuberculosis	21
Mycobacterium Avium-intracellulare Infection	13
Helicobacter Pylori Infection	6

Condition MeSH

Condition MeSH for rifabutin
Intervention	Trials
HIV Infections	39
Infections	30
Infection	27
Tuberculosis	26

Clinical Trial Locations for rifabutin

Trials by Country

Trials by Country for rifabutin
Location	Trials
United States	250
Canada	20
South Africa	8
Taiwan	4
China	4

Trials by US State

Trials by US State for rifabutin
Location	Trials
California	22
New York	17
Maryland	15
Texas	14
District of Columbia	12

Clinical Trial Progress for rifabutin

Clinical Trial Phase

Clinical Trial Phase for rifabutin
Clinical Trial Phase	Trials
PHASE4	1
PHASE1	2
Phase 4	18

Clinical Trial Status

Clinical Trial Status for rifabutin
Clinical Trial Phase	Trials
Completed	51
Recruiting	15
Unknown status	9

Clinical Trial Sponsors for rifabutin

Sponsor Name

Sponsor Name for rifabutin
Sponsor	Trials
National Institute of Allergy and Infectious Diseases (NIAID)	12
Pfizer	7
Pharmacia	6

Sponsor Type

Sponsor Type for rifabutin
Sponsor	Trials
Other	93
Industry	48
U.S. Fed	14

Last updated: July 29, 2026

Rifabutin clinical trials update, market analysis, and forecast (2024–2035)

Rifabutin is an established rifamycin antibiotic used primarily for treatment and prevention of Mycobacterium avium complex (MAC) in advanced HIV and for Mycobacterium tuberculosis (TB) regimens as a second-line option in specific drug-resistance or intolerance contexts. In the last several years, rifabutin’s commercial trajectory has been shaped more by HIV and TB program demand, diagnostic access, and generic competition than by large-scale late-stage innovation programs. Broad, drug-level “pipeline refresh” coverage for rifabutin is limited because the active ingredient is off-patent in many jurisdictions and most current activity is expected to concentrate on formulation changes, combination regimens, and new dosing strategies rather than de novo clinical development.

What clinical trials are recruiting or ongoing for rifabutin right now?

Rifabutin trials in public registries typically cluster into four categories: HIV/MAC, TB combination strategies, pediatric dosing tolerability/safety, and formulation/PK studies (bioequivalence or exposure optimization).

HIV and MAC prevention: what trial designs show up most

• Patient populations: adults with advanced HIV (commonly low CD4 counts) and/or history of MAC.
• Endpoints: MAC incidence, time to treatment initiation, microbiologic response, and safety tolerability.
• Common design patterns: open-label comparative prophylaxis, randomized dosing comparisons, and pharmacokinetic bridging.

TB regimens: what trial goals dominate

• Patient populations: adults with drug-resistant TB or intolerance to standard rifamycins.
• Endpoints: culture conversion time, adverse-event incidence, and pharmacokinetic exposure adequacy.
• Common design patterns: regimen optimization studies and combination-product evaluation when rifabutin is used as an alternative rifamycin.

Formulation and dosing studies: why they matter commercially

Even when no new “indication expansion” is approved, changes that improve:

• adherence (dose timing, reduced side effects),
• drug-drug interaction management,
• or exposure in special populations (pediatrics, hepatic impairment), can change formulary adoption and procurement behavior.

What rifabutin phase trials have reported results, and what are the key readouts?

For rifabutin, the most meaningful clinical readouts historically are tied to:

• efficacy and safety in MAC prophylaxis,
• regimen compatibility in TB treatment contexts,
• and tolerability improvements in HIV co-therapy settings.

Late-stage innovation has been less visible at the active-ingredient level compared with newer TB and MAC candidates, so the highest-value evidence for market forecasting tends to come from:

• guideline updates,
• rollout programs,
• and real-world prescribing patterns.

How does rifabutin’s market size move by indication: HIV/MAC vs TB?

Rifabutin demand is directionally driven by two macro demand engines.

HIV-associated MAC prophylaxis

Key demand drivers:

• growth or contraction in the treated advanced-HIV population,
• ART coverage and viral suppression rates,
• persistence of late-stage HIV presentation,
• guideline intensity for primary vs secondary prophylaxis.

Commercial implication:

• Rifabutin remains a procurement line item where MAC prophylaxis is indicated and where clinicians prefer rifabutin for interaction management relative to alternatives.

TB regimens

Key demand drivers:

• drug-resistant TB prevalence,
• availability of alternative rifamycins and clinician adherence to regimen selection,
• supply stability and price competitiveness of rifabutin-containing regimens.

Commercial implication:

• TB-driven use is typically less “volume consistent” than routine HIV/MAC prophylaxis, but it can swing with policy and resistance patterns.

Where is rifabutin sold and what are the leading procurement markets?

Rifabutin procurement is strongest in:

• the US and EU for HIV care pathways and for TB second-line use,
• major ROW HIV programs with established prophylaxis protocols,
• and TB reference centers that adopt rifamycin alternatives in drug-resistant or intolerance scenarios.

Commercial implication:

• forecasting must treat region-by-region formularies and reimbursement policy as primary levers, not purely clinical evidence.

What is the competitive landscape for rifabutin (brand vs generic, and who dominates)?

Rifabutin’s active ingredient is widely available as generics in many markets, which compresses pricing and reduces incremental revenues unless:

• a branded product has protected formulations, packaging, or dosing convenience, or
• a combination product or specific label creates formulary “sticky” behavior.

Brand positioning vs generic pricing

• Branded products tend to command higher unit price but face rapid substitution where generics are listed and reimbursed.
• Generics expand volume but reduce value per unit.
• Prescriber behavior is influenced by tolerability and drug interaction familiarity as much as by price.

Market projection: what volume and pricing trends drive rifabutin revenue growth (2024–2035)?

A practical projection model for rifabutin is “volume by indication” times “net price after generic discounting,” adjusted for guideline and program intensity.

Base-case mechanics

1. HIV/MAC prophylaxis volume
   • Stabilizes with ongoing ART scale-up but can remain resilient because late presenters and resistant infection risk persist.
2. TB usage
   • Tracks drug-resistant TB burden and the availability of acceptable rifamycin alternatives.
3. Net pricing
   • Moves toward a lower plateau under generic competition.
4. Formulary effects
   • Any change in guideline recommendations or drug-interaction guidance can alter relative share between rifamycins.

Scenario view

• Bull case (incremental growth): stronger adoption for MAC prevention where clinicians use rifabutin for interaction management, plus sustained procurement in TB programs where rifabutin is part of second-line choices.
• Base case (modest growth or flat): stable demand with continued price pressure.
• Bear case (downside): further shifts toward alternative agents or regimens that reduce rifamycin reliance, plus accelerated generic substitution and reimbursement tightening.

How do drug-drug interactions affect rifabutin demand and prescribing?

Rifabutin is used in HIV contexts where drug-drug interactions with antiretrovirals are central. Prescribers and hospitals increasingly manage these interactions through:

• interaction-aware regimen selection,
• therapeutic drug monitoring in certain scenarios,
• and protocol-driven substitution when rifabutin is preferred or avoided.

Commercial implication:

• rifabutin demand is partly an interaction-management tool, not only a clinical efficacy choice.

What is the regulatory status of rifabutin in the US and key geographies?

Rifabutin is an established prescription product in major markets, with approvals tied to:

• MAC prevention in HIV,
• and specific TB indications or second-line regimens depending on local labeling.

Forecast implication:

• Regulatory “pathway innovation” is less likely for rifabutin at the active-ingredient level than for newer candidates, so market movement is driven by supply, pricing, and label maintenance rather than new approvals.

Patent and exclusivity: what risks exist for incumbents, and how does generic entry shape projections?

With an established active ingredient, market forecasts for rifabutin must incorporate:

• generic substitution timing,
• potential patent estate remnants limited to specific formulation or manufacturing processes,
• and the likelihood that late entrants do not require costly clinical trials if bioequivalence is supported.

Commercial implication:

• revenue upside is constrained by pricing competition unless protected niches exist (specific dosage forms, packaging, or controlled release concepts).

What formulation or dosing updates could change rifabutin’s competitive position?

The most commercially relevant near-term categories are:

• pediatric-friendly dosing enablement,
• improved tolerability through formulation adjustments,
• simplified dosing schedules that support adherence in TB treatment and MAC prevention,
• and drug-product stability improvements that reduce procurement risk.

These can shift share even without label expansion.

How strong is the patent estate for rifabutin and its derivatives?

For rifabutin itself, the patent estate is generally not positioned as a long-term valuation anchor at the active-ingredient level in most major markets, given the drug’s age. Any remaining value typically comes from:

• late-filed process patents (where granted),
• formulation patents tied to specific product characteristics,
• or proprietary packaging and supply-chain controlled manufacturing.

Competitive scenario analysis: how does rifabutin compare with other MAC prophylaxis options?

Rifabutin competes indirectly in MAC prevention with other standard-of-care approaches used in HIV, where clinical protocols balance:

• efficacy,
• tolerability,
• and interaction burden with antiretrovirals.

Commercial implication:

• share is a function of clinician confidence in interaction management and institutional guideline adherence, not only antibiotic activity.

What could accelerate or slow rifabutin demand in the next 2 to 5 years?

Accelerants

• policy reinforcement of MAC prophylaxis protocols where rifabutin is preferred,
• sustained access to HIV care and consistent screening for MAC risk,
• stable supply and procurement continuity in major markets.

Decelerants

• migration to alternative prophylaxis standards where rifabutin is less favored,
• aggressive pricing actions by generic suppliers that reduce value but may not reduce volume,
• shifts in TB regimen design away from rifabutin-dependent pathways.

Key takeaways

• Rifabutin demand is anchored to HIV/MAC prophylaxis and second-line TB regimen usage.
• Market value growth is likely constrained by generic price pressure, with forecast sensitivity higher on volume and program intensity than on net pricing.
• The most plausible near-to-mid-term changes are formulation and dosing optimization, plus guideline-driven utilization rather than major late-stage clinical breakthroughs.
• Next-period outcomes for incumbents depend on supply stability, procurement contracting, and interaction-aware prescribing behavior in HIV care.

FAQs

Is rifabutin used for MAC treatment or only prevention in HIV?

Rifabutin is used in MAC strategies in HIV that include prophylaxis, and it can be part of treatment regimens depending on clinical context and local labeling.

What is rifabutin’s main drug-drug interaction risk in HIV?

The main issue is interaction with antiretrovirals, which can affect rifamycin exposure and necessitate regimen selection and monitoring.

Does rifabutin have ongoing pediatric clinical development?

Pediatric activity commonly appears as dosing optimization or bridging studies rather than late-stage efficacy trials.

Will generics reduce rifabutin revenues even if volume holds up?

Yes. Even if volume remains stable, net pricing typically falls under generic substitution, reducing revenue per patient.

What are the biggest drivers of rifabutin procurement in TB programs?

Drug-resistant TB burden, regimen selection practices, and availability of rifamycin alternatives drive utilization.

References

1. ClinicalTrials.gov. Rifabutin search results and study records. (accessed 2026-07-29).
2. FDA Orange Book. Rifabutin listed products and patent/exclusivity entries. (accessed 2026-07-29).
3. WHO. Guidelines for tuberculosis and HIV-associated opportunistic infections (latest editions available). (accessed 2026-07-29).
4. NIH/CDC/HIVMA guidance for MAC prophylaxis and treatment in advanced HIV. (latest editions available). (accessed 2026-07-29).