Potential cost-effectiveness of rifampin vs. isoniazid for latent tuberculosis: implications for future clinical trials

Int J Tuberc Lung Dis. 2011 Oct;15(10):1340-6. doi: 10.5588/ijtld.10.0575.

Abstract

Setting: Standard treatment for latent tuberculosis infection (LTBI) is 9 months daily isoniazid (9INH). An alternative is 4 months daily rifampin (4RMP), associated with better completion and less toxicity; however, its efficacy remains uncertain.

Objectives: To assess the cost-effectiveness of these regimens for treating LTBI in human immunodeficiency virus negative persons, using results from a recent clinical trial, plus different scenarios for 4RMP efficacy, and to estimate the costs of an adequately powered noninferiority trial and resulting savings from substitution with 4RMP.

Design: A decision-analysis model tracked TB contacts and lower-risk tuberculin reactors receiving 9INH, 4RMP or no treatment. For different 4RMP efficacy scenarios, we estimated the cost-effectiveness, sample size and cost of non-inferiority trials, and potential cost savings substituting 4RMP for 9INH for 10 years in Canada.

Results: With an assumed 4RMP efficacy of 60%, 9INH was more effective but slightly more expensive. Above a threshold efficacy of 69%, 4RMP was cheaper and more effective than 9INH. If the true efficacy of 4RMP is ≥75%, a trial powered to detect non-inferiority with a lower limit of 60% estimated efficacy (~20 000 subjects) may lead to cost savings within 10 years, even with the extreme assumption that Canada bears the entire cost.

Conclusion: 4RMP may be a reasonable alternative to 9INH. Costs of a large-scale non-inferiority trial may be offset by subsequent savings.

Publication types

  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antitubercular Agents / administration & dosage*
  • Antitubercular Agents / adverse effects
  • Antitubercular Agents / economics*
  • Brazil
  • Canada
  • Cost-Benefit Analysis
  • Decision Support Techniques
  • Drug Administration Schedule
  • Drug Costs*
  • Female
  • Humans
  • Isoniazid / administration & dosage*
  • Isoniazid / adverse effects
  • Isoniazid / economics*
  • Latent Tuberculosis / diagnosis
  • Latent Tuberculosis / drug therapy*
  • Latent Tuberculosis / economics*
  • Latent Tuberculosis / microbiology
  • Male
  • Middle Aged
  • Models, Economic
  • Research Design
  • Rifampin / administration & dosage*
  • Rifampin / adverse effects
  • Rifampin / economics*
  • Saudi Arabia
  • Time Factors
  • Treatment Outcome
  • Young Adult

Substances

  • Antitubercular Agents
  • Isoniazid
  • Rifampin