TB Notes Newsletter
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No. 1, 2006
TB TRIALS CONSORTIUM UPDATE
Study 24 is a single-arm study of largely intermittent, short-course therapy for patients with INH-resistant TB or INH intolerance. Enrollment closed December 2004 with a total of 98 patients. By mid 2007, all patients will have reached the end of follow-up for study outcomes (e.g., treatment failure and relapse).
Study 26 is a trial of short-course treatment of latent TB infection among contacts of active cases, using a 3-month, once-weekly regimen of isoniazid 900 mg and rifapentine 900 mg, compared to standard 9-month daily therapy with isoniazid 300 mg. As of January 19, 2006, Study 26 enrollment was up to 5,485, over 68% of the intended subjects for total enrollment. These 5,485 subjects include 294 persons under 18 years of age.
Study 27 is a double-blind, placebo-controlled evaluation of 2-month culture conversion rates when substituting moxifloxacin for ethambutol in the 2-month intensive phase of treatment of pulmonary TB. A total of 336 patients were enrolled between July 2003 and March 2005. Over 50% of patients were enrolled from two African study sites. The first preliminary results were presented in May 2005. There was no difference between the moxifloxacin and the ethambutol study arms in 2-month culture conversion; these rates were both 71%. There were differences, however, between North American sites and African sites, with significantly more North American patients converting their sputum to negative by 2 months (85%) compared to African patients (63%). Further analyses are ongoing.
Study 28 is a double-blind, placebo-controlled study of 2-month culture conversion rates when substituting moxifloxacin for isoniazid in the 2-month intensive phase of treatment of pulmonary TB. This isoniazid-sparing regimen for TB treatment is based on data from the murine model of tuberculosis. In the murine model, the substitution of moxifloxacin for isoniazid resulted in significant reduction in the time to sterilization when compared to the standard combination of rifampin, isoniazid, and pyrazinamide. Improved sputum culture conversion after 2 months of treatment with a moxifloxacin-containing regimen would support movement to phase-3 clinical trials of moxifloxacin-based treatment regimens of less than the current 6-month standard duration. Study 28 will enroll 410 patients from both domestic and international TBTC sites. Enrollment is expected to begin in early 2006.
—Reported by Susan Ray, MD
Emory University School of Medicine
Member, Advocacy & External Relations Committee
TB Trials Consortium