Sterilizing activity of R207910 (TMC207)-containing regimens in the murine model of tuberculosis

Abstract

Rationale: The diarylquinoline R207910 (TMC207) has potent bactericidal activity in a murine model of tuberculosis (TB), but its sterilizing activity has not been determined.

Objectives: To evaluate the sterilizing activity of R207910-containing combinations in the murine model of TB.

Methods: Swiss mice were intravenously inoculated with 6 log(10) of Mycobacterium tuberculosis strain H37Rv, treated with R207910-containing regimens, and followed for 3 months to determine relapse rates (modified Cornell model).

Measurements and main results: Quantitative lung and spleen colony-forming unit counts and bacteriological relapse rates 3 months after the end of therapy were compared for the following regimens: 2, 3, or 4 months of R207910 (J) and pyrazinamide (Z) combined with rifampin (R) or isoniazid (H) or both and 3 or 4 months of a moxifloxacin (M)-containing regimen and 6 months of the standard WHO regimen RHZ. All J-treated mice were culture negative after 4 months of therapy. The relapse rate in the group treated with 4 months of JHRZ was similar to that of mice treated for 6 months with the RHZ regimen (6 vs. 17%; P = 0.54) and lower than that of RMZ (6 vs. 42%; P = 0,03), a moxifloxacin-containing regimen that was the most active in mice on once-daily basis.

Conclusions: Four months of treatment with some J-containing regimens was as effective as the 6-month standard regimen and more effective than 4 months of treatment with M-containing regimens. Supplementation of standard regimen (RHZ) with J or substitution of J for H may shorten the treatment duration needed to cure TB in patients.