Randomized, placebo-controlled Phase II trial of heat-killed Mycobacterium vaccae (Immodulon batch) formulated as an...

A 1-month Phase II trial was conducted in 41 patients with pulmonary TB who were randomized into treatment (n = 20) and placebo (n = 21) arms to investigate the safety and efficacy of an orally-administered therapeutic TB vaccine (V7) containing 10 µg heat-killed Mycobacterium vaccae provided by Immodulon Therapeutics Ltd (London, UK).

Both arms received conventional anti-TB therapy administered along with a daily pill of V7 or placebo. The subject population had four categories of TB: drug-sensitive TB; retreated TB; drug-resistant TB; and TB with HIV distributed in V7 and placebo arms at 9:4:7:6 and 14:1:6:8 ratios, respectively.

The mycobacterial clearance in sputum smears was observed in 72.2% (p < 0.0001) and 19% (p = 0.03) of patients on V7 and placebo, respectively. The average weight accrual among V7 recipients was 2.6 kg (p = 0.002) versus -0.2 kg (p = 0.69) in the control group. Except reduction in fever and increased lymphocyte counts, the changes in other secondary end points, such as hemoglobin, erythrocyte sedimentation rate and leukocyte counts, were not statistically different, although the proportion of patients responding favorably to V7 was invariably higher compared with placebo (p = 0.002). In control patients, no difference from baseline levels was noted except decreased hemoglobin content (p = 0.02).

Oral M. vaccae was safe and has potential as an adjunct immunotherapy, targeting mucosal immunity, to improve efficacy and shorten treatment duration of TB chemotherapy.