Development of the food supplement Nyaditum resae as a new tool to reduce the risk of tuberculosis development

Abstract

Nyaditum resae (NR) is a galenic preparation of heat-killed Mycobacterium manresensis (hkMn). This is a new species that belongs to the Mycobacterium fortuitum complex, and it is present in drinking water—thus, regulatorily speaking, it is considered a food supplement.

Preclinical studies in the murine model of active tuberculosis (TB) in the C3HeB/FeJ strain have demonstrated that daily administration of NR containing 10³–10⁶ hkMn for 14 days was able to stop the progression toward active TB [1]. The mechanism of action was linked to the induction of low dose tolerance and was related to the increase of Tuberculin Purified Protein Derivative (PPD) memory-specific Tregs (CD4⁺CD25⁺CD39⁺ cells) after ex vivo incubation of splenocytes for 7 days. This increase of Tregs was related to the increase of inter-leukin (IL)-10 in the spleen and in the reduction of IL-17 in the lungs, where there was also a reduction in bacillary load and the pathology caused by a reduction of neutrophiles’ infiltration [2].

Two randomized, double-blind placebo-controlled clinical trials (CTs) have been conducted in humans. The NYADATREG study (Clinicaltrials.gov identifier NCT02076139; 2013–2014) was aimed to evaluate the safety and the immunogenicity of two concentrations of NR (containing 10⁴ hkMn and 10⁵ hkMn) versus placebo (all administered orally everyday for 14 days) in tuberculin-positive and tuberculin-negative volunteers (total n = 51). The results demonstrated an excellent safety record, with no differences between groups in terms of adverse effects. A significant increase in PPD-specific memory regulatory T cells was also detected in both NR groups [3]. The NYADAPETRICS study (Clinicaltrials.gov identifier NCT02581579) is evaluating the safety and immunogenicity of NR 10⁵ hkMn (capsule format, orally) in the pediatric population. Currently, an efficacy study (randomized, double-blinded, placebo-controlled CT) is being conducted in Georgia. This NYADAGEORG trial includes close contacts of active TB cases with positive sputum not tributaries of chemoprophylaxis (<5-year-old children and HIV-positive individuals), which will receive NR (containing 10⁵ hkMn) or placebo (orally, every day for 14 days). A total of 3300 participants will be recruited in four medical centers around Tbilissi. The participants are monitored by telephone for up to 2 years to evaluate the incidence of active TB. The hypothesis is that the NR group will exhibit a 40% reduction in expected TB incidence. Thus, the anticipated TB incidence will be 3% in the NR group versus 5% in the placebo group. The CT is projected to end by 2021 (Clinicaltrials.gov identifier NCT02897180).

The administration of the food supplement NR appears to be a new, easy, safe, and reliable method for reducing the risk of developing active TB, and new CTs must be encouraged to discern the particular efficacy power according to different population characteristics.