Inhalable dry powders of mycobacteriophages for tuberculosis therapy

Tuberculosis (TB) is one of the most infectious and deadly diseases in human history, accounting for about 1.5 million deaths annually. Worldwide, about one out of every three people is infected with the bacteria that causes TB, i.e., Mycobacterium tuberculosis (Mtb), a massive reservoir for future outbreaks. Moreover, the overuse and misuse of antibiotics have accelerated the rise of drug-resistant forms of the bacterium that are increasingly making treatment difficult even in areas with readily accessible healthcare. Bacteriophages or phages are viruses that have evolved to target specific bacterial species. Unlike antibiotics, phages offer a more targeted approach to selectively eliminate pathogenic bacteria, leaving the other microbiota largely unharmed. Moreover, when phages infect and lyse their preferred bacterial host, they replicate and increase in number, which could result in a reduction in dosing frequency and duration of treatments. In contrast, the current standard antibiotic-based regimen for TB demands prolonged and rigorous treatment schedules, often leading to patient non-compliance and greater risk of developing antibiotic resistance. Despite the promising potential of phage therapy for TB, there are challenges in developing a stable phage product to deliver viable phages to deep lung to kill extracellular and intracellular Mtb. We propose to use our thin-film freeze-drying (TFFD) technology to create an aerosolizable dry powder of D29 mycobacteriophages capable of reaching and eliminating Mtb after pulmonary delivery. TFFD produces brittle, porous matrix powders that are readily sheared into respirable particles using a passive dry powder inhaler for efficient deposition in deep lung. This process also ensures that the phages remain viable and active throughout processing and administration. We have already developed a prototype stable, aerosolizable dry powder of D29 phages. Our goal in this Phase 1 application is to develop a new, improved powder with D29 phages encapsulated in a biocompatible polymer to enable the phages to access and destroy both extracellular and intracellular Mtb. Our specific aims are: (1) to develop a stable, aerosolizable dry powder comprised of D29 phages encapsulated in polymeric microparticles, which will be uniquely achieved during oral inhalation wherein the brittle matrix phage powder is sheared into respirable microparticles using a dry powder inhaler; (2) to identify the degree to which the encapsulated D29 phages in a thin-film freeze-dried powder will kill mycobacteria in bronchoalveolar fluid and in macrophages; and (3) to evaluate the pharmacokinetics of the D29 phages after they are administered into the lung as a dry powder in a mouse model. In summary, we will utilize TFFD and its unique mechanism of generating respirable particles to develop a phage product for the treatment of TB. The new product will ensure the stability and viability of the phages, enhance their targeted delivery to the lung, and increase the likelihood of successful treatment of pulmonary Mtb infections. The same technology could also be adapted to develop inhaled phage dry powder products for the treatment of other pulmonary bacterial infections.