Proof-of-Principle Study in a Murine Lung Infection Model of Antipseudomonal Activity of Phage PEV20 in a Dry-Powder Formulation

Abstract

Bacteriophage therapy is a promising alternative treatment to antibiotics, as it has been documented to be efficacious against multidrug-resistant bacteria with minimal side effects. Several groups have demonstrated the efficacy of phage suspension to treat lung infections using intranasal delivery; however, phage dry-powder administration to the lungs has not yet been explored. Powder formulations provide potential advantages over a liquid formulation, including easy storage, transport, and administration. The purpose of this study was to assess the bactericidal activities of phage dry-powder formulations against multidrug-resistant (MDR) strain FADDI-PA001 in a mouse lung infection model. Phage PEV20 spray dried with lactose and leucine produced an inhalable powder at a concentration of 2 × 10 PFU/mg. lung infection was established by intratracheal administration of the bacterial suspension to neutropenic mice. At 2 h after the bacterial challenge, the infected mice were treated with 2 mg of the phage powder using a dry-powder insufflator. At 24 h after the phage treatment, the bacterial load in the lungs was decreased by 5.3 log ( < 0.0005) in the phage-treated group compared with that in the nontreated group. Additionally, the phage concentration in the lungs was increased by 1 log at 24 h in the treated group. These results demonstrate the feasibility of a pulmonary delivery of phage PEV20 dry-powder formulation for the treatment of lung infection caused by antibiotic-resistant .

Inhalable bacteriophage powders: Glass transition temperature and bioactivity stabilization

“…Lactose monohydrate (DFE Pharma, Goch, Germany) and L‐leucine (Sigma‐Aldrich, NSW, Australia) were used as excipients for spray drying PEV20. These two excipients can protect and stabilize phage particles from the stresses of spray drying with minimal titer loss, and form partially‐crystalline and partially‐amorphous particles 1,7 . Furthermore, our recent long‐term stability study has shown that lactose, despite being a reducing sugar, provides superior phage protection to trehalose 23 .…”

“…Delivering them as aerosols can achieve direct targeting in the lungs. The feasibility of bioengineering phages into inhalable powders by spray drying has been demonstrated in vitro 1‐6 along with efficacy studies in vivo 7,8 . In the production process, it is essential to preserve phage bioactivity in the dry state by suitable excipients.…”

Pharmacokinetics and pharmacodynamics of inhaled antipseudomonal bacteriophage therapy in mice

“…These studies provide strong support for inhaled phage therapy with reduction in bacterial load and inflammation in the mouse lung infection model. Compared with intranasal route, intratracheal administration enables direct application of bacteria and phages to the mouse lungs with minimal loss in other parts of the respiratory route, including nose, throat and upper airways (8,27). Hence, the exact phage doses of interest were given in the PK study, and in the PD study.…”

“…Despite these advantages, studies on intratracheal administration of phages for lung infections have been scarce (8,28). In this study, intratracheal instillation was used to administer and assess the PK of phage PEV31 at two different doses.…”

“…Phage therapy has distinct advantages over conventional antibiotic treatment in that phages are (i) a naturally occurring antibacterial, (ii) self-replicating, (iii) self-limiting upon resolution of infection, (iv) effective against both MDR or antibiotic sensitive bacteria, (v) highly specific with low inherent toxicity, (vi) able to co-evolve with bacteria, and (vii) able to penetrate biofilms (5). The potential use of phages as antibacterial agents has been demonstrated in in vitro (6,7), preclinical (8)(9)(10)(11) and in compassionate single case studies (12)(13)(14).…”