New Patent on Phage Therapy to Overcome Antibiotic Resistance in CF Awarded

Daniela Semedo, PhD avatar

by Daniela Semedo, PhD |

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Harmful gut bacteria in CF

The Japanese Patent Office has granted AmpliPhi Biosciences a patent for the “Beneficial effects of bacteriophage treatments” targeting Pseudomonas aeruginosa infections. A similar patent has already been granted in the United States and a request for one has been filed in Canada.

In Australia and in the European Union, the company has been issued patents with wider bacterial species claims.

Chronic lung infections caused by Pseudomonas aeruginosa are a major cause of morbidity and mortality in cystic fibrosis (CF) patients, and the bacteria chronically infects some 80 percent of CF patients ages 25-34, and 60 percent of patients of any age. These infections can lead to respiratory damage called bronchiectasis and, in some cases, effective antibiotic therapy is no longer available, with multi-drug resistant forms of the bacteria becoming increasingly challenging to treat. New means of controlling drug-resistant P. aeruginosa infections are urgently needed.

Bacteriophage-based therapy is a potential therapeutic tool for the treatment of bacterial infections. Bacteriophages are viruses able to infect and replicate within bacteria.

The new patent covers the treatment of Pseudomonas infections through the sequential use of a bacteriophage (phage) therapy, followed by an antibiotic to which the bacteria were previously resistant. During the first stage of phage administration, Pseudomonas resistant to antibiotics are placed under pressure by the attacking phage, killing most of the bacteria.  But a small portion can mutate and evade the phage attack, although the effort renders them again sensitive to antibiotics .

At this point, antibiotics are administered to deplete the remaining bacteria. This resensitization experience has been seen in in vitro and in vivo experiments and in some human infections resistant to antibiotics, including a case in Australia where an antibiotic-resistant Pseudomonas bladder infection was treated and cleared.

AB-PA01 is an investigational drug therapy targeting CF, as well as non-CF, Pseudomonas isolates and is designed to completely eradicate the infection. Currently in preclinical development, an early clinical study of AB-PA01 as a CF treatment using a nebulized formulation of the phage cocktail is anticipated for 2017.

“Through a step-wise treatment paradigm of AB-PA01 followed by antibiotics, we envision a treatment modality that effectively clears chronic Pseudomonas infections in CF patients,” said M. Scott Salka, CEO of AmpliPhi Biosciences, in a press release. “By resensitizing Pseudomonas to antibiotics, we can turn back the clock on currently ineffective antibiotics and make them relevant again. Antibiotic resensitization has the potential to provide patients and caregivers with a new set of weapons … against the growing threat of antibiotic resistance.”