Therefore, the Pittsburgh team with colleagues from the University of California at San Diego reports 20 cases of use of this treatment and concludes that the therapy is successful in more than half of the patients. The experimental procedure using viruses to treat life-threatening Mycobacterium infections here improved the health of 11 out of 20 patients. None of the patients developed any adverse effects.
“The bacteriophages have done their job”,
conclude the researchers who now say they are able to deliver these bacteria-killing viruses to patients who have no other options for treating antibacterial-resistant infections (RAM).
“Some of these results are spectacular, others more complex”says lead author Dr. Graham Hatfull, professor of biotechnology at the University of Pittsburgh: “However, in a series of 20 cases, it becomes much more evident that phages can bring favorable results in patients who have no other alternative.” In 2019, Dr. Hatfull had already documented a successful first use of phages to treat an antibiotic-resistant infection, and since then his team has responded to requests from more than 200 doctors seeking treatments for their patients, working with those doctors, to find phages that might be effective against the particular strain of bacteria that infects each patient.
I study: each patient treated had an infection with one or more strains of Mycobacterium, a group of bacteria that can cause life-threatening and treatment-resistant infections in people who are immunocompromised or with cystic fibrosis. These infections are among the most difficult to treat with antibiotics, say the authors.
New evidence of efficacy : The case series shows that the therapy was successful in 11 out of 20 cases. No patient had an adverse reaction to the treatment. In another 5 patients, the results of therapy are inconclusive and 4 patients showed no improvement. The researchers will analyze these refractory cases to understand why they did not work and thus be able to further improve the therapy.
Unexpected trends emerging:
- in 11 cases, the researchers could not find more than one type of phage that could kill the patient’s infection, even if the common practice was – until then – to inject a cocktail of different viruses;
- Some patients’ immune systems attack the virus, however in some cases the immune system renders the virus ineffective. And, in some of these cases, despite this adverse immune reaction to phage therapy, the treatment is still successful. These mechanisms will need to be better understood.
The team continues to provide phages to more patients: “We have not yet figured out how to find or design phages capable of destroying all strains of bacteria in these patients, but we are working on it”conclude the authors.
