Armata Pharmaceuticals’ investigational phage therapy, AP-SA02, demonstrated earlier resolution in patients with Staphylococcus aureus bacteremia (SAB) in a Phase IIa trial, reinforcing the growing clinical promise of bacteriophage-based treatments. The findings highlight the therapy’s potential to address antibiotic resistance and provide a new treatment option for patients with serious bloodstream infections, says GlobalData.
Stephanie Kurdach, Infectious Disease Analyst at GlobalData, comments, “Bacteriophages, or phages, are viruses that can selectively target and kill bacteria. Phages are particularly advantageous anti-infectives because they can target antibiotic-resistant bacteria, such as S. aureus. The World Health Organization (WHO) has categorised methicillin-resistant S. aureus (MRSA) as a high-priority pathogen in the 2024 WHO Bacterial Priority Pathogens List.”
The Phase IIa portion of the diSArm trial included 42 patients who were 18 years of age or older and had been hospitalised and diagnosed with a positive blood culture for S. aureus. These patients were randomised into two groups: those receiving intravenous AP-SA02 every six hours for five days, in addition to intravenous standard of care (SOC) best available antibiotic therapy (BAT) for 14-56 days, or those in the placebo group receiving SOC BAT for 14-56 days. The site of infections in the patients in the study included septic joint, cellulitis, osteomyelitis, pneumonia, sepsis, and endocarditis.
On average, the AP-SA02 plus BAT-treated patients observed an initial resolution of their SAB infection in 2.7 days, compared to 9.3 days in the placebo plus BAT-treated group. Additionally, the AP-SA02 plus BAT-treated patients were discharged from the hospital after approximately 11.7 days and had a mean C-reactive protein level of 50.2mg/L on Day 12, compared to 19.2 days and 97.3mg/L, respectively, in the placebo plus BAT group. Overall, AP-SA02 was found to be generally safe and well tolerated.
Kurdach adds, “The results of the Phase IIa study demonstrate AP-SA02’s clinical success. When administered in combination with BAT, the drug was associated with earlier resolution of infection and shorter hospitalisation rates compared to a placebo.”
AP-SA02 offers an entirely novel approach to the treatment of SAB. It is a phage cocktail, consisting of natural lytic phages that target S. aureus, ARSA0001 and ARSA0002.
According to GlobalData, Armata’s AP-SA02 is the only bacteriophage in clinical development for bacteremia, although other companies such as Phiogen have bacteriophage candidates in preclinical development in this space.
Other advantages of phages include their ability to be used as monotherapy or combination therapy, their lack of microbiome disruption in patients, and their categorisation as novel therapeutics, all of which emphasise the potential that these therapies hold in combating challenging bacterial infections.
Kurdach concludes, “The results of AP-SA02’s Phase IIa trial support its advancement into Phase III development. Armata Pharmaceuticals has already announced plans to initiate this pivotal study in 2026. The clinical success of AP-SA02 highlights its potential to fulfil a critical need for SAB patients.”