During IDWeek 2025 in Atlanta, Georgia, Loren G. Miller, MD, MPH , investigator at The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center , presented landmark findings from the Phase 2a diSArm study . Conducted in collaboration with Armata Pharmaceuticals, Inc. , the study demonstrated for the first time in a randomized clinical trial the efficacy of an intravenous bacteriophage therapy in treating complicated Staphylococcus aureus bacteremia (“SAB”).
Bacteriophages are virus-like particles that infect bacteria. Bacteriophages may have advantages over traditional antibiotics in that they address the problem of increasing antibiotic resistance among bacteria by attacking with a novel mechanism. Additionally, bacteriophages target a single pathogenic bacteria and thus have minimal or no disruption of the healthy human microbiome.
The diSArm study evaluated AP-SA02, a high-purity, pathogen-specific bacteriophage cocktail developed by Armata Pharmaceuticals, in combination with best available antibiotic therapy (BAT) compared to placebo plus BAT. Results showed that AP-SA02 was safe and demonstrated encouraging efficacy in patients with complicated S. aureus bacteremia, one of the most serious and difficult-to-treat bacterial infections. At each multiple time points after treatment, patients receiving the AP-SA02 had higher clinical success than those who received placebo.
Dr. Miller played a pivotal role in the execution of the diSArm trial and presented results of the trial at IDWeek 2025 in Atlanta as a late breaker oral abstract. IDWeek 2025 only accepts highly competitive, novel, and timely abstracts as late breakers, highlighting the importance of the trial’s findings.
“The results of the diSArm study confirm, for the first time, the efficacy of intravenous phage therapy for S. aureus bacteremia,” said Dr. Miller. “These findings provide strong rationale for a Phase 3 study and signal a potential paradigm shift in how we treat antibiotic-resistant infections. High-purity, phage-based therapeutics like AP-SA02 may one day become a new standard of care for patients facing this life-threatening condition.”
Armata Pharmaceuticals’ CEO, Dr. Deborah Birx, recognized Dr. Miller and the clinical team for their contributions: “The positive results from the diSArm study represent another significant achievement as we advance AP-SA02 toward a pivotal Phase 3 trial,” said Dr. Birx. “We extend our gratitude to Dr. Miller and the other investigators for their leadership and commitment to bringing innovative therapies to patients with severe bacterial infections.”
The diSArm study was conducted with support from the U.S. Department of Defense and Innoviva, Armata’s major shareholder, both of whom have played critical roles in enabling the development of phage-based therapeutics as a potential solution to the global challenge of antimicrobial resistance.
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About AP-SA02 and diSArm Study
Armata is developing AP-SA02, a fixed multi-phage phage cocktail, for the treatment of complicated bacteremia caused by Staphylococcus aureus ( S. aureus ), including methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains.
The diSArm study ( NCT05184764 ) was a Phase 1b/2a, multicenter, randomized, double-blind, placebo-controlled, multiple ascending dose escalation study of the safety, tolerability, and efficacy of intravenous AP-SA02 in addition to best available antibiotic therapy (BAT) compared to BAT alone (placebo) for the treatment of adults with complicated S. aureus bacteremia. The results from the diSArm study are an important step forward in Armata’s effort to confirm the potent antimicrobial activity of phage therapy and the completion of the study represents a significant milestone in the development of AP-SA02, moving Armata one step closer to introducing an effective new treatment option to patients suffering from complicated S. aureus bacteremia.
The Phase 1b/2a clinical development of AP-SA02 was partially supported by a $26.2 million Department of Defense (DoD) award, received through the Medical Technology Enterprise Consortium (MTEC) and managed by the Naval Medical Research Command (NMRC) – Naval Advanced Medical Development (NAMD) with funding from the Defense Health Agency and Joint Warfighter Medical Research Program.