Safety and Tolerability of Bacteriophage Therapy for Chronic Rhinosinusitis Due to Staphylococcus aureus

Importance

Staphylococcus aureus infections are associated with recalcitrant chronic rhinosinusitis (CRS). The emerging threat of multidrug-resistant S aureus infections has revived interest in bacteriophage (phage) therapy.

Objective

To investigate the safety, tolerability, and preliminary efficacy of ascending multiple intranasal doses of investigational phage cocktail AB-SA01 in patients with recalcitrant CRS due to S aureus.

Design, Setting, and Participants

This phase 1, first-in-humans, open-label clinical trial of multiple ascending doses was conducted at a single tertiary referral center from December 1, 2015, through September 30, 2016, with follow-up completed on December 31, 2016. Patients with recalcitrant CRS (aged 18-70 years) in whom surgical and medical treatment had failed and who had positive S aureus cultures sensitive to AB-SA01 were recruited. Findings were analyzed from February 2 through August 31, 2017.

Interventions

Three patient cohorts (3 patients/cohort) received serial doses of twice-daily intranasal irrigations with AB-SA01 at a concentration of 3 × 108 plaque-forming units (PFU) for 7 days (cohort 1), 3 × 108 PFU for 14 days (cohort 2), and 3 × 109 PFU for 14 days (cohort 3).

Main Outcomes and Measures

The primary study outcome was the safety and tolerability of intranasal AB-SA01. Safety observations included vital signs, physical examinations, clinical laboratory test results, and adverse events. The secondary outcome was preliminary efficacy assessed by comparing pretreatment and posttreatment microbiology results, disease-relevant endoscopic Lund-Kennedy Scores, and symptom scores using a visual analog scale and Sino-Nasal Outcome Test-22.

Results

All 9 participants (4 men and 5 women; median age, 45 years [interquartile range, 41.0-71.5 years]) completed the trial. Intranasal phage treatment was well tolerated, with no serious adverse events or deaths reported in any of the 3 cohorts. No change in vital signs occurred before and 0.5 and 2.0 hours after administration of AB-SA01 and at the exit visit. No changes in biochemistry were found except for 1 participant in cohort 3 who showed a decrease in blood bicarbonate levels on exit visit, with normal results of physical examination and vital signs. All biochemistry values were normalized 8 days later. No changes in temperature were recorded before, during, or after treatment. Six adverse effects were reported in 6 participants; all were classified as mild treatment-emergent adverse effects and resolved by the end of the study. Preliminary efficacy results indicated favorable outcomes across all cohorts, with 2 of 9 patients showing clinical and microbiological evidence of eradication of infection.

Conclusions and Relevance

Intranasal irrigation with AB-SA01 of doses to 3 × 109 PFU for 14 days was safe and well tolerated, with promising preliminary efficacy observations. Phage therapy could be an alternative to antibiotics for patients with CRS.

Trial Registration

http://anzctr.org.au identifier: ACTRN12616000002482.

Safety and efficacy of a bacteriophage cocktail in an in vivo model of Pseudomonas aeruginosa sinusitis

Pseudomonas aeruginosa (PA) is a bacterial pathogen that frequently displays antibiotic resistance. Its presence within the sinuses of chronic rhinosinusitis sufferers is associated with poorer quality of life. Obligately lytic bacteriophages (phages) are viruses that infect, replicate within, and lyse bacteria, causing bacterial death. The aims of this study were to assess the safety and efficacy of a PA phage cocktail (CT-PA) in a sheep model of rhinosinusitis. The sheep rhinosinusitis model was adapted to simulate PA infection in sheep frontal sinuses. To assess efficacy, after a 7-day biofilm formation period, sheep received twice-daily frontal trephine flushes of CT-PA or saline for 1 week. Biofilm quantitation on frontal sinus mucosa was performed using LIVE/DEAD BacLight staining. To assess safety, sheep received twice-daily frontal trephine flushes of CT-PA or vehicle control for 3 weeks. Blood and fecal samples were collected throughout treatment. Histopathology of frontal sinus, lung, heart, liver, spleen, and kidney tissue was performed. Sinus cilia were visualized using scanning electron microscopy (SEM). The Efficacy arm showed a statistically significant reduction in biofilm biomass with all concentrations of CT-PA tested (P < 0.05). Phage presence in sinuses was maintained for at least 16hours after the final flush. All Safety arm sheep completed 3 weeks of treatment. Phage was detected consistently in feces and sporadically in blood and organ samples. Histology and SEM of tissues revealed no treatment-related damage. In conclusion, CT-PA was able to decrease sinus PA biofilm at concentrations of 10⁸-10¹⁰ PFU/mL. No safety concerns were noted.