1420. Successful Treatment of Acute Osteomyelitis with Once-Weekly Oritavancin

BACKGROUND: Osteomyelitis is a complex infection with high morbidity and without standard treatment guidelines. Intravenous therapy is the standard of care, often requiring multiple daily antibiotic doses in an infusion center or home setting. Many of these infections are gram-positive and therefore are commonly treated with vancomycin or daptomycin. Oritavancin, a lipoglycopeptide antibiotic was FDA-approved in 2014 as a single dose regimen for treatment of ABSSSI and may be useful for the treatment of osteomyelitis where once-weekly therapy presents logistical advantages over vancomycin. METHODS: This was a retrospective case series of patients treated with four to six weekly doses of oritavancin at 20 infusion centers in 6 states under the care of 37 infectious diseases physicians. Patients were administered oritavancin between January 1, 2016 and December 31, 2018. Post therapy evaluation was completed by an ID PharmD utilizing a standardized set of questions. This study has been approved by an IRB. RESULTS: One-hundred 34 patients received oritavancin during the study period, all for acute osteomyelitis. All patients received baseline diagnostic imaging with MRI, along with clinical evaluation from a Metro Infectious Disease Consultants physician throughout their care. Cultures showing staph aureus, either MSSA or MRSA, were present in 120/134 (89.5%) of patients with MRSA encompassing the majority of patients 96/120 (80%). Patients were dosed with 1200 mg initially, and 800 mg weekly thereafter. At the end of therapy, clinical cure or improvement was achieved in one-hundred eighteen patients (88%). Follow-up was obtained through phone calls with all patients at 3 months and 6 months post-therapy in one-hundred thirty patients. Persistent or relapsing infection was diagnosed in patients 13/120 patients (10.8%). Nine patients were readmitted, but none for osteomyelitis or adverse drug reactions. Adverse reactions were reported in 5 patients (3.7%) including hypoglycemia (3) and tachycardia (2) in which 2 went to the emergency room, but were not admitted. CONCLUSION: The use of oritavancin for gram-positive infections resulted in clinical cure or improvement in the majority of patients treated, offering a convenient and effective therapeutic option for the treatment of osteomyelitis. DISCLOSURES: All authors: No reported disclosures.