999. Clinical Outcomes of Off-label Dalbavancin Use within an Outpatient Parenteral Antibiotic Therapy (OPAT) Program

Background Dalbavancin is approved for the treatment of acute bacterial skin and soft structure infections (ABSSSI). There is less data on outcomes of off-label use of dalbavancin for orthopedic and other complex infections. In this case series, we aim to analyze clinical outcomes of deep-seated infections treated with IV dalbavancin instead of long-term IV antibiotics post-discharge. Methods We conducted a retrospective review of adult patients treated with off-label IV dalbavancin between January 2020 and February 2022 at an academic center in the Bronx, NY within a long-standing outpatient parenteral antibiotic therapy (OPAT) program. Outcomes of interest included 90-d infection recurrence, prothesis retention, mortality, adverse events, and characteristics of antibiotic regimens. Results Nineteen patients received dalbavancin for off-label indications. Dalbavancin was used primarily for hardware, bone and joint, and complicated soft tissue infections (table 1). The predominant pathogen was Staphylococcus aureus. Source control was achieved in 12 (63%) patients via debridement alone (5), debridement with prosthetic device retention (4), or debridement and complete hardware removal (3). The most common dosing regimen was two-doses (1000-mg, 500-mg) one week apart. Two (11%) patients (both with initial prosthesis retention) had infection recurrence within 90 days of dalbavancin and eventually required removal (table 2). One patient experienced recurrence after 90 days and required removal. The remaining patient with prothesis retention has not experienced infection recurrence to date. Concomitant antibiotics while on dalbavancin and suppressive antibiotics following therapy were common. No patient died within 90 days of therapy and no adverse drug effects were reported. Conclusion Dalbavancin use for hardware infections, osteomyelitis, complicated soft tissue infections, and spinal infections is associated with favorable cure rates, safety profile, and tolerability. Improved outcomes may be achieved with hardware removal. Dalbavancin off-label use within an OPAT program may facilitate early discharge or prevent admissions in eligible patients, although further study is needed. Disclosures All Authors: No reported disclosures.