Orbactiv and Dalbavancin: One and Done

Oritavancin (Orbactiv) and dalbavancin (Dalvance) are semisynthetic lipoglycopeptide antibiotics with activity against Gram-positive organisms, including methicillin-resistant Staphylococcus aureus. They both received FDA approval in 2014 for the treatment of acute bacterial skin and skin structure infections (ABSSSI).

The game-changing property of these antibiotics is their one-time dosing, although dalbavancin can be given as a 2-dose regimen. They also have long terminal half-lives of 245 hours and 346 hours for oritavancin and dalbavancin, respectively.

Both antibiotics are bactericidal and inhibit the transglycosylation and transpeptidation step of cell wall biosynthesis. Oritavancin also disrupts of bacterial membrane integrity, but dalbavancin does not. Given oritavancin’s dual mechanisms, the drug may have increased efficacy and reduced risk of resistance.

From an emergency department standpoint, the possibility of avoiding admission among stable patients with ABSSSI is appealing.

Both drugs are costly, with wholesale prices around $3000 to $5000, but consider the cost of vancomycin. My guess is that it’s probably not that much higher, but other pertinent pros and cons for oritavancin and dalbavancin should be taken into account when deciding whether to use these antibiotics in the emergency department.

Pros

• Assures compliance because only 1 dose is needed.
• Targets common organisms in ABSSSI.
• Convenient for patients to avoid admission and pharmacy visits.
• No drug-level monitoring is required.
• Peripherally inserted central catheter isn’t needed for outpatient antibiotic therapy.
• Safety and efficacy are comparable with vancomycin’s in clinical trials for ABSSSI.

Cons

• They’re expensive.
• Delayed hypersensitivity reactions given long duration.
• If treatment fails, there’s the question about which antibiotic to use next.
• Oritavancin is a 3-hour infusion and dalbavancin is a 30-minute infusion.
• Both antibiotics are only compatible with 5% dextrose in water.
• Little data on oritavancin dosing in severe renal insufficiency.
• Use of intravenous (IV) heparin is contraindicated with oritavancin for 120 hours because of false elevations of the activated partial prothrombin time.

While I believe that the use of oritavancin and dalbavancin should be rare, there may be certain cases and circumstances where the antibiotics could be ideal. Although I’m not generally a proponent of giving IV antibiotics to patients who will be discharged home, avoiding admission for patients who may need them is an attractive option.