Drug of the Month – Daptomycin (Cubicin ®) from Cubist pharmaceuticals, marketed by Novartis
Bacterial resistance to antibiotics has been an increasing problem for decades. Resistance is a particular concern with certain pathogens such as Staphylococcus aureus and E. faecium. The CDC has estimated the incidence of methicillin-resistant S. aureua (MRSA) infections at around 50% (1). Glycopeptide-resistant E. faecium (GRE) is also a commonly encountered nosocomal pathogen in the US (2). Overall treatment costs are increased by an average of 20% by resistant pathogens (3). Home infusion therapy with newer drugs like Cubicin can play a pivotal role in better outcomes and lower costs.
What is Cubicin (4)?
Cubicin is daptomycin, is a lipopeptide. Its main mechanism of action is to bind to the bacterial cell membrane leading to a loss of the membrane potential, which results in the inhibition of protein, DNA and RNA synthesis. Ultimately, this causes cell death. Daptomycin is indicated for complicated skin and skin structure infections, bacteraemia and right-sided endocarditis caused by S. pyogenes, S. aureus (including MRSA), S. dysglactiae subsp. equisimilis and Enterococci including GRE and VRE.
How is Daptomycin provided and prepared?
Daptomycin is supplied as a sterile preservative-free pale yellow to light brown lyophilized 500 mg cake that must be reconstituted with 0.9% saline prior to use. The solution is preservative free and must be administered by intravenous infusion given over a period of at least 30 minutes. There is limited compatibility data available for Cubicin, but it is known to be compatible with normal saline and lactate ringers and it is not compatible with dextrose-containing diluents.
What are the adverse reactions associated with daptomycin infusion?
The most common adverse reactions associated with daptomycin are injection site pain and allergic reactions, Daptomycin infusion has notably been associated with myopathy. Monitoring of the CPK is necessary during the duration of therapy with daptomycin. It is recommended to discontinue daptomycin in patients with CPK elevated beyond 1000 with symptoms or with CPK elevations 10 times the upper normal limit without symptoms. Other reported common adverse events were constipations, headache and nausea.
How is Daptomycin administered at home?
The current prescribing information states that the solution has been shown to have stability in the vial for 12 hours at room temperature or 48 hours refrigerated. If a 500 mg dose is necessary, the Mini-bag plus ® system (Baxter) can be utilized, of which the daptomycin infusion bag can have an extended stability of 15 days as soon as the protective over-wrap is disposed of.
How can we sell daptomycin?
With the increase of MRSA vancomycin treatment failures, daptomycin can be considered the next line therapy for its recommended indications (5).
Compared to Daptomycin:
- Synercid – not active against E. faecalis, multiple daily dosing and similar side effect profile.
- Linezolid – multiple daily dosing
- Tigecycline – multiple daily dosing, possible sun sensitivity allergy, increase incidence of pseudomembranous colitis and more drug interactions
Once daily dosing allows for convenient administration of daptomycin in the patient’s home. Thus if daptomycin is the preferred regimen for a patient’s infection, referring a patient to a home infusion company will reduce overall treatment costs compared to hospitalization, and will improve quality of life.
Who pays for Daptomycin?
Virtually all private third-party payers will pay for this medication, though it typically requires prior authorization. Though the availability of specific IV infusions, such as Cubicin ®, under Medicare will vary based on the individual drug formularies and plan benefit designs of the Part D plans. Medicare beneficiaries may need to pay out-of-pocket or find other sources of coverage for the supplies and administration services associated with home infusions under Part D, as plans will not cover the costs of these items and services. Thus it is beneficial to determine if the medication will be covered prior to admission with a home care company.
How is Daptomycin coded?
The J code for daptomycin is J0878.
What is the financial impact of Daptomycin?
The AWP of daptomycin is $134.49 per 500mg vial. Complicated skin and skin structure infections are treated with 4mg/kg/day IV (FDA approved dose), while bloodstream and/or endocardial infections are dosed at 6 mg/kg/day.
What are the special considerations that pertain to daptomycin?
Daptomycin is not an inhibitor or inducer of human cytochrome P450 isoform. Pharmacokinetic and pharmacodynamic interaction studies involving aztreonam, tobramycin, warfarin (single dose study), simvastatin (though the possibility of myopathy is increased), and probenecid did not result in significant drug interactions.
- www.cdc.gov
- Abb. Int J Anti Agents. 2007;29:356-365
- Engemann, Carmeli, Cosgrove, et al. Clin Infect Dis. 2003;36:592
- Cubicin prescribing information. Lexington, Mass, Cubist Pharmaceuticals. 2007
- Hidayat LK, Hsu DI, et al.. Arch Internal Med. 2006; 116: 2139-2144