Cost-effectiveness of daptomycin comparable to vancomycin-gentamicin

The cost-effectiveness of daptomycin may be similar to that of vancomycin-gentamicin, even when the cost of vancomycin is $0, according to results of a new study.

Researchers compiled data from an open-label, randomized trial comparing daptomycin (Cubicin, Cubist) with vancomycin-gentamicin in patients who had methicillin-resistant Staphylococcus aureus with or without endocarditis.

The researchers considered three cost strata to determine results. The first was study drug acquisition, which included daptomycin ($0.37/mg), vancomycin ($7/g) and gentamicin ($0.12/mg). The second stratum was stratum one plus the cost of therapy for treatment failures and adverse events, therapeutic drug monitoring and preparation and administration of all medications. The third was stratum two plus hospital bed costs.

The average wholesale price of the drugs and the costs in a typical community hospital were used for calculations.

The cost-effectiveness ratio was defined as the costs divided by the proportion of instances of successful treatment. Among 45 patients in the daptomycin group, there were 20 cases of successful treatment. Among 44 patients in the vancomycin-gentamicin group, there were 14 successes.

The average cost-effectiveness ratios for daptomycin were as follows:

$4,082 (range, $1,062-$13,893) for stratum one (P<.001).
$4,582 (range, $1,109-$21,882) for stratum two (P=.026).
$23,639 (range, $6,225-$141,132) for stratum three (P=.82).

The average cost-effectiveness in the vancomycin-gentamicin groups were as follows:

$560 (range $66-$1,649) for stratum one (P<.001).
$1,635 (range, $163-$33,444) for stratum two (P=.026).
$26,073 (range, $5,349-$187,287) for stratum three (P=.82).

The results of sensitivity analyses indicated that if the cost of vancomycin was $0, the cost effectiveness of the stratum three ratios were not different ($23,639 and $25,668; P=.85).

Bhavnani SM et al. Clin Infect Dis. 2009;49:691-698.