Influence of Ly146032 on chemotaxis, chemiluminescence of PMN and lymphocyte transformation in vitro

Daptomycin: The First Approved Lipopeptide Antimicrobial

OBJECTIVE

To review the literature concerning the first Food and Drug Administration-approved lipopeptide antimicrobial, daptomycin.

DATA SOURCES

A PUBMED search was conducted to identify pertinent English-language journal articles between 1985 and November 2003, and additional references were obtained from the bibliographies of these articles. Abstracts from the Interscience Conference on Antimicrobial Agents and Chemotherapy meetings from 1985 through 2003 also were reviewed.

STUDY SELECTION

All studies evaluating any aspect of daptomycin.

DATA SYNTHESIS

Daptomycin is a semisynthetic lipopeptide, the first such antimicrobial agent to reach the marketplace. Its mechanism of action differs from that of the related agent vancomycin in that much of its effect is not because of inhibition of peptidoglycan biosynthesis, but instead is a result of alterations in cell-membrane electrical charge and transport. It exhibits a broad spectrum of activity against gram-positive aerobes and anaerobes, including methicillin-, penicillin-, aminoglycoside-, and vancomycin-resistant strains. In subjects with normal renal function, the terminal disposition half-life is about 7 to 10 hours. It is principally eliminated as unchanged drug in the urine. Available clinical trial data demonstrate efficacy in complicated skin and skin-structure infections resulting from susceptible gram-positive pathogens, but not in pneumonia. The principal adverse event of concern, although rare, is myotoxicity, manifested by muscle pain and/or weakness and elevated serum creatine phosphokinase (CPK) concentrations. The approved dosage regimen is 4 mg/kg intravenously over 30 minutes once daily for 7 days to 14 days. Studies are underway evaluating doses of up to 8 mg/kg once daily.

CONCLUSIONS

Daptomycin, the first lipopeptide antimicrobial to be marketed, exhibits activity against multiresistant gram-positive pathogens, including linezolid- and quinupristindalfopristin-resistant strains. As such, it is a potentially valuable agent to treat infections resulting from such pathogens. To preserve its utility, it should not be used indiscriminately for infections resulting from pathogens sensitive to other antimicrobials. It is probably best used with restricted access and used only for multiresistant gram-positive pathogens where alternative agents cannot be employed. If used, careful monitoring for the signs and symptoms of myotoxicity, including obtaining weekly serum CPK levels, is mandatory. In addition, bacterial sensitivities to this agent should be prospectively monitored by national antimicrobial surveillance programs like SENTRY, TRUST, and LIBRA.

Daptomycin

Daptomycin is a lipopeptide antibacterial with rapid in vitro activity against Gram-positive cocci. It is approved for use in patients with complicated skin and skin structure infections (cSSSIs) caused by specified Gram-positive cocci. In vitro, daptomycin was active against Staphylococcus aureus (including meticillin-resistant strains), Streptococcus pyogenes, S. agalactiae, group C and G beta-haemolytic streptococci and vancomycin-susceptible Enterococcus faecalis. Bactericidal activity in vitro was rapid and concentration dependent. In two randomised, investigator-blinded, multicentre trials in patients with cSSSIs, intravenous daptomycin 4 mg/kg once daily was as effective as standard therapy (intravenous semi-synthetic penicillin 4-12 g/day or vancomycin 1 g 12-hourly). Clinical success rates assessed 6-20 days after treatment end were 82.1% in daptomycin recipients and 82.9% in recipients of standard therapy (pooled data). In patients with cSSSIs, the adverse event profiles of daptomycin and vancomycin were similar. Creatine phosphokinase (CPK) levels increased in 2.8% of daptomycin recipients and 1.8% of patients who received standard therapy; only one daptomycin recipient (0.2%) experienced increased CPK levels and muscle symptoms that were not associated with any comorbid factors.

Effects of vancomycin, teicoplanin, daptomycin and coumermycin on normal immune capabilities

Vancomycin, teicoplanin, daptomycin, and coumermycin were investigated for immunomodulatory activity on both humoral and cell-mediated immune responses in Balb/c mice. All four antibiotics did not produce any interference with these responses as measured by hemolytic plaque assay and delayed-type hypersensitivity to sheep red blood cells. The administration of these antibiotics for seven days did not affect the peripheral blood leukocyte count or spleen weights. When these antibiotics were tested for their interaction with human polymorphonuclear phagocytic activity, no alteration in this activity was observed. These findings suggest that vancomycin, teicoplanin, daptomycin, and coumermycin may be safely used for the treatment of infections without altering host-defence mechanisms.