Single-agent therapy for infections in neutropenic cancer patients.

The initial therapy of febrile neutropenic cancer patients is an evolving, interesting, and important area of medical research. The introduction of carbenicillin provided the clinician with an antibiotic that had significant activity against Pseudomonas aeruginosa. Prior to the availability of this drug, neutropenic patients with bacteremia due to this organism did no better with antibiotic therapy than without it. Since then, several agents including carboxy- and ureidopenicillins, aminoglycosides, cephalosporins, monobactams, and carbapenems have appeared on the scene and strengthened our therapeutic armamentarium. Since some of them have an expanded spectrum of activity, they have been widely utilized for combination therapy. More recently, several clinical trials have addressed the feasibility of using them alone as initial empiric therapy in these patients. Some of the studies have achieved good results, especially when treating gram-negative infections, although these results should be interpreted with caution, since the studies were usually conducted under controlled conditions. These trials have, however, not been as successful when treating gram-positive organisms, which have again become an important cause of infection in these patients; in some of them, a specific antibiotic against these organisms had to be added. How will this approach utilizing newer antibiotics compare against a more conventional regimen of two synergistic agents? Hopefully, this will be better investigated and defined in the near future.