Sparfloxacin may have role in your formulary

Antibiotic is potent against LRT infections

On the eve of apparent Food and Drug Administration approval, sparfloxacin, a potent antibiotic already in heavy use in Japan and Europe, may have difficulty finding a therapeutic niche in some managed care organizations in the United States. Cost is the main reason, but officials at Rhone-Poulenc Rorer, maker of the drug, say sparfloxacin is not just another

fluoroquinolone, but a possible replacement for Biaxin in the treatment of resistant lower respiratory tract (LRT) infections.

Rob Livesay, RPR’s director of marketing for anti-infectives, says the company plans to target sparfloxacin as a treatment for community-acquired pneumonia, a disease that costs the American health care system more than $20 billion a year, according to the Centers for Disease Control and Prevention. An estimated four million Americans develop the disease each year, with about 15% requiring hospitalization. The only other indication the company is seeking approval for at this point is acute bacterial exacerbations of chronic bronchitis.

Pharmacy directors should expect the following pitch from RPR this winter: Sparfloxacin is a respiratory fluoroquinolone, not a replacement for ciprofloxacin, but a replacement, perhaps, for Biaxin — a drug Livesay says has a big share of the pneumonia market but questionable effectiveness against certain pathogens — Haemophilus influenzae for example.

Sparfloxacin’s main advantage over currently available antibiotics is its effectiveness against a wide range of gram-positive bacteria, including penicillin-resistant Streptococcus pneumoniae, and its ability to eradicate atypical pathogens — chlamydial pneumonias, for example, or mycoplasma infections.

Benjamin Lipsky, MD, an epidemiologist at the VA Puget Sound Health Care System and lead U.S. investigator for the drug, says sparfloxacin has a future in this country because of rising penicillin resistance. Lipsky says some cities have penicillin-resistant rates approaching 20%, and in most areas of the country resistance is rising, he adds.

Still, cheaper treatments are available for amoxicillin-resistant pneumonias, and that, as they say, is the bottom line in managed care. Otto Wolke, RPh, chief of the in-house formulary at Geisenger Health Plan in Danville, Ill, says he probably won’t put sparfloxacin on the formulary for precisely that reason. "For us, the place for fluoroquinolones is below the belt. Anything to replace trimethoprim-sulfamethoxazole, cephalexin, or amoxicillin is a therapy I don’t need."

Wolke says boycotting sparfloxacin at his institution makes economic sense. "You’re probably looking at a 10 to 14 day course of therapy at $7 or $8 a dose. That’s $80 to $120 — which is outrageous, given what’s out there." (RPR hasn’t yet disclosed the price of sparfloxacin tablets.)

What’s out there for Geisenger patients who need medication for a respiratory problem are the old (and cheap) standbys. Patients usually start off with a course of amoxicillin, then graduate to a second-generation cephalosporin if needed. Erythromycin is occasionally used, with graduation to Biaxin if needed.

Wolke admits amoxicillin often doesn’t work in patients with community-acquired pneumonia at his organization, and thus patients wind up taking more expensive drugs anyway.

Lipsky suggests this is one place where using sparfloxacin might make sense. "I think when it can substitute for a combination of drugs — an erythromycin and a fluoroquinolone or a penicillin and a macrolide — it would be cost-effective."

With community-acquired pneumonia often affecting young people — college students, for example — as well as the elderly, compliance is another consideration, Lipsky says. Sparfloxacin is dosed once daily; erythromycin, sometimes up to four times a day.

Sparfloxacin is gaining some pre-market notoriety for two side effects: significant photosensitivity and a slight prolongation of the QTc interval in some study subjects. Lipsky says the former side effect is more annoying than dangerous ("It’s not life-threatening. It’s like a bad sunburn."), and the latter effect, while statistically significant, is of little clinical import. "It’s very unlikely to be a a problem," Lipsky says. Still, patients on sparfloxacin will probably be advised not to combine it with drugs that also affect the EKG — terfenadine, for example.

Livesay says RPR’s marketing plan for sparfloxacin will target areas of the United States where penicillin resistance is especially high. If you’re in one of those areas, pharmacy directors, get ready for the hard sell.