WASHINGTON, Dec. 19 (UPI) -- An experimental antibiotic may prove life-saving if there is another anthrax attack in the United States, similar to the one that killed five people in 2001.
New treatment options against the deadly disease are crucial, since some anthrax strains have already developed resistance against the only current treatment, ciprofloxacin, sold as Bayer's Cipro, researchers say.
That new anti-anthrax alternative might be an antibiotic known as dalbavancin.
Researchers said that dalbavancin, which is still undergoing testing among people with a variety of infectious diseases, has such a long half-life that it could be offered as a once-a-week IV therapy, making treatment easier for people exposed to anthrax.
"Dalbavancin appears to be a good candidate for treatment in post-anthrax exposure situations," said Henry Heine, a microbiologist at the United States Army Medical Institute of Infectious Diseases (USAMRIID), Ft. Detrick, Md.
Once dalbavancin is approved, a course of treatment would require only 7 or 8 administrations as opposed to 120 doses of Cipro pills.
In a presentation at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy, Heine said the drug has already proved effective to animals exposed to anthrax during laboratory studies.
Because human testing with anthrax spores cannot be performed, Heine and colleagues tested the potency of dalbavancin as a life-saving treatment using mice. The animals were placed in an enclosure and were exposed to aerosolized anthrax from the Ames strain of Bacillus anthracis.
About 24 hours after exposure, some of the mice were given dalbavancin. Another batch of mice was given the drug after 48 hours, and if there were mice still alive at 60 hours, they were also given the drug.
All the untreated mice were dead within 72 hours of exposure. Depending upon the dose of the drug administered to the mice or the time of delivery after exposure, 80 percent to 100 percent of the treated animals survived, Heine said. He said his research is being funded by the Defense Threat Reduction Agency.
"I'm impressed to see that there are mice that recovered after 36 hours of exposure to B. anthracis," said John Finn, president of Rx3 Pharmaceuticals, San Diego, Calif. "We need other drugs. I go to sleep every night worried about the possibility of a Cipro-resistant strain of anthrax being released."
Finn suggested that fairly competent laboratory technicians working in low levels of a sophisticated facility could create a Cipro-resistant anthrax. However, he said that engineering a strain of anthrax that could be resistant to dalbavancin would be far more difficult, and maybe not possible.
Whatever the possibility, Finn said, "We have to accelerate our research in this area."
