FDA Approves New Treatment for Anthrax

From the WebMD Archives

Aug. 31, 2000 (Washington) -- There is a new first-line of defense against anthrax, a deadly infection that could be brought about by the hands of a bioterrorist. U.S. regulators Thursday approved the antibiotic Cipro to treat and protect people, should they become exposed to Bacillus anthracis, the germ that can cause a form of the infection called inhaled anthrax.

In nature, inhaled anthrax is an extremely rare form of the disease. It generally results from exposure to contaminated animal hides and hairs. But it's easy to incorporate the germ into an aerosol preparation, which can be used as a weapon against the general public. And with only a little more tinkering, strains of the germ can be developed that are resistant to some common antibiotics. Today's federal approval is an attempt to be ready for an anthrax crisis if it ever happens.

"The approval of Cipro for this indication represents both the manufacturer's and FDA's response to a public health need. This is the first antimicrobial drug application submitted to the FDA for an indication which would result from the intentional use of a biological agent," the FDA says.

"We recognize the government's need to be prepared for a biological attack, and we are pleased that Cipro can play an important role in the preparedness plans," says Carl Calcagini, vice president of regulatory affairs at Bayer Corp., the maker of Cipro.

Still, there is no direct evidence that Cipro will work. The approval was based upon animal studies and Cipro's historical profile. Human clinical trials were not possible because of the ethics involved with using a deadly biological agent in tests on people.

In the animal studies, the antibiotic resulted in about a 90% survival rate, depending upon the amount used and when it was administered. It also was more effective than two older antibiotics often used to treat less-deadly versions of anthrax.

But while difficult to determine, this evidence combined with Cipro's historical profile provides at least some assurance that the antibiotic will work, the FDA says. Cipro has been used to treat a total of 14 infections in more than 100 million Americans since its approval in 1987, including a number of respiratory symptoms that are similar to those caused by anthrax, the feds note.

The threat of an anthrax attack is also very real, says Michael Osterholm, president of the Infection Control Advisory Network and a noted expert on bioterrorism. "Cipro is just a better drug in general," he tells WebMD. But the approval was also necessary in order to prepare the nation for a potential attack with aerosolized versions of anthrax specifically tailored to resist the older antibiotics, says Osterholm, who often advises the government on issues regarding bioterrorism.

"What we really have here today is a number of groups that have the ability to use anthrax and want to do it," Osterholm says.

To account for these needs, the government already has begun stockpiling Cipro, Osterholm tells WebMD. How much Cipro is on hand remains a matter of national security. However, the Department of Health and Human Services is spending $278 million this year on preparations for bioterrorism, such as stockpiling Cipro, and the approval of Cipro for this indication can only help move those preparations along.