A treatment regimen using a combination of two established drugs may alleviate radiation sickness, with potential application in nuclear emergencies, according to a study led by Harvard-affiliated researchers at the Dana-Farber Cancer Institute and the Children’s Hospital of Boston.

The study, funded primarily by a grant from the Defense Advanced Research Projects Agency, found that the therapy was effective in mice even when administered up to a day after radiation exposure, giving it an enormous advantage over existing therapies. The drug combination thus has potential for use in response to emergencies like the recent Fukushima nuclear disaster in Japan.

The study was led by Harvard Medical School professors Eva C. Guinan and Ofer Levy. Mice exposed to radiation were administered a combination of the antibiotic fluoroquinolone and a synthetic version of the immune system protein BPI. While such radiation exposure would normally prove fatal for mice within thirty days, 80% of those treated with both agents were still alive a month later. Furthermore, the treatment was shown to be effective even if administered 24 hours after exposure.

“I remember that day, where we all wanted to crowd around the microscope together,” said Levy. “As a scientist, there’s a reflex to think ‘could this be too good to be true?’ But we’ve repeated these results with hundreds of mice and it’s highly statistically significant.”

The research, which represents five years of work, is the latest in the pair’s long-time collaboration. Levy came to Boston after training at the New York University research laboratory where BPI was discovered by Jerrold P. Weiss, one of the study’s co-authors, and Peter Elsbach. Soon after, Levy was introduced to Guinan and the pair began investigating the abnormal deficiency of BPI in transplant patients after being exposed to radiation.

“That made us believe that replacing BPI could decrease toxicity,” explains Guinan.

After publishing a study together, the pair were contacted by DARPA and asked to consider investigating radiation mitigation by applying their research on irradiated transplant patients.

“They proposed to give us a grant with the specific scope of looking at treatment effective at 24 hours after radiation exposure,” recalls Levy. “That’s a tall order.”

Although much remains to be done, the federal government could decide to stockpile the combination of agents for use in emergency situations. The drugs’ effectiveness 24 hours post-exposure is important from a practical standpoint, given the time it could take to deliver treatment in a mass casualty situation.

“It’s important to have things like this available worldwide where this might be necessary. Let’s cross our fingers and hope it won’t be necessary,” said Guinan.

Despite the study’s success, further research would be required to develop an effective treatment regime for radiation sickness.

“We have to remember to not get too impressed with a first study,” said Guinan. “We’re incredibly excited, but we also recognize this is a first step. There’s a lot of work left to do.”