By Brenda L. Mooney
BETHESDA, MD – After years of red tape, the military finally has received approval to proceed with the human-use protocol for Arbekacin, an antibiotic shown in laboratory tests to be effective against multi-drug resistant (MDR) pathogens such as Acinetobacter, nicknamed Iraqibacter due to its prevalence during the war in Iraq.
“Isn’t it ironic that approval was finally given at a time when the [Afghanistan] war is winding down and our population of wounded warriors is shrinking?” said Army Col. Michael Zapor, MD, an infectious diseases physician at Walter Reed National Military Medical Center (WRNMMC), in Bethesda, MD. Zapor was instrumental in pushing for the new antibiotic to treat increasingly resistant infections.
“Of all the bacterial species found on the planet, relatively few are intrinsically multi-drug resistant pathogens,” Zapor said in an Army press release. “In Iraq and Afghanistan, the bacterium known as Acinetobacter is one such MDR bacterium that has caused problems in our patient population.”
Acinetobacter, often found in the water and soil of regions such as Iraq and Afghanistan, is not especially virulent and causes serious problems only in patients whose immune systems are severely compromised or when the bacterium insinuates itself deep into macerated tissue, as is the case with open, battlefield wounds.
The bacteria also infected the wounded during the Vietnam War, Zapor noted, but had not yet become resistant to most antibiotics.
“We’re losing antibiotics much faster than new ones are coming through the pipeline and made commercially available,” he said. “In the 1950s, penicillin cured a lot of bacterial infections. Not so now.”
Because of fears that more pathogens will become pan-resistant, Zapor and others have fought for the ability to use new antibiotics not yet approved in the United States.
Zapor, who was a battalion surgeon with the 10th Mountain Division in Iraq, first recognized in 2004 that Arbekacin, which was being used in Japan for the treatment of pneumonia and septicemia caused by methicillin-resistant Staphylococcus aureus (MRSA), could be a weapon against other MDR pathogens, including Acinetobacter.
Lab trials at Walter Reed found Arbekacin to be effective against many isolates of Acinetobacter, as well as other potentially harmful bacteria, such as E. coli, Klebsiella pneumoniae, Enterobacter and Pseudomonas aeruginosa, in addition to MRSA. As a result, Zapor drafted a human-use protocol, with the U.S. Army Medical Materiel Development Activity (USAMMDA) coming on as a sponsor in 2010.
While the Food and Drug Administration was encouraging, the protocol had to work its way through a maze of scientific and institutional reviews. Approval was received this summer.
No one was immediately treated with the antibiotic upon the approval of the human protocol, however, partly because of the strict eligibility requirements to delay development of resistance to Arbekacin, Zapor said.
The drug is only approved for use at WRNMMC in patients with MDR infections of the lungs, urinary tract, soft tissues, skin, bones and blood and only when other antibiotics are either ineffective or contraindicated.
In addition, with troops out of Iraq and the Afghanstan war winding down, “we anticipate an infrequent need for Arbekacin at this time,” he added.
Long before Arebekacin became available for use, infection-control measures, such as separating Iraqi and U.S. wounded in intensive-care units, had reduced the incidence of Acinetobacter, according to DoD data.
Zapor recounted that military medical leadership “learned that the wounded Iraqi soldiers tended to be colonized with Acinetobacter” at a much higher rate than the Americans, he said. “One possible scenario is that, as doctors and nurses moved from bed to bed, they might have unintentionally transmitted the bacterium between patients.”
“Over time, the indigenous wounded were separated from the American wounded, and the prevalence of Acinetobacter colonization among the latter declined,” he said.
Meiji Seika Pharma Co. Ltd. has agreed to supply Arbekacin for the protocol at no cost. During an earlier investigation phase, a U.S. Army Medical Materiel Development Activity (USAMMDA) site-assessment team visited three Meiji Seika Pharma facilities in Japan to determine acceptability of the company’s manufacturing capabilities supporting the protocol.
During the site assessment, the team visited three facilities: the Meiji headquarters in Tokyo, the initial drug product facility in Kitakami and the final drug product facility in Odawara.
“The assessment of these facilities is vital to due diligence for the U.S. Army to ensure proper quality of this antibiotic when used in the treatment of the wounded warriors,” Christa Madock, site-assessment team leader and product manager for the Force Health Protection Division at USAMMDA, said in a press release at the time.
The goal of the visit was to confirm that the facilities are compliant with good manufacturing practices that meet U.S. federal regulatory requirements.
Arbekacin, a semi-synthetic aminoglycoside antibiotic, is licensed in Japan under the trade name Habekacin for the treatment of pneumonia and septicemia caused by MRSA. Arbekacin was originally synthesized from dibekacin in 1972. In 1990, it was registered and marketed in Japan.
According to Madock, Arbekacin also has a broad spectrum of activity against Gram-negative bacteria including multidrug-resistant organisms isolated from Walter Reed inpatients.