The government's approval of Periostat won't end the scraping away of hardened plaque that patients now endure, but the pill did significantly improve their gums in tests and might make dental visits less painful.
"This is a whole new concept" in treating gum disease, said Dr. Sebastian Ciancio, past president of the American Academy of Periodontology, who studied Periostat at the State University of New York, Buffalo. "For the first time, we have a drug that ... helps the body begin to heal."
Until now, periodontal treatments have focused just on attacking the bacteria that cause gum disease.
But scientists at SUNY's Stony Brook campus accidentally discovered that bacteria aren't the whole problem. The mouth reacts to the germs with inflammation that literally breaks down the gums and eventually the bones that hold teeth in place.
Periostat suppresses the enzyme responsible for that breakdown, so the pill together with scraping away hardened bacteria helps slow, or perhaps even halt, gum disease.
Finding that enzyme's role "was the eureka discovery," recalled lead researcher Dr. Lorne Golub. Using Periostat daily, "it looks like we've arrested the disease in cases where patients were told by their dentists that they were probably going to lose their teeth."
Manufacturer CollaGenex Pharmaceuticals announced the Food and Drug Administration's approval of Periostat on Thursday, saying the pill available by prescription only will be on pharmacy shelves within two months. A price has not been finalized, but a spokeswoman said treatment would cost between $1 and $4 a day.
The American Dental Association greeted the pill "with guarded optimism," said Dr. Dan Myer, its associate scientific director.
Dentists want more detailed studies of the drug's long term effects, and patients still must properly brush and fight the bacteria that cause gum disease, he stressed. But Periostat "does have the promise of slowing down the disease."
Half of all Americans have gingivitis, a gum inflammation often controlled with proper brushing and flossing. But in at least 20 million Americans, the problem advances to serious periodontal disease, where gums pull away from the root of teeth and underlying bone is destroyed.
Dentists use special instruments to regularly scrape off plaque, sticky bacteria, that hardens below the gum's surface, a painful procedure called "scaling and planing." Dentists also prescribe topical antibiotics. Still, some patients need extensive gum surgery and lose teeth.
Golub discovered that antibiotics sprayed onto the gums of rats both attacked germs and suppressed the enzyme collagenase, the substance that destroys gum tissue. Wondering if that was just an extra effect of antibiotics or clinially important, Golub studied specially bred germ-free rats so rare they cost $70 each and found that suppressing collagenase was a new and separate way to attack gum disease.
A weakened form of the antibiotic doxycycline, so weak that it doesn't attack bacteria but does target collagenase, seemed to work best. CollaGenex named the pill Periostat and studied it in 800 patients. In one pivotal study, patients who took Periostat after standard plaque scraping had their gums reattach to teeth 52 percent better than patients who had plaque removal alone. Periostat patients also had 67 percent more improvement in the depth of gum loss.
Study participant Jo Ann Buczkowski of North Tonawanda, N.Y., said that since taking Periostat, her regular plaque scalings are less painful. "I used to do a lot of bleeding before and I get very little bleeding now," she said.
Nobody knows how long patients should take Periostat, something scientists continue to study. Their chief concern is whether chronic use could contribute to the threat of antibiotic resistance, but a study of 100 patients who took Periostat for a year concluded the pill is too weak to attack germs and thus isn't a threat, Ciancio said.
Periostat is the third new gum treatment the FDA has approved in six months. Dentists also now can place on the gums a gelatin-like chip and biodegradable polymer to directly deliver germ-attacking drugs.
By Lauran Neergaard