The drug, Campath , is a cancer treatment that has showed promise as a once-a-year infusion for multiple sclerosis patients.

Compared to a standard MS drug, Campath sharply reduced the number of disabling relapses suffered by patients in a clinical trial. But in 2005, Genzyme disclosed that one patient on Campath had died of bleeding in the brain. The Cambridge company voluntarily suspended its clinical testing of Campath and put a tight surveillance system in place to watch for symptoms of the bleeding disorder.

At a meeting of financial analysts in Boston yesterday, a Genyzme executive said the FDA had lifted the suspension. He said the clinical trial so far has yielded five other cases of the bleeding disorder, called immune thrombocytopenic purpura , or ITP. All of those patients were treated and recovered. With early detection and treatment, the problem amounts to a "manageable risk" for Campath patients, said the company.

Although the trial was effectively complete before the suspension, the lifting of the suspension allows Genzyme to move ahead in discussions with the FDA on two larger trials of Campath. Genzyme expects to launch those trials later this year.

Genzyme, the state's largest biotechnology company, also offered updates yesterday on several other drug-development programs that are underway.

Doctors saw promising results in a small test of a new pill to treat Gaucher disease, a rare genetic disorder. An effective pill would mark a significant change in the care of Gaucher patients, who are currently treated chiefly with an expensive intravenous biotechnology drug also made by Genzyme.

In five patients tested, Genzyme said, its experimental pill helped decrease the severe spleen swelling characteristic of Gaucher disease. The company said one patient was hospitalized for a heart problem that may be related to the drug, but recovered. Based on the current trial, which will ultimately include at least 19 patients, Genzyme plans to ask federal regulators to speed approval of its new pill.

David Meeker , the Genyzme executive in charge of its rare-disease drugs, called the results on the new Gaucher disease pill "great."

"They were at a magnitude and rapidity that we were not necessarily expecting," he said.

Genzyme currently records $1 billion a year in revenues by treating Gaucher patients with Cerezyme, a replacement enzyme manufactured at its Allston factory.

Also during yesterday's presentation, the company forecast that its kidney-dialysis drug Renagel , responsible last year for about $500 million of the company's $3.2 billion in annual revenue, would likely grow into a "blockbuster," or billion-dollar drug, as a next-generation version is introduced.

http://www.boston.com/business/technology/biotechnology/articles/2007/05/17/genzyme_gets_ok_to_resume_testing_of_ms_drug/