Analysis: Transplant drug fights leukemia

ORLANDO, Fla., Dec. 11 (UPI) -- Doctors said Monday that a drug often used in preventing organ rejection in transplant patients appears to have a major impact on the most common form of adult leukemia.

"Campath (alemtuzumab), used as a single agent, produced the highest response rate among patients with chronic lymphocytic leukemia (CLL), seen in any front-line trial," Peter Hillmen, consultant hematologist at the Leeds Infirmary in the United Kingdom, told United Press International.

In the study presented at the 48th annual meeting of the American Society of Hematology in Orlando, Fla., Hillmen told more than 21,000 conference attendees that 83 percent of patients treated with Campath responded to therapy.

That was significantly greater that patients who responded to an alternative medication, chlorambucil, Hillmen said.

But the bigger story, he added, is that the toxicity of Campath was similar to that of the other anti-cancer drug.

"We have had concerns that there might be some problems with Campath being involved in excess infections," said William Wierda, assistant professor of medicine at the University of Texas M.D. Anderson Cancer Center in Houston. "I use Campath frequently in treating patients with (CLL), so this study is encouraging."

Hillmen and colleagues recruited 297 patients for the study and compared outcomes with chlorambucil, considered by many doctors as the best tolerated medicine for patients with CLL. The disease, a slow progressing form of leukemia, is diagnosed in as many as 12,000 people a year in the United States. Ninety percent of patients are diagnosed when they are over 50 years of age.

"The most important findings of the study are first of all, that the effectiveness of Campath as a single agent has been confirmed now in a randomized trial and it is very similar to what we found to the previous non-randomized trials," Hillmen explained.

"The second and very striking message is that the toxicity when we compare the Campath patients with chlorambucil patients is very similar," he said. "In fact, all of the toxicities seen in the Campath were expected and manageable. This is very important because, in the past, Campath has been used in people who have failed treatment and who were refractory to conventional treatments.

"Those patients, regardless of what therapy you use, have a very high incidence of infections and high risk with any treatment. It had been thought that Campath could be responsible for many of these infections and high-risk problems that patients got. This study, to some extent, allays that fear. A lot of the complications, we found, are due to the disease, not the Campath. "

The researchers reported that:

-- About 83 percent of patients on Campath responded to treatment, compared to 55 percent of patients on chlorambucil.

-- About 24 percent of the patients on Campath experienced a complete response to the drug -- there was no evidence of disease in the patients, compared to 2 percent of the patients on chlorambucil.

-- The risk of suffering disease progression or dying from the disease was reduced by 42 percent compared to chlorambucil.

Wierda told UPI that most people are diagnosed with CLL when routine blood tests come back showing excess white blood cell counts.

"This is the type of disease in which a doctor would say to a patient, 'You have leukemia. But don't worry, it's a good leukemia,'" he said.

Wierda said he has a patient who had chronic lymphocytic leukemia for more than 20 years but has not needed any treatment. In most cases, however, the patient will begin to suffer symptoms such as fatigue, night sweats and fevers that occur without evidence of infection.

Although the course of the disease can be lengthy, untreated CLL lymphocytic leukemia can be deadly, although a variety of treatments can keep the disease process in check.

"We can't really say we can cure this disease," Wierda said, "but we can change it into something that is truly chronic such as diabetes."

He said most initial treatments for the disease include fludarabine-containing regimens, although many doctors are experimenting with use of drugs such as Campath or in combination with drugs such as chlorambucil.