'Smart Bomb' Drug Latest Weapon Against Lymphoma
Zevalin targets cancer cells with radiation
THURSDAY, April 18, 2002 (HealthDayNews) -- A new drug that targets cancer cells like a missile armed with a warhead may prolong the lives of people suffering from non-Hodgkin's lymphoma, a disease whose slowest-acting forms are the most deadly.
"There's real good reason to have a high measure of hope," says Dr. Morton Coleman, director of the Center for Lymphoma and Myeloma at New York Presbyterian Hospitals-Weill Cornell Medical Center.
With the advent of Zevalin and other medications, "we're beginning to see some impact on the survival curve," he says.
Lymphomas are cancers that affect lymph nodes, part of the body's immune system. An estimated 55,000 people are diagnosed with non-Hodgkin's lymphoma each year, and about 65 percent have a slow-growing type that can be sent into remission but is incurable, according to the U.S. Food and Drug Administration (FDA).
Scientists have developed effective drugs to combat lymphoma tumors that grow quickly. Their growth spurts actually make them more vulnerable, Coleman says. The ones that grow at slow rates are more challenging to treat.
Even if doctors do succeed in eliminating the slow-growth tumors, they often come back a few years later. Coleman estimated the average survival time at eight to 10 years.
Ultimately, the tumors "tend to kill the patient. They're very difficult to treat," says Alan Kinniburgh, vice president of research with the Leukemia and Lymphoma Society.
In recent years, some lymphoma specialists have embraced a drug called Rituxan. Once that drug links to a cancer cell, it often causes that cell to commit suicide by instigating a process known as "programmed cell death." Exactly how this works isn't clear, however.
"Nobody knows exactly why it kills cells," says Dr. Joseph Bertino, associate director of the Cancer Institute of New Jersey.
The new drug, Zevalin, acts in a similar fashion. "As it circulates [through the bloodstream], it seeks out the tumor wherever it is," Bertino says.
However, Zevalin comes with a "payload" -- a dose of radioactivity that zaps cancer cells.
In February, the FDA approved Zevalin for use in lymphoma patients. Two studies had shown that 74 percent to 80 percent of patients responded to treatment.
The agency cautions, however, that the drug is toxic and should be used only when other treatments have failed. Also, Zevalin must be used with Rituxan.
Coleman compares the drug to an antiballistic missile armed with a warhead.
"A missile could hit [a target] by sheer force of collision, or you could attach a warhead to the missile so you not only knock out the plane, but you also have an explosive," he explains.
Zevalin does have side effects. It can disrupt the inner working of bone marrow, reducing the number of white blood cells it produces, Bertino says. That, in turn, can lead to infection.
Bertino is optimistic about Zevalin, but says its true powers won't be known for a few years as doctors watch patients to see if they relapse after treatment.
"The hope is that this is going to make a difference," he says.