WEDNESDAY, Jan. 23, 2002 (HealthDayNews) -- Adding a potent immune-stimulating protein to conventional therapy significantly improves remission and survival rates for older patients with certain blood cancers, a new study says.
The drug, rituximab, plus standard chemotherapy boosted the rate of complete remission from 63 to 76 percent, while prolonging survival, according to the study. A report on the findings, by European researchers, appears in the Jan. 24 issue of the New England Journal of Medicine.
Rituximab is sold as Rituxan in the United States by Genentech. The drug, a so-called monoclonal antibody, was approved by the U.S. Food and Drug Administration in 1997 for the treatment of lymphoma. A monoclonal antibody seeks a specific target, whereas chemotherapy is a systemic treatment.
Non-Hodgkin's lymphoma is a frequently aggressive form of cancer that is becoming increasingly common in the United States and abroad. The disease, which affects 1.5 million people worldwide, is the fifth and sixth leading cancer killer of men and women, respectively, in this country.
A form of non-Hodgkin's lymphoma, called diffuse large-B-cell lymphoma, is the most common aggressive strain of the disease. This illness involves unchecked growth of B-cells, which normally help the body fight infection by producing proteins known as antibodies that identify invading organisms. Rituximab targets proteins on the surface of malignant B-cells, marking them for destruction by the immune system.
For the last 25 years, doctors have treated B-cell lymphomas with a therapy called CHOP (a rough acronym for the four drugs that make up the regimen). This approach cures between 30 percent and 40 percent of patients, but for the remainder the cancer is fatal.
Researchers have tested many other drugs to enhance CHOP, with disappointing results. But in recent years they have been able to better the odds for patients by adding infusions of rituximab to the standard course of CHOP.
The latest work confirms the utility of that tactic. A team led by Dr. Bertrand Coiffier, a blood specialist at the Hospices Civils de Lyon, the researchers compared rituximab plus CHOP to CHOP alone in nearly 400 patients with diffuse large-B-cell lymphomas. The patients ranged in age from 60 to 80, and had not had previously been treated for their disease. Subjects received infusions of CHOP and either rituximab or a dummy solution over eight three-week cycles.
Three in four patients (76 percent) who got the extra drug went into complete remission, compared with 63 percent of those who received CHOP only. They were also significantly more likely survive at least two years after treatment -- 70 percent vs. 57 percent -- and to avoid relapses.
Rituximab tends to cause more severe reactions during the first infusion, which lasts five hours as opposed to one to two for CHOP. But Coiffier says that since patients generally improve more quickly with the additional therapy, they generally report feeling better than those on CHOP.
B-cell lymphomas typically appear in patients 60 or older, and the latest study didn't examine whether rituximab is effective in younger people. "We don't know the results for younger patients, but there isn't any scientific reason that it will not be the same," says Coiffier.
For all its benefits, however, rituximab isn't cheap. A single weekly infusion runs about $3,000, and treatment can last two months. And while the French study found that it was no more toxic than CHOP, the drug has been shown to cause rare but potentially deadly side effects, including heart and lung failure and severe tissue reactions.
Dr. Bruce Cheson, a researcher at the National Cancer Institute and author of an editorial accompanying the journal article, says the new study leaves a few important questions unanswered. It's not clear, for example, if using rituximab with or after CHOP is the better strategy against diffuse large-B-cell lymphomas. And more work is needed to see if the drug can help treat other forms of blood cancers.
Cheson notes that scientists are now studying several related monoclonal antibodies, as well as immune-boosting agents to enhance them. They also have a hodgepodge of other drugs and therapies for lymphoma in development. "In the future, the game of chemotherapy Scrabble may spell 'cure' for patients with lymphoma," he writes.
What To Do
To find out more about rituximab and non-Hodgkin's lymphoma, try cancerbacup, a site from the U.K.
You can also get more information by visiting the National Cancer Institute.
