Apr. 25, 2002
     Non-Hodgkin's Lymphoma

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Researchers test custom-made vaccine

BALTIMORE -- April 25, 2002 (Cancer Digest) -- Researchers hope to cure cancer patients with a form of lymphoma using a vaccine tailor-made from each patient's own tumor cells.

As part of a national multi-center study, researchers at the University of Maryland Greenebaum Cancer Center in Baltimore have begun testing a custom-made vaccine for low-grade non-Hodgkin's lymphoma. Led by Dr. Aaron Rapoport, the research team hopes the vaccine will result in long-term cure of the cancer of the immune system.

"This type of low-grade follicular lymphoma has traditionally been highly treatable, but essentially incurable," Rapoport said in a prepared statement. "This technique for harnessing the immune system may result in long-term disease remission and potential cures for some patients."

Low-grade follicular lymphomas are generally treated with radiation if they are localized or chemotherapy if they are widespread. While the cancer responds well to treatment, it is likely to recur.

Researchers hope to recruit about 480 patients at 25 institutions in the United States and Canada for the study sponsored by Genitope Corporation, a California-based biotechnology company.

To be eligible for the study, patients must have been diagnosed with follicular lymphoma, a common form of cancer of the lymphatic system, and have not yet received treatment. If enrolled, they will have a small tissue sample (biopsy) taken of their cancer, either from a lymph node or bone marrow, which will be sent to Genitope Corporation to make a vaccine unique to each patient.

The customized vaccine is designed to target a tumor-specific marker, or idiotype, which, like a fingerprint, is unique to every lymphoma patient. Once injected, the vaccine is intended to activate the immune system to attack cells that have the idiotype protein on their cell surfaces. With the cancerous lymph cells displaying the marker in elevated quantities, the hope is that the immune system will preferentially attack and destroy the cancer cells.

"Without this, the body's immune system is somewhat blind to the lymphoma," says Rapoport, an associate professor of medicine at the University of Maryland School of Medicine. "Lymphomas and other types of cancers use a variety of mechanisms to evade the body's immune system."

In this trial, patients will first receive eight rounds of chemotherapy with three drugs ­ cytoxan, vincristine and prednisone. If they experience at least a 50 percent remission, they remain in the study and are observed for another five months while their bodies rest from the chemotherapy.

If there is still no progression of their disease, two-thirds of the patients will be randomly assigned to receive a vaccine crafted from their own tumor cells, plus an immune system stimulant, while one-third receive a vaccine using only a carrier protein and the stimulant, which may also activate the immune system in a beneficial way.

The patients will receive a series of seven vaccinations over six months and then have follow-up scans to check on the progress of their disease for the next two years. The results of the clinical trial are expected within two to three years, depending on when the last patient is treated.

Rapoport said that in earlier clinical trials, about two-thirds of the patients showed positive immunological responses to the vaccinations.

"But it is difficult to know the clinical impact of that," he says. "Does it mean that they have better responses or longer-lasting responses? That's what this study is designed to show."

Non-Hodgkin's lymphoma is the fifth most common cancer in the United States, with about 57,000 new cases diagnosed each year.