Radiation Drug Tested in Type of Lymphoma

Therapy Could Be an Alternative to Traditional Radiation

A drug that attaches to cancer cells and delivers a dose of radiation is being tested at two cancer centers to help prevent recurrence of the most common type of lymphoma, researchers say.

The drug Zevalin (ibritumomab tiuxetan) is being studied in a joint clinical trial at M. D. Anderson and Memorial Sloan-Kettering Cancer Center to help prevent relapse of diffuse large B-cell lymphoma (DLBCL) following initial therapy.

DLBCL is an aggressive malignancy which is often difficult to treat in patients older than 60. While some patients remain free of disease for long periods of time, more than 50% will develop recurrence and then receive other types of chemotherapy, or treatments, for their relapse.

External beam radiation is delivered outside of the body to an area inside a patient where a cancer is believed to exist. This traditional form of radiation therapy has not proven to prevent recurrence when used as a part of initial treatment planning because patients often will develop recurrence outside of radiation fields, says Fredrick Hagemeister, M. D., professor in M. D. Anderson's Lymphoma and Myeloma Center.

Researchers believe Zevalin may offer a good alternative. Zevalin has a special protein that can "find" and stick to lymphoma cells wherever they hide. The drug "carries" a radioisotope that then kills the cell as well as other nearby cancer cells. Zevalin is among the first radioimmunotherapy drugs to be used in human subjects.

Interim report states there is no relapse

Because B-cell lymphomas have a known sensitivity to radiation, researchers hope the drug can improve upon treatment options for patients with aggressive DLBCL, as well as for other forms of lymphoma.

The trial was initially developed by researchers at Memorial Sloan-Kettering. Interim results from patients there appear to be promising. Researchers reported at a December scientific meeting that none of the patients who entered remission with chemotherapy and then received Zevalin had relapsed. Other groups around the country are also testing Zevalin and Bexxar (Tositumomab and Iodine I 131 Tositumomab), the other radioimmunotherapeutic drug approved by the Food and Drug Administration (FDA) for treatment of lymphoma.

Including the Zevalin trial, six studies are now under way or planned at M. D. Anderson for various forms of lymphoma, Hagemeister says. "These unified studies of Zevalin are examining the concept that lymphoma is a systemic disease, and that radiation that can be delivered throughout the body might offer a better result."

Patient eligibility criteria includes:

• Minimum age of 61 at time of enrollment
• Diagnosis of DLBCL with high relapse risk
• No prior treatment with:
• • Chemotherapy
  • Biologic therapy
  • Radiation therapy

Patients in the study receive standard treatment, which includes rituximab (Rituxan) and traditional chemotherapy drugs. Rituximab is a monoclonal antibody drug, like Zevalin, in that it is designed to attach to a protein called CD20 on the surface of lymphoma cells and trigger an immune response against the cells, causing cell death.

Those patients who have a complete response or partial remission are then given a dose of Zevalin as "consolidation" therapy (treatment given to prevent recurrence of lymphoma cells) to decrease the chances of recurrence.

"I think that if this drug turns out to be effective as consolidation therapy for aggressive lymphoma, radioimmunotherapies like Zevalin and Bexxar will be widely used," Hagemeister says.

For more information, please contact the M. D. Anderson Information Line at 1-800-392-1611, option 3.