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IDEC Pharmaceuticals Reports Interim Results of Phase I/II Trial of IDEC-Y2B8 in the Treatment of Relapsed or Refractory Non-Hodgkin's Lymphoma
December 10, 1997 12:20 PM EST
SAN DIEGO--(BW HealthWire)--Dec. 9, 1997--IDEC Pharmaceuticals (Nasdaq: IDPH) today reported interim results from a Phase I/II clinical trial incorporating both of the company's treatments for relapsed or refractory B-cell non-Hodgkin's lymphoma: the investigational immunotherapy, IDEC-Y2B8, and the newly approved immunotherapy, RITUXAN(tm) (Rituximab). IDEC-Y2B8 is a murine monoclonal antibody tightly conjugated to the radioisotope yttrium-90, which targets the CD20 antigen on mature normal and malignant B cells. The objectives of the Phase I/II trial were to evaluate IDEC-Y2B8's safety and activity in a variety of types of non-Hodgkin's lymphoma (NHL) across three dose levels, 0.2mCi/kg, 0.3mCi/kg and 0.4mCi/kg.
Clinical results to date showed an overall response rate (complete and partial responses) of 82% (14/17) across all dose groups in all low grade or follicular NHL patients, with a 100% response rate (7/7) for patients with low grade or follicular disease who received the standard 0.4mCi/kg dose of IDEC-Y2B8. Response rates in patients with other forms of NHL were lower: 50% (3/6) in intermediate grade disease, and no responses to treatment in three patients with mantle cell disease. The interim study results are being presented today by Dr. Thomas Witzig of the Mayo Clinic at the annual meeting of the American Society of Hematology (ASH) held in this city.
Interim analysis of 31 patients for whom full safety data was available indicated that adverse events associated with the treatment regimen were primarily hematologic (grade 3 or 4 cytopenia (blood cell count reductions) in 18/31 patients) and dose-dependent. Investigators reported no renal, hepatic, pulmonary or cardiac dysfunction, and human anti-mouse or anti-chimeric antibody (HAMA/HACA) reactions were not a therapy-limiting factor.
"The treatment regimen employed in this study is designed to provide therapeutic benefit for patients with bulky, rapidly growing or refractory disease who otherwise would typically be candidates for aggressive and potentially toxic combination chemotherapies," said Antonio Grillo-Lopez, M.D., IDEC's senior vice president of medical and regulatory affairs. "In this trial, Rituxan is first used as pretreatment to clear malignant and normal B cells from the patient's blood. This allows the subsequent IDEC-Y2B8 treatment to penetrate the lymphatic system and attach to lymphoma tumors where radiation from the yttrium-90 isotope has its killing effect." In addition, IDEC-Y2B8 treatment is completed in approximately one week, whereas the typical course of chemotherapy requires four to eight months of repeat treatment.
Dr. Grillo-Lopez noted that patient accrual in the trial is now complete, and that the Food and Drug Administration has accepted IDEC's protocol design for a Phase III pivotal trial of the IDEC-Y2B8/Rituxan therapy. IDEC anticipates beginning patient enrollment in the Phase III trial by early 1998.
The Phase I portion of the Phase I/II trial examined the safety and appropriate dosing for both the pretreatment dose of Rituxan and the therapeutic dose of IDEC-Y2B8. Based on those results, patients participating in the Phase II portion of the trial received a pretreatment dose of Rituxan (250mg/m2). This was followed by a 5.0mCi/kg dose of IDEC-In2B8, an anti-CD20 antibody conjugated to the radioisotope indium, which enabled imaging of the patient's disease. One week later, patients received a second pretreatment dose of Rituxan (250 mg/m2) followed by a therapeutic dose of IDEC-Y2B8. This dose of IDEC-Y2B8 was standardized at 0.4mCi/kg, except for patients with mild depletion of pretreatment platelet counts who received a reduced dose of 0.3mCi/kg.
"IDEC is committed to developing IDEC-Y2B8 as an additional tool in the management of lymphoma," said William H. Rastetter, IDEC chairman, president and chief executive officer. "Rituxan is approved for single agent use in the management of relapsed or refractory low grade or follicular CD20-positive B-cell NHL. We believe Rituxan will be used primarily in the community-based oncology practice where the majority of lymphomas are treated today. In contrast, IDEC-Y2B8 is intended for use by radiation oncologists and nuclear medicine specialists as an outpatient therapy which combines both immunotherapy and radiation therapy."
IDEC is developing IDEC-Y2B8 as a treatment for low grade or follicular, relapsed or refractory non-Hodgkin's B-cell lymphomas. The company currently plans to commercialize IDEC-Y2B8 on its own in the United States, and is in various stages of discussion with potential corporate partners for product commercialization in the rest of the world. |
