A Monoclonal Antibody Attached to Radiation
Lymphoma tumors are very sensitive to radiation, but targeting external beam radiation to cancerous immune system cells throughout the body is difficult. IDEC is developing a complementary product to Rituxan (Rituximab), called ZEVALINTM (Ibritumomab Tiuxetan), formerly known as IDEC-Y2B8. This investigational therapy seeks to combine the targeting power of monoclonal antibodies with the cancer-killing ability of radiation.
ZEVALIN is a murine monoclonal antibody that targets the CD20 antigen, like Rituxan. There’s a difference, however. A chelating agent links this antibody to the radioisotope yttrium-90. In ongoing clinical studies, ZEVALIN, an investigational drug, is used in conjunction with Rituxan to treat patients with B-cell non-Hodgkin’s lymphoma (NHL).
Regimen Completed in Two Administrations
Patients receive a single infusion (250 mg/m2). One week later the patient receives a second infusion of Rituxan (250 mg/m2) followed by ZEVALIN (2 mg antibody labeled with 0.3 or 0.4 mCi/kg of yttrium-90 depending on the patient’s baseline platelet count).
Mouse Antibody Used
A mouse or murine anti-CD20+ antibody is used as the carrier of the yttrium-90 radioisotope because it is eliminated from the body faster than Rituxan, which is a combination of human and mouse antibodies, and is, thus, more in line with the physical half life of yttrium-90.
Clinical Trial Update
Two Phase III studies are underway at over 35 medical centers throughout the United States. Patient accrual on both studies is nearly complete. Additional support trials are open or planned, including several studies sponsored by the National Cancer Institute.
Ex-US Marketing and Distribution Rights
In June, 1999, IDEC and Schering AG, Berlin, Germany, entered into a licensing agreement valued at approximately $47.5 million granting Schering AG exclusive marketing and distribution rights to IDEC’s investigational drug, ZEVALINTM. IDEC retains U.S. rights to ZEVALIN.