On February 19th, 2002, the first radioimmunotherapy drug, Zevalin, was approved by the United States FDA to treat B-cell non-Hodgkin’s lymphoma. Developed by IDEC Pharmaceuticals Corp. based in San Diego, California, Zevalin works like a guided bomb targeted towards cancer cells, using CD20 antibodies as the carrier to target the yttrium-90 radioisotopes to the B cells, including the malignant B cells in patients with non-Hodgkins lymphoma.

Nearly 55,000 people are diagnosed with the disease each year in the United States, with 65% of the cases falling into a low-grade or follicular subgroup that frequently relapses and is ultimately untreatable. IDEC has already co-marketed with Genentech a drug called Rituxan, a CD20 antibody drug first approved to treat the non-Hodgkins lymphoma. Zevalin comes as a complementary treatment for those who fail to respond to the standard chemotherapy or the use of Rituxan alone.

Zevalin has to be used together with Rituxan and its therapeutic regimen can be completed in a week on an outpatient basis. Patients were first given a low Zevalin test dose together with Rituxan. Following whole body scans that assure tumors are correctly targeted, patients receive a high radioactive therapeutic dose of Zevalin together with Rituxan. Clinical trials showed over 74% response rate compared to 56% of Rituxan alone. Whether Zevalin can prolong patients’ lifespan is unclear, and side effects do exist.

Zevalin will be on the market with a yet-to-be disclosed price tag in about two months. While retaining US marketing rights itself, IDEC granted Germany’s Schering AG the exclusive non-US marketing and distribution rights for a $47.5 million payment. In a twist, IDEC is being sued by Seattle, Washington-based Corixa Corp., who is making a drug called Bexxar currently under FDA’s review, that IDEC infringes its patent of using antibodies to deliver radioactivity, according to Reuters.

(Discovery Medicine, Vol. 1, No. 4, p4, 2002)