Yttrium isotope 90 is part of the treatment for Non-Hodgkins lymphoma in which form it is called Zevalin. The web site refers to a commercial site, (http://www.zevalin.com/) which is less descriptive.
Zevalin (Ibritumomab tiuxetan) works like a smart bomb. It's an antibody with a radiation attached that seeks and binds to cells that have a receptor called CD20 -- present on both normal and malignant mature b-cells.
Once bound to the target cells, Zevalin delivers radiations, which enhances the killing effect of the antibody.
Normal b-cells will recover in about 9 months because the parent b-cells do not have the CD20 receptor.
Rituxan is administered prior to Zevalin (an unbound antibody) with the goal of clearing the majority normal b-cells and thus reducing the toxicity of Zevalin.
Who it's for (Indication): Patients with relapsed or refractory low-grade, follicular, or transformed B-cell non-Hodgkin's lymphoma, including patients with Rituximab refractory follicular non-Hodgkin's lymphoma.
The effects of Zevalin on survival is unknown. Source: Zevalin.com pdf
Mechanism of Action: After Y-90 ZEVALIN (the therapeutic component of the ZEVALIN regimen) enters the bloodstream, the monoclonal antibody ibritumomab recognizes and attaches to the CD20 antigen, allowing beta radiation emitted by the Yttrium-90 isotope to penetrate and damage the B-cell as well as neighboring cells.
Pivotal Clinical Trial Results: A pivotal Phase 3 randomized, controlled trial was conducted in 143 patients with relapsed or refractory, low-grade or follicular NHL or transformed B-cell NHL comparing the ZEVALIN therapeutic regimen vs. Rituximab administered alone. The overall response rate in 73 patients who received the ZEVALIN therapeutic regimen was 80% (with 30% complete responses) compared to an overall response rate of 56% (with 16% complete responses) in patients who received Rituximab alone. The estimated mean duration of response was 13.9 months for patients receiving the ZEVALIN therapeutic regimen and 11.8 months for patients receiving Rituximab. Median time to disease progression in the intent-to-treat populations was 10.6 months and 10.1 months for the ZEVALIN therapeutic regimen and Rituximab, respectively.