Yttrium-90 ibritumomab tiuxetan is clinically active in patients with advanced diffuse large B-cell lymphoma ineligible for stem-cell transplantation

Researchers have reported that yttrium-90 ibritumomab tiuxetan (Zevalin®; Biogen Idec, Bayer Schering Pharma) has clinical activity in patients with advanced diffuse large B-cell lymphoma who were unable to undergo stem-cell transplantation, in a study reported in the journal Blood this week.

Yttrium-90 ibritumomab tiuxetan is a monoclonal antibody bound via a linker (tiutexan) to the radioisotopes Yttrium-90 or Indium-11, targeting the CD20 antigen on normal and malignant B-lymphocytes. As a result, radiation is directed against CD20 positive cells, inducing cellular damage on the target and neighboring cells.

Yttrium-90 ibritumomab tiuxetan is currently indicated for for the treatment of patients with relapsed or refractory low-grade, follicular, or transformed B-cell non-Hodgkin's lymphoma, including patients with rituximab-refractory follicular NHL.

In the current Phase II study, elderly patients with first relapsed or primary refractory diffuse large B-cell lymphoma and ineligible for stem-cell transplantation received a single dose of yttrium-90 ibritumomab tiuxetan. Patients had previously been treated with chemotherapy or chemotherapy plus rituximab. Those patients who had previously been treated with chemotherapy were further divided into a) patients in whom induction therapy had failed and b) patients who had relapsed after achieving a complete response.

The overall response rate was higher in patients who had previously received chemotherapy than those who had previously received chemotherapy plus rituximab (52.5% vs. 19%, respectively). The complete response/complete response unconfirmed rates were higher in patients who had previously received chemotherapy and either failed induction therapy or relapsed after achieving a complete response (24% and 39.5%, respectively) than those patients who had previously been treated with chemotherapy plus rituximab (12%). Median progression free and overall survival were also higher in patients who had previously received chemotherapy than those who had previously received chemotherapy plus rituximab.

Two patients died from thrombocytopenic cerebral bleeding following administration of therapy. Haematologic adverse events were mild to moderate in nature.

Author’s conclusions: ‘Yttrium-90 ibritumomab is active in patients with relapsed and refractory diffuse large B-cell lymphoma and its further evaluation in phase 3 studies is ongoing'.

Source: http://bloodjournal.hematologylibrary.org/cgi/content/abstract/110/1/54