Durable responses after ibritumomab tiuxetan radioimmunotherapy for CD20+ B-cell lymphoma: long-term follow-up of a phase 1/2 study.

Author(s): Gordon LI, Molina A, Witzig T, Emmanouilides C, Raubtischek A, Darif M, Schilder RJ, Wiseman G, White CA

Affiliation(s): Division of Hematology/Oncology, Northwestern University Feinberg School of Medicine, 676 N St Clair, Ste 850, Chicago, IL 60611, USA. l-gordon@northwestern.edu

Publication date & source: 2004-06-15, Blood., 103(12):4429-31. Epub 2004 Mar 11.

Publication type: Clinical Trial; Clinical Trial, Phase I; Clinical Trial, Phase II; Multicenter Study

We previously demonstrated that yttrium-90 (Y-90) ibritumomab tiuxetan (Zevalin) radioimmunotherapy (RIT) was safe and effective for relapsed or refractory CD20(+), B-cell, non-Hodgkin lymphoma (NHL). We now provide long-term follow-up data in responding patients based on International Workshop Response Criteria. Complete (CR), CR unconfirmed (CRu), and partial response (PR) rates were 29%, 22%, and 22%, respectively (overall response rate 73%, 51% in CR/CRu). Mean time to progression (TTP) and duration of response (DR) in responders were 12.6 months and 11.7 months, respectively. At the maximum tolerated dose (0.4 mCi/kg [14.8 MBq/kg]), TTP and DR in complete responders (CR/CRu) were 28.3 and 27.5 months, respectively. Nine patients (24% of responding patients) had a TTP of more than 3 years. Long-term responders (> 5 years) have been identified. Ibritumomab tiuxetan produces durable responses in patients with indolent and diffuse large B-cell lymphoma.