1. Extended rituximab therapy in Waldenström's macroglobulinemia.
- Author
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Treon SP, Emmanouilides C, Kimby E, Kelliher A, Preffer F, Branagan AR, Anderson KC, and Frankel SR
- Subjects
- Adult, Aged, Aged, 80 and over, Antibodies, Monoclonal administration & dosage, Antibodies, Monoclonal, Murine-Derived, Antigens, CD analysis, Antigens, CD biosynthesis, Antineoplastic Agents administration & dosage, CD55 Antigens analysis, CD55 Antigens biosynthesis, CD59 Antigens analysis, CD59 Antigens biosynthesis, Drug Administration Schedule, Female, Humans, Immunoglobulin M analysis, Immunohistochemistry, Male, Membrane Cofactor Protein, Membrane Glycoproteins analysis, Membrane Glycoproteins biosynthesis, Middle Aged, Rituximab, Treatment Outcome, Waldenstrom Macroglobulinemia immunology, Waldenstrom Macroglobulinemia pathology, Antibodies, Monoclonal therapeutic use, Antineoplastic Agents therapeutic use, Waldenstrom Macroglobulinemia drug therapy
- Abstract
Background: Waldenström's macroglobulinemia (WM) is a CD20 expressing B-cell malignancy represented by the pathological diagnosis of IgM secreting lymphoplasmacytic lymphoma. Major response rates of 30% have been reported in most studies with standard dose rituximab, i.e. 4 weekly infusions at 375 mg/m(2)/week., Methods: In an effort to increase rituximab activity in WM, an extended dose schedule employing two sets of four (375 mg/m(2)/week) infusions at weeks 1-4 and 12-16 was evaluated. Expression of the complement resistance antigens CD46, CD55 and CD59 was also evaluated on tumor cells pre- and post-therapy to determine impact on response., Results: Twenty-nine patients were enrolled and 26 patients completed the intended therapy. On an intent to treat analysis, 14 (48.3%) patients achieved a partial response, and 5 (17.2%) patients achieved a minor response. Responses were observed in 18/24 (75%) patients with a serum IgM level of <6000 mg/dl, and only 1 of 5 (20%) patients with a level of >6000 mg/dl (P=0.03). The median time to best response was 17 months, and only 2 of 19 responding patients progressed with a median follow-up of 29 months. No differences in baseline expression of the complement resistance antigens CD46, CD55 and CD59 were observed among responding and non-responding patients, although post-therapy CD55 expression was higher in non-responding patients (P=0.002)., Conclusions: These data show that extended rituximab therapy is active and may lead to more major responses over standard dose rituximab in WM. WM patients with serum IgM levels of <6000 mg/dl are more likely to benefit from extended rituximab therapy.
- Published
- 2005
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