Interest in using Rituxan for subsets of myeloma with CD20 positivity, was provoked by a Phase II study of Moreau et al evaluating four weekly infusions of single-agent rituximab (375 mg/m2) therapy in a cohort of patients with CD20+ multiple myeloma (MM) with either stage I, never treated disease, or stage III MM in relapse, or refractory after two lines of therapy. The authors concluded that rituximab as a single agent had minor activity in this cohort of patients with CD20 expression on at least 33% of tumor cells. A 2008 review concluded: “Clinical trials show that anti-CD20 therapy with rituximab elicits a partial response in approximately 10% of CD20+ patients with multiple myeloma. In addition, there is preliminary evidence of disease stabilization in 50-57% of CD20+ patients for a period of 10-27 months. Further large-scale clinical trials are therefore needed to establish the role of this promising strategy in the treatment of myeloma.” There are several other reports in different settings, including in maintenance.
All in all, there is sufficient literature to consider it supported.
J M Bergua, C Cabrera, E G Arteta and J Prieto
Rituximab in CD20 positive multiple myeloma, Letter to the Editor, Leukemia 22, 1082-1083 (May 2008)
P Moreau, L Voillat, L Benboukher, C Mathiot, C Dumontet, N Robillard, O Hérault, F Garnache, R Garand, N Varoqueaux, H Avet-Loiseau, J L Harousseau and R Bataille
Rituximab in CD20 positive multiple myeloma, Leukemia 21, 835-836 (April 2007)
Kapoor P, Greipp PT, Morice WG, Rajkumar SV, Witzig TE, Greipp PR.
Anti-CD20 monoclonal antibody therapy in multiple myeloma.
Br J Haematol. 2008 Apr;141(2):135-48. Epub 2008 Mar 3.
Long-term response to maintenance treatment with rituximab in CD20+ multiple myeloma
Hitoshi OhnoLeukemia & Lymphoma
November 2010, Vol. 51, No. 11 : Pages 2144-2146