Lenalidomide combined with low-dose cyclophosphamide and prednisone modulates Ikaros and Aiolos in lymphocytes, resulting in immunostimulatory effects in lenalidomide-refractory multiple myeloma patients.

Abstract

We recently showed that the outcome of multiple myeloma (MM) patients treated in the REPEAT study (evaluation of lenalidomide combined with low-dose cyclophosphamide and prednisone (REP) in lenalidomide-refractory MM) was markedly better than what has been described with cyclophosphamide-prednisone alone. The outcome with REP was not associated with plasma cell Cereblon expression levels, suggesting that the effect of REP treatment may involve mechanisms independent of plasma cell Cereblon-mediated direct anti-tumor activity. We therefore hypothesized that immunomodulatory effects contribute to the anti-MM activity of REP treatment, rather than plasma cell Cereblon-mediated effects. Consequently, we now characterized the effect of REP treatment on immune cell subsets in peripheral blood samples collected on day 1 and 14 of cycle 1, as well as on day 1 of cycle 2. We observed a significant mid-cycle decrease in the Cereblon substrate proteins Ikaros and Aiolos in diverse lymphocyte subsets, which was paralleled by an increase in T-cell activation. These effects were restored to baseline at day one of the second cycle, one week after lenalidomide interruption. In vitro, lenalidomide enhanced peripheral blood mononuclear cell-mediated killing of both lenalidomide-sensitive and lenalidomide-resistant MM cells in a co-culture system. These results indicate that the Cereblon-mediated immunomodulatory properties of lenalidomide are maintained in lenalidomide-refractory MM patients and may contribute to immune-mediated killing of MM cells. Therefore, combining lenalidomide with other drugs can have potent effects through immunomodulation, even in patients considered to be lenalidomide-refractory.

• Authors: Laurens E Franssen, Inger S Nijhof, Chad C Bjorklund, Hsiling Chiu, Ruud Doorn, Jeroen van Velzen, Maarten Emmelot, Berris van Kessel, Mark-David Levin, Gerard M J Bos, Annemiek Broijl, Saskia K Klein, Harry R Koene, Andries C Bloem, Aart Beeker, Laura M Faber, Ellen van der Spek, Reinier Raymakers, Pieter Sonneveld, Sonja Zweegman, Henk M Lokhorst, Anjan Thakurta, Xiaozhong Qian, Tuna Mutis, Niels W C J van de Donk
• Journal: Oncotarget (Oncotarget) Vol. 9 Issue 74 Pg. 34009-34021 (Sep 21 2018) ISSN: 1949-2553 [Electronic] United States
• PMID: 30338042 (Publication Type: Journal Article)