Impact of Lenalidomide On Immune Functions in the Setting of Maintenance Therapy for Multiple Myeloma
Authors: Brissot Eolia , Clavert Aline , Blin Nicolas , Roland Virginie , Guillaume Thierry , Dubruille Viviane , Mahe Beatrice , Gastinne Thomas , Le Gouill Steven , Gaugler Béatrice , Moreau Philippe , Mohty Mohamad 
Published: October 2019

Abstract
Abstract 4045
Lenalidomide is an effective and widely used therapeutic agent for multiple myeloma. This agent exhibits both anti-tumor and immunomodulatory properties. Recent data suggested a positive impact on outcome of this drug in the setting of maintenance therapy in young multiple myeloma patients receiving autologous stem cell transplantation. On the long term, Lenalidomide is thought to enhance activation of T and NK cells, however its precise immune effects remain to be elucidated, and only a few data is available in this field. This single centre pilot prospective study aimed to assess T-cell polarization and the cytokine secretion profile in ten patients treated with lenalidomide alone in the maintenance setting.
In this cohort, patients received at time of analysis between 4 and 12 cycles of lenalidomide alone (one cycle=28 days) at a dose ranging between 5 and 15 mg/day. Five patients received prior high-dose therapy (HDT) and autologous peripheral blood stem cell transplant (PBSCT) and 5 patients received maintenance after induction with the VRD (lenalidomide, bortezomib and dexamethasone) combination. Seven patients were in very good partial response (VGPR) and 3 were in complete response (CR) at the time of analysis. Intracellular cytokine secretion by peripheral blood lymphocytes was analyzed in peripheral blood mononuclear cells (PBMC) by multicolour staining. PBMCs were stimulated for 5 hours with PMA and ionomycin in the presence of 10 μg/mL Brefeldin A. Cells were first stained with CD3 APC-H7, CD4 PE-Cy7 and CD8 APC and permeabilized using Cytofix/cytoperm and were then incubated with FITC-, PE-, PeCy7, V450 Horizon-, AlexaFluor 647- conjugated anti-IFN-gamma, IL-4, IL-10, IL-17A and IL-21. In parallel, we analyzed a total of 39 cytokines in the plasma collected simultaneously from these same patients. Concentrations of IL-21, IL-23, TARC (CCL17), TRAIL (Apo2L), CD40L, Flt3L, Fractalkine (CX3CL1), IFNalpha, IFN-gamma, IL-10, IL-12p40, IL-12p70, IL-13, IL-15, IL-17, IL-1a, IL-1b, IL-1Ralpha, IL-2, IL-2Ralpha, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8 (CXCL8), IL-9, IP10 (CXCL10), MCP-1 (CCL2), MCP-3(CCL17), MIP-1alpha (CCL3), MDC (CCL22), MIP-1beta (CCL4), TGFalpha, TNFalpha, TNFbeta, VEGF, Eotaxin and EGF were determined by the bead-based multiplex protein array technology.
We observed that T cells derived from myeloma patients receiving lenalidomide maintenance therapy exhibited a significantly higher secretion of TNF-alpha (p=0.03), IL-4 (p=0.003), IL-10 and IL-21 (p=0.004), compared to stimulated T cells obtained from 5 healthy donors (Figure 1 A-B). In the multiplex bead assay, we observed that IP10 (p=0.008), IL-8 (p=0.018), and MIP1beta (p=0.022) levels were also statistically increased in the plasma of patients treated with lenalidomide compared to the control group (Figure 2).
Overall, these results suggest that the use of lenalidomide as maintenance therapy in myeloma can induce some potent and critical immunostimulatory activities through induction of a chronic inflammatory reaction. Interestingly, IP10 is a major Th1-related chemokine involved in anti-tumor responses, while IL-8 and MIP1b can positively influence NK cell functions (maturation, migration and augmenting their cytolytic activity). Altogether, these data shed some new light on the immunostimulatory mechanism of action of lenalidomide in the setting of long term maintenance therapy for myeloma, highlighting the need for detailed immunomonitoring studies to be performed as part of the large multicentre randomized trials.

Disclosures:
No relevant conflicts of interest to declare.