Anti-KIR Antibody Enhancement Of Anti-Lymphoma Activity Of Natural Killer Cells As Monotherapy and In Combination With Anti-CD20 Antibodies

Abstract

Natural killer (NK) cells mediate anti-lymphoma activity by spontaneous cytotoxicity and antibody-dependent cell-mediated cytotoxicity (ADCC) when triggered by rituximab, an anti-CD20 monoclonal antibody (mAb) used to treat patients with B cell lymphomas. The balance of inhibitory and activating signals determines the magnitude of NK cell's efficacy by spontaneous cytoxicity. Using a killer cell immunoglobulin-like receptor (KIR) transgenic murine model, we show that blockade of the interface of inhibitory KIRs with MHC class I antigens on lymphoma by anti-KIR antibodies prevents a tolerogenic interaction and augments NK cell spontaneous cytotoxicity. In combination with anti-CD20 mAbs, anti-KIR treatment induces enhanced NK cell-mediated, rituximab-dependent cytotoxicity against lymphoma in vitro and in vivo in syngeneic and KIR transgenic murine lymphoma models. Specifically targeting murine NK cells in vitro, anti-Ly49C/I F(ab')2 increased anti-CD20 mAb-mediated NK cell degranulation as measured by CD107a mobilization and interferon-γ release, as well as increased cytotoxicity as assessed by chromium release. In the syngeneic EL4-huCD20 lymphoma model, anti-Ly49C/I F(ab')2 enhanced the anti-lymphoma activity of anti-CD20 mAb in vivo (Fig 1A-1B) and was NK cell-dependent with efficacy abrogated by NK cell depletion with anti-Asialo-GM1. To validate these observations and the potential efficacy of a fully human anti-KIR mAb (IPH2101, lirilumab), we demonstrated, in vitro, dose-dependent KIR2DL3 saturation and tumor lysis following blockade of KIR2DL3/HLA-C with lirilumab. In the transgenic KIR murine model, lirilumab therapy improved survival in an NK cell-dependent manner in both a prophylactic and therapeutic HLA+ (221 HLA-Cw3) lymphoma model. In combination, lirilumab therapy synergistically enhanced rituximab's anti-lymphoma efficacy in vivo in an NK cell-dependent manner (Fig 2A-C). These results support a therapeutic strategy of combination, rituximab and KIR blockade through lirilumab, illustrating the potential efficacy of combining a tumor targeting therapy with an NK cell agonist thus stimulating the post-rituximab anti-lymphoma immune response. Disclosures: Thielens: Innate Pharma: Employment, Equity Ownership. Sola:Innate Pharma: Employment, Equity Ownership. Chanuc:Innate Pharma: Employment, Equity Ownership. Fuseri:Innate Pharma: Employment. Bonnafous:Innate Pharma: Employment, Equity Ownership. Vivier:Innate Pharma: Membership on an entity’s Board of Directors or advisory committees. Romagne:Innate Pharma: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees. Andre:Innate-Pharma: Employment, Equity Ownership. Blery:Innate Pharma: Employment, Equity Ownership.

Natural killer (NK) cells and anti-tumor therapeutic mAb: unexplored interactions

“…This result supports the hypothesis that NK cells may positively contribute to the vaccinal effect of anti-tumor mAb therapy [140,141]. A further combination strategy to enhance anti-tumor mAb-triggered NK cell functions relies on the interference with the restraining function of MHC I-specific inhibitory receptors [26,50,125,128,130,131,196,197].…”

“…KIR/MHC I interaction was shown to interfere with therapeutic mAbdependent ADCC [26,50,[125][126][127][128][129]. Moreover, an anti-KIR mAb was shown to increase anti-CD20 or anti-CD38 mAb-triggered ADCC in vitro and therapeutic mAb efficacy in a preclinical model of B lymphoma [130,131]. On the other hand, several studies pointed out that the engagement of natural cytotoxicity activating receptors enhances the efficiency of ADCC.…”

Deciphering the killer‐cell immunoglobulin‐like receptor system at super‐resolution for natural killer and T‐cell biology

“…For example Lirilumab, the monoclonal antibody that binds KIR, is currently in a phase II clinical trial for lymphoma. 237 By blocking the interaction of inhibitory KIR with their HLA class I ligands this antibody facilitates activation of NK cells by impeding inhibitory signalling, potentially promoting destruction of tumour cells.…”

Immune checkpoint molecules in acute myeloid leukaemia: managing the double‐edged sword

“…The KIR blocking antibody lirilumab augmented NK cell-mediated lysis of autologous tumour cells expressing HLA-C, including AML blasts and multiple myeloma cells, in vitro (Romagne et al, 2009). Furthermore, lirilumab, in combination with anti-CD20, augmented NK cell reactivity against CD20 + B cell lymphoma cells in in vitro and in vivo mouse models (Aranda et al, 2014;Kohrt et al, 2014). In elderly AML patients, lirilumab was shown to be safe in a dose-escalation study, capable of blocking KIRs with minimal toxicity and favourable effects on overall and relapse-free survival (Vey et al, 2012).…”