Daratumumab, a Novel Human Anti-CD38 Monoclonal Antibody for the Treatment of Chronic Lymphocytic Leukemia and B-Cell Non–Hodgkin Lymphoma

Abstract

3935 Daratumumab (DARA) is a human CD38 antibody with broad-spectrum killing activity. DARA induces killing of tumor cells, mainly via complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) (de Weers M, J Immunol 2011). DARA is currently being evaluated in phase I/II clinical trials in patients with multiple myeloma. In these clinical studies the adverse events have been manageable and marked reductions in paraprotein and bone marrow plasma cells have been observed. In the present study, we have analyzed the potential of targeting CD38 using DARA in two types of B-cell non-Hodgkin lymphoma (B-NHL) (follicular lymphoma (FL) and mantle cell lymphoma (MCL)), and in chronic lymphocytic leukemia (CLL). Flow cytometry analysis demonstrated that MCL and CLL tumor cells show heterogeneous expression of CD38, while FL cells showed invariable high CD38 levels. CD38 has attracted special attention in CLL where high CD38 expression is a marker of bad prognosis (Hamblin et al, Blood 1999 and 2002) and is expressed preferentially in the proliferating fraction of the tumor (Damle RN, Blood 2007). In addition, we have recently shown that high CD38 expression in MCL was associated with resistance to the proteasome inhibitor bortezomib (Pérez-Galán P, Blood 2011). Here, we tested the cytotoxic activity of DARA in tumor cell lines and in fresh tumor cells obtained from patients. DARA did not induce CDC in MCL cell lines (MINO, REC, HBL2, JEKO), irrespective of CD38 expression levels. Also, FL cell lines (WSU-FSCCL, RL) expressing relatively high CD38 levels were insensitive to DARA-induced CDC. This low CDC was associated with high expression of the complement inhibitors CD55 and CD59. In addition, the number of CD38 molecules per cell in these MCL and FL cell lines was lower than that found on the CDC-sensitive Daudi Burkitt lymphoma cell line, suggesting a threshold for CD38-targeted CDC lysis. In the presence of PBMC effector cells obtained from healthy donors, DARA showed significant levels of ADCC in cells from MCL, FL and CLL. In CLL primary cases (n=8) tested, DARA (14–43% lysis) was generally superior or at least equally effective (mean+/−SD=28,78 +/− 9,78) in inducing ADCC as compared to the anti-CD20 antibodies ofatumumab (mean+/−SD=21,35 +/− 15,71) and rituximab (mean+/−SD=29,30 +/− 15,90). The immunomodulatory agent lenalidomide shows considerable single agent activity in MCL, FL and CLL. Interestingly, it has been shown that lenalidomide may be able to increase ADCC, probably via activation of NK cells. We therefore tested whether the combination of lenalidomide and DARA could enhance ADCC. Noteworthy, DARA-induced ADCC in MCL, FL cell lines and primary CLL cells was significantly (p<0,05) enhanced when effector cells were pretreated with the immunomodulatory agent lenalidomide (3 μM, 72 h) with DARA doses ranging from 0,01–1 μg/ml. Finally, CD38 is important for cell migration and adhesion, especially for CXCR4-CXCL12-induced migration of tumor cells (Vaisitti et al, Leukemia 2010). Our preliminary results suggest that in the CLL subtype with high CD38 and more migratory capacity DARA (10–30 μg/ml) inhibits CXCL12/SDF1α mediated migration up to 70%. These results are of high importance because inhibition of tumor cell trafficking to tissue sites as bone marrow and lymph nodes, may be clinically relevant, as increasing evidence indicates that tumor–microenvironment interactions may play an important role in drug resistance and contribute to clinical failures. We are currently validating this in vitro results in a CLL mouse model. Taken together, these results suggest that DARA may be a promising therapeutic agent both for MCL, FL and CLL, in which DARA exerts its effects mainly via ADCC and for CLL also via inhibition of migration of tumor cells. Interestingly, the cytotoxic activity of DARA by ADCC could be further augmented by addition of lenalidomide in these three models. Disclosures: Lammerts van Bueren: Genmab: Employment. Bakker:genmab: Employment. Parren:genmab: Employment. Perez-Galan:Genmab: Research Funding.

Therapeutic Opportunities with Pharmacological Inhibition of CD38 with Isatuximab

“…Both daratumumab and isatuximab were shown to have activity against lymphoma and leukemia cell lines and xenograft mouse models [13,14,52]. Daratumumab has been shown to induce disruption of chronic lymphocytic leukemia (CLL) adhesion and migration [53] and ADCC in a panel of 10 NK-cell-T-cell lymphoma (NKTCL) cell lines [54]. Moreover, daratumumab induces a cytotoxic effect in Waldenstrom macroglobulinemia (WM) cells, but results were variable and cell-line dependent, with ADCC and not CDC was shown to be the prominent mechanism of action [55].…”

Efficacy and safety of daratumumab in the treatment of relapsed/refractory multiple myeloma: A meta-analysis of randomized controlled trials

“…[ 35 ] It serves various functions, including receptor-mediated adhesion, cell signaling, and regulation of cyclase and hydrolase activities. [ 36 ] The high expression of CD38 on multiple myeloma cell membranes has made it an ideal therapeutic target for interventions in multiple myeloma. [ 17 ] Consequently, the development of novel treatment drugs targeting CD38 has become a hot topic in RRMM management.…”

Immunomodulatory properties of CD38 antibodies and their effect on anticancer efficacy in multiple myeloma

“…89,90 This limited CDC induction may be explained by the high expression of complement inhibitors CD46, CD55, and CD59, and by insufficient expression of CD38. 141 Resistance to ADCP may also occur through the overexpression on MM cells of CD47, which binds to SIRPα on tumor-associated macrophages (TAMs) and contributes to the immune escape of tumor cells by inhibiting ADCP. 142 Daratumumab has been combined with a CD47 antibody in a preclinical model of pediatric T-cell ALL, and was able to prolong survival of the mice compared with single-agent treatments.…”

“…Daratumumab typically induces marginal CDC in mantle cell lymphoma, follicular lymphoma, or chronic lymphocytic leukemia cells 89,90 . This limited CDC induction may be explained by the high expression of complement inhibitors CD46, CD55, and CD59, and by insufficient expression of CD38 141 …”