Fc-engineered anti-CD40 antibody enhances multiple effector functions and exhibits potent in vitro and in vivo antitumor activity against hematologic malignancies

Abstract

IntroductionIn the past decade, monoclonal antibodies directed against B-cell antigens have proven beneficial for patients with B-lineage neoplasms. Approved immunotherapeutics include the anti-CD52 antibody alemtuzumab (Campath-1H), 1 2 anti-CD20 antibodies, rituximab (Rituxan) 2 and most recently ofatumumab (Arzerra), 3 and 2 anti-CD20 conjugates carrying radioactive isotopes, 90 Yibritumomab tiuxetan (Zevalin) 4 and 131 I-tositumomab (Bexxar). 5 In particular, when used as a single agent or in combination with chemotherapy, rituximab has shown efficacy and relative safety in many B-cell non-Hodgkin lymphomas (NHLs) and some B-cell leukemias. 2,6 However, some patients do not respond to rituximab, and many of those that do will relapse. 2 In addition, some B-cell tumors either lack CD20 expression or lose it during rituximab treatment. 7 Thus, antibodies targeting other B-cell antigens are warranted, and several are being explored, including those targeting CD40, a 45-to 50-kDa transmembrane glycoprotein belonging to the tumor necrosis factor receptor family.CD40 is broadly expressed on hematologic cells, including B cells and on several types of epithelial and endothelial cells. [8][9][10] The ligand of CD40, CD40L (CD154), is preferentially expressed on activated T cells but has also been found on other hematologic cell types. Signaling via the CD40 pathway plays a key role in defining cellular and humoral immune responses. 10 CD40 is overexpressed by the malignant counterparts to Blineage cells and is found on most mature B-cell malignancies, including NHL, Hodgkin disease, and chronic lymphocytic leukemia (CLL), and on some early acute lymphocytic leukemias (ALL) 8,11,12 ; it is also expressed on multiple myeloma (MM) cells. 13 Many solid tumors express CD40, including melanoma and carcinomas of the kidney, bladder, lung, pancreas, colon, prostate, ovary, breast, head, and neck. 14 CD40 agonists have been shown to trigger immune responses against various tumors 15,16 and to inhibit the growth of different neoplastic cells, both in vitro and in vivo. 17,18 Broad stimulation of the immune system and expression on a wide range of malignancies make CD40 an attractive target for antibody-based immunotherapy. Over the past 2 decades, several CD40-specific antibodies have been tested against B-lineage malignancies in vitro and in animal models, yielding various degrees of success. [19][20][21][22][23] Recently, 2 humanized antibodies have emerged for further development: a mild CD40 agonist, 20,24,25 and a CD40 antagonist, HCD122 (CHIR-12.12). 21,23 These agents were evaluated in phase 1 and 2 trials in patients with relapsed MM, NHL, and CLL. Thus far, they have demonstrated a favorable safety profile and have shown some antitumor activity in NHL and MM. [26][27][28] In addition, a strongly agonistic anti-CD40 antibody, CP-870,893, evaluated in phase 1 trials in patients with melanoma and other solid tumors, was found to be well tolerated and to have antitumor activity. 29 Therefore, preclinical and early clinic...

Human IgG Fc domain engineering enhances antitoxin neutralizing antibody activity

“…This in turn suggests that it may be possible to enhance the toxin-neutralizing activity of antibodies by engineering the Fc domain to selectively engage certain classes of FcγRs. Indeed, engineering of the Fc region of an immunoglobulin can increase its protective efficacy against different pathogens and improve effector functions, including antibody-dependent cell-mediated cytotoxicity and opsonization (11)(12)(13).…”

RANKL Expression, Function, and Therapeutic Targeting in Multiple Myeloma and Chronic Lymphocytic Leukemia

“…17). Several Fcengineered antilymphoma antibodies that mediate markedly enhanced ADCC are presently in preclinical and early clinical development, and it is hoped that their therapeutic activity is increased accordingly (18,19). As multiple myeloma cells do not express CD20, the target antigen of rituximab and its successors, novel antibodies directed to multiple myeloma antigens are presently being developed, and recently an Fcmodified antibody that potently targets multiple myeloma cells for NK cell reactivity was reported (20,21).…”

The antitumor activity of the human FOLR1-specific monoclonal antibody, farletuzumab, in an ovarian cancer mouse model is mediated by antibody-dependent cellular cytotoxicity

“…[17][18][19][20] Strategies to assess the role of ADCC on antitumor efficacy mediated by antibodies in vivo have employed severe compromised immunodeficient non-obese diabetic (SCID/NOD) mice (which largely lack functional NK cells and monocytes), 19 F(ab') (2) fragments (which lack the Fc domain), 20 mice lacking activating Fc gamma receptors, 18,20 or antibody mutagenesis analyses. In the latter approach, the amino acid substitutions G236R/ L328R, 21,22 N297Q, 23 and D265A 18,24 were used to remove or alter the Fc gamma receptor binding region with the intent of demonstrating loss of antitumor effect in vivo. To our knowledge, ours is the first report describing the use of an antibody carrying the triple mutation L234A/L235A/K322A for assessing the effects of disrupting the antibody-mediated interaction between immune effector and tumor cells in vivo.…”