Wen-Kai Weng

Two Immunoglobulin G Fragment C Receptor Polymorphisms Independently Predict Response to Rituximab in Patients With Follicular Lymphoma

PURPOSE Although rituximab is now routinely used in the treatment of B-cell non-Hodgkins lymphoma, the mechanism of its antitumor effect is not clear. One potential mechanism of action involves antibody-dependent cellular cytotoxicity (ADCC). Two aspects of ADCC influence the effectiveness of this process: the susceptibility of tumor cells and the activation of effector cells via their immunoglobulin G fragment C receptors (Fc gamma Rs). Several Fc gamma R polymorphisms have been identified that may affect the killing function of natural killer cells and macrophages. PATIENTS AND METHODS The pretreatment tumor cells from 43 patients with follicular lymphoma were tested for their intrinsic susceptibility to rituximab-mediated ADCC. In addition, the Fc gamma RIIIa (CD16) and Fc gamma RIIa (CD32) polymorphisms were determined in an expanded group of 87 patients. The results were then correlated with clinical outcome of these patients. RESULTS No difference was found between the susceptibility of tumors from patients who clinically responded to rituximab versus those who did not respond. Conversely, both the Fc gamma RIIIa 158 valine/valine and the Fc gamma RIIa 131 histidine/histidine genotypes were found to be independently associated with the response rate and freedom from progression. CONCLUSION These data support the hypothesis that ADCC plays an important role in the clinical effect of rituximab at the level of the effector cell. It will be important to include information on Fc receptor polymorphisms in future trials of rituximab therapy.

Clinical Outcome of Lymphoma Patients After Idiotype Vaccination Is Correlated With Humoral Immune Response and Immunoglobulin G Fc Receptor Genotype

PURPOSE The unique immunoglobulin idiotype (Id) expressed by each B-cell lymphoma is a target for immunotherapy. Vaccination with Id induces humoral and/or cellular anti-Id immune responses. However, the clinical impact of these anti-Id immune responses is unknown. We and others have previously reported that immunoglobulin G Fc receptor (FcgammaR) polymorphisms predict the clinical response of lymphoma patients to passive anti-CD20 antibody infusions. In this study, we tested whether anti-Id immune responses or FcgammaR polymorphisms associate with clinical outcome of patients who received Id vaccination. PATIENTS AND METHODS We analyzed 136 patients with follicular lymphoma who had received Id vaccination. The anti-Id immune responses were measured and FcgammaRIIIa and FcgammaRIIa polymorphisms were determined and correlated with clinical outcome for these patients. RESULTS Patients who mounted humoral immune responses had a longer progression-free survival (PFS) than those who did not (8.21 v 3.38 years; P = .018). Patients with FcgammaRIIIa 158 valine/valine (V/V) genotype also had a longer PFS than those with valine/phenylalanine (V/F) or phenylalanine/phenylalanine (F/F) genotypes (V/V, 8.21 v V/F, 3.38 years; P = .004; v F/F, 4.47 years; P = .035). Multivariate analysis using the Cox proportional hazards model showed that V/V genotype and humoral immune responses were independent positive predictors for PFS. CONCLUSION This study is the first to identify the predictive value of FcgammaR polymorphism on clinical outcome in patients who received active immunotherapy with tumor antigen vaccines. Our results imply that the antibodies induced against a tumor antigen are beneficial and that FcgammaR-bearing cells mediate an antitumor effect by killing antibody-coated tumor cells.

Stimulation of natural killer cells with a CD137-specific antibody enhances trastuzumab efficacy in xenotransplant models of breast cancer

Trastuzumab, a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2; also known as HER-2/neu), is indicated for the treatment of women with either early stage or metastatic HER2(+) breast cancer. It kills tumor cells by several mechanisms, including antibody-dependent cellular cytotoxicity (ADCC). Strategies that enhance the activity of ADCC effectors, including NK cells, may improve the efficacy of trastuzumab. Here, we have shown that upon encountering trastuzumab-coated, HER2-overexpressing breast cancer cells, human NK cells become activated and express the costimulatory receptor CD137. CD137 activation, which was dependent on NK cell expression of the FcγRIII receptor, occurred both in vitro and in the peripheral blood of women with HER2-expressing breast cancer after trastuzumab treatment. Stimulation of trastuzumab-activated human NK cells with an agonistic mAb specific for CD137 killed breast cancer cells (including an intrinsically trastuzumab-resistant cell line) more efficiently both in vitro and in vivo in xenotransplant models of human breast cancer, including one using a human primary breast tumor. The enhanced cytotoxicity was restricted to antibody-coated tumor cells. This sequential antibody strategy, combining a tumor-targeting antibody with a second antibody that activates the host innate immune system, may improve the therapeutic effects of antibodies against breast cancer and other HER2-expressing tumors.

TLI and ATG conditioning with low risk of graft-versus-host disease retains antitumor reactions after allogeneic hematopoietic cell transplantation from related and unrelated donors

A hematopoietic cell transplantation regimen was adapted from a preclinical model that used reduced-intensity conditioning (RIC) and protected against graft-versus-host disease (GVHD) by skewing residual host T-cell subsets to favor regulatory natural killer T cells. One hundred eleven patients with lymphoid (64) and myeloid (47) malignancies received RIC using total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) followed by the infusion of granulocyte colony-stimulating factor-mobilized grafts. Included were 34 patients at least 60 years of age, 32 patients at high risk of lymphoma relapse after disease recurrence following prior autologous transplantation, and 51 patients at high risk of developing GVHD due to lack of a fully human leukocyte antigen (HLA)-matched related donor. Durable chimerism was achieved in 97% of patients. Cumulative probabilities of acute GVHD (grades II-IV) were 2 and 10% of patients receiving related and unrelated donor grafts. Nonrelapse mortality (NRM) at 1 year was less than 4%. Cumulative incidence of chronic GVHD was 27%. The 36-month probability of overall and event-free survival was 60% and 40%, respectively. Disease status at start of conditioning and the level of chimerism achieved after transplantation significantly impacted clinical outcome. The high incidence of sustained remission among patients with active disease at time of transplantation suggests retained graft-versus-tumor reactions. Active trial registration currently at clinicaltrials.gov under IDs of NCT00185640 and NCT00186615.

A polymorphism in the complement component C1qA correlates with prolonged response following rituximab therapy of follicular lymphoma.

Purpose: Complement may play a role in the clinical response to rituximab and other monoclonal antibody–based therapies of cancer. The purpose of this study was to explore the relationship between the C1qA[276] polymorphism and the clinical response to rituximab in patients with follicular lymphoma. Experimental Design: Genotyping for C1qA[276A/G] was done in 133 subjects with follicular lymphoma treated with single-agent rituximab, and correlation with clinical response was done using Cox regression analysis. Results: Prolonged remission was observed among subjects that responded clinically to rituximab therapy and were carriers of the A allele compared with homozygous G subjects. Homozygous G subjects had a time to progression of 282 days, whereas A-allele carriers had a time to progression of 708 days [hazard ratio, (HR), 2.5; 95% confidence interval (95% CI), 2.0-3.1; P = 0.02]. Among subjects who achieved complete remission, homozygous G subjects had a time to progression of 250 days, whereas A-allele carriers had a time to progression of 1,118 days (HR, 4.5; 95% CI, 4.1-4.8, P = 0.04). The difference persisted after controlling for CD32 and CD16 polymorphisms. In patients who responded to rituximab used as first-line agent, a linear trend was observed among the C1qA[276] genotypes, with homozygous A subjects achieving complete response at a higher rate compared with heterozygous or homozygous G subjects. Conclusions: Our findings indicate that polymorphisms in the C1qA gene may affect the clinical response and duration of response to rituximab therapy of follicular lymphoma. These results could have direct implications on designing antibodies with improved efficiency and enhance our understanding of the role of complement in monoclonal antibody therapy.

Targeting CD137 enhances the efficacy of cetuximab

Treatment with cetuximab, an EGFR-targeting IgG1 mAb, results in beneficial, yet limited, clinical improvement for patients with head and neck (HN) cancer as well as colorectal cancer (CRC) patients with WT KRAS tumors. Antibody-dependent cell-mediated cytotoxicity (ADCC) by NK cells contributes to the efficacy of cetuximab. The costimulatory molecule CD137 (4-1BB) is expressed following NK and memory T cell activation. We found that isolated human NK cells substantially increased expression of CD137 when exposed to cetuximab-coated, EGFR-expressing HN and CRC cell lines. Furthermore, activation of CD137 with an agonistic mAb enhanced NK cell degranulation and cytotoxicity. In multiple murine xenograft models, including EGFR-expressing cancer cells, HN cells, and KRAS-WT and KRAS-mutant CRC, combined cetuximab and anti-CD137 mAb administration was synergistic and led to complete tumor resolution and prolonged survival, which was dependent on the presence of NK cells. In patients receiving cetuximab, the level of CD137 on circulating and intratumoral NK cells was dependent on postcetuximab time and host FcyRIIIa polymorphism. Interestingly, the increase in CD137-expressing NK cells directly correlated to an increase in EGFR-specific CD8+ T cells. These results support development of a sequential antibody approach against EGFR-expressing malignancies that first targets the tumor and then the host immune system.

The antileukemia activity of a human anti-CD40 antagonist antibody, HCD122, on human chronic lymphocytic leukemia cells

B-cell chronic lymphocytic leukemia (B-CLL) is a lymphoproliferative disorder characterized by the surface expression of CD20, CD5 antigens, as well as the receptor CD40. Activation of CD40 by its ligand (CD40L) induces proliferation and rescues the cells from spontaneous and chemotherapy-induced apoptosis. CD40 activation also induces secretion of cytokines, such as IL-6, IL-10, TNF-alpha, IL-8, and GM-CSF, which are involved in tumor cell survival, migration, and interaction with cells in the tumor microenvironment. Here we demonstrate that in primary B-CLL tumor cells, the novel antagonist anti-CD40 monoclonal antibody, HCD122, inhibits CD40L-induced activation of signaling pathways, proliferation and survival, and secretion of cytokines. Furthermore, HCD122 is also a potent mediator of antibody-dependent cellular cytotoxicity (ADCC), lysing B-CLL cells more efficiently than rituximab in vitro, despite a significantly higher number of cell surface CD20 binding sites compared with CD40. Unlike rituximab, however, HCD122 (formerly CHIR-12.12) does not internalize upon binding to the cells. Our data suggest that HCD122 may inhibit B-CLL growth by blocking CD40 signaling and by ADCC-mediated cell lysis.

Phase II Investigator-Initiated Study of Brentuximab Vedotin in Mycosis Fungoides and Sézary Syndrome With Variable CD30 Expression Level: A Multi-Institution Collaborative Project

PURPOSE In contrast to Hodgkin lymphoma and systemic anaplastic large-cell lymphoma, CD30 expression of malignant lymphocytes in mycosis fungoides (MF) and Sézary syndrome (SS) is quite variable. Clinical activity and safety of brentuximab vedotin, a CD30 targeting antibody-drug conjugate, was evaluated in MF and SS. Tissue and blood biomarkers of clinical response were explored. PATIENTS AND METHODS In this phase II study, patients with MF or SS with negligible to 100% CD30 expression levels were treated with brentuximab vedotin (1.8 mg/kg) every 3 weeks for a maximum of sixteen doses. The primary end point was overall global response rate. Secondary end points included correlation of tissue CD30 expression level with clinical response, time to response, duration of response, progression-free and event-free survivals, and safety. RESULTS Of the 32 patients enrolled and treated, 30 patients had available efficacy evaluations. Objective global response was observed in 21 (70%) of 30 patients (90% CI, 53% to 83%). CD30 expression assessed by immunohistochemistry was highly variable, with a median CD30max of 13% (range, 0% to 100%). Those with <5% CD30 expression had a lower likelihood of global response than did those with 5% or greater CD30 expression (P < .005). CD163 positive tumor-associated macrophages, many of which coexpress CD30, were abundant in tissue. Peripheral neuropathy was the most common adverse event. CONCLUSION Brentuximab vedotin demonstrated significant clinical activity in treatment-refractory or advanced MF or SS with a wide range of CD30 expression levels. Additional biomarker studies may help optimize rational design of combination therapies with brentuximab vedotin.

Hepatitis C virus (HCV) and lymphomagenesis.

Hepatitis C virus (HCV) is the major cause for non-A, non-B hepatitis. Most HCV-infected individuals do not clear the virus resulting in a chronic infection that may potentially lead to liver cirrhosis and hepatocellular carcinoma. In addition to hepatic manifestations, HCV infection is associated with B cell lymphoproliferative disorders, including mixed cryoglobulinemia, usually a benign condition, and overt B cell lymphoma. A direct role of HCV infection in the genesis of these B cell lymphoproliferative disorders has been suggested initially by epidemiological studies and is supported by recent studies, which analyzed the monoclonal B cells that proliferate in these disorders. How HCV induces B cell lymphoproliferative disorders is still unclear, it is probably not due to direct change of phenotype in B cells after viral infection, but may be due to an HCV-antigen driven process. Support for this hypothesis comes from the analysis of monoclonal B cells found in these disorders, which use a restricted repertoire of immunoglobulin variable region genes that are similar to those used by B cells that secrete anti-HCV antibodies. The fact that monoclonal IgM is resolved in HCV-infected patients who responded to anti-viral treatment supports the linkage between antigen persistence and B cell proliferation. Finally, the linkage between benign B cell proliferation and overt lymphoma is supported by the identification of a pre-malignant B cell clone that subsequently converted to an overt B cell lymphoma. The molecular basis for viral induced B cell proliferation is still unknown. One possibility is that HCV stimulates the proliferation of monoclonal B cells via their HCV-specific B cell receptor (BCR) on the cell surface. Binding of the HCV envelope proteins to a cellular ligand, CD81, may also enhance this antigen-driven process. A recent report on regression of splenic marginal zone lymphoma after anti-viral treatment with interferon and ribavirin has significantly strengthened the cause–effect relationship between HCV infection and lymphoma. Further studies should determine whether BCRs expressed on HCV-associated lymphomas, particularly those that regress in response to anti-viral therapy, bind HCV antigens that stimulate their proliferation.

Genomic analysis of mycosis fungoides and Sézary syndrome identifies recurrent alterations in TNFR2

Mycosis fungoides and Sézary syndrome comprise the majority of cutaneous T cell lymphomas (CTCLs), disorders notable for their clinical heterogeneity that can present in skin or peripheral blood. Effective treatment options for CTCL are limited, and the genetic basis of these T cell lymphomas remains incompletely characterized. Here we report recurrent point mutations and genomic gains of TNFRSF1B, encoding the tumor necrosis factor receptor TNFR2, in 18% of patients with mycosis fungoides and Sézary syndrome. Expression of the recurrent TNFR2 Thr377Ile mutant in T cells leads to enhanced non-canonical NF-κB signaling that is sensitive to the proteasome inhibitor bortezomib. Using an integrative genomic approach, we additionally discovered a recurrent CTLA4-CD28 fusion, as well as mutations in downstream signaling mediators of these receptors.