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Review article

The clinical application of monoclonal antibodies in chronic

lymphocytic leukemia
Samantha M. Jaglowski,1 Lapo Alinari,1 Rosa Lapalombella,1 Natarajan Muthusamy,1 and John C. Byrd1,2
1Divisionof Hematology-Oncology, Department of Internal Medicine, College of Medicine, and 2Division of Medicinal Chemistry, College of Pharmacy, The Ohio
State University, Columbus, OH

Chronic lymphocytic leukemia (CLL) rep- CLL and as salvage therapy. Recent data ies targeting alternative B-cell–specific
resents the most prevalent adult leuke- suggest that the addition of rituximab to antigens in CLL has been less success-
mia. Treatment with chemotherapy over fludarabine with or without cyclophospha- ful, although many promising candidate
the past 3 decades has been palliative. mide prolongs survival in younger pa- antibodies and/or small modular immune
The introduction of therapeutic antibod- tients with CLL. Other improved CD20 pharmaceuticals (SMIPs) are coming for-
ies has increased the number of treat- antibodies with promising clinical activ- ward. In addition, recent efforts to com-
ment options for this disease. Despite ity, including ofatumumab and GA-101, bine currently applied therapeutic anti-
this increase, our true understanding of are coming forward. Alemtuzumab, a bodies with other biologic and targeted
the mechanism of action of antibody CD52 antibody, likewise has demonstrated therapies with efficacy in CLL offers the
therapy in CLL remains limited. Ritux- benefit in both symptomatic, previously potential to move toward alternative non–
imab, a CD20 antibody, is currently widely untreated CLL and in patients with re- chemotherapy-based treatment approaches.
used in combination-based strategies for lapsed disease but has less selectivity. (Blood. 2010;116(19):3705-3714)
both previously untreated symptomatic Development of other therapeutic antibod-

Introduction
Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/ p53 respond very poorly to standard therapies that mainly act
SLL) is the most common leukemia, with an incidence rate of 2 to through mechanisms relying on an intact p53 pathway. Identifying
6 cases per 100 000 people per year.1 The median survival is highly therapies that circumvent p53 is therefore a priority for the
variable with some patients exhibiting an indolent natural history, treatment of this high-risk population. Attempts to intensify
whereas others develop aggressive disease with a survival of less chemotherapy beyond fludarabine/alkylator-based combinations
than 2 to 3 years. Genomic features such as immunoglobulin have been pursued with enhanced toxicity but little evidence of
herpesvirus (IGHV) mutational status, ␤2-microglobulin, ZAP70 clinical benefit. As with many other types of cancers, treatment
expression, interphase cytogenetics, and complex karyotype on outcomes of CLL patients with chemotherapy-based approaches
metaphase cytogenetics, recently reviewed by Zenz et al,2 provide reached a plateau with no improvements in survival or hints of cure
further differentiation of disease prognosis. Because there is no in even a subset of patients. This review will focus on how the
proven survival benefit with early treatment, CLL patients are clinical application of therapeutic monoclonal antibodies more than
observed until symptoms appear. the past decade has impacted the therapeutic approach to CLL and
Therapy for CLL has evolved significantly from 1970 when point to potential opportunities in the future with other targeted
alkylator-based therapy such as chlorambucil or cyclophosphamide therapies currently being explored.
was used. Late 1990 saw multiple randomized phase 3 studies
comparing fludarabine to alkylator-based therapy and demonstrat- History of monoclonal antibodies in B-cell malignancies
ing improved response and progression-free survival (PFS), as
recently reviewed in Ricci et al.3 Success prompted phase 3 studies Monoclonal antibodies have a fixed effector cell binding region
combining fludarabine with cyclophosphamide, in which further (Fc) and a variable region with affinity toward a specific antigen.
improved response and PFS were noted.3 Treatment intensification Antibodies can mediate cytotoxicity toward tumor cells via both
in CLL from alkylator to fludarabine and cyclophosphamide direct and indirect mechanisms based upon the target. Direct
combinations resulted in increased cellular immune suppression cytotoxicity of tumor cells can occur though transmembrane
and myelosuppression. In addition, chemotherapy intensification signaling, and recruitment of effector cells (natural killer [NK]
did not greatly improve treatment outcomes in patients with cells, macrophages, neutrophils) that mediate antibody-dependent
high-risk genomic features, such as those with IGHV unmutated cell cytotoxicity (ADCC) and complement that mediates comple-
disease, del(17p13.1), and p53 mutations.2 These patients all ment-dependent cytotoxicity (CDC). Indirect cytotoxicity can
display poorer outcomes, with markedly reduced survivals com- occur by interfering with both the interaction of a tumor cell with
pared with patients with normal genomic features or good-risk the microenvironment-generated survival signal and with its bind-
features, as recently reviewed by Zenz et al.4 Of all prognostic ing to soluble factors that enhance tumor cell survival. Given the
factors examined in CLL, patients with mutated or deleted specificity of antibodies for a single antigen and the multiple

Submitted April 24, 2010; accepted June 23, 2010. Prepublished online as © 2010 by The American Society of Hematology
Blood First Edition paper, July 7, 2010; DOI 10.1182/blood-2010-04-001230.

BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19 3705

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3706 JAGLOWSKI et al BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19

Table 1. Newer monoclonal antibodies in clinical development

Agent Target Humanized/chimeric Direct cell death ADCC CDC Development status

MDX-1342 CD19 Humanized Yes Yes No Phase 1

XmAb5574 CD19 Humanized Modest Yes No Phase 1
Ofatumumab CD20 Humanized Yes Yes Yes Phase 3
GA-101 CD20 Humanized Yes Yes Modest Phase 2
PRO131921 CD20 Humanized Yes Yes Yes Phase1/2
Veltuzumab CD20 Humanized Yes Yes Yes Phase1/2
LFB-R603 CD20 Chimeric Yes Yes Yes Phase 1
Lumiliximab CD23 Primatized Yes Yes Yes Phase 3
TRU-016 CD37 Humanized Yes Yes No Phase 1
SGN40 CD40 Humanized Yes Yes No Phase1/2
HCD122 CD40 Humanized No Yes No Phase 1
MDX-1411 CD70 Humanized No Yes No Phase 1
Milatuzumab CD74 Humanized Yes No No Phase1/2
Ipilimumab CTLA-4 Humanized Yes No No Phase 2
Bevacizumab VEGF Humanized No No No Phase 2

ADCC indicates antibody-dependent cell-mediated cytotoxicity; and CDC, complement-dependent cytotoxicity.

mechanisms by which they can mediate cytotoxicity, antibody- B cells.6 These data support CD20 as an ideal target for antibody-
based cancer therapy was seen as a potential “silver bullet” therapy based therapy in mature B-cell malignancies.
for patients with CLL, particularly if the antigen is selectively Rituximab was the first approved therapeutic antibody for the
expressed on B cells. Numerous target antigens offered the oppor- treatment of cancer. Not surprisingly, the majority of mechanism of
tunity to selectively target B cells, including CD19, CD37, CD20, action studies of therapeutically used antibodies come from
and idiotype. Murine antibodies derived from mouse plasma cell preclinical studies with rituximab. As with most immunoglobulin
hybridoma cells directed toward these targets were the first- G1 (IgG1) therapeutic antibodies, rituximab can mediate CDC,
generation agents evaluated in multiple clinical studies from 1980. ADCC, and direct apoptosis with a cross-linking antibody (Figure
These studies were impaired by production issues that limited 1).7 Extensive investigation of each mechanism has been pursued
antibody supply, diminished antibody activity toward the tumor in lymphoma and CLL. Although CDC is relevant to rituximab-
cell, and development of human antibody–mouse antibody reac- mediated cytotoxicity in some B-cell lines, CLL cells express dim
tions with repeated administration. As a consequence, very modest CD20 and only a small subset of cells are susceptible to CDC by
activity with essentially all murine antibody-based treatments was
observed, limiting the development of this modality. Technologic
advances allowing engineering of mouse-derived antibodies includ-
ing a minimal mouse component of the variable complementarity-
determining region in the final product (chimeric or humanized)
represented a major advance for this modality. In general, chimeric
and humanized therapeutic antibodies directed toward human
B-cell antigens mediate improved ADCC and CDC compared with
their murine counterparts. In addition, chimeric and humanized
antibodies generally lack human anti–mouse antibody even on
repeated administration. Concurrent with advances in chimeric and
humanization technologies were improvements in the ability to
produce larger amounts of antibodies. These advances fostered the
rebirth of antibody-based therapeutics, impacting treatment of
many diseases including CLL. This review will summarize evalua-
tions of antibody and peptide therapies that directly target CLL
cells that are either approved or under clinical investigation at this
time (Table 1).

Rituximab
Figure 1. Mechanisms of rituximab-mediated cell death. Rituximab coated B cells
Rituximab target and mechanism of action are killed by at least 4 different mechanisms. (A) Binding of rituximab to CD20 on
B cell surface causes activation of the complement cascade, which generates the
Rituximab is a chimeric murine/human antibody directed against membrane attack complex (MAC) that can directly induce B-cell lysis by complement-
mediated cytotoxicity (CDC). (B) Binding of rituximab allows interaction with NK cells
CD20. CD20 is expressed relatively selectively on B cells from the via Fc receptors III (FcRIII), which leads to antibody-dependent cell-mediated
pre–B-cell stage until postgerminal cells differentiate to become cytotoxicity (ADCC). (C) The Fc portion of rituximab and the deposited complement
plasma cells. CD20 knockout mice demonstrate normal B-cell fragments allow for recognition by both FcR and complement receptors on macro-
phages, which lead to phagocytosis and ADCC. (D) The crosslinking of several
development and function, but CD19-induced calcium responses
molecules of rituximab and CD20 in the lipid raft determine the interaction of these
and B-cell receptor signaling are significantly altered.5 Unlike other complexes with elements of a signaling pathway involving Src kinases that mediate
antigens, CD20 is neither shed nor internalized in resting normal direct apoptosis.
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BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19 ANTIBODY THERAPY FOR CLL 3707

rituximab.8,9 Very elegant preclinical in vitro and in vivo studies reasons for lower response in CLL included diminished CD20
have demonstrated that CLL cells are prone to CD20-shaving after expression,38 altered innate immune function,17,18 and different
treatment, and this diminishes the ability of CDC to occur.10-12 pharmacokinetic features37 compared with lymphoma. Two trials
Attempts to abrogate the phenomenon of shaving have been performed by our group39 and the M. D. Anderson Cancer Center
undertaken by administering very low doses of rituximab on a (MDACC)40 administered either thrice weekly doses or higher
thrice weekly schedule with very modest clinical activity.11,13 Thus, doses of rituximab weekly (up to 2250 mg/m2 per dose) to relapsed
although a very strong hypothesis with supportive preclinical data CLL patients with improved response. Benefit was predominately
support shaving as a reason for modest rituximab clinical activity in the blood and nodal compartment with response duration
when administered at higher doses, it is not clear what CDC approaching that achieved in follicular B-NHL trials. These
contributes to tumor elimination. Monocytes mediate antibody- 2 studies established a role for single-agent rituximab in relapsed
dependent cellular phagocytosis (ADCP),14 and NK cells mediate CLL and encouraged subsequent trials of rituximab as a single
ADCC14 against rituximab-labeled CLL cells in vitro. Despite this, agent in previously untreated patients where improved efficacy was
the function of both monocytes15,16 and NK cells17,18 to mediate observed41 and in combination strategies with chemotherapy.
ADCP and ADCC, respectively, are certainly compromised in vitro
and are likely compromised in vivo in CLL patients. The mecha- Rituximab chemoimmunotherapy studies in CLL
nism of innate immune ADCP and ADCC is not known but may be
Numerous phase 2 studies combining rituximab with other thera-
from the increased T regulatory cells documented in CLL patients
pies used in CLL have been pursued. Due to reference limitations,
with active disease.19 A recent study demonstrated that T regulatory
those impacting current CLL therapy approaches are outlined
cells can dramatically dampen ADCC mediated toward rituximab-
below.
labeled tumor cells.20 With the increased T regulatory cells in CLL
A phase 2 study performed by the German CLL Study Group
patients,19 diminished monocyte15,16 and NK cell17,18 function, the
(GCLLSG) of fludarabine and rituximab (FR) in both refractory
contribution of these cells to tumor elimination is not clear. In
and previously untreated patients resulted in an overall response
addition, single nucleotide polymorphisms of Fc␥RIIIa and Fc␥RIIa
rate (ORR) of 87% with a subset achieving complete response
that enhance ADCC and are associated with improved response to
(CR).42 CALGB 9712 evaluated fludarabine in combination with
rituximab,21,22 in lymphoma have no impact on rituximab treatment
response in CLL.23,24 Strategies directed at either reversing the rituximab given either concurrently or sequentially. Patients in the
innate immune dysfunction with immune modulating agents such concurrent arm experienced more severe hematologic and infusion-
as interleukin-21,14 TLR agonists,25 or agents that deplete T related toxicity, but the ORR was 90% with a CR of 47% compared
regulatory cells26 offer the best opportunity to optimize immune with an ORR of 78% and CR of 28% in the sequential arm.43 An
cell participation in tumor clearance by rituximab. Finally, several evaluation of outcome based on genetic features demonstrated
groups have demonstrated that rituximab can mediate both caspase- worse 3 year survival among those patients with del(17p13.1) or
dependent and -independent apoptosis in vitro (reviewed in Ja- del(11q22.3) compared with those with normal cytogenetics or
glowski and Byrd27) and in vivo.28 Apoptosis appears to be the most other abnormalities, with 33% and 53% of patients with del(17p13.1)
important mechanism of action in CLL and involves the activation and del(11q22.3) respectively surviving at 3 years compared with
of the p38 mitogen-activated protein kinase, a pathway that 86% of patients with normal cytogenetics.44 A retrospective
requires an intact p53 gene, and caspase 9 cleavage.7-9 Ofatu- comparison of outcome of patients on this trial to a similarly
mumab, a second-generation fully humanized anti-CD20 that designed CALGB study evaluating, in part, fludarabine alone
recognizes a different CD20 epitope than rituximab, has similar demonstrated chemoimmunotherapy improved PFS and overall
ADCC, stronger CDC, and requires cross-linking to induce direct survival (OS).45 Long-term follow-up data recently presented
apoptosis similar to riutximab.29,30 GA101 binds with high affinity shows no increased risk of treatment-related acute myeloid leuke-
to the CD20 epitope and, as a result, induction of ADCC is 5 to mia (AML).24 An Italian phase 2 study of sequential FR confirmed
100 times greater than with rituximab.31-34 Type II anti-CD20 good response rates, with 78% of patients achieving a CR, but only
antibodies such as B1 and GA101 promote direct apoptosis without patients who had stable disease (SD) or better with fludarabine
a cross-linking antibody.35 Other differences between type I remained on the study to receive rituximab.46
(rituximab, ofatumumab) and type II (GA101, B1) anti-CD20 The combination of fludarabine, cyclophosphamide, and ritux-
antibodies lie predominately in their ability to redistribute CD20 imab (FCR) has been extensively explored. A single-arm study of
into plasma membrane lipid rafts.36 Type II anti-CD20 antibodies 300 previously untreated patients with progressive CLL from the
do not segregate CD20 into lipid rafts and are very effective at MDACC reported an ORR of 95% with 72% of patients attaining a
activating a caspase-independent, lysosomal-dependent mecha- CR, 10% nodular partial remission (nPR), and 13% a PR.47 The
nism of death that is dependent upon homotypic adhesion.35 The 6-year OS and PFS were 77% and 51%, respectively.47 Toxicity in
relevance of this observation in vivo among CLL patients receiving this study included predominately cytopenias and associated infec-
type II CD20 antibody therapy remains unexplored. tion. Eight patients developed treatment-related myelodysplasia. A
second study of 177 previously treated patients at this same
Early rituximab studies and single-agent CLL trials
institution was pursued using the same schedule of FCR.48 The
Although the phase 3 pivotal approval study of rituximab in results of this study demonstrated a CRR in 25% of patients with an
non-Hodgkin lymphomas (NHL) demonstrated promising clinical ORR of 73%.48 The median time to progression was 28 months,
activity, the response among the 33 patients with SLL was modest, which varied significantly based upon response. The median time
with only 12% of patients achieving a partial response (PR).37 to progression for patients achieving CR, nPR, and PR was 39,
Similarly disappointing results were obtained in several other small 33, and 15 months, respectively. Toxicities observed were predomi-
studies (reviewed in Jaglowski and Byrd27). The very modest nately grade 3 or 4 neutropenia (81%) and grade 3 or greater
response to rituximab compared with follicular lymphoma pro- infection (16%). Whereas patients with del(11q22.3) appeared to
vided some pause for developing this agent in CLL/SLL. Potential benefit from FCR with loss of the adverse PFS observed in
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3708 JAGLOWSKI et al BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19

fludarabine-monotherapy studies, based on a retrospective evalua- cyclophosphamide in this regimen seems to be important for
tion of patients treated at the MDACC,49 those with IGHV patients with del(11q22.3) as both the MDA and German CLL
unmutated disease and del(17p13.1) continued to have an inferior study group showed no adverse outcome in this group compared
outcome with FCR.4750 with low risk karyotype whereas CALGB 9712 did. For other
Pentostatin is a nucleoside analog that has been suggested to be genetic groups the benefit of cyclophosphamide is uncertain as
less myelotoxic than fludarabine while still active in CLL. This there has not been a comparison of FCR to FR. A randomized
prompted a study in patients with previously treated CLL51 study (CALGB 10404) is ongoing and seeks to answer whether
substituting pentostatin for fludarabine. This pentostatin, cyclophos- the combination of FCR has an advantage over FR and, if so,
phamide, and rituximab (PCR) regimen had an ORR of 75% with a whether the increased risk of secondary AML associated with
CR rate of 25%. The major toxicities were infections and myelosup- cyclophosphamide justifies that advantage.
pression. When evaluated in previously untreated patients, 91%
had responses with a 41% CR rate. Similar to the study with FCR, Maintenance rituximab in CLL
patients with del(11q22.3) had similar PFS as those without this
The use of maintenance rituximab is common in NHL. Contrasting
aberration,52 again suggesting that cyclophosphamide may be an
important addition for del(11q22.3) patients. Infections and myelo- with this approach, no randomized trials have been performed to
suppression were again the predominant toxicities observed. determine whether benefit is derived in CLL/SLL from extended
With the approval of bendamustine for clinical use in newly maintenance therapy using rituximab. A phase 2 study of 75 previ-
diagnosed CLL, pilot studies combining this agent with rituximab ously untreated patients with CLL evaluated the efficacy of
have recently been reported in previously untreated patients where rituximab maintenance after treatment with fludarabine for
a 90% ORR and 33% CRR was observed.53 A parallel study in 6 cycles.59 All patients received 4 weekly doses of 375 mg/m2
relapsed CLL demonstrated a 76% ORR and 13% CRR.54 Toxicity rituximab after therapy, and then those who were minimal residual
in both of these studies included myelosuppression and infection. A disease (MRD)–positive went on to consolidation with 4 monthly
randomized phase 3 study comparing bendamustine and rituximab cycles of 375 mg/m2 rituximab followed by 12 monthly cycles of
to FCR is currently ongoing. 150 mg/m2. MRD-positive patients in CR or PR receiving consoli-
dation had a longer PFS than the patients not receiving consolida-
Phase 3 studies with rituximab in CLL
tion (87% vs 32% at 5 years). A randomized study comparing
Two phase 3 studies, CLL8 from the GCLLSG and the REACH maintenance rituximab is now underway by the Polish CLL group
trial, have been presented and confirm improved response rates and until results from this trial are available, this approach should
and overall survivals with the addition of rituximab. In CLL8, at only be applied as part of clinical trials.
a median observation time of 37.7 months, the ORR for FCR Rituximab in the treatment of autoimmune complications
among the 761 previously untreated patients evaluable for
response was 95.1% versus 88.4% for FC, and the CRR was Autoimmune complications of CLL occur in 10% to 25% of
44.1% compared with 21.8% for FC.55,56 The median PFS was patients during their disease course. Autoimmune hemolytic ane-
32.8 months for FC and 51.8 months for FCR (P ⬍ .001, hazard mia (AIHA) is the most common, followed by immune thrombocy-
ratio [HR] .56), and the OS was longer for those patients who topenia (ITP). These occur both as an intrinsic process associated
received FCR at 84.1% versus 79.0% in the FC arm (P ⫽ .01), with the pathogenesis of CLL and as a result of treatment with
with statistically significant differences seen in patients with purine analogues such as fludarabine.60 Rituximab was initially
Binet stages A (P ⫽ .09, HR .19) and B (P ⬍ .001, HR .45) but described for the treatment of steroid-refractory pure red cell
not in patients with Binet stage C disease (P ⫽ .168, HR 1.4). aplasia or AIHA61; subsequently, the successful treatment of
Patients with del(17p13.1) had particularly poor outcome, and 2 patients with CLL who developed red cell aplasia with 375 mg/
shorter overall survival was seen in the FC arm; likewise, there m2 rituximab weekly for 2 weeks was described.62 A series of 8
was no significant improvement in CR, PFS, and OS among the patients with CLL and steroid-refractory AIHA was treated with a
subgroup of patients with del(17p13.1) treated with FCR. A
combination of rituximab and dexamethasone, and all patients
trend toward shorter overall survival in the FCR arm in patients
achieved a remission of their AIHA, with 5 patients achieving a
with unmutated IGHV status was observed. Patients with
Coombs-negative status. Retreatment was also found to be success-
del(11q22.3) again appeared to benefit from the addition of
ful.63 In a series of 14 patients with CLL and AIHA treated with
cyclophosphamide, with response rates approaching that of
rituximab monotherapy, all but 2 patients had an increase in their
patients without this mutation.57 There was not an increased
infection rate observed with the addition of rituximab, and more hemoglobin levels after treatment.64 Rituximab is effective in
deaths occurred in the FC arm.55 The REACH trial compared FC patients with chronic refractory ITP as well and is of interest in
to FCR in 552 patients with relapsed/refractory CLL. These CLL specifically as fludarabine-related ITP is not responsive to
patients had received a median one line of previous treatment steroids. Three patients who developed ITP while receiving
with the majority consisting of single-agent alkylator therapy; fludarabine and who did not respond to treatment with steroids or
patients who had received combination FC or rituximab were IVIG were treated with weekly rituximab for 4 doses. All patients
not eligible. Treatment with FCR resulted in an ORR of 70%, had rapid and dramatic improvements in their platelet counts, and
versus 58% for FC alone, and the CRRs were 24% versus 13% the response durations were 6 months or greater for all 3 patients.65
for FCR and FC, respectively. Observed PFS in the FCR arm While randomized data demonstrating the exact benefit of ritux-
was 30.6 months compared with 20.6 months in the FC arm.58 imab in autoimmune complications is lacking, these data provide
Hematologic toxicities remained the most significant adverse evidence for its effectiveness. In the author’s opinion, rituximab
events. Collectively, these 2 phase 3 studies provide justification represents one of the more active therapies for the treatment of
for the use of rituximab as part of combination chemoimmuno- autoimmune complications of CLL not responding to initial steroid
therapy in both newly diagnosed and relapsed CLL. The use of treatment.
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BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19 ANTIBODY THERAPY FOR CLL 3709

rates were 77% and 73% respectively. The most common grade
Newer CD20 antibodies for CLL 3-4 toxicities were infections, reported in 11 patients, and hemato-
logic adverse events, including neutropenia in 29 patients, anemia
Ofatumumab in 8 patients, and thrombocytopenia in 9 patients. Grade 3-4 hemo-
lytic anemia occurred in 3 patients.70
Ofatumumab is a newly approved, human type I CD20 monoclonal
Currently, NCCN guidelines provide the recommendation for
antibody. In vitro, it has been demonstrated to mediate CDC against
rituximab-resistant Raji cells and CLL cells with low expression of use of ofatumumab in previously treated CLL patients.71 Clinical
CD20. It appears to have greater potency in CDC than rituximab, as trials to define the activity of ofatumuamb in previously untreated
well as a slower off-rate and more stable CD20 binding.29 In CLL and in combination with most forms of chemoimmunotherapy
addition, it appears to bind a different epitope of CD20 than explored with rituximab are ongoing. Determining the actual
rituximab.30 A phase 1/2 study of ofatumumab in relapsed/ scientific advance of ofatumumab over rituximab will require
refractory patients demonstrated that it is generally well tolerated, randomized phase 3 trials.
even at high doses and is active, with an ORR of 50%. Infusion- GA101
related adverse events are similar to those reported with rituximab
and decrease after the first infusion. Infections were fairly common, GA101 is a type II glycoengineered humanized CD20 monoclonal
occurring in 51% of patients, including one fatal infection.66 A antibody that binds CD20 in a completely different orientation than
planned interim analysis of the seminal study of 138 patients rituximab and over a larger surface area.31 It initiates nonapoptotic
treated with 8 weekly infusions of ofatumumab followed by 4 cell death via an actin-dependent lysosome-mediated mechanism
monthly infusions over a 24-week period has been reported. The that is reliant on cell-to-cell contact.32 Depletion of CLL cells in
patients included in this study were required to be refractory to at whole blood samples has been demonstrated, and it may be more
least one fludarabine-containing regimen and either refractory to at potent than rituximab at similar concentrations.33,34 GA-101 is
least one alemtuzumab-containing regimen (FA-refractory group) internalized less by CLL cells compared with type I CD20
or to have bulky lymphadenopathy (⬎ 5 cm) rendering them less antibodies, making it an ideal agent for investigation. A recently
suitable for alemtuzumab treatment (BF-refractory group). Re- reported phase 1 study in 13 relapsed/refractory CLL patients
sponse criteria were based on physical examination or hematologic demonstrated that GA101 is relatively well tolerated, with the most
criteria alone, limiting assessment of internal lymphadenopathy. common grade 3-4 toxicity being transient neutropenia in 9
The ORR was 58% for the FA-refractory group and 47% for the patients. One CRi, 7 PRs, and 3 patients with SD were observed.
BR-refractory group with one CR observed in the BF-refractory No clear dose-effect relationship was established.72 GA101 is being
group. All other responses were partial. The median duration of evaluated in a phase 2 study as a single agent in relapsed/refractory
response was 7.1 months in the FA-refractory group and 5.6 months CLL and in combination with chlorambucil in previously untreated
in the BF-refractory group with most patients progressing during elderly patients. A phase 3 study is currently underway in patients
treatment. The presence of del(17p13.1) in the BF-refractory group with comorbidity comparing monotherapy with chlorambucil,
was associated with lower response, which was most apparent chlorambucil plus rituximab, and chlorambucil plus GA-101.
among patients with bulky lymph nodes. The median PFS was
5.7 months in the FA-refractory group and 5.9 months in the
BF-refractory group with median OS of 13.7 months and
15.4 months, respectively. A landmark analysis done at week Alemtuzumab
12 demonstrated that median OS was significantly longer among
responding patients compared with those who did not respond Target and mechanism of action
although the meaning of this is uncertain. Infusion-related reactions
were seen in 64% of patients in the FA-refractory group and 61% in Alemtuzumab (Campath-1H, Genzyme) is a recombinant DNA-
the BF-refractory group, almost all of which were grade 1 or 2. One derived humanized IgG1 kappa monoclonal antibody that recog-
hundred eighty-nine infectious events were reported, 74% of which nizes the cell-surface antigen CD52. CD52 is a 21- to 28-kDa,
were grade 1 or 2. Thirteen infections with onset during treatment heavily glycosylated, membrane-anchored glycoprotein, highly
resulted in death, including one reported case of progressive expressed on all B and T lymphocytes at most stages of differentia-
multifocal leukoencephalopathy (PML).67 Although the lack of CT tion (except plasma cells), as well as on granulocytes, monocytes,
scan monitoring of nodal disease in this study has been criticized, it macrophages, eosinophils, NK cells, and dendritic cells.73 The
is unclear that such monitoring adds benefit in terms of predicting CD52 antigen is also expressed on tumor cells, particularly T-cell
PFS to therapy in CLL.68,69 From this study and other data prolymphocytic leukemia (T-PLL) as well as CLL, hairy cell
presented, it is unlear that ofatumumab offers relative benefit over leukemia, NHL, and acute lymphoblastic leukemia.74 Despite the
the use of high dose rituximab previously reported.39,40 Only a frequent use of alemtuzumab in clinical trials, detailed mechanistic
randomized comparative study will be able to discern such a studies to elucidate specific pathways of cell killing have been
difference. hampered by the lack of cell lines expressing CD52. Thus, the
Combination studies are being done to enhance the therapeutic mechanism of action of alemtuzumab remains to be completely
efficacy of ofatumumab. A study evaluating the combination of clarified. Alemtuzumab can act through immunologic mechanisms,
ofatumumab with fludarabine and cyclophosphamide (O-FC) was such as CDC75,76 and/or ADCC by virtue of its IgG Fc region.77,78 It
recently presented. Sixty-one previously untreated patients re- has also been shown that alemtuzumab can induce direct CLL cell
ceived either 500 mg or 1000 mg ofatumumab combined with death through a membrane raft-dependent mechanism.79 Unlike
fludarabine and cyclophosphamide every 4 weeks for a total of rituximab, alemtuzumab has been shown to induce cell death in
6 courses. The CRR was 32% for patients who received 500 mg vitro in CLL cells through a mechanism that is independent of p53
ofatumumab and 50% for those who received 1000 mg. The OR status and caspase activation.79 Moreover several in vivo clinical
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3710 JAGLOWSKI et al BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19

studies80-82 report that alemtuzumab therapy is effective in sub- neutropenia or major bacterial infections. CMV reactivation oc-
group of patients with high-risk cytogenetic markers (such as curred in 10% of patients. These promising results promoted a
del(17p13.1), which points to its unique mechanism of action. recent phase 3 trial of 297 CLL patients who were prospectively
randomized to receive either IV alemtuzumab 30 mg 3 times
Alemtuzumab single-agent activity
weekly for up to 12 weeks or oral chlorambucil 40 mg/m2 every
The dosing schedule of alemtuzumab was developed empirically 4 weeks for up to 12 cycles.88 Alemtuzumab-treated patients
using primarily clinical response as a surrogate end point in initial obtained a significantly superior response rate with significantly
phase 1 studies. The intravenous (IV) dosing schedule currently improved PFS compared with chlorambucil (ORR 83% vs 56%
used as the standard regimen for alemtuzumab therapy comprises a and CRR 24% vs 2%). In addition, this trial prospectively
2-hour IV infusion at a starting dose of 3 mg on day 1, 10 mg on demonstrated the superiority of alemtuzumab versus chlorambucil
day 2, and 30 mg 3 times weekly for a total of 8 to 12 weeks. in patients with del(17p13). No differences in terms of grade
The effectiveness of single-agent alemtuzumab in refractory/ 3-4 hematologic toxicities were noticed between the 2 arms;
relapsed CLL patients has been demonstrated (reviewed in Alinari however, 52% of alemtuzumab-treated patients developed CMV
et al83). In this setting, alemtuzumab produced an ORR of 33% to reactivation, in contrast to only 2% of the patients treated with
54%. In the majority of these studies, antitumor effects of chlorambucil. Despite approval for this indication, the use of
alemtuzumab were more significant in blood and bone marrow than alemtuzumab as monotherapy for primary therapy of CLL is not
in lymph nodes (especially if larger than 5 cm). The reason for this generally used, given both the improved results with chemoimmu-
differential response is not clear, although it has been postulated to notherapy and the immune suppression associated with this
be related to poor bioavailability of the drug in bulky sites causing a treatment.
low saturation of the binding sites on the neoplastic cells’ surface.
Moreover, there may be variability in the immune effector mecha- Alemtuzumab as consolidation therapy for CLL
nisms in lymph nodes compared with other sites. Given that alemtuzumab works best against blood and bone
Alemtuzumab was initially approved in 2001 as a consequence marrow disease, efforts to apply alemtuzumab as a consolidation
of the pivotal CAM 211 phase 3 study, in which 93 patients with approach occurred early in its development (reviewed in Alinari et
relapsed or refractory CLL who had failed prior therapy with al83). O’Brien and colleagues89 administered alemtuzumab 10 or
fludarabine and an alkylating agent were treated with stepped-up 30 mg IV 3 times weekly to 41 CLL patients with residual disease
dosing followed by 30 mg 3 times weekly for a total of 12 weeks.84
after their most recent therapy. The ORR was 46% including 56%
The ORR was 33% (2% CR, 31% PR) and the median duration of
among the 29 patients treated with 30 mg. Eleven of these 29
response was 8.7 months. Given that the majority of patients
patients (38%) achieved a MRD-negative marrow, assessed by
treated with IV alemtuzumab experience infusional toxicity com-
polymerase chain reaction. Infectious occurred in 15 patients
bined with the observation that subcutaneous (SC) alemtuzumab
(37%) with 9 being CMV reactivation. The authors reported that 3
had comparable biologic activity with diminished infusion-related
patients developed Epstein-Barr virus (EBV)–positive large B-cell
events, interest in SC administration has progressively increased.
lymphoma (LCL) within 6 weeks after finishing therapy. It is
In a phase 2 study by the GCLLSG,80 103 patients with fludarabine-
known that T and B lymphocytes subpopulations are heavily
refractory CLL received at least one dose of alemtuzumab,
depleted by alemtuzumab and remain subnormal for more than a
administered subcutaneously at 30 mg 3 times weekly for up to
year.83 Therefore the development of these LCLs is probably due to
12 weeks. The ORR was 34% (4% CR, 30% PR). The median PFS
proliferation of EBV-positive B cells in severely immunocompro-
was 7.7 months and the median OS was 19.1 months. This trial
confirmed earlier studies that alemtuzumab was effective for mised patients. Development of LCL represents a major concern in
del(17p13.1) CLL.81,82 alemtuzumab treated patients, although fortunately it is not that
In studies involving patients with relapsed/refractory CLL common. The GCLLSG90 reported the results of a phase 3 trial
treated with alemtuzumab, the most common adverse events were where patients responding to fludarabine-based induction therapy
cytopenia and infection as a consequence of profound cellular were randomized to receive IV alemtuzumab 30 mg 3 times weekly
immune suppression. Reactivation of herpesvirus including cyto- for a maximum of 12 weeks or observation. Of 21 evaluable
megalovirus (CMV) were the most common opportunistic infec- patients, 11 were randomized to receive alemtuzumab. This study
tions observed. Prophylaxis against opportunistic infections to- was prematurely closed because of severe infections in 7 of 11
gether with monitoring for CMV reactivation is highly patients in the alemtuzumab arm. The PFS was significantly
recommended in these patients. Recently, O’Brien et al85 demon- improved for patients receiving alemtuzumab at a median fol-
strated that the addition of valganciclovir 450 mg orally twice daily low-up of 21.4 months. The CALGB performed 2 studies adminis-
was highly effective for prophylaxis of CMV reactivation in tering alemtuzumab after fludarabine91 or fludarabine and ritux-
patients receiving alemtuzumab. Our own approach is to administer imab.92 Both of these studies demonstrated the ability of
bactrim (or equivalent) and anti-herpes antiviral (acyclovir, valacy- alemtuzumab to improve response to treatment.92 However, reacti-
lovir) and to monitor for reactivation of CMV with subsequent vation of CMV was observed in both studies and unacceptable
preemptive early treatment due to the prohibitive cost of infectious toxicity was observed in patients when alemtuzumab
valgancyclovir. was administered after fludarabine and rituximab. A community-
Several pilot studies in previously untreated CLL patients86,87 based clinical trial administering alemtuzumab after fludarabine
have shown benefit with alemtuzumab. Lundin and colleagues87 and rituximab also noted problematic toxicity with combined
treated 41 CLL patients with SC alemtuzumab as first-line therapy chemoimmunotherapy.93 Future attempts to explore this consolida-
for up to 18 weeks, with an observed ORR of 87%, including a 19% tion approach after chemoimmunotherapy regimens should allow
CR rate with a median TTF of more than 18 months. The treatment an extended recovery time before administration of alemtuzumab.
was generally well tolerated, with adverse events mainly compris- Consolidation with alemtuzumab should only be considered in the
ing local injection site reactions, and with no episodes of febrile context of a clinical trial.
 From www.bloodjournal.org by guest on November 17, 2018. For personal use only.

BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19 ANTIBODY THERAPY FOR CLL 3711

Alemtuzumab combination strategies in CLL 1/2 combination study with FCR showing potential benefit,105
results from a phase 3 study comparing FCR plus lumiliximab
In an attempt to enhance the therapeutic activity observed with versus FCR did not confirm benefit in terms of improved response
fludarabine-based regimens, alemtuzumab has been added to this or PFS. Therapeutic antibodies directed at CD40 with partial
modality by several investigators (reviewed in Alinari et al83). agonist (SGN40106) and blocking properties (HCD122; personal
These studies have, in general, demonstrated feasibility of adminis- communication, J.C.B., September 5, 2010) have completed phase
tration with an acceptable toxicity profile. A phase 3 study 1 testing with minimal clinical activity in CLL and likely will be
comparing fludarabine combined with alemtuzumab (FluCAM) applied as combination therapies. Other new antibodies targeting
versus fludarabine alone was recently reported.94 This study of 335 CD19 (MDX-1342 and XmAb5574) and CD74 (milatuzamab) are
previously treated CLL patients receiving second line therapy either entering into or currently being tested in early phase 1
demonstrated a higher ORR, CRR and PFS with the combination clinical trials for CLL. Extending beyond new targets for therapeu-
therapy. Adverse events included cytopenias and infections and tic antibodies and SMIPs is the opportunity to combine these
were similar between both treatment arms. The only toxicity therapies with new immune-modulating agents (interleukin-21,
uniformly associated with FluCAM was CMV reactivation in 8% lenalidomide, CpG oligonucleotides) and targeted therapies (CAL-
of patients.94 Attempts to further intensify this regimen with the 101, fostamatinib, PCI-32 765, SCH727965, ABT-263, and fla-
addition of cyclophosphamide to FluCAM resulted in increased vopiridol) with the potential to avoid the immunosuppressive
infectious morbidity.95 Concomitantly, efforts to combine alemtu- effects of chemotherapy treatments.
zumab with the FCR regimen were undertaken in both relapsed96
and previously untreated high risk CLL.97 Although these studies
demonstrated feasibility, it is unclear that any benefit was offered
over the FCR-based treatment. Combination of alemtuzumab with Conclusions
rituximab98-100 has also been evaluated by several groups with
improved response. The FCGCLL/MW and GOELAMS recently Monoclonal antibodies represent an exciting addition to the
presented results in a phase 3 study comparing FCR to the growing armamentarium of agents used to treat CLL. To date, those
combination of fludarabine, cyclophosphamide, and alemtuzumab agents targeting CD20 and CD52 have shown greatest promise.
(FCCam). Response rates of the first 100 patients were reported in a While both CD20- and CD52-directed antibodies have demon-
preliminary analysis with safety data presented for the entire cohort strated activity as single agents, their greatest contribution (as has
of 178 patients. The ORR in the first 100 patients was 96% for FCR been demonstrated with rituximab) may lie in their combination
compared with 85% in the FCCam arm (P ⫽ .086) with a CRR of 78% with more traditional chemotherapies. When added to chemo-
in the FCR arm versus 58% in the FCC am arm (P ⫽ .072). The therapy, the use of rituximab has resulted in improved ORR and CR
percentage of grade 4 neutropenia increased during FCCam treatment rate and longer PFS and OS compared with chemotherapy alone,
(28.4% for cycle 1 and 45.5% for cycle 6), and 44 of the 63 reported and this has been borne out in phase 3 studies. Monoclonal
serious adverse events (SAE) declared occurred in the FCCam arm. antibodies promise to be a fertile source of preclinical and clinical
Seven patients died, all of whom were in the FCCam arm.101 Thus, this investigation and will likely continue to revolutionize the way we
particular combination appears to be associated with unacceptable care for patients with CLL.
infectious toxicities for no obvious clinical benefit.

Acknowledgments
Other targets
This work was supported by grants from Leukemia & Lymphoma
Efforts to target other B cell–specific antigens are underway as part Society (P50-CA140158, PO1-CA95426, PO1 CA81534) and by
of clinical trials at this time. Of antibody and peptide therapeutics the D. Warren Brown Foundation.
currently in clinical development, those targeting CD37 appear the
most promising. CD37 is expressed on B cells and transformed
mature B cell leukemias and lymphomas but not on T cells. Authorship
TRU-016 is a CD37 small modular immunopharmaceutical (SMIP)
that represents a structural modification of a CD37 antibody that Contribution: S.J. and J.C.B. wrote the entire manuscript; and L.A.,
lacks the CH1 domain. In vitro studies with the chimeric version of R.L., and R.M. wrote components of the manuscript and reviewed
TRU-016 demonstrate that this is a potent inducer of apoptosis and and approved the final version.
ADCC-dependent cytotoxicity against CLL cells.102 Interim results Conflict-of-interest disclosure: J.C.B. is a consultant for Calis-
of a phase 1 study of TRU-016 reported a favorable toxicity profile toga Pharmaceuticals and has a financial interest in the develop-
and partial responses at higher doses.103 Whereas the CD23 anti- ment of this compound. The remaining authors declare no compet-
body lumiliximab is most mature with respect to clinical investiga- ing financial interests.
tion in CLL, with a completed phase 1 single-agent study showing Correspondence: John C. Byrd, MD, 455B, OSUCCC, 410 W.
minimal activity but favorable toxicity profile104 and a phase 12th Ave, Columbus, OH 43210; e-mail: John.byrd@osumc.edu.

References
1. Rozman C, Montserrat E. Chronic lymphocytic 3. Ricci F, Tedeschi A, Morra E, Montillo M. Fludarabine Res Clin Haematol. 2007;20(3):439-
leukemia. N Engl J Med. 1995;333(16):1052-1057. in the treatment of chronic lymphocytic leukemia: a 453.
2. Zenz T, Mertens D, Kuppers R, Dohner H, review. Ther Clin Risk Manag. 2009;5(1):187-207. 5. Uchida J, Lee Y, Hasegawa M, et al. Mouse
Stilgenbauer S. From pathogenesis to treatment 4. Zenz T, Dohner H, Stilgenbauer S. Genetics CD20 expression and function. Int Immunol.
of chronic lymphocytic leukaemia. Nat Rev Can- and risk-stratified approach to therapy in 2004;16(1):119-129.
cer. 2010;10(1):37-50. chronic lymphocytic leukemia. Best Pract 6. Press OW, Howell-Clark J, Anderson S, Bernstein
 From www.bloodjournal.org by guest on November 17, 2018. For personal use only.

3712 JAGLOWSKI et al BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19

I. Retention of B-cell-specific monoclonal antibod- 23. Farag SS, Flinn IW, Modali R, Lehman TA, Young chronic lymphocytic leukemia and small lympho-
ies by human lymphoma cells. Blood. 1994;83(5): D, Byrd JC. Fc gamma RIIIa and Fc gamma RIIa cytic lymphoma demonstrates clinical activity and
1390-1397. polymorphisms do not predict response to ritux- acceptable toxicity. J Clin Oncol. 2001;19(8):
7. Maloney DG. Mechanism of action of rituximab. imab in B-cell chronic lymphocytic leukemia. 2153-2164.
Anticancer Drugs. 2001;12 Suppl 2):S1-S4. Blood. 2004;103(4):1472-1474. 40. O’Brien SM, Kantarjian H, Thomas DA, et al. Rit-
8. Bellosillo B, Villamor N, Lopez-Guillermo A, et al. 24. Woyach JA, Lin TS, Lucas MS, et al. A phase I/II uximab dose-escalation trial in chronic lympho-
Complement-mediated cell death induced by rit- study of rituximab and etanercept in patients with cytic leukemia. J Clin Oncol. 2001;19(8):2165-
uximab in B-cell lymphoproliferative disorders is chronic lymphocytic leukemia and small lympho- 2170.
mediated in vitro by a caspase-independent cytic lymphoma. Leukemia. 2009;23(5):912-918. 41. Hainsworth JD, Litchy S, Barton JH, et al. Single-
mechanism involving the generation of reactive 25. Friedberg JW, Kelly JL, Neuberg D, et al. Phase II agent rituximab as first-line and maintenance
oxygen species. Blood. 2001;98(9):2771-2777. study of a TLR-9 agonist (1018 ISS) with ritux- treatment for patients with chronic lymphocytic
9. Golay J, Lazzari M, Facchinetti V, et al. CD20 lev- imab in patients with relapsed or refractory follicu- leukemia or small lymphocytic lymphoma: a
els determine the in vitro susceptibility to ritux- lar lymphoma. Br J Haematol. 2009;146(3):282- phase II trial of the Minnie Pearl Cancer Re-
imab and complement of B-cell chronic lympho- 291. search Network. J Clin Oncol. 2003;21:1746-
cytic leukemia: further regulation by CD55 and 26. Gowda A, Ramanunni A, Cheney C, et al. Differ- 1751.
CD59. Blood. 2001;98(12):3383-3389. ential effects of IL-2 and IL-21 on expansion of 42. Schulz H, Klein SK, Rehwald U, et al. Phase 2
10. Li Y, Williams ME, Cousar JB, Pawluczkowycz the CD4(⫹)CD25(⫹)Foxp3(⫹) T regulatory cells study of a combined immunochemotherapy using
AW, Lindorfer MA, Taylor RP. Rituximab-CD20 with redundant roles in natural killer cell mediated rituximab and fludarabine in patients with chronic
complexes are shaved from Z138 mantle cell lym- antibody dependent cellular cytotoxicity in chronic lymphocytic leukemia. Blood. 2002;100(9):3115-
phoma cells in intravenous and subcutaneous lymphocytic leukemia. mAbs. 2010;2(1):35-41. 3120.
SCID mouse models. J Immunol. 2007;179(6): 27. Jaglowski SM, Byrd JC. Rituximab in chronic lym- 43. Byrd JC, Peterson BL, Morrison VA, et al. Ran-
4263-4271. phocytic leukemia. Semin Hematol. Apr;47(2): domized phase 2 study of fludarabine with con-
11. Williams ME, Densmore JJ, Pawluczkowycz AW, 156-169. current versus sequential treatment with ritux-
et al. Thrice-weekly low-dose rituximab de- imab in symptomatic, untreated patients with
28. Byrd JC, Kitada S, Flinn IW, et al. The mecha-
creases CD20 loss via shaving and promotes en- B-cell chronic lymphocytic leukemia: results from
nism of tumor cell clearance by rituximab in vivo
hanced targeting in chronic lymphocytic leuke- Cancer and Leukemia Group B 9712 (CALGB
in patients with B-cell chronic lymphocytic leuke-
mia. J Immunol. 2006;177(10):7435-7443. 9712). Blood. 2003;101(1):6-14.
mia: evidence of caspase activation and apopto-
sis induction. Blood. 2002;99(3):1038-1043. 44. Byrd JC, Gribben JG, Peterson BL, et al. Select
12. Beum PV, Kennedy AD, Williams ME, Lindorfer
high-risk genetic features predict earlier progres-
MA, Taylor RP. The shaving reaction: rituximab/ 29. Teeling JL, French RR, Cragg MS, et al. Charac-
sion following chemoimmunotherapy with fludara-
CD20 complexes are removed from mantle cell terization of new human CD20 monoclonal anti-
bine and rituximab in chronic lymphocytic leuke-
lymphoma and chronic lymphocytic leukemia bodies with potent cytolytic activity against non-
mia: justification for risk-adapted therapy. J Clin
cells by THP-1 monocytes. J Immunol. 2006; Hodgkin lymphomas. Blood. 2004;104(6):1793-
Oncol. 2006;24(3):437-443.
176(4):2600-2609. 1800.
45. Byrd JC, Rai K, Peterson BL, et al. Addition of
13. Aue G, Lindorfer MA, Beum PV, et al. Fraction- 30. Teeling JL, Mackus WJ, Wiegman LJ, et al. The
rituximab to fludarabine may prolong progres-
ated subcutaneous rituximab is well-tolerated and biological activity of human CD20 monoclonal
sion-free survival and overall survival in patients
preserves CD20 expression on tumor cells in pa- antibodies is linked to unique epitopes on CD20.
with previously untreated chronic lymphocytic
tients with chronic lymphocytic leukemia. Haema- J Immunol. 2006;177(1):362-371.
leukemia: an updated retrospective comparative
tologica. 2009;95(2):329-332. 31. Niederfellner GJ, Lammens A, Schwaiger M, et analysis of CALGB 9712 and CALGB 9011.
14. Gowda A, Roda J, Hussain SR, et al. IL-21 medi- al. Crystal structure analysis reveals that the Blood. 2005;105(1):49-53.
ates apoptosis through up-regulation of the BH3 novel type II anti-CD20 antibody GA101 interacts
46. Del Poeta G, Del Principe MI, Consalvo MA, et al.
family member BIM and enhances both direct with a similar epitope as rituximab and ocreli-
The addition of rituximab to fludarabine improves
and antibody-dependent cellular cytotoxicity in zumab but in a fundamentally different way [ab-
clinical outcome in untreated patients with ZAP-
primary chronic lymphocytic leukemia cells in stract]. Blood (ASH Annual Meeting Abstracts).
70-negative chronic lymphocytic leukemia. Can-
vitro. Blood. 2008;111(9):4723-4730. 2009;114(22):3726.
cer. 2005;104(12):2743-2752.
15. Flieger D, Emmerich B, Meyer N, Riethmuller G, 32. Alduaij W, Potluri S, Ivanov A, et al. New-genera-
47. Tam CS, O’Brien S, Wierda W, et al. Long-term
Ziegler-Heitbrock HW. Deficient production of tu- tion anti-CD20 monoclonal antibody (GA101)
results of the fludarabine, cyclophosphamide,
mor necrosis factor by peripheral-blood mono- evokes homotypic adhesion and actin-depen-
and rituximab regimen as initial therapy of chronic
cytes in chronic lymphocytic leukemia. Int J Can- dent, lysosome-mediated cell death in B-cell lym-
lymphocytic leukemia. Blood. 2008;112(4):975-
cer. 1990;45(2):280-286. phoma [abstract]. Blood (ASH Annual Meeting
980.
16. Yang L, Zhao T, Shi X, et al. Functional analysis Abstracts). 2009;114(22):725-.
48. Wierda W, O’Brien S, Wen S, et al. Chemoimmu-
of a dominant negative mutation of interferon 33. Zenz T, Volden M, Mast T, et al. In vitro activity of
notherapy with fludarabine, cyclophosphamide,
regulatory factor 5. PLoS One. 2009;4(5):e5500. the type II anti-CD20 antibody GA101 in refrac-
and rituximab for relapsed and refractory chronic
17. Ziegler HW, Kay NE, Zarling JM. Deficiency of tory, genetic high-risk CLL [abstract]. Blood (ASH
lymphocytic leukemia. J Clin Oncol. 2005;23(18):
natural killer cell activity in patients with chronic Annual Meeting Abstracts). 2009;114(22):2379.
4070-4078.
lymphocytic leukemia. Int J Cancer. 1981;27(3): 34. Patz M, Forcob N, Muller B, et al. Depletion of
49. Tsimberidou AM, Tam C, Abruzzo LV, et al. Che-
321-327. chronic lymphocytic leukemia cells from whole
moimmunotherapy may overcome the adverse
18. Kay NE, Zarling JM. Impaired natural killer activity blood samples mediated by the anti-CD20 anti-
prognostic significance of 11q deletion in previ-
in patients with chronic lymphocytic leukemia is bodies rituximab and GA101 [abstract]. Blood
ously untreated patients with chronic lymphocytic
associated with a deficiency of azurophilic cyto- (ASH Annual Meeting Abstracts). 2009;114(22):
leukemia. Cancer. 2009;115(2):373-380.
plasmic granules in putative NK cells. Blood. 2365.
50. Lin KI, Tam CS, Keating MJ, et al. Relevance of
1984;63(2):305-309. 35. Ivanov A, Beers SA, Walshe CA, et al. Monoclo- the immunoglobulin VH somatic mutation status
19. Beyer M, Kochanek M, Darabi K, et al. Reduced nal antibodies directed to CD20 and HLA-DR can in patients with chronic lymphocytic leukemia
frequencies and suppressive function of elicit homotypic adhesion followed by lysosome- treated with fludarabine, cyclophosphamide, and
CD4⫹CD25hi regulatory T cells in patients with mediated cell death in human lymphoma and leu- rituximab (FCR) or related chemoimmunotherapy
chronic lymphocytic leukemia after therapy with kemia cells. J Clin Invest. 2009;119(8):2143- regimens. Blood. 2009;113(14):3168-3171.
fludarabine. Blood. 2005;106(6):2018-2025. 2159.
51. Lamanna N, Kalaycio M, Maslak P, et al. Pen-
20. Gowda A, Ramanunni A, Cheney C, et al. Differ- 36. Cragg MS, Glennie MJ. Antibody specificity con- tostatin, cyclophosphamide, and rituximab is an
ential effects of IL-2 and IL-21 on expansion of trols in vivo effector mechanisms of anti-CD20 active, well-tolerated regimen for patients with
the CD4⫹ CD25⫹ Foxp3⫹ T regulatory cells with reagents. Blood. 2004;103(7):2738-2743. previously treated chronic lymphocytic leukemia.
redundant roles in natural killer cell mediated anti- 37. Berinstein NL, Grillo-Lopez AJ, White CA, et al. J Clin Oncol. 2006;24(10):1575-1581.
body dependent cellular cytotoxicity in chronic Association of serum Rituximab (IDEC-C2B8) 52. Kay NE, Geyer SM, Call TG, et al. Combination
lymphocytic leukemia. mAbs. 2010;2(1):35-41. concentration and anti-tumor response in the chemoimmunotherapy with pentostatin, cyclo-
21. Cartron G, Dacheux L, Salles G, et al. Therapeu- treatment of recurrent low-grade or follicular non- phosphamide, and rituximab shows significant
tic activity of humanized anti-CD20 monoclonal Hodgkin’s lymphoma. Ann Oncol. 1998;9(9):995- clinical activity with low accompanying toxicity in
antibody and polymorphism in IgG Fc receptor 1001. previously untreated B chronic lymphocytic leuke-
FcgammaRIIIa gene. Blood. 2002;99(3):754-758. 38. Ginaldi L, De Martinis M, Matutes E, Farahat N, mia. Blood. 2007;109(2):405-411.
22. Weng WK, Levy R. Two immunoglobulin G frag- Morilla R, Catovsky D. Levels of expression of 53. Fischer K, Cramer P, Stilgenbauer S, et al. Ben-
ment C receptor polymorphisms independently CD19 and CD20 in chronic B cell leukaemias. damustine Combined with Rituximab (BR) in
predict response to rituximab in patients with fol- J Clin Pathol. 1998;51(5):364-369. First-Line Therapy of Advanced CLL: A Multi-
licular lymphoma. J Clin Oncol. 2003;21(21): 39. Byrd JC, Murphy T, Howard RS, et al. Rituximab center Phase II Trial of the German CLL Study
3940-3947. using a thrice weekly dosing schedule in B-cell Group (GCLLSG). Vol 114;2009:205-.
 From www.bloodjournal.org by guest on November 17, 2018. For personal use only.

BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19 ANTIBODY THERAPY FOR CLL 3713

54. Fischer K, Stilgenbauer S, Schweighofer CD, et ment of Patients with Chronic Lymphocytic Leu- 84. Keating MJ, Flinn I, Jain V, et al. Therapeutic role
al. Bendamustine in Combination with Rituximab kemia (CLL): Results of a Metaanalysis from of alemtuzumab (Campath-1H) in patients who
(BR) for Patients with Relapsed Chronic Lympho- Three Phase III Studies of the German CLL Study have failed fludarabine: results of a large interna-
cytic Leukemia (CLL): A Multicentre Phase II Trial Group (GCLLSG). Vol 112;2008:1053-. tional study. Blood. 2002;99(10):3554-3561.
of the German CLL Study Group (GCLLSG). Vol 69. Blum KA, Young D, Broering S, et al. Computed 85. O’Brien S, Ravandi-Kashani F, Wierda WG, et al.
112;2008:330-. tomography scans do not improve the predictive A Randomized Trial of Valacyclovir Versus Val-
55. Hallek M, Fingerle-Rowson G, Fink A-M, et al. power of 1996 national cancer institute spon- ganciclovir To Prevent CMV Reactivation in Pa-
First-Line Treatment with Fludarabine (F), Cyclo- sored working group chronic lymphocytic leuke- tients with CLL Receiving Alemtuzumab. ASH
phosphamide (C), and Rituximab (R) (FCR) Im- mia response criteria. J Clin Oncol. 2007;25(35): Annual Meeting Abstracts. 2005;106(11):2960-.
proves Overall Survival (OS) in Previously Un- 5624-5629. 86. Osterborg A, Fassas AS, Anagnostopoulos A,
treated Patients (pts) with advanced chronic 70. Wierda WG, Kipps TJ, Durig J, et al. Ofatu- Dyer MJ, Catovsky D, Mellstedt H. Humanized
lymphocytic leukemia (CLL): results of a random- mumab Combined with Fludarabine and Cyclo- CD52 monoclonal antibody Campath-1H as first-
ized phase III trial on behalf of an International phosphamide (O-FC) Shows High Activity in Pa- line treatment in chronic lymphocytic leukaemia.
Group of Investigators and the German CLL tients with Previously Untreated Chronic Br J Haematol. 1996;93(1):151-153.
Study Group. Blood. ASH Annual Meeting Ab- Lymphocytic Leukemia (CLL): Results From a 87. Lundin J, Kimby E, Bjorkholm M, et al. Phase II
stracts. 2009;114(22):535. Randomized, Multicenter, International, Two- trial of subcutaneous anti-CD52 monoclonal anti-
56. Hallek M, Fingerle-Rowson G, Fink A-M, et al. Dose, Parallel Group, Phase II Trial. Blood (ASH body alemtuzumab (Campath-1H) as first-line
Immunochemotherapy with fludarabine (F), cyclo- Annual Meeting Abstracts). 2009;114(22):207-. treatment for patients with B-cell chronic lympho-
phosphamide (C), and rituximab (R) (FCR) ver- 71. Zelenetz AD, Abramson JS, Advani RH, et al. cytic leukemia (B-CLL). Blood. 2002;100(3):768-
sus fludarabine and cyclophosphamide (FC) im- NCCN Clinical Practice Guidelines in Oncology: 773.
proves response rates and progression-free Non-Hodgkin’s Lymphomas. J Natl Compr Canc
survival (PFS) of previously untreated patients 88. Hillmen P, Skotnicki AB, Robak T, et al. Alemtu-
Netw. Mar;8(3):288-334. zumab compared with chlorambucil as first-line
(pts) with advanced chronic lymphocytic leukemia
72. Morschhauser F, Cartron G, Lamy T, et al. Phase therapy for chronic lymphocytic leukemia. J Clin
(CLL). Blood. ASH Annual Meeting Abstracts.
I Study of RO5072759 (GA101) in Relapsed/Re- Oncol. 2007;25(35):5616-5623.
2008;112(11):325.
fractory Chronic Lymphocytic Leukemia. Blood
57. Stilgenbauer S, Zenz T, Winkler D, et al. Genomic 89. O’Brien SM, Kantarjian HM, Thomas DA, et al.
(ASH Annual Meeting Abstracts). 2009;114(22):
Aberrations, VH Mutation status and outcome Alemtuzumab as treatment for residual disease
884-.
after fludarabine and cyclophosphamide (FC) or after chemotherapy in patients with chronic lym-
73. Rossmann ED, Lundin J, Lenkei R, Mellstedt H, phocytic leukemia. Cancer. 2003;98(12):2657-
FC plus rituximab (FCR) in the CLL8 trial. Blood.
Osterborg A. Variability in B-cell antigen expres- 2663.
ASH Annual Meeting Abstracts. 2008;112(11):
sion: implications for the treatment of B-cell lym-
781. 90. Wendtner CM, Ritgen M, Schweighofer CD, et al.
phomas and leukemias with monoclonal antibod-
58. Robak T, Moiseev SI, Dmoszynska A, et al. Ritux- Consolidation with alemtuzumab in patients with
ies. Hematol J. 2001;2(5):300-306.
imab, Fludarabine, and cyclophosphamide (R- chronic lymphocytic leukemia (CLL) in first remis-
74. Ginaldi L, De Martinis M, Matutes E, et al. Levels sion–experience on safety and efficacy within a
FC) prolongs progression free survival in re-
of expression of CD52 in normal and leukemic B randomized multicenter phase III trial of the Ger-
lapsed or refractory chronic lymphocytic leukemia
and T cells: correlation with in vivo therapeutic man CLL Study Group (GCLLSG). Leukemia.
(CLL) compared with FC alone: final results from
responses to Campath-1H. Leuk Res. 2004;18(6):1093-1101.
the International Randomized Phase III REACH
1998;22(2):185-191.
Trial. Blood. ASH Annual Meeting Abstracts. 91. Byrd JC, Peterson BL, Rai KR, et al. Fludarabine
2008;112(11):lba-1. 75. Golay J, Manganini M, Rambaldi A, Introna M. followed by alemtuzumab consolidation for previ-
Effect of alemtuzumab on neoplastic B cells. ously untreated chronic lymphocytic leukemia:
59. Del Poeta G, Del Principe MI, Buccisano F, et al. Haematologica. 2004;89(12):1476-1483.
Consolidation and maintenance immunotherapy final report of Cancer and Leukemia Group B
with rituximab improve clinical outcome in pa- 76. Zent CS, Chen JB, Kurten RC, Kaushal GP, study 19901. Leuk Lymphoma. 2009;50(10):
tients with B-cell chronic lymphocytic leukemia. Marie Lacy H, Schichman SA. Alemtuzumab 1589-1596.
Cancer. 2008;112(1):119-128. (CAMPATH 1H) does not kill chronic lymphocytic 92. Lin TS, Donohue KA, Byrd JC, et al. Consolida-
leukemia cells in serum free medium. Leuk Res. tion Therapy with Subcutaneous (SC) Alemtu-
60. Dearden C. Disease-Specific Complications of 2004;28(5):495-507.
Chronic Lymphocytic Leukemia. Hematology. zumab After Fludarabine and Rituximab (FR) In-
2008;2008(1):450-456. 77. Crowe JS, Hall VS, Smith MA, Cooper HJ, Tite duction Therapy Improves the Complete
JP. Humanized monoclonal antibody CAMPATH- Response (CR) Rate in Chronic Lymphocytic
61. Zecca M, De Stefano P, Nobili B, Locatelli F. Anti- 1H: myeloma cell expression of genomic con- Leukemia (CLL) and Eradicates Minimal Residual
CD20 monoclonal antibody for the treatment of structs, nucleotide sequence of cDNA constructs Disease (MRD) but Is Associated with Severe
severe, immune-mediated, pure red cell aplasia and comparison of effector mechanisms of my- Infectious Toxicity: Final Analysis of CALGB
and hemolytic anemia. Blood. 2001;97(12):3995- eloma and Chinese hamster ovary cell-derived Study 10101. Vol 114;2009:210-.
3997. material. Clin Exp Immunol. 1992;87(1):105-110. 93. Hainsworth JD, Vazquez ER, Spigel DR, et al.
62. Ghazal H. Successful treatment of pure red cell 78. Hale G, Clark M, Waldmann H. Therapeutic po- Combination therapy with fludarabine and ritux-
aplasia with rituximab in patients with chronic tential of rat monoclonal antibodies: isotype imab followed by alemtuzumab in the first-line
lymphocytic leukemia. Blood. 2002;99(3):1092- specificity of antibody-dependent cell-mediated treatment of patients with chronic lymphocytic
1094. cytotoxicity with human lymphocytes. J Immunol. leukemia or small lymphocytic lymphoma: a
63. Gupta N, Kavuru S, Patel D, et al. Rituximab- 1985;134(5):3056-3061. phase 2 trial of the Minnie Pearl Cancer Re-
based chemotherapy for steroid-refractory auto- 79. Mone AP, Cheney C, Banks AL, et al. Alemtu- search Network. Cancer. 2008;112(6):1288-1295.
immune hemolytic anemia of chronic lymphocytic zumab induces caspase-independent cell death 94. Engert A, Gercheva L, Robak T, et al. Improved
leukemia. Leukemia. 2002;16(10):2092-2095. in human chronic lymphocytic leukemia cells Progression-Free Survival (PFS) of Alemtuzumab
64. D’Arena G, Laurenti L, Capalbo S, et al. Ritux- through a lipid raft-dependent mechanism. Leu- (Campath(R), MabCampath(R)) Plus Fludarabine
imab therapy for chronic lymphocytic leukemia- kemia. 2006;20(2):272-279. (Fludara(R)) Versus Fludarabine Alone as Sec-
associated autoimmune hemolytic anemia. Am J 80. Stilgenbauer S, Zenz T, Winkler D, et al. Subcuta- ond-Line Treatment of Patients with B-Cell
Hematol. 2006;81(8):598-602. neous alemtuzumab in fludarabine-refractory Chronic Lymphocytic Leukemia: Preliminary Re-
65. Hegde UP, Wilson WH, White T, Cheson BD. Rit- chronic lymphocytic leukemia: clinical results and sults From a Phase III Randomized Trial [ab-
uximab treatment of refractory fludarabine-asso- prognostic marker analyses from the CLL2H stract]. Blood (Am Soc Hematol Ann Meeting).
ciated immune thrombocytopenia in chronic lym- study of the German Chronic Lymphocytic Leuke- 114; 2009:Abstract 537.
phocytic leukemia. Blood. 2002;100(6):2260- mia Study Group. J Clin Oncol. 2009;27(24): 95. Elter T, James R, Stilgenbauer S, et al. Chemoim-
2262. 3994-4001. muno-Therapy with Fludarabine, Cyclophospha-
66. Coiffier B, Lepretre S, Pedersen LM, et al. Safety 81. Lozanski G, Heerema NA, Flinn IW, et al. Alemtu- mide and Alemtuzumab (FC-Cam) in Patients
and efficacy of ofatumumab, a fully human mono- zumab is an effective therapy for chronic lympho- with Relapsed or Genetic High-Risk CLL: Final
clonal anti-CD20 antibody, in patients with re- cytic leukemia with p53 mutations and deletions. Analysis of the CLL2L Trial of the German CLL
lapsed or refractory B-cell chronic lymphocytic Blood. 2004;103(9):3278-3281. Study Group [abstract]. Blood (Am Soc Hematol
leukemia: a phase 1-2 study. Blood. 2008;111(3): 82. Stilgenbauer S, Dohner H. Campath-1H-induced Ann Meeting). 114;2009:Abstract 209.
1094-1100. complete remission of chronic lymphocytic leuke- 96. Badoux XC, Keating M, O’Brien S, et al. Chemo-
67. Wierda WG, Kipps TJ, Mayer J, et al. Ofatu- mia despite p53 gene mutation and resistance to immunotherapy with Cyclophosphomide, Flu-
mumab as single-agent CD20 immunotherapy in chemotherapy. N Engl J Med. 2002;347(6):452- darabine, Alemtuzumab and Rituximab (CFAR) Is
fludarabine-refractory chronic lymphocytic leuke- 453. Effective in Relapsed Patients with Chronic Lym-
mia. J Clin Oncol. Apr 1;28(10):1749-1755. 83. Alinari L, Lapalombella R, Andritsos L, Baiocchi phocytic Leukemia (CLL) [abstract]. Blood (Am
68. Eichhorst BF, Fischer K, Fink A-M, et al. The Per- RA, Lin TS, Byrd JC. Alemtuzumab (Campath- Soc Hematol Ann Meeting). 114;2009:Abstract
formance of Computed Tomography (CT) Scans 1H) in the treatment of chronic lymphocytic leuke- 3431.
or Ultrasound Has No Clinical Relevance in Treat- mia. Oncogene. 2007;26(25):3644-3653. 97. Parikh SA, Keating M, O’Brien S, et al. Frontline
 From www.bloodjournal.org by guest on November 17, 2018. For personal use only.

3714 JAGLOWSKI et al BLOOD, 11 NOVEMBER 2010 䡠 VOLUME 116, NUMBER 19

combined chemoimmunotherapy with fludara- motherapy with fludarabine (F), cyclophospha- lapsed and refractory CLL: early promising clini-
bine, cyclophosphamide, alemtuzumab and ritux- mide (C), and rituximab (R) (FCR) versus fludara- cal activity. Blood. ASH Annual Meeting Ab-
imab (CFAR) in high-risk chronic lymphocytic leu- bine (F), cyclophosphamide (C) and stracts. 2009;114:3424.
kemia [abstract]. Blood (Am Soc Hematol Ann mabCampath (Cam) (FCCam) in previously un-
104. Byrd JC, O’Brien S, Flinn IW, et al. Phase 1
Meeting). 114;2009:Abstract 208. treated patients (pts) with advanced B-chronic
study of lumiliximab with detailed pharmacoki-
98. Zent CS, Call TG, Shanafelt TD, et al. Early treat- lymphocytic leukemia (B-CLL): experience on
netic and pharmacodynamic measurements in
ment of high-risk chronic lymphocytic leukemia safety and efficacy within a randomised multi-
patients with relapsed or refractory chronic lym-
with alemtuzumab and rituximab. Cancer. 2008; center phase III trial of the French Cooperative
phocytic leukemia. Clin Cancer Res.
113(8):2110-2118. Group On CLL and WM (FCGCLL/MW) and the
2007;13(15 Pt 1):4448-4455.
“Groupe Ouest-Est d’Etudes Des Leucemies
99. Faderl S, Thomas DA, O’Brien S, et al. Experi- Aigues Et Autres Maladies Du sang” (GOEL- 105. Byrd JC, Kipps TJ, Flinn IW, et al. Phase 1/2
ence with alemtuzumab plus rituximab in patients AMS): CLL2007FMP (for fit medically patients). study of lumiliximab combined with fludarabine,
with relapsed and refractory lymphoid malignan- Blood. ASH Annual Meeting Abstracts. cyclophosphamide, and rituximab in patients
cies. Blood. 2003;101(9):3413-3415. 2009;114(22):538. with relapsed or refractory chronic lymphocytic
100. Faderl S, Ferrajoli A, Wierda W, O’Brien S, Lerner 102. Zhao X, Lapalombella R, Joshi T, et al. Targeting leukemia. Blood. Jan 21;115(3):489-495.
S, Keating MJ. Alemtuzumab by continuous intra- CD37-positive lymphoid malignancies with a 106. Furman RR, Forero-Torres A, Shustov A,
venous infusion followed by subcutaneous injec- novel engineered small modular immunopharma- Drachman JG. A phase I study of dacetuzumab
tion plus rituximab in the treatment of patients ceutical. Blood. 2007;110(7):2569-2577. (SGN-40, a humanized anti-CD40 monoclonal
with chronic lymphocytic leukemia recurrence. 103. Andritsos L, Furman RR, Flinn IW, et al. A phase antibody) in patients with chronic lymphocytic
Cancer. 2010;116(10):2360-2365. 1 trial of TRU-016, an anti-CD37 small modular leukemia. Leuk Lymphoma. Feb;51(2):228-
101. Lepretre S, Aurran T, Mahe B, et al. Immunoche- immunopharmaceutical (SMIPTM) protein in re- 235.
 From www.bloodjournal.org by guest on November 17, 2018. For personal use only.

2010 116: 3705-3714

doi:10.1182/blood-2010-04-001230 originally published
online July 7, 2010

The clinical application of monoclonal antibodies in chronic lymphocytic

leukemia
Samantha M. Jaglowski, Lapo Alinari, Rosa Lapalombella, Natarajan Muthusamy and John C. Byrd

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