Chemoimmunotherapy With a Modified Hyper-CVAD and Rituximab Regimen Improves Outcome in De Novo Philadelphia Chromosome–Negative Precursor B-Lineage Acute Lymphoblastic Leukemia (original) (raw)

Abstract

Purpose

The adverse prognosis of CD20 expression in adults with de novo precursor B-lineage acute lymphoblastic leukemia (ALL) prompted incorporation of monoclonal antibody therapy with rituximab into the intensive chemotherapy regimen hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone). Other modifications (irrespective of CD20 expression) included early anthracycline intensification, alterations in number of risk-adapted intrathecal chemotherapy treatments for CNS prophylaxis, additional early and late intensifications, and extension of maintenance phase chemotherapy by 6 months.

Patients and Methods

Two hundred eighty-two adolescents and adults with de novo Philadelphia chromosome (Ph)–negative precursor B-lineage ALL were treated with standard or modified hyper-CVAD regimens. The latter incorporated standard-dose rituximab if CD20 expression ≥ 20%.

Results

The complete remission (CR) rate was 95% with 3-year rates of CR duration (CRD) and survival (OS) of 60% and 50%, respectively. In the younger (age < 60 years) CD20-positive subset, rates of CRD and OS were superior with the modified hyper-CVAD and rituximab regimens compared with standard hyper-CVAD (70% v 38%; P < .001% and 75% v 47%, P = .003). In contrast, rates of CRD and OS for CD20-negative counterparts treated with modified versus standard hyper-CVAD regimens were similar (72% v 68%, P = not significant [NS] and 64% v 65%, P = NS, respectively). Older patients with CD20-positive ALL did not benefit from rituximab-based chemoimmunotherapy (rates of CRD 45% v 50%, P = NS and OS 28% v 32%, P = NS, respectively), related in part to deaths in CR.

Conclusion

The incorporation of rituximab into the hyper-CVAD regimen appears to improve outcome for younger patients with CD20-positive Ph-negative precursor B-lineage ALL.

INTRODUCTION

The prognostic relevance of immunophenotypic classification of acute lymphoblastic leukemia (ALL) relates to associations with cytogenetic and molecular aberrancies. While detection of surface antigens (eg, CD19, CD20, CD22, CD33, CD52) on lymphoblasts by flow cytometry (FC) identifies targets for monoclonal antibody (MoAb) therapy, expression of particular antigens may have prognostic implications. CD20 is a B-lineage antigen expressed on normal and malignant cells during nearly all stages of differentiation (except early B-cell precursors or plasma cells). Heterogeneity in CD20 expression among B-cell malignancies has been well-described.1 It ranges from 40% to 50% in precursor B-lineage ALL compared with 80% to 90% in mature B-cell or Burkitt-type leukemia/lymphoma.

CD20 functions as a calcium channel that influences cell cycle progression and differentiation via downstream signaling pathways, modulating levels of proapoptosis proteins, such as sarco/endoplasmic reticulum Ca2+ (SERCA3) and Bax/Bak.2 Constitutive activation of survival pathways involving nuclear factor-κB and extracellular receptor kinase (ERK1/2) results in overexpression of antiapoptotic Bcl-2 proteins and associated Bcl-2 genes.3 Expression of CD20 likely confers drug resistance via these mechanisms, resulting in persistence of leukemia subclones which eventually re-emerge.

The prognostic significance of CD20 expression in de novo precursor B-lineage ALL was initially evaluated in the pediatric setting with conflicting results. The Pediatric Oncology Group assessed CD20 expression by the traditional 20% cut point and mean fluorescence intensity.4 CD20 expression and increasing mean fluorescence intensity were independently associated with inferior event-free survival rates irrespective of known prognostic factors such as age and karyotype. In contrast, the St Jude experience suggested that CD20 expression was associated with slightly more favorable prognosis.5 It was postulated that these disparate results could be accounted for by differences in intensity of regimens and/or application of risk-adapted strategies.

The influence of CD20 expression on outcome for adults with de novo precursor B-lineage ALL was studied in the context of conventional (vincristine, doxorubicin, dexamethasone [VAD]6) or intensive (fractionated cyclophosphamide plus VAD [hyper-CVAD]7,8) chemotherapy.9 Complete remission (CR) rates were similar regardless of CD20 status (positive/negative by 20% cut point). However, CD20 expression was associated with significantly higher relapse rates (61% v 37%; P < .01) and lower 3-year CR duration (CRD) and survival (OS) rates (22% v 58%; P < .001 and 27% v 60%, P < .01, respectively) after hyper-CVAD therapy. These findings were particularly significant for the younger subsets, whereas CRD and OS rates were uniformly poor for the older group (age ≥ 60 years). Association of CD20 expression with higher cumulative incidence of relapse was subsequently confirmed in the Group for Research in Adult Acute Lymphoblastic Leukemia (GRAALL) 2003 trial, which applied a pediatric regimen to younger adults with de novo Philadelphia chromosome (Ph) –negative ALL.10

Rituximab, a chimerical MoAb directed at surface CD20, induces apoptosis, antibody-dependent cell-mediated cytotoxicity, and complement-mediated cytolysis.11 Incorporation of rituximab into first-line chemotherapy regimens has significantly improved outcome for subsets of non-Hodgkin's lymphoma such as Burkitt-type leukemia/lymphoma and mantle-cell lymphoma/leukemia.12–14 The favorable impact of chemoimmunotherapy has even extended to chronic lymphocytic leukemia, where CD20 expression of the malignant clone is lower than normal B lymphocytes.15,16

The hyper-CVAD program has proven to be an effective first-line therapy for adults with de novo ALL and lymphoblastic lymphoma (LL).7,8,17 Modifications to the regimen were implemented in order to improve on the results. Early anthracycline intensification was initially incorporated based on earlier reports suggesting that this therapeutic strategy improved relapse-free survival.18 Maintenance therapy was extended by 6 months with additional early and late intensifications to avoid relapses in close proximity to completion of therapy. Interventions targeting certain subsets included administration of induction chemotherapy in a protective environment if older to reduce early infection-related mortality; alteration in number of intrathecal chemotherapy treatments (IT) for CNS prophylaxis from four to six if classified as low CNS risk and from 16 to 8 if high CNS risk since prior isolated CNS relapse rates were 6% and 1%, respectively; and incorporation of rituximab for CD20 expression ≥ 20%. Herein, we summarize the results of modified hyper-CVAD regimens for de novo Ph-negative precursor B-lineage ALL with emphasis on outcomes by CD20 expression.

PATIENTS AND METHODS

Study Group

The diagnosis of ALL was established according to WHO criteria.19 Eligibility criteria included age ≥ 10 years without other active malignancy with expected consequent death within 12 months or known positivity for HIV 1. Adequate hepatorenal function was required unless attributable to leukemia. Protocols were approved by the institutional review board at M. D. Anderson Cancer Center. Informed consent for participation was obtained in accordance with institutional guidelines and Declaration of Helsinki. Mature B-cell ALL or Burkitt-type leukemia/lymphoma and Ph-positive ALL were treated on separate protocols with details reported elsewhere.13,20–22 Since October 2006, patients with de novo Ph-negative precursor B-lineage ALL younger than 31 years of age were allocated to first-line therapy with an augmented Berlin-Frankfurt-Münster regimen modeled after an established pediatric program.23

Therapy

Comparative details of the standard and modified hyper-CVAD 1 or 2 regimens are delineated in Table 1 and online-only Appendix.7,13,17,24 Treatment included eight or nine induction-consolidation courses of hyper-CVAD, liposomal daunorubicin with cytarabine (only if anthracycline intensification [modified hyper-CVAD 125]), and high-dose methotrexate with cytarabine. Intensive cycles were administered every 21 days or earlier (at least 14 days apart) on recovery (absolute neutrophil count [ANC] ≥ 1 × 109/L after granulocyte colony-stimulating factor discontinued for ≥ 24 hours and untransfused platelet [PLT] count 50-60 × 109/L). If marrow lymphoblasts were CD20-positive (≥ 20%), rituximab 375 mg/m2 was given on days 1 and 11 of hyper-CVAD cycles and on days 1 and 8 of liposomal daunorubicin and cytarabine or high-dose methotrexate and cytabarine cycles, for eight total doses over the first four courses. Rituximab was given with early and late hyper-CVAD intensifications during months 6 and 18 of maintenance therapy.

Table 1.

Hyper-CVAD and Modified Hyper-CVAD Chemoimmunotherapy Regimens

Regimen Modified Hyper-CVAD 1 and 2 (± rituximab) Standard Hyper-CVAD (1992-1999)
2: Without Intensification (2001-present) 1: With Intensification (2000-2001)
Induction
Hyper-CVAD Y Y Y
Laminar air flow rooms if age ≥ 60 years Y Y N
Rituximab 375 mg/m2 IV days 1, 11 if CD20 ≥ 20% Y Y N
Consolidation
Cycle 2 (anthracycline intensification)
LDNR 150 mg/m2 IV over 12 h days 1-2 N Y N
Cytarabine 1.5 g/m2 CI IV daily days 1-2
Prednisone 200 mg PO days 1-5
Cycles 2, 4, 6, 8 or cycles 3, 5, 7, 9
MTX 200 mg/m2 IV over 2 h, then 800 mg/m2 IV over 22 h day 1 Y Y Y
Cytarabine 3 g/m2 (1 g/m2 if age ≥ 60) IV over 2 h every 12 h × 4 doses on days 2-3
Solu-Medrol 50 mg IV every 12 h × 6 doses on days 1-3
Leucovorin 50 mg IV 12 h after end MTX then 15 mg IV every 6 h × 8 doses or until MTX level < 0.1 μmol/L
Acetazolamide if urine pH < 7
Cycles 1, 3, 5, 7 or cycles 1, 4, 6, 8
Cyclophosphamide 300 mg/m2 IV over 2 h every 12 h × 6 doses on days 1-3 Y Y Y
Mesna 600 mg/m2 CI IV daily days 1-3
Dexamethasone 40 mg IV or PO days 1-4, 11-14
Doxorubicin 50 mg/m2 CI IV over 2-24 h day 4 (48 h if EF < 50%)
VCR 2 mg IV days 1,11
Cycles 1-4
If CD20 ≥ 20%: 8 doses rituximab 375 mg/m2 IV Y Y N
Days 1, 11 (hyper-CVAD)
Days 1, 8 (LDNR- or MTX-cytarabine)
CNS prophylaxis
MTX 12 mg (6 mg if Ommaya) day 2 Y Y
Cytarabine 100 mg day 7 or 8
No. of ITs
Liposomal cytarabine in modified hyper-CVAD 2 (n = 32)24 Y N
Risk adapted (LDH ≥ 1,400 U/L, S + G2M ≥ 14%)
High (one elevated) 8 16
Indeterminate (one unknown) 8 8
Low 6 4
Maintenance
Oral POMP (6-mercaptopurine, VCR, MTX, prednisone) Months 1-5, 8-17, 20-30 Months 1-6, 8-10, 12-24
Intensification
Hyper-CVAD (plus rituximab 375 mg/m2 IV days 1, 11 if CD20 ≥ 20%) Months 6, 18 N
Intensification†
MTX 100 mg/m2 IV day 1 weekly × 4 Months 7, 19 Months 7, 11
L-asparaginase 20,000 units IV day 2 weekly × 4
Supportive care
IV/oral alkalinzation all courses; rasburicase/allopurinol for induction
G-CSF 10 μg/kg subcutaneously daily until ANC > 109/L; pegfilgastrim 6 mg subcutaneously could be substituted after 2007
Duration of doxorubicin infusions increased for modified hyper-CVAD regimens for cardioprotection
Leucovorin rescue: 50-100 mg IV every 4-6 h if MTX levels were elevated at the end of infusion [0 h, confirmed on repeat sample] to greater than 20 μmol/L, > 1 μmol/L at 24 h, or > 0.1 μmol/L at 48 h

Methods

FC was performed on diagnostic bone marrow aspirates (BMA) to establish lineage and CD20 expression as previously described.9 BMA specimens collected at the time of morphological CR (approximately day 21 of induction therapy) were assessed for minimal residual disease (MRD) when feasible (modified hyper-CVAD 2 cohort). BMA cells were stained with four-color antibody panel (multiparameter FC [MFC], sensitivity < 10−4) including markers for CD9, CD10, CD13, CD15, CD19, CD20, CD22, CD33, CD34, CD38, CD58, CD66c, and cytoplasmic-terminal deoxynucleotide transferase by methodology previously described (Appendix).26,27 Total DNA was extracted from BMA samples using automated methods (Autopure; Genta, Minneapolis, MN). B-cell clonality was determined using nonquantitative polymerase chain reaction (PCR) method with V consensus primers (cPCR) derived from framework 1 (FR1), framework 2 (FR2), and framework 3 (FR3) regions, in combination with mixture of fluorescently labeled J primers; sensitivity ranged from 10−2 to 10−4 depending on number of polyclonal B-cells.28

Response Criteria

CR was defined as ≤ 5% blasts in normocellular or hypercellular marrow with ANC ≥ 1 × 109/L, PLT ≥ 100 × 109/L, and resolution of extramedullary disease. CR with incomplete PLT recovery included CR criteria except for incomplete PLT recovery. Other outcomes were induction death if occurred after start of therapy without meeting definitions of CR or resistant disease, and resistant disease if survived the induction period but leukemia persisted. Relapse was defined as disease recurrence at any site after achievement of CR. Toxicity was graded according to National Cancer Institute Common Toxicity Criteria (version 3.0).

Statistical Considerations

The end points of these sequential prospective, open label, single-center, phase II trials of hyper-CVAD and its variants were response and CRD. OS was measured from initiation of therapy until death. CRD was measured from CR until relapse. Differences in CR rates or pretreatment characteristics among subgroups were analyzed by χ2 or Fisher's exact tests. Unadjusted CRD and OS analyses were performed using Kaplan-Meier plots29 with differences among them analyzed by the log-rank test.30 Goodness-of-fit was assessed by Martingale residual plots.31 The Cox proportional hazards model32 was used to assess treatment and characteristics predicting CR, CRD, and OS. Factors significant for CR, CRD, and OS outcomes by univariate analysis were analyzed further by stepwise regression using assumption of proportional hazards as suggested by Cox.32

RESULTS

Study Group

From July 1992 to August 2009, 282 adolescents and adults with de novo Ph-negative precursor B-lineage ALL were treated with standard (n = 109) or modified hyper-CVAD regimens (with [n = 47] or without [n = 126] anthracycline intensification; Table 2). Median age was 41 years (range, 13 to 83); 21% were 60 years or older and 57% were males. There were no significant differences in distribution among treatment categories by CD20 status (positive or negative), except for higher incidence of CD20 expression in the older group.

Table 2.

Characteristics of Adolescents and Adults With De Novo Philadelphia Chromosome–Negative Precursor B-Lineage ALL (n = 282)

Characteristic Modified Hyper-CVAD ± Rituximab Hyper-CVAD Without Rituximab(n = 109)
2: Without Intensification (n = 126) 1: With Intensification* (n = 47)
CD20 Negative CD20 Positive CD20 Negative CD20 Positive CD20 Negative CD20 Positive
No. % No. % No. % No. % No. % No. %
No. 53 73 23 24 56 53
Age, years
≤ 30 13 25 25 34 8 35 6 25 25 45 19 36
31-59 30 57 29 40 9 39 9 38 26 46 25 47
≥ 60 10 19 19 26 6 26 9 38 5 9 9 17
Median 42 47 40 53 32 43
Range 15-75 15-79 18-80 19-83 13-70 16-78
Sex
Female 31 49 22 35 10 43 14 58 21 38 17 32
Zubrod performance status
0-1 48 91 60 82 19 83 15 63 44 79 33 62
2-3 5 9 13 18 4 17 9 38 12 21 20 38
Leukocyte count, ×109/L
< 5 26 49 42 58 11 48 18 75 20 36 25 47
5-29.9 17 32 22 30 4 17 4 17 24 43 20 38
≥ 30 10 19 9 12 8 35 2 8 12 21 8 15
Hemoglobin, g/dL
< 10 36 68 62 85 19 83 20 83 41 73 41 77
Platelet count, ×109/L
< 100 35 66 64 88 15 65 18 75 40 71 42 79
β-2 microglobulin, mg/dL
≥ 3 17/47 36 35/61 57 12/23 52 8/21 38 20/45 44 12/35 34
Lactate dehydrogenase, U/L
≥ 1,400 25 47 32 44 7 30 6 25 29 52 22 42
% peripheral blasts
Any 41 77 61 84 16 70 19 79 53 95 45 85
Karyotype (except IM; n = 50;58;21;23;48;45)
Diploid 22 44 30 52 12 54 12 52 18 38 19 42
Hyperdiploid 9 18 5 9 — 5 22 4 8 6 13
Hypodiploid 1 2 5 9 2 9 — 2 4 4 9
Translocation/other 18 36 18 31 7 33 6 26 24 50 16 36
CNS leukemia
Yes 3 6 9 12 — 1 4 1 2 3 6
Splenomegaly
Yes 9 17 15 21 2 9 3 12 11 20 18 34
Lymphadenopathy
Yes 12 23 21 29 8 35 5 21 18 32 14 26
Hepatomegaly
Yes 4 7 10 14 1 4 2 8 6 11 8 15
CNS relapse risk (n = 56;60;23;24;44;45)
Low 17 30 24 40 6 26 5 21 12 27 18 40
Indeterminate 6 10 6 10 7 30 12 50 1 2 1 2
High 33 59 30 50 10 43 7 29 31 70 26 58
Systemic risk classification
Low 13 25 26 36 2 9 6 25 18 32 16 30
High 40 75 46 64 21 91 18 75 38 68 37 70

Response

The overall CR rate was 95% (Table 2). Lower CR rates were observed in the older group (88% v 97%; P = .02, with failures equally divided between resistant disease and induction death). CR rates by pretreatment characteristics are provided in Table 3. There were no significant differences in CR rates by regimen or CD20 expression. Assessments of MRD were performed on BMAs collected at the time of CR in 93 of 126 patients (74%) treated with modified hyper-CVAD 2. The incidence of MRD-negativity by MFC (< 0.01%) was higher (81% v 58%; P = .02) for the CD20-positive subset (n = 57) treated with rituximab compared with the CD20-negative group (n = 36). The respective rates for MRD-negativity by cPCR for immunoglobulin heavy chain gene rearrangements in 91 evaluable patients were 85% versus 70% (P = .1). Discordance between MFC and cPCR was observed in 21 of 81 BMAs with concurrent assessments (5 of 56 [9%] MRD-negative by MFC were positive by cPCR whereas 16 of 25 [64%] MRD-positive by MFC were negative by cPCR).

Table 3.

Outcome for Adults With De Novo Philadelphia Chromosome–Negative Precursor B-Lineage Acute Lymphoblastic Leukemia by Pretreatment Characteristics (n = 282)

Characteristic No. % % CR P (χ2) % CRD P % OS P (χ2)
3 Year 5 Year 3 Year 5 Year
Age, years
Overall 282 95 — 60 50 — 58 50 —
≤ 30 96 34 99 .02 63 50 NS 70 64 < .001
31-59 128 45 98 66 55 60 50
≥ 60 58 21 88 53 47 29 21
Sex
Male 282 57 96 NS 57 60 .1 57 48 NS
Female 120 43 96 69 45 57 50
Performance status
0-1 219 78 96 NS 65 55 .04 60 50 NS
2-3 63 22 97 50 40 50 44
Leukocyte count, ×109/L
< 5 142 50 96 NS 65 54 < .001 60 49 < .01
5-29.9 91 32 98 65 54 64 54
≥ 30 49 17 94 47 44 42 35
Hemoglobin, g/dL
< 10 219 78 97 NS 60 62 NS 55 45 NS
≥ 10 63 22 94 67 48 59 55
Platelet count, ×109/L
< 100 214 76 95 NS 60 48 .03 53 43 < .01
≥ 100 68 24 98 68 61 69 67
Serum creatinine, mg/dL
< 1.3 252 89 97 < .01 64 54 .06 60 56 < .01
≥ 1.3 30 11 87 51 35 43 25
Serum bilirubin, mg/dL
< 1.3 254 91 96 NS 64 50 NS 59 50 NS
≥ 1.3 27 10 93 45 45 46 41
Serum albumin, g/dL
< 3 232 83 94 NS 42 39 .01 45 40 .04
≥ 3 49 17 97 65 53 60 50
β–2 microglobulin, mg/dL (n = 232)
< 3 128 55 98 NS 70 55 NS 65 55 .05
≥ 3 104 45 95 53 55 52 46
Lactate dehydrogenase, U/L
< 1,400 161 57 95 NS 60 48 NS 57 50 NS
≥ 1,400 121 43 98 60 52 57 48
Systemic risk classification
Low 81 29 99 NS 64 52 NS 72 65 < .001
High 200 71 95 63 50 51 43
Karyotype (n = 275)
Diploid 113 40 96 NS 68 55 NS 60 50 .06
Hyperdiploid 29 10 97 75 75 65 65
Hypodiploid 14 5 100 48 39 55 42
t(1;19) 8 3 100 85 68 62 62
del 9p 13 5 92 67 45 69 61
t(4;11), t(11;19), 11q 18 6 94 14 14 20 10
Other 44 16 93 64 56 59 48
Insufficient metaphases 36 13 94 49 39 50 42
CD20 expression
Positive 150 53 94 NS 53 48 .002* 60 52 NS
Without rituximab 55 93 40 40 45 39
With rituximab 95 96 67 53 61 49
Negative 132 47 96 69 52 54 46
Myeloid marker expression (n = 269)
Positive 125 46 94 NS 64 50 NS 55 45 NS
Negative 144 54 97 53 50 57 52
Regimen
Hyper-CVAD 109 39 96 NS 53 46 < .01 55 49 NS
Modified hyper-CVAD 1 47 17 99 54 44 55 44
Modified hyper-CVAD 2 126 45 94 78 56 60 50

Remission Duration and Survival Outcomes

With a median follow-up of 64 months (range, 4 to 200), the overall 3-year CRD and OS rates were 60% and 58%, respectively (Table 3). Favorable predictors of longer CRD included better performance status, lower WBC, higher PLT, and higher serum albumin before initiation of therapy. Worse OS rates were noted for older age, higher WBC, lower PLT, elevated serum creatinine levels, lower albumin levels, elevated β-2 microglobulin levels, and high systemic risk classification. Multivariable analysis for OS identified younger age, lower WBC, higher PLT, and therapy with rituximab as independent predictors of favorable outcome.

Treatment with modified hyper-CVAD 2 was associated with improvement in 3-year CRD rates compared with modified hyper-CVAD 1 or hyper-CVAD (78%, 54%, and 53%, respectively; P < .01). When analyzing the entire CD20-positive precursor B-lineage ALL group, incorporation of rituximab into the modified hyper-CVAD regimens was associated with significant improvement in 3-year CRD rates (67% v 40%; P = .002), but not OS rates (61% v 45%; P = not significant [NS]). Relapse rates declined from 60% to 37% (P = .003; Table 4). In the CD20-positive group treated with modified hyper-CVAD 2 (n = 57), absence of detectable MRD by MFC at the time of CR was associated with significantly better 3-year CRD rates (82% v 24%; P = .002) but not OS rates (70% v 27%; P = NS), in part related to deaths in CR (n = 10) for the MRD-negative group.

Table 4.

Outcome With Hyper-CVAD and Modified Hyper-CVAD Regimens in De Novo Philadelphia Chromosome–Negative Precursor B-Lineage Acute Lymphoblastic Leukemia by Therapy and CD20 Status

Characteristic Modified Hyper-CVAD ± Rituximab Hyper-CVAD Without Rituximab (n = 109)
2: Without Intensification (n = 126) 1: With Intensification (n = 47)
CD20 Negative CD20 Positive CD20 Negative CD20 Positive CD20 Negative CD20 Positive
No. % No. % No. % No. % No. % No. %
No. 53 73 23 24 56 53
Response, overall
CR 50 94 67 92 22 96 24 100 55 98 50 94
CRp 1 2 1 1 1 4 — — —
NR 1 2 2 3 — — 1 —
ED 1 2 3 4 — — — 3 6
Follow-up, months
Median 41 90 132
Range 4-81+ 24-106+ 6-200+
Relapse rate 10 19 20 28 12 52 11 46 31 56 30 60
Time to relapse, months
Median 30 27 10 25 30 11
Range 4-72 2-75 2-47 7-38 5-140 2-124
Deaths in CR
Overall 4 8 13 18 4 17 3 13 5 9 2 4
No. age ≥ 60 years 0 9 4 3 2 1
% 3-year CRD
Overall by therapy 78 53 54
% 3-year CRD
Overall 84 73 50 54 68 37
Age, years
≤ 30 84 75 62* 40* 75 26
31-59 89 75 45* 67* 62 48
≥60 71 65 0* 45* 50* 50*
% 3-year OS
Overall by therapy 60 55 55
% 3-year OS
Overall 63 57 44 65 65 45
Age, years
≤ 30 77 75 63* 80* 84 47
31-59 56 66 55* 78* 58 48
≥ 60 60* 15 0* 45* 20* 34*

Since our prior analysis established the lack of prognostic significance of CD20 expression in the older group,9 a subset analysis excluding these patients was conducted to assess influence of rituximab therapy in the younger CD20-positive subsets (Table 4; Figs 1A, 1B, 1C). Significant improvements in 3-year CRD (70% v 38%; P < .001; Fig 1A) and OS (75% v 47%; P = .003; Fig 1B) rates favoring rituximab were observed. The outcomes were either similar or superior to those for their CD20-negative counterparts within the age subcategories (Table 4). There were no significant differences in rates of OS by regimen for younger CD20-negative precursor B-lineage ALL (Fig 1D), in contrast to better OS rates for modified hyper-CVAD and rituximab regimens within the CD20-positive group (Fig 1C). Notably there was no benefit to anthracycline intensification (modified hyper-CVAD 124), rather there appeared to be an inferior outcome, particularly in the CD20-negative elderly group (Table 4; Fig 2A).

Fig 1.

Fig 1.

Outcomes by therapy for younger patients (age younger than 60 years) with Philadelphia chromosome–negative precursor B-lineage acute lymphoblastic leukemia. In the CD20-positive subset, (A) complete remission (CR) duration and (B) survival by inclusion or exclusion of rituximab therapy, and (C) survival by hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone) regimen (standard, modified hyper-CVAD 1 with rituximab inclusive of anthracycline intensification, or modified hyper-CVAD 2 with rituximab eliminating anthracycline intensification) are depicted. (D) Survival by regimen (without rituximab) for the CD20-negative group is also depicted.

Fig 2.

Fig 2.

Outcomes by therapy for older patients (age 60 years or older) with Philadelphia chromosome–negative precursor B-lineage acute lymphoblastic leukemia. (A) In the CD20-negative subset, survival by regimen is depicted. (B) In the CD20 positive subset, complete remission (CR) duration (CRD) and survival by rituximab therapy is depicted. OS, overall survival.

Outcome in Elderly Subset

The overall CR rate for 58 patients age 60 years or older was 88%; 3-year CRD and OS rates were 53% and 29%, respectively (Table 4; Appendix Table A1, online only). Eighteen (62%) of 29 older patients treated with modified hyper-CVAD 2 were assessed for MRD by MFC at the time of CR. Patients in the CD20-positive subset treated with rituximab had a higher rate of MRD-negativity than their CD20-negative counterparts (11 of 12 [92%] v three of six [50%]; P = .05). However, this did not translate into improved CRD or OS outcomes compared with the older CD20-positive subgroup treated with standard hyper-CVAD, in part related to deaths in CR (Appendix Table A1; Fig 2B; Appendix).

Treatment Delivery and Toxicity

Toxicity profiles of the chemoimmunotherapy regimens were similar to previous reports detailing modified hyper-CVAD 1 for LL and hyper-CVAD and rituximab for Burkitt-type leukemia/lymphoma.8,13,17,25 There was no difference in time to CR with the addition of rituximab (median 23 v 21 days). There was no increase in induction mortality for the CD20-positive subset treated with rituximab, rather, overall early mortality rates in older patients treated in the protective environment declined from 11% to 2% (P = NS).

Treatment realization for the intensive phase of chemotherapy was reviewed for 121 (96%) of 126 patients treated with modified hyper-CVAD 2. Seventy-eight of 121 patients (64%) completed eight cycles of chemotherapy within a median time (start of induction to start of cycle 8) of 5.8 months (range, 4.4 to 10 months). Nineteen patients (16%) received four or fewer cycles; 12 (63%) were CD20-positive and 10 (53%) were 60 years or older. Reasons for early discontinuation of intensive chemotherapy (after four cycles or less in 19, after five cycles in eight, after six cycles in 13, after seven cycles in three patients) included relapse (n = 9), deaths in CR (n = 7; 6 were CD20-positive), or infectious-related toxicity (n = 2). Five patients underwent allogeneic stem-cell transplantation (SCT) in first CR; four for t(4;11)(q21;q23) karyotype and one for persistent MRD. An additional 20 patients were transitioned to 6-mercaptopurine, vincristine, methotrexate, and prednisone maintenance phase chemotherapy early owing to recurrent life-threatening infections (n = 13), persistent cytopenias (n = 2), CNS toxicity (n = 2, ventriculoperitoneal shunt; cerebrovascular accident), and myocardial infarction (n = 1).

Despite similar toxicity profiles and recovery times from myelosuppression (data not shown), the number of deaths in CR was higher for the CD20-positive subset treated with modified hyper-CVAD 2, predominantly related to infections with multidrug resistant organisms in the older group (n = 6) during consolidation chemotherapy, before implementation of rotating antibacterial antibiotic prophylaxis (online-only Appendix). Other causes of death in this subgroup included complications related to secondary myelodysplastic syndrome (n = 2), cardiovascular events (n = 2), or seizure-related anoxic encephalopathy (n = 1); two others were not on active therapy at the time of their demise (Appendix Table A1).

DISCUSSION

The hyper-CVAD regimen, modeled after a pediatric treatment designed for childhood Burkitt lymphoma, has proven to be an effective program for de novo ALL and LL.7,8,17,33 Further improvements in outcome have been observed with incorporation of targeted agents such as tyrosine kinase inhibitors (eg, imatinib) for Ph-positive ALL and MoAb therapy (eg, rituximab) for Burkitt-type leukemia/lymphoma.13,20

The results of our study suggest that the addition of rituximab to hyper-CVAD-based regimens for CD20-positive precursor B-lineage ALL significantly improved 3-year rates of CRD (70% v 38%; P < .001) and OS (75% v 47%; P = .003). In striking contrast to the Burkitt-type leukemia/lymphoma experience,13 where outcome was significantly improved for the older subset, the benefit of rituximab in precursor B-lineage ALL appears to be confined to the younger group (3-year rates for CRD 45% v 50%; OS 28% v 32% if 60 years or older). These results are not inconsistent with our previous findings that outcome was uniformly poor in the elderly subset treated with hyper-CVAD in the prerituximab era, regardless of CD20 expression. It is plausible that alternative dosing schemas using rituximab in conjunction with lower intensity therapy in the postinduction phase (to avoid infectious complications of myelosuppression) may yield better survival outcomes for this older group.

Although these prospective analyses are comparative in nature (ie, nonrandomized), the absence of significant differences in outcome among the standard or modified hyper-CVAD regimens in the contemporaneously treated CD20-negative precursor B-lineage ALL subset suggests that other factors such as improvements in supportive care cannot account for these findings.

Preliminary results of other regimens incorporating rituximab for de novo CD20-positive precursor B-lineage ALL have been presented. In 26 elderly patients (> 55 years) treated with chemoimmunotherapy (eight applications of standard-dose rituximab) according to the German Multicenter Study Group for Adult ALL (GMALL) 2002 protocol, the CR rate was 63% with 1-year OS rate of 54%.34 Younger patients were treated per GMALL 07/2003 according to risk group. If high-risk (HR; WBC > 30 × 109/L or late CR), standard-dose rituximab was administered with three phases of induction (I, II) and first consolidation chemotherapy followed by allogeneic SCT. Patients with standard risk (SR) received eight treatments with standard-dose rituximab before induction (phase I, II), reinduction, and six consolidation chemotherapy cycles. Preliminary results were presented for 185 patients (133 SR; 52 HR) with CD20-positive precursor B-lineage ALL; 117 (63%) received rituximab and were compared with 70 treated with the same chemotherapy regimen without rituximab.35 In the SR subset, addition of rituximab improved 3-year CRD and OS rates (64% v 48%, P = .009 and 75% v 54%, P = not reported, respectively). In the HR group, allogeneic SCT was performed in 66% of cases with improvement in 3-year OS rates after rituximab (75% v 40%; P = not reported). Rates of death in first CR in this younger group were similar (4% v 3%).

Prospective randomized clinical trials incorporating rituximab into first-line therapy for precursor B-lineage ALL (some irrespective of CD20 expression) are planned. In our prior analysis, lower cut points of CD20 expression (eg, 10%) were discriminatory in predicting outcome.9 Upregulation of CD20 expression during induction chemotherapy in ALL cases deemed CD20-negative at baseline suggests that anti-CD20 MoAb therapy may be beneficial even with low levels of expression.36–38 Similar to the non-Hodgkin's lymphoma experience, extended dosing of rituximab during 6-mercaptopurine, vincristine, methotrexate, and prednisone maintenance therapy may further reduce relapses. Incorporation of novel agents which not only have antileukemic activity but also counter mechanisms of resistance to rituximab (eg, anti-Bcl-2 agents, mammalian target of rapamycin inhibitors, hypomethylating agents) should be explored.36 Higher-affinity novel antibodies directed against different CD20 epitopes (eg, ofatumumab) or other lymphoblast surface antigens such as epratuzumab (targeting CD22) and alemtuzumab (targeting CD52) may further improve outcome.39–43

Appendix

Study group.

From July 1992 to August 2009, 440 adolescents and adults with de novo Ph-negative acute lymphoblastic leukemia (n = 391; 89%) or lymphoblastic lymphoma (n = 49; 11%) were treated with hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone; n = 210) or modified hyper-CVAD regimens (with [n = 69] or without [n = 161] anthracycline intensification). Median age was 38 years (range, 13 to 92); 18% were 60 years or older and 62% were male. In the precursor B-lineage acute lymphoblastic leukemia subgroup (n = 313), data on CD20 expression was available in 282 patients (90%; limited immunophenotypic analyses in 31 patients treated with hyper-CVAD). This group forms the basis of the detailed subset analysis (no significant differences in distribution of characteristics or outcomes noted with inclusion/exclusion of the group with unknown CD20 status, data not shown).

Intensive therapy.

The first course in all regimens was accompanied by appropriate intravenous hydration and alkalinization (eg, dextrose water or one half normal saline with 75 to 100 milliequivalents of sodium acetate per liter to run at 50-100 mL/h) and allopurinol to reduce the incidence of tumor lysis syndrome. Oral sodium bicarbonate supplemented the intravenous formulation on days 1 to 3. Rasburicase could be substituted for allopurinol in cases with high WBC count or bulky disease at presentation. The duration of the doxorubicin infusion for the hyper-CVAD cycles was extended from 2 to 24 hours (48 hours if left ventricular ejection fraction lower than 50%) for the modified hyper-CVAD regimens owing to the addition of anthracycline-based intensifications during maintenance therapy. The high-dose methotrexate (MTX) and cytarabine courses incorporated automatic dose reduction of the cytarabine from 3 g/m2 to 1 g/m2 for patients age 60 years or older. Intravenous alkalinization was utilized to promote excretion of MTX (as for course 1 above) at a rate of 100 to 125 mL/h with prehydration period of at least 4 hours before MTX until urine pH was at least 7.0. An algorithm of additional leucovorin rescue (50 to 100 mg IV every 4 to 6 hours) was implemented if serum MTX levels were greater than 20 μmol/L at the end of infusion (0 hour, confirmed on repeat sample), more than 1 μmol/L at 24 hours, or more than 0.1 μmol/L at 48 hours. Oral acetazolamide 250 mg was administered by mouth twice daily if the urine pH was lower than 7.0 until serum MTX level lower than 0.1 μmol/L.

CNS therapy.

CNS prophlyaxis with intrathecal chemotherapy (IT) was administered according to CNS risk (Table 1). From January 2005 to December 2005, 32 patients received IT prophylaxis with liposomal cytarabine.24 Therapy for active CNS leukemia at presentation included alternating IT MTX and cytarabine twice weekly during the induction course until cerebrospinal fluid cell count normalized and cytological examination was negative for malignant cells on two sequential assessments, then weekly for 4 weeks, then according to the prophylactic schedule for all remaining cycles of intensive chemotherapy. Therapeutic radiation therapy was given if indicated (eg, 24 to 30 Gy in 10 to 12 fractions to base of the skull for cranial nerve palsies). No prophylactic cranial irradiation was administered.

Maintenance therapy.

Included treatment with 6-mercaptopurine (6-MP), vincristine (VCR), MTX, and prednisone (POMP) for 24 months with the standard hyper-CVAD regimen. Between 1992 and 1995, oral POMP was given with 6-MP 50 mg orally 3 times daily, MTX 20 mg/m2 orally or IV weekly, VCR 2 mg IV every 28 days, and prednisone 200 mg daily days 1 to 5. Thereafter, IV POMP was given with 6-MP 1 g/m2 IV over 1 hour daily for 5 days every 28 days concurrently with MTX 10 mg/m2 IV over 1 hour daily for 5 days and VCR with prednisone as just described. The 6-MP and MTX doses were reduced by 25% (to 750 mg/m2 IV and 7.5 mg/m2 IV, respectively) for moderate toxicity and by 50% (to 500 mg/m2 IV and 5 mg/m2 IV, respectively) in cases of severe toxicity. The MTX dose was usually reduced selectively for mucositis or hepatic dysfunction attributable to the agent. Oral POMP was resumed in 1999 when the intravenous formulation of 6-MP was no longer available. Two intensification courses interrupted the POMP maintenance during months 9 and 12 with VP-16 100 mg/m2 IV daily days 1 to 5 and pegylated asparaginase 2,500 U/m2 IV day 1. After July 2000, these intensifications were changed to MTX 100 mg/m2 IV day 1 and L-asparaginase 20,000 units IV day 2 weekly for 4 weeks during months 7 and 11 of maintenance therapy. For the modified hyper-CVAD regimens, the oral POMP maintenance was extended to 30 months with the addition of hyper-CVAD (with or without rituximab) to the early and late intensifications for months 6 and 18 preceeding therapy with MTX and L-asparaginase for months 7 and 19.

Guidelines for dose reductions.

Guidelines for dose reductions included (1): cytarabine 1 g/m2 for age 60 years or older, creatinine ≥ 1.5 mg/dL, or MTX level at 0 hour (repeated) ≥ 20 μmol/L;(2) VCR 1 mg for total bilirubin higher than 2 mg/dL or grade 2 persistent peripheral neuropathy or VCR eliminated for total bilirubin above 3 g/dL, grade 3 to 4 peripheral neuropathy, or grade 3 to 4 ileus; (3) doxorubicin decreased by 50% for total bilirubin 2 to 3 mg/dL, by 75% if 3 to 5 mg/dL, and eliminated if above 5 mg/dL; and (4) MTX decreased by 50% for calculated creatinine clearance 10 to 50 mL/min (eliminated if < 10 mL/min) or if pleural effusions/ascites (with thoracentesis/paracentesis as feasible) or decreased by 25% to 50% for delayed excretion, nephrotoxicity, or grade 3 or greater mucositis with prior courses.

Supportive care.

Filgastrim 10 μg/kg (rounded) subcutaneously daily commenced 24 hours after completion of the induction chemotherapy (approximately day 6) until absolute neutrophil count was greater than 1 × 109/L. The filgastrim could be delayed until 48 to 72 hours after completion of the chemotherapy for the consolidation cycles. After December 2007, pegfilgastrim 6 mg subcutaneously could be administered in lieu of the filgastrim at the discretion of the treating physician. For the modified hyper-CVAD regimens, patients age 60 years or older were placed in a laminar air flow room or protective environment for the induction course until absolute neutrophil count reached 0.5 × 109/L. Hematologic profiles were obtained at least biweekly during induction and at least weekly during consolidations. Packed RBCs were given for symptomatic and/or severe anemia. Platelet transfusions were given prophylactically for platelet count lower than 10 to 15 × 109/L or therapeutically for platelet count lower than 30 to 50 × 109/L with hemorrhage. All blood products were irradiated.

During the intensive phase, prophylactic anti-infective therapy included either a quinolone, amoxicillin-clavulanate potassium, trimethoprim-sulfamethoxazole, or other antibacterial antibiotic; fluconazole 200 mg daily with the standard hyper-CVAD regimen or itraconazole, voriconazole, or caspofungin with the modified hyper-CVAD regimens for antifungal prophylaxis as the latter agents became available; and acyclovir 400 mg twice daily or valacyclovir 500 mg daily for antiviral coverage. Since 2005, antibacterial antibiotics were rotated with each intensive chemotherapy cycle (as opposed to continuous therapy with quinolones) to reduce the incidence of infections with multidrug resistant organisms. During the maintenance phase, recommended anti-infective prophylaxis included trimethoprim-sulfamethoxazole one double strength twice daily 2 days weekly and acyclovir 400 mg twice daily (or valacyclovir 500 mg daily) to reduce the probability of Pneumocystis jirovecii infection and varicella zoster or herpes simplex infections, respectively. Neutropenic febrile episodes generally resulted in hospitalization with initiation of broad spectrum parenteral antibiotics.

Assessments.

Pretreatment evaluations included history/physical examination with documentation of extramedullary disease by imaging and/or appropriate cytological/histological evaluations; complete blood count/differential; hepatorenal function studies including lactate dehydrogenase and uric acid levels; and bone marrow aspirate/biopsy for morphology, immunohistochemical stains, immunophenotyping, and karyotyping. Analysis of cerebrospinal fluid was performed concomitantly with prophylactic IT treatment. Bone marrow aspirations were repeated on days 14 and 21 of course 1 to determine response (or later to confirm CR if needed), then every two to three courses until end of consolidation chemotherapy, then every 3 to 6 months for the first 3 years.

Methods.

Bone marrow aspirates (BMA) samples were assessed for minimal residual disease (MRD) using the panel of markers (detailed in the text). MRD was identified in comparison with the known patterns of antigen expression by normal maturing CD19 positive B-cells using an approach similar to that described by Weir et al.26 A distinct cluster of at least 20 cells showing altered antigen expression was regarded as an aberrant population. An aberrant expression of at least 2 antigens was required for definitive diagnosis of MRD. 1 × 106 bone marrow cells were stained using a standard stain-lyse-wash procedure, using Ortho Lyse Buffer (BD Biosciences, San Jose, CA). Data were acquired on FACSCalibur cytometers using CellQuest software (BD Biosciences). At least 2 × 105 cells were acquired when specimen quality permitted. Data on B-cells were selectively acquired by gating on CD19/CD34 positive cells with low side scatter.

Table A1.

Summary of Deaths in Complete Remission by Age and Therapy

Modified Hyper-CVAD 2 (n = 126) Modified Hyper-CVAD 1 (n = 47) Hyper-CVAD (n = 109)
CD20 Positive Age (years) Cause CD20 Positive Age (years) Cause CD20 Positive Age (years) Cause
No 27 Pneumonia after SCT No 35 Pneumonia No 40 Unknown
No 42 HHV6 encephalitis after SCT No 37 PCP pneumonia No 50 Sepsis
No 45 Hepatic failure after SCT for secondary MDS No 68 Peritonitis No 52 Meningitis
No 57 Sudden death No 72 Sepsis No 65 Sepsis
Yes 16 Seizure with anoxic encephalopathy No 80 Hepatic failure No 70 Pneumonia
Yes 49 Sepsis (MDR Pseudomonas) Yes 61 Pneumonia Yes 55 Sepsis
Yes 53 Sepsis after therapy for secondary MDS Yes 78 Unknown Yes 78 Unknown
Yes 55 Abdominal aeortic aneurysm Yes 80 Sepsis
Yes 62 Cardiopulmonary arrest
Yes 63 Sepsis (MDR Pseudomonas)
Yes 64 Sepsis after therapy for secondary MDS
Yes 69 Sepsis (Enterococcus)
Yes 69 Pneumonia (not on active therapy)
Yes 73 Unknown (not on active therapy)
Yes 76 Sepsis (MDR E. coli)
Yes 76 Sepsis (Staphylococcus)
Yes 79 Sepsis (MDR Pseudomonas)

Footnotes

Supported in part by Grant No. 5K12 CA88084-2 from the National Institutes of Health and a research grant from Amgen.

Presented in part at the 50th Annual Meeting of the American Society of Hematology, San Francisco, CA, December 6-8, 2008 and at the 51st Annual Meeting of the American Society of Hematology, New Orleans, LA, December 5-8, 2009.

Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.

Clinical trial information can be found for the following: NCT00671658.

AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

Although all authors completed the disclosure declaration, the following author(s) indicated a financial or other interest that is relevant to the subject matter under consideration in this article. Certain relationships marked with a “U” are those for which no compensation was received; those relationships marked with a “C” were compensated. For a detailed description of the disclosure categories, or for more information about ASCO's conflict of interest policy, please refer to the Author Disclosure Declaration and the Disclosures of Potential Conflicts of Interest section in Information for Contributors.

Employment or Leadership Position: None Consultant or Advisory Role: Susan O'Brien, Genentech (C); Michael J. Keating, Genentech (C) Stock Ownership: None Honoraria: William Wierda, Genentech Research Funding: Deborah A. Thomas, Amgen, Genentech; Susan O'Brien, Genentech, Biogen Idec; Farhad Ravandi, Genentech; Hagop M. Kantarjian, Amgen; William Wierda, Genentech Expert Testimony: None Other Remuneration: None

AUTHOR CONTRIBUTIONS

Conception and design: Deborah A. Thomas

Provision of study materials or patients: Deborah A. Thomas, Susan O'Brien, Stefan Faderl, Guillermo Garcia-Manero, Alessandra Ferrajoli, William Wierda, Farhad Ravandi, Srdan Verstovsek, Jeffrey L. Jorgensen, Carlos Bueso-Ramos, Michael Andreeff, Michael J. Keating, Jorge Cortes, Hagop M. Kantarjian

Collection and assembly of data: Deborah A. Thomas, Sherry Pierce, Rebecca Garris

Data analysis and interpretation: Deborah A. Thomas, Jeffrey L. Jorgensen, Carlos Bueso-Ramos, Sherry Pierce, Rebecca Garris

Manuscript writing: Deborah A. Thomas, Jeffrey L. Jorgensen,Hagop M. Kantarjian

Final approval of manuscript: Deborah A. Thomas, Susan O'Brien, Stefan Faderl, Guillermo Garcia-Manero, Alessandra Ferrajoli, William Wierda, Farhad Ravandi, Srdan Verstovsek, Jeffrey L. Jorgensen, Carlos Bueso-Ramos, Michael Andreeff, Sherry Pierce, Rebecca Garris, Michael J. Keating, Jorge Cortes, Hagop M. Kantarjian

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