Daclizumab, a humanized monoclonal IgG1 directed against the  chain of the interleukin-2 receptor (IL-2R), is a competitive inhibitor of IL-2 on activated lymphocytes. To test the hypothesis that specific inhibition of activated lymphocytes in patients with ongoing acute graft-versus-host disease (GVHD) might ameliorate the process, we treated 43 patients with advanced or steroid-refractory GVHD with daclizumab. The first cohort of 24 patients was treated with daclizumab 1 mg/kg on days 1, 8, 15, 22, and 29. On day 43, the complete response (CR) rate was 29% (95% confidence interval [CI], 13%-51%). Survival on day 120 was 29% (95% CI, 13%-51%). A second cohort of 19 patients was treated with daclizumab 1 mg/kg on days 1, 4, 8, 15, and 22. For these patients, the CR rate on day 43 was 47% (95% CI, 24%-71%), and survival on day 120 was 53% (95% CI, 29%-76%). There were no infusion-related reactions and no serious side effects related to daclizumab. Following treatment, there was a reduction in serum concentrations of soluble IL-2R and peripheral blood CD3 + 25+ lymphocytes, but these changes were not predictive of response. Daclizumab has substantial activity for the treatment of acute GVHD, and the second regimen evaluated is recommended for a controlled study. (Blood, 2000; 95:83-89)

The high-affinity interleukin-2 receptor (IL-2R) is a heteromultimer comprised of the α (p55), β (p75) and γ (p64) chains.1,2 The IL-2Rβ and IL-2Rγ chains are expressed on the surface of most T, NK, and B cells as an intermediate-affinity receptor; signal transduction occurs via the IL-2Rβγ complex.2 The IL-2Rα chain is found predominantly on activated cytotoxic T cells and confers high-affinity properties on the heteromultimer.3,4 Interaction of IL-2R with its ligand IL-2 triggers activation of the ras pathway and results in enhancement of lymphocyte proliferation and differentiation.5 

The limited distribution of IL-2Rα on activated lymphocytes suggested that it could be an appropriate target for strategies designed to eliminate antigen-specific alloreactive T cells. Indeed, in vitro treatment of alloantigen-stimulated lymphocytes with IL-2Rα immunotoxin conjugates or depleting IL-2Rα+ cells by immunomagnetic techniques resulted in a decreased reactivity of the purged population following secondary stimulation against the primary antigen, whereas third-party responses were largely maintained.6-8 In addition, in a murine model, such allodepleted lymphocytes had a reduced capacity to induce graft-versus-host disease (GVHD).9 Administration of anti-IL-2R antibody in vivo early after transplantation was also at least partially effective in preventing GVHD in an F1→P model and in a model with a minor H-2 disparity,10 11 but whether administration of anti-IL-2R in vivo would be effective in abrogating an ongoing GVH response has not been tested in an animal model.

Daclizumab (humanized anti-Tac, HAT) is a human monoclonal IgG1 that incorporates the complementarity-determining regions of a murine monoclonal antibody raised against the human IL-2Rα chain.12,13 In vitro daclizumab displayed specific binding to IL-2Rα+ cells and inhibited the T-cell proliferative response to tetanus toxoid as well as influenza antigen and alloantigen in a dose-dependent fashion, but it did not fix complement.12,13 The mechanism of action of daclizumab is thought to be the competitive inhibition of binding of IL-2 to its receptor.14 In preclinical primate studies, daclizumab was effective in prolonging cardiac allograft survival and in reducing inflammation in experimental uveitis,15,16 and subsequent phase I-III clinical trials demonstrated the safety and efficacy of daclizumab for prevention of renal allograft rejection.17 18 

In a phase I study in patients with acute GVHD, Anasetti et al19 reported no serious side effects after administration of a single dose of daclizumab up to 1.5 mg/kg, and the t1/2β was approximately 3.5 days. Moreover, improvement in or resolution of acute GVHD was seen in 8 of 20 patients in the phase I study19 and in 3 of 5 patients in a subsequent single-dose pilot study.20 Herein we report the results of a multidose strategy with the use of daclizumab for treatment of severe or steroid-refractory GVHD.

Patients

Forty-two patients were enrolled on the prospective study, and one additional patient was treated on a compassionate basis according to the protocol just before the start of the study. The diagnosis of GVHD was made clinically, and appropriate biopsies were obtained for histologic confirmation. Patients were eligible if they were < 100 days after allogeneic marrow or blood stem cell transplantation and had visceral GVHD or steroid-resistant GVHD (any stage of GVHD persisting for 3 days while receiving ≥ 2 mg/kg/d methylprednisolone or developing while on ≥ 1 mg/kg/d methylprednisolone). Mechanical ventilation, serum creatinine > 3 mg/dL, renal dialysis, total bilirubin > 12 mg/dL, use of vasopressors, and uncontrolled infections at the start of therapy were criteria for exclusion. The protocol was approved by the Institutional Review Board at each of the treatment centers, and written informed consent was obtained for each patient.

Treatment plan and monitoring

Daclizumab was administered at 1 mg/kg iv on study days 1, 8, 15, 22, and 29 (regimen 1) for the first 24 patients and at 1 mg/kg iv on study days 1, 4, 8, 15, and 22 (regimen 2) for 19 subsequent patients. Doses were calculated on actual body weight, and the maximum single dose was limited to 100 mg. The appropriate dose of daclizumab was diluted in 50 mL normal saline USP and infused over 30 minutes. Vital signs were recorded before and at 15, 30, and 90 minutes after start of infusion of daclizumab. Cyclosporine or tacrolimus was continued according to the patient's original prophylaxis protocol, and methylprednisolone was administered intravenously at 2 mg/kg in divided doses for at least 7 days before tapering. If there was no improvement in GVHD of the skin after 3 days or of the liver or gut after 7 days, or if there was substantial progression of GVHD after 2 days, then antithymocyte globulin (ATG) could be added at 10 mg/kg iv daily for at least 7 days for patients on regimen 1 or at 40 mg/kg iv daily for 4 days for patients on regimen 2. If there was no improvement in GVHD of the skin after 3 days of ATG or of the liver or gut after 7 days, or if there was substantial progression of GVHD after 2 days of ATG, then patients were considered a treatment failure and eligible for any available salvage therapy. Patients were evaluated for GVHD on study days 1, 8, 15, 22, 29, 36, and 43. GVHD was scored according to the consensus criteria.21 A complete blood count with differential, platelet count, and chemistry panel was done at least twice weekly through study day 29 and on study day 43.

Response criteria

Response was the primary end point of the study and was scored on study day 43; patients who received ATG or expired before study day 43 were considered nonresponders. Patients were evaluable for response in an organ if they had GVHD in that organ at the start of treatment with daclizumab or if GVHD developed after the start of daclizumab but before the time point of evaluation. A complete response (CR) in an organ was defined as stage 0, and a partial response (PR) required a reduction in at least one stage without additional therapy. All patients were evaluable for the overall response. For the overall assessment, a CR was defined as complete resolution of rash, normalization of bilirubin, and absence of diarrhea because of GVHD without the use of antimotility agents, and a partial response (PR) was defined as a decrease by at least one stage in at least one organ system without worsening in the other organ systems. Survival was a secondary end point. Survival was scored on study day 120.

Flow cytometry

Heparinized peripheral blood was collected on study days 1, 8, 15, 22, 29, 36, and 43 as well as at 2 and 3 months on study. CD3+ and CD3 + 25+ cells were enumerated by multiparameter flow cytometry22,23 with the use of fluorochrome-conjugated 2A3 (anti-CD25, Becton Dickinson, San Jose, CA; BD) that binds at or near the same epitope on p55 as daclizumab,24 and fluorochrome-conjugated SK7 (anti-CD3) (BD) that binds the epsilon chain of the T-cell receptor. For five normal volunteers, the median absolute lymphocyte count/μL was 1755 (range, 944-2397), the median absolute number of CD3+cells/μL was 1366 (range, 717-1457), and the median absolute number of C3 + 25+ cells/μL was 140 (range, 85-215). For patients at the M. D. Anderson Cancer Center (MDACC), absolute numbers of CD3+CD4+, CD3+CD8+, CD3+HLA-DR+, and CD3CD56+ in peripheral blood samples were also determined at each study time point with the use of commercial antibodies (BD). In addition, the CD3+ cells in these patients were evaluated for staining with PE-conjugated daclizumab and with FITC-conjugated 7G7, a murine monoclonal antibody that binds p55 at an epitope not recognized by daclizumab.25 

Cytokine and receptor ELISA

For patients at MDACC, serum was collected on study days 1, 8, 15, 22, 29, 36, and 43 as well as at 2 and 3 months on study, and they were tested for IL-2 and soluble IL-2 receptor (sIL-2R) levels with the use of ELISA kits (BioSource International, Camarillo, CA) according to the manufacturer's instructions. The sIL-2R ELISA uses an antibody against p55 that crossreacts with daclizumab; addition of as little as 100 ng of daclizumab totally suppressed detection of the 1000 pg/mL sIL-2R standard.

Statistical considerations

At the time of analysis, all patients had completed follow-up through study day 120. The protocol was originally designed as a two-step phase II study with sufficient power to detect a response rate of 20% or more with a standard error of 10%. When this part was completed, the protocol was modified to allow for treatment of a second cohort (regimen 2). The second regimen included an additional dose of daclizumab in the first week to increase the response rate, and salvage therapy was compressed to 4 days to minimize infectious complications from prolonged use of immunosuppression. Results are reported as a proportion; 95% CIs were calculated by the binomial distribution. Frequencies were compared by log-likelihood ratio or Fisher exact test with a two-sidedP < .05 considered significant. Serial measurements were compared with the use of the Friedman analysis of variance with a two-sided P < .01 considered significant. Medians were compared with the use of the signed rank test for matched samples and the Mann-Whitney U test for independent samples with a two-sided P < .05 considered significant. The statistical analysis was performed with the use of True Epistat v5.3 (True Epistat, Richardson, TX).

Study participants

Patient characteristics are described in Table1. All patients had been transplanted for hematologic malignancies or for nonmalignant hematologic disorders, and all had received a myeloablative preparative regimen. There were 12 patients less than 18 years of age. The majority of the patients had received transplants from HLA-nonidentical donors. For prevention of GVHD, 31 patients had received cyclosporine or tacrolimus with methotrexate or methylprednisolone, whereas 12 received a T-cell–depleted transplant with or without cyclosporine. Eight patients had received ATG as part of GVHD prophylaxis, and six had received ATG as part of the preparative regimen before transplantation. Four patients received daclizumab as part of primary treatment of multiorgan GVHD, and the remainder of the patients were steroid refractory. The episode of GVHD treated on this protocol started at a median of 25 days posttransplant (range, 3-95 days), and the median duration of methylprednisolone use for treatment before study entry was 6 days (range, 0-35 days). The distributions of the stages and grades of GVHD are shown in Table 2. Eleven (46%) patients on regimen 1 and 9 (47%) patients on regimen 2 had grades 3-4 GVHD.

Table 1.

Patient characteristics

Number of patients 43  
Sex (male/female) 25/18  
Median age, y (range) 31 (1-53) 
Diagnosis  
 Leukemia/myelodysplastic syndrome 32 
 Malignant lymphoma 9  
 Aplastic anemia 
 Histiocytosis 1  
Preparative regimen  
 TBI-based 33  
 Busulfan-based 10 
Transplant  
 Marrow 25  
 Blood 11  
 Both 
Donor  
 HLA-identical sibling 14  
 Mismatched related 15  
 Unrelated 14  
GVHD prophylaxis  
 Tacrolimus-based 18 
 Cyclosporine-based 13  
 Cyclosporine + T-cell depletion 7  
 T-cell depletion + other 5  
Daclizumab regimen  
 1 (days 1, 8, 15, 22, 29) 24  
 2 (days 1, 4, 8, 15, 22) 19 
Number of patients 43  
Sex (male/female) 25/18  
Median age, y (range) 31 (1-53) 
Diagnosis  
 Leukemia/myelodysplastic syndrome 32 
 Malignant lymphoma 9  
 Aplastic anemia 
 Histiocytosis 1  
Preparative regimen  
 TBI-based 33  
 Busulfan-based 10 
Transplant  
 Marrow 25  
 Blood 11  
 Both 
Donor  
 HLA-identical sibling 14  
 Mismatched related 15  
 Unrelated 14  
GVHD prophylaxis  
 Tacrolimus-based 18 
 Cyclosporine-based 13  
 Cyclosporine + T-cell depletion 7  
 T-cell depletion + other 5  
Daclizumab regimen  
 1 (days 1, 8, 15, 22, 29) 24  
 2 (days 1, 4, 8, 15, 22) 19 
Table 2.

Distribution of graft-versus-host disease by organ stage or overall grade at the start of treatment with daclizumab

Site Stage or Grade
0 12 3 4
Skin  8  2  7  22  4  
Liver 36  1  3  2  1  
Gut  19  2  8  
Overall   1  22  12  
Site Stage or Grade
0 12 3 4
Skin  8  2  7  22  4  
Liver 36  1  3  2  1  
Gut  19  2  8  
Overall   1  22  12  

Study compliance

Ten patients received fewer than five doses of daclizumab. Five patients on regimen 1 failed to complete the course because of early death. On regimen 2, five patients did not get all doses. Three patients did not receive the fifth dose at the discretion of the attending physician; two of the three had achieved a complete response with the first four doses alone. The fourth patient developed Epstein-Barr virus lymphoproliferative disease (LPD) before completion of therapy. The fifth patient stopped receiving the drug after the fourth dose because of rising liver enzymes; this condition was shown by liver biopsy to be viral in etiology.

Response to therapy

Responses were seen as early as study day 8 (Figure1), but overall response was scored on study day 43. Sixteen (37%; 95% CI, 23%-53%) patients achieved a complete response, and six (14%; 95% CI, 5%-30%) achieved a partial response for a total response rate of 51% (95% CI, 35%-67%) (Table3). Complete responses varied with the organ involved (P = .014) (Table 3) and with multiorgan involvement (P = .014), but there was no significant difference in the complete response rates when compared by initial grade of GVHD, age, or use of T-cell depletion. The four patients with untreated visceral GVHD failed to respond to daclizumab. Seven (29%, 95% CI, 13-51%) patients on regimen 1 and 9 (47%, 95% CI, 24-71%) patients on regimen 2 achieved a complete response. Six patients survived to the end of follow-up (study day 120) free of recurrent acute GVHD or chronic GVHD.

Fig. 1.

Percentage of evaluable patients at each study time point with a complete (solid bars) or partial (hatched bars) response overall (A) or in skin (B), liver (C), or gut (D).

Fig. 1.

Percentage of evaluable patients at each study time point with a complete (solid bars) or partial (hatched bars) response overall (A) or in skin (B), liver (C), or gut (D).

Close modal
Table 3.

Response to treatment with daclizumab

Response on day 43 
 Complete response  16 of 43 (37%) 
 Partial response  6 of 43 (14%)  
 Failed but alive 13 of 43 (30%)  
 Death before day 43  8 of 43 (19%) 
Complete response by organ involvement 
 Skin 20 of 37 (54%)  
 Liver  2 of 12 (17%)  
 Gut 10 of 27 (37%)  
Complete response by extent 
 Skin alone 10 of 16 (63%)  
 Gut alone  0 of 3 (0%)   
 Multiorgan  6 of 24 (25%)  
Complete response by baseline grade 
 Grade 1-2  10 of 23 (43%)  
 Grade 3-4 6 of 20 (30%)  
Complete response by age group 
 < 18 y 5 of 12 (42%)  
 ≥ 18 y  11 of 31 (35%) 
Complete response by regimen 
 Regimen 1  7 of 24 (29%) 
 Regimen 2  9 of 19 (47%) 
Response on day 43 
 Complete response  16 of 43 (37%) 
 Partial response  6 of 43 (14%)  
 Failed but alive 13 of 43 (30%)  
 Death before day 43  8 of 43 (19%) 
Complete response by organ involvement 
 Skin 20 of 37 (54%)  
 Liver  2 of 12 (17%)  
 Gut 10 of 27 (37%)  
Complete response by extent 
 Skin alone 10 of 16 (63%)  
 Gut alone  0 of 3 (0%)   
 Multiorgan  6 of 24 (25%)  
Complete response by baseline grade 
 Grade 1-2  10 of 23 (43%)  
 Grade 3-4 6 of 20 (30%)  
Complete response by age group 
 < 18 y 5 of 12 (42%)  
 ≥ 18 y  11 of 31 (35%) 
Complete response by regimen 
 Regimen 1  7 of 24 (29%) 
 Regimen 2  9 of 19 (47%) 

Seventeen patients (40%) were treated with ATG; this included 13 (54%) patients on regimen 1 and four (21%) patients on regimen 2. Median time to start of ATG after daclizumab was 8 days (range, 2-19 days). Seven patients (41%) achieved a complete response to salvage therapy with ATG, two of two with skin GVHD alone and five of 15 with visceral involvement. All responders had been treated initially on daclizumab regimen 1.

Drug-related toxicities

There were no infusion-related side effects, and no serious clinical adverse events related to daclizumab were reported.

Laboratory correlates

For 36 patients who completed follow-up through the end of therapy, there was no significant difference between the absolute lymphocyte count or absolute CD3+ count at baseline and at 2 weeks after the end of treatment, but the number of CD3 + 25+ lymphocytes detected was significantly lower after treatment with daclizumab (20 vs 0 CD3 + 25+ lymphocytes/μL;P < .0001). Response did not correlate with the elimination of detectable CD3 + 25+ lymphocytes as almost all patients had no detectable CD3 + 25+lymphocytes by study day 8. It was noted, however, that, although reactivity of peripheral blood lymphocytes with anti-CD25 or daclizumab was lost during the treatment period, CD3+ cells continued to display HLA-DR, an activation marker, and had a low level of positivity for 7G7, the antibody that binds p55 but does not crossreact with daclizumab (Figure 2).

Fig. 2.

Flow cytometric analysis of peripheral blood lymphocytes of a patient treated with daclizumab.

The dot plots in the first two columns are gated on lymphocytes, and those in the third and fourth columns are gated on CD3+cells. Following treatment, p55 is not detected by anti-CD25 nor by anti-humanized Tac (daclizumab) on CD3+ cells (first and second columns), but the CD3+ cells remain positive for HLA-DR (third column) and faintly positive for p55 using 7G7 (fourth column).

Fig. 2.

Flow cytometric analysis of peripheral blood lymphocytes of a patient treated with daclizumab.

The dot plots in the first two columns are gated on lymphocytes, and those in the third and fourth columns are gated on CD3+cells. Following treatment, p55 is not detected by anti-CD25 nor by anti-humanized Tac (daclizumab) on CD3+ cells (first and second columns), but the CD3+ cells remain positive for HLA-DR (third column) and faintly positive for p55 using 7G7 (fourth column).

Close modal

Over the course of the treatment period, a significant change was seen in the absolute lymphocyte count (P = .002) and the absolute CD3 + 56 cell count (P = .005) but no significant change in the absolute CD356+ cell count (Figure3A). The changes in the number of CD3+ cells affected both the CD4+ and CD8+ subsets (data not shown). When only patients who did not receive ATG within the first 15 days were assessed, no significant difference was seen in the absolute lymphocyte counts or absolute numbers of CD3+ cells from baseline to day 15, suggesting that the previous observation was because of ATG. CD3 + 25+ cells were essentially undetectable until study day 60, whereas 48% to 75% of patients had 7G7+ cells at various time points through the treatment period (Figure 3B).

Fig. 3.

Absolute numbers of cells after treatment with daclizumab.

Note the difference in scale of the y-axis between graphs. (A) Absolute number of lymphocytes (ALC) (solid line), CD3 + 56 (dashed line) and CD3  56+(dotted line) cells after treatment with daclizumab. (B) Absolute number of CD3 + 56 cells (solid line), CD3+DR+ cells (dashed line), CD3 + 7G7+ cells (dotted line), and CD3 + 25+ cells (thin line) after treatment with daclizumab.

Fig. 3.

Absolute numbers of cells after treatment with daclizumab.

Note the difference in scale of the y-axis between graphs. (A) Absolute number of lymphocytes (ALC) (solid line), CD3 + 56 (dashed line) and CD3  56+(dotted line) cells after treatment with daclizumab. (B) Absolute number of CD3 + 56 cells (solid line), CD3+DR+ cells (dashed line), CD3 + 7G7+ cells (dotted line), and CD3 + 25+ cells (thin line) after treatment with daclizumab.

Close modal

Serum sIL-2R concentrations decreased following treatment with daclizumab (Table 4) and returned to near baseline by study day 90. No significant difference was seen between responders and nonresponders in the serum sIL-2R levels on study day 8 or on study day 15. Serum IL-2 concentrations did not vary significantly over the time period tested (Table 4).

Table 4.

Serum IL-2 and soluble IL-2 receptor concentrations after treatment with daclizumab

Study Day IL-2sIL-2R
n pg/mL (range) n pg/mL (range)
1  25  189 (21-1478)  25  3095 (106-10 330) 
8  26  109 (11-1336)  26  188 (37-2452)  
15  25 119 (14-1229)  25  243 (51-1635)  
22  —  — 21  172 (42-1200)  
29  —  —  20  171 (53-738) 
36  —  —  20  185 (50-1920)  
43  —  — 12  307 (86-875)  
60  —  —  17 1432 (124-17 177)  
90  —  —  12 4668 (243-10 312) 
Study Day IL-2sIL-2R
n pg/mL (range) n pg/mL (range)
1  25  189 (21-1478)  25  3095 (106-10 330) 
8  26  109 (11-1336)  26  188 (37-2452)  
15  25 119 (14-1229)  25  243 (51-1635)  
22  —  — 21  172 (42-1200)  
29  —  —  20  171 (53-738) 
36  —  —  20  185 (50-1920)  
43  —  — 12  307 (86-875)  
60  —  —  17 1432 (124-17 177)  
90  —  —  12 4668 (243-10 312) 

—, not done.

Survival

Twenty-six patients died by study day 120; the causes of death included active GVHD and infection (10), infection (7), active GVHD (3), EBV LPD (3), thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (1), relapse (1), and sudden death of unknown etiology (1). The median survival on study was 77 days, 70 days for patients on regimen 1 and more than 120 days for patients on regimen 2. Study day 120 survival was 40% (95% CI, 25%-56%), 29% (95% CI, 13%-51%) for patients on regimen 1, and 53% (95% CI, 29%-76%) for patients on regimen 2. There was no significant difference in study day 120 survival when compared by age (6/12 < 18 years vs 11/31 > 18 years, P = .49) or GVHD grade at baseline (12/23 grades 1-2 vs 5/20 grades 3-4, P = .12).

Abrogation of steroid-refractory acute GVHD by blockade of the IL-2 binding site with the use of murine monoclonal antibodies directed against the IL-2R α chain has been reported by several groups.26-31 Complete response rates with the use of the murine antibodies varied from 10% to 88%, and high response rates were seen with high blood levels of antibody26 or prolonged administration of antibody.30,31 Maintaining therapeutic serum concentrations of bioavailable antibody has been difficult with murine antibodies, which have a relatively short half-life and substantial immunogenicity. By contrast, daclizumab, a humanized anti-IL-2Rα antibody, has a terminal half-life of 3.5 days and is much less immunogenic than its murine counterpart.19,32 In the initial studies of daclizumab for treatment of refractory acute GVHD, 7 of 25 patients achieved a complete response with one or two doses of the drug.19 20 With the use of multidose schedules in our study, we found that 29% of patients achieved a complete response with 5 weekly doses of daclizumab and 47% when doses were given on days 1, 4, 8, 15, and 22.

The optimal duration of therapy with daclizumab is unclear. The role of laboratory testing to guide treatment with anti–T-cell antibodies has been an area of controversy, although in the field of solid organ transplantation there is some evidence that after treatment with ATG or OKT3, it may be useful to monitor CD3+ cells, the target of therapy.33,34 In our study, we monitored CD3 + 25+ cells, the target of daclizumab, and found that elimination of detectable CD3 + 25+ was nearly universal and independent of response to therapy. Serum sIL-2R has been cited as a potential measure of GVHD activity,35-38 but neither we nor Tiberghien et al39 found a correlation between serum sIL-2R levels and response to treatment of GVHD with an anti-IL-2R antibody. Serum soluble CD8 and tumor necrosis factor levels may correlate with response,39 but prospective studies will be required to determine if these assays can identify patients in whom the subclinical graft-versus-host reaction has abated and antibody therapy can be discontinued.

We found no significant clinical adverse events attributable to daclizumab, a striking distinction from the side-effect profiles of ATG and OKT3. Others have also reported that daclizumab, as well as anti-IL-2R antibodies in general, has little or no clinical toxicity.18-20,26-31 Of concern, however, are the three patients who developed EBV LPD during or after treatment with daclizumab. All three patients had received T-cell–depleted transplants from alternative donors, which is associated with a high risk for developing EBV LPD.40 Although no increased risk of EBV LPD was reported in previous controlled trials of daclizumab for prevention of organ allograft rejection, we cannot exclude daclizumab as a contributing factor, and the potential for development of EBV LPD must be considered when use of daclizumab is contemplated in the high-risk marrow transplant population.40 

Because the activity of daclizumab for treatment of GVHD was unknown at the start of this study, early salvage with ATG was allowed by design. The intention was not to test a sequential daclizumab-ATG regimen but rather to intervene as early as possible for treatment failures. The response rate to secondary salvage to ATG was 41%, including both patients with skin involvement only and 33% with visceral GVHD. These response rates are similar to those reported for primary salvage with ATG,41 suggesting that prior treatment with daclizumab does not eliminate subsequent responsiveness to ATG.

Whether the activity of daclizumab might impair the graft-versus-leukemia (GVL) effect of the allogeneic transplant is also of interest. With the use of an animal model, Weiss et al42found that pretreatment of allografts with anti-IL-2R antibody reduced the GVL effect after transplantation in comparison to untreated allografts. Further, Blaise et al43 reported a higher relapse rate in allogeneic marrow transplant patients given 33B3.1, a murine monoclonal anti-IL-2R antibody, for prevention of GVHD in comparison to control patients. Although only one of our patients relapsed within the study period, the heterogeneity of the patients and the short follow-up in our study preclude meaningful conclusions about the effect of daclizumab on GVL after treatment of GVHD.

We were disappointed to find that some patients with single-organ involvement failed to respond to treatment with daclizumab. Possible reasons for treatment failure include (1) functionally redundant cytokines, such as IL-4 and IL-15, that bypass IL-2Rα blockade16,44; (2) “cold target inhibition” by high levels of sIL2R 45; and (3) loss of activation-induced cell death (AICD).46 The potential lack of AICD has important implications for induction of tolerance. IL-2Rα knockout mice display an autoimmune disorder47,48 similar to that of humans with a truncated IL-2Rα chain.49 Activated T cells devoid of the IL-2Rα chain fail to trigger the pro-apoptotic pathway and are resistant to Fas-mediated lysis.46-48 Functionally redundant cytokines can reinduce AICD but only at supraphysiologic concentrations.46,47 Thus, excessive IL-2Rα blockade may predispose patients to recurrence of GVHD because of a lack of clonal deletion. This phenomenon may also explain why anti-IL-2Rα antibodies used for GVHD prophylaxis delayed but did not decrease the incidence of acute GVHD.43 49-52 

In design of regimen 2, an additional dose of daclizumab was given early in the treatment period to saturate free sIL-2R and to maximize binding to cellular IL-2R, and immunosuppression was reduced earlier than in regimen 1 to avoid infectious complications. The dose-schedule of daclizumab 1 mg/kg iv days 1, 4, 8, 15, and 22 had a response rate of 47%, and a day 120 survival of 53% that compares favorably with ATG but without the toxicities of ATG.53 This regimen would be appropriate for a controlled trial.

We are grateful to Dr John Hakimi, who supplied the fluorochrome-conjugated daclizumab and 7G7 for the flow cytometry studies, and to Dr Claudio Anasetti for helpful advice throughout the project.

Supported in part by grants from Hoffmann-La Roche, Inc., and from the National Institutes of Health (CA16672).

Reprints:Donna Przepiorka, Baylor College of Medicine, Center for Cell and Gene Therapy, 6565 Fannin St., M964, Houston, TX 77030; e-mail: donnap@bcm.tmc.edu.

The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked “advertisement” in accordance with 18 U.S.C. section 1734.

1
Waldmann
TA
The structure, function, and expression of interleukin-2 receptors on normal and malignant lymphocytes.
Science.
232
1986
727
732
2
Takeshita
T
Asao
H
Ohtani
K
et al
Cloning of the gamma chain of the human IL-2 receptor.
Science.
257
1992
379
382
3
Uchiyama
T
Broder
S
Waldmann
TA
A monoclonal antibody (anti-Tac) reactive with activated and functionally mature human T cells. I. Production of anti-Tac monoclonal antibody and distribution of Tac (+) cells.
J Immunol.
126
1981
1393
1397
4
Uchiyama
T
Nelson
DL
Fleisher
TA
Waldmann
TA
A monoclonal antibody (anti-Tac) reactive with activated and functionally mature human T cells. II. Expression of Tac antigen on activated cytotoxic killer T cells, suppressor cells, and on one of two types of helper T cells.
J Immunol.
126
1981
1398
1403
5
Nelson
BH
Willerford
DM
Biology of the interleukin-2 receptor.
Adv Immunol.
70
1998
1
81
6
Cavazzana-Calvo
M
Fromont
C
Le Deist
F
et al
Specific elimination of alloreactive T cells by an anti-interleukin-2 receptor α-chain-specific immunotoxin.
Transplantation.
50
1990
1
7
7
Mavroudis
DA
Jiang
YZ
Hensel
N
et al
Specific depletion of alloreactivity against haplotype mismatched related individuals by a recombinant immunotoxin: a new approach to graft-versus-host disease prophylaxis in haploidentical bone marrow transplantation.
Bone Marrow Transplant.
17
1996
793
799
8
Garderet
L
Snell
V
Przepiorka
D
et al
Effective depletion of alloreactive lymphocytes from peripheral blood mononuclear cell preparations.
Transplantation.
67
1999
124
130
9
Cavazzana-Calvo
M
Stephan
JL
Sarnacki
S
et al
Attenuation of graft-versus-host disease and graft rejection by ex vivo immunotoxin elimination of alloreactive T cells in an H-2 haplotype disparate mouse combination.
Blood.
83
1994
288
298
10
Ferrara
JLM
Marion
A
McIntyre
JF
Murphy
GF
Burakoff
SJ
Amelioration of acute graft vs host disease due to minor histocompatibility antigens by in vivo administration of anti-interleukin 2 receptor antibody.
J Immunol.
137
1986
1874
1877
11
Volk
HD
Brocke
S
Osawa
H
Diamantstein
T
Effects of in-vivo administration of a monoclonal antibody specific for the interleukin-2 receptor on the acute graft-versus-host reaction in mice.
Clin Exp Immunol.
66
1986
126
131
12
Queen
C
Schneider
WP
Selick
HE
et al
A humanized antibody that binds to the interleukin 2 receptor.
Proc Natl Acad Sci U S A.
86
1989
10,029
10,033
13
Junghans
RP
Waldmann
TA
Landolfi
NF
Avdalovic
NM
Schneider
WP
Queen
C
Anti-Tac-H, a humanized antibody to the interleukin 2 receptor with new features for immunotherapy in malignant and immune disorders.
Cancer Res.
50
1990
1495
1502
14
Depper
JM
Leonard
WJ
Robb
RJ
Waldmann
TA
Greene
WC
Blockade of the interleukin-2 receptor by anti-Tac antibody: Inhibition of human lymphocyte activation.
J Immunol.
131
1983
690
696
15
Brown
PS
Parenteau
GL
Dirbas
FM
et al
Anti-Tac-H, a humanized antibody to the interleukin 2 receptor, prolongs primate cardiac allograft survival.
Proc Natl Acad Sci U S A.
88
1991
2663
2667
16
Guex-Crosier
Y
Raber
J
Chan
CC
et al
Humanized antibodies against the α-chain of the IL-2 receptor and against the β-chain shared by the IL-2 and IL-15 receptors in a monkey uveitis model of autoimmune disease.
J Immunol.
158
1997
452
458
17
Vincenti
F
Lantz
M
Birnbaum
J
et al
A phase I trial of humanized anti-interleukin 2 receptor antibody in renal transplantation.
Transplantation.
63
1997
33
38
18
Vincenti
F
Kirkman
R
Light
S
et al
for the Daclizumab Triple Therapy Study Group. Interleukin-2-receptor blockade with daclizumab to prevent acute rejection in renal transplantation.
N Engl J Med.
338
1998
161
165
19
Anasetti
C
Hansen
JA
Waldmann
TA
et al
Treatment of acute graft-versus-host disease with humanized anti-Tac: an antibody that binds to the interleukin-2 receptor.
Blood.
84
1994
1320
1327
20
Pinto
RM
Arcese
W
Fattore
P
et al
A phase I study of humanized anti-TAC (HAT) in patients with acute GVHD refractory to cyclosporine and corticosteroid [abstract].
Bone Marrow Transplant.
15
1998
S142
21
Przepiorka
D
Weisdorf
D
Martin
P
et al
Report of the 1994 consensus conference on acute GVHD grading.
Bone Marrow Transplant.
15
1995
825
828
22
Körbling
M
Huh
YO
Durett
A
et al
Allogeneic blood stem cell transplantation: peripheralization and yield of donor-derived primitive hematopoietic progenitor cells (CD34+ Thy-1dim) and lymphoid subsets, and possible predictors of engraftment.
Blood.
86
1995
2842
2848
23
Small
TN
Keever
CA
Weiner-Fedus
S
Heller
G
O'Reilly
RJ
Flomenberg
N
B-Cell differentiation following autologous, conventional, or T-cell depleted bone marrow transplantation: a recapitulation of normal B-cell ontogeny.
Blood.
76
1990
1647
1656
24
Urdal
DC
March
CJ
Gillis
S
Larsen
A
Dower
SK
Purification and chemical characterization of the receptor for the interleukin-2 from activated human T lymphocytes and from a human T cell lymphoma cell line.
Proc Natl Acad Sci U S A.
81
1984
6481
6485
25
Rubin
LA
Kurman
CC
Biddison
WE
Goldman
ND
Nelson
DL
A monoclonal antibody 7G7/B6 binds to an epitope on the human interleukin-2 (IL-2) receptor that is distinct from that recognized by IL-2 or anti-Tac.
Hybridoma.
4
1985
91
102
26
Hervè
P
Wijdenes
J
Bergerat
JP
et al
Treatment of corticosteroid resistant acute graft-versus-host disease by in vivo administration of anti-interleukin-2 receptor monoclonal antibody (B-B10).
Blood.
75
1990
1017
1023
27
Anasetti
C
Martin
PJ
Hansen
JA
et al
A phase I-II study evaluating the murine anti-IL-2 receptor antibody 2A3 for treatment of acute graft-versus-host disease.
Transplantation.
50
1990
49
54
28
Tiley
C
Powles
R
Teo
CP
Treleaven
J
Findlay
M
Hewetson
M
Treatment of acute graft-versus-host disease with a murine monoclonal antibody to the IL-2 receptor.
Bone Marrow Transplant.
7
1991
151
29
Cuthbert
RJG
Phillips
GL
Barnett
MJ
et al
Anti-interleukin-2 receptor monoclonal antibody (BT563) in the treatment of severe acute GVHD refractory to systemic corticosteroid therapy.
Bone Marrow Transplant.
10
1991
451
455
30
Herbelin
C
Stephan
J-L
Donadieu
J
et al
Treatment of steroid resistant acute graft-versus-host disease with an anti-IL-2-receptor monoclonal antibody (BT563) in children who received T cell-depleted, partially matched, related bone marrow transplants.
Bone Marrow Transplant.
13
1994
563
569
31
Hertenstein
B
Stefanic
M
Sandherr
M
Bunjes
D
Mertens
T
Arnold
R
Treatment of steroid-resistant acute graft-vs-host disease after allogeneic marrow transplantation with anti-interleukin-2 receptor antibody (BT563).
Transplant Proc.
26
1994
3114
3116
32
Hakimi
J
Chizzonite
R
Luke
DR
et al
Reduced immunogenicity and improved pharmacokinetics of humanized anti-Tac in cynomolgus monkeys.
J Immunol.
47
1991
1352
1359
33
Abouna
GM
Al-Abdullah
IH
Kelly-Sullivan
D
et al
Randomized clinical trial of antithymocyte globulin induction in renal transplantation comparing a fixed daily dose with dose adjustment according to T cell monitoring.
Transplantation.
15
1995
1564
1568
34
Bhat
G
Schroeder
TJ
Clinical role of immunologic monitoring during OKT3 treatment.
Transplant Proc.
29
1997
21S
26S
35
Siegert
W
Josimovic-Alasevic
O
Schwerdtfeger
R
et al
Soluble interleukin 2 receptors in patients after bone marrow transplantation.
Bone Marrow Transplant.
6
1990
97
101
36
Miyamoto
T
Akashi
K
Hayashi
S
et al
Serum concentration of the soluble interleukin-2 receptor for monitoring acute graft-versus-host disease.
Bone Marrow Transplant.
17
1996
185
190
37
Grimm
J
Zeller
W
Zander
AR
Soluble interleukin-2 receptor serum levels after allogeneic bone marrow transplantation as a marker for GVHD.
Bone Marrow Transplant.
21
1998
29
32
38
Foley
R
Couban
S
Walker
I
et al
Monitoring soluble interleukin-2 receptor levels in related and unrelated donor allogeneic bone marrow transplantation.
Bone Marrow Transplant.
21
1998
769
773
39
Tiberghien
P
Racadot
E
Lioure
B
et al
Soluble CD8, IL-2 receptor, and tumor necrosis factor-alpha levels in steroid-resistant acute graft-versus-host disease.
Transplantation.
52
1991
475
480
40
Zutter
MM
Martin
PJ
Sale
GE
et al
Epstein-Barr virus lymphoproliferation after bone marrow transplantation.
Blood.
72
1988
520
529
41
Martin
PJ
Schoch
G
Fisher
L
Byers
V
Appelbaum
FR
McDonald
GB
et al
A retrospective analysis of therapy for acute graft-versus-host disease: secondary treatment.
Blood.
77
1991
1821
1828
42
Weiss
L
Reich
S
Slavin
S
The role of antibodies to IL-2 receptor and Asialo GM1 on graft-versus-leukemia effects induced by bone marrow allografts in murine B cell leukemia.
Bone Marrow Transplant.
16
1995
457
461
43
Blaise
D
Olive
D
Michallet
M
Marit
G
Leblond
V
Maraninchi
D
Impairment of leukemia-free survival by addition of interleukin-2-receptor antibody to standard graft-versus-host prophylaxis.
Lancet.
345
1995
1144
1146
44
Steinmann
X
Herwartz
C
Muller-Ruchholtz
W
Interleukin-4 bypass of the immunosuppressive effect mediated by interleukin-2 receptor antibodies.
Scand J Immunol.
37
1993
217
225
45
Junghans
RP
Carrasquillo
JA
Waldmann
TA
Impact of antigenemia on the bioactivity of infused anti-Tac antibody: implications for dose selection in antibody immunotherapies.
Proc Natl Acad Sci U S A.
95
1998
1752
1757
46
Zheng
L
Trageser
CL
Willerford
DM
Lenardo
MJ
T cell growth cytokines cause the superinduction of molecules mediating antigen-induced T lymphocyte death.
J Immunol.
160
1998
763
769
47
Van Parijs
L
Biuckians
A
Ibragimov
A
Alt
FW
Willerford
DM
Abbas
AK
Functional responses and apoptosis of CD25 (IL-2R alpha)-deficient T cells expressing a transgenic receptor.
J Immunol.
158
1997
3738
3745
48
Sharfe
N
Dadi
HK
Shahar
M
Roifman
CM
Human immune disorder arising from mutation of the alpha chain of the interleukin-2 receptor.
Proc Natl Acad Sci U S A.
94
1997
3168
3171
49
Anasetti
C
Martin
PJ
Storb
R
et al
Prophylaxis of graft-versus-host disease by administration of the murine anti-IL-2 receptor antibody 2A3.
Bone Marrow Transplant.
7
1991
375
381
50
Belanger
C
Esperou-Bourdeau
H
Bordigoni
P
et al
Use of an anti-interleukin-2 receptor monoclonal antibody for GVHD prophylaxis in unrelated donor BMT.
Bone Marrow Transplant.
11
1993
293
297
51
Ferrant
A
Latinne
D
Bazin
H
et al
Prophylaxis of graft-versus-host disease in identical sibling donor bone marrow transplant by anti-IL-2 receptor monoclonal antibody LO-Tact-1.
Bone Marrow Transplant.
16
1995
577
581
52
Anasetti
C
Lin
A
Nademanee
A
et al
for the HAT Study Group. A phase II/III randomized, double-blind, placebo-controlled multicenter trial of humanized anti-Tac for prevention of acute graft-versus-host disease (GVHD) in recipients of marrow transplants from unrelated donors.
Blood
86(Suppl 1)
1995
621a
53
Martin
PJ
Schoch
G
Fisher
L
et al
A retrospective analysis of therapy for acute graft-versus-host disease: Initial treatment.
Blood.
76
1990
1464
1472
Sign in via your Institution