Outcome of patients with acute myeloid leukemia (AML) who are older than 60 years of age remains unsatisfactory, with low remission rates and poor overall survival. We have previously established the activity of clofarabine plus cytarabine in AML relapse. We have now conducted a phase 2 study of clofarabine plus cytarabine in patients aged 50 years or older with previously untreated AML. Clofarabine was given at 40 mg/m2 as a 1-hour intravenous infusion for 5 days (days 2 to 6) followed 4 hours later by cytarabine at 1 g/m2/d as a 2-hour intravenous infusion for 5 days (days 1 to 5). Of 60 patients, 29 (48%) had secondary AML, 30 (50%) had abnormal karyotypes (monosomy 5 and/or 7 in 15 [25%]), and 11 (21%) showed FLT3 abnormalities. The overall response (OR) rate was 60% (52% CR, 8% CRp). Four patients (7%) died during induction. Adverse events were mainly grade 2 or lower and included diarrhea, nausea, vomiting, mucositis, skin reactions, liver test abnormalities, and infusion-related facial flushing and headaches. Myelosuppression was common. Clofarabine plus cytarabine has activity in adult AML, achieving a good CR rate. However, survival does not appear to be improved compared with other regimens. Modifications of this combination in AML therapy of older patients warrant further evaluation.

The Intergroupe Francophone du Myélome (IFM) initiated 2 trials in 1999 to study patients with high-risk (beta2-microglobulin level greater than 3 mg/L and chromosome 13 deletion at diagnosis) de novo multiple myeloma. In both protocols, the induction regimen consisted of vincristine, doxorubicin, and dexamethasone (VAD) followed by first autologous stem cell transplantation (ASCT) prepared by melphalan 200 mg/m(2). Patients with an HLA-identical sibling donor were subsequently treated with dose-reduced allogeneic stem cell transplantation (IFM99-03 trial), and patients without an HLA-identical sibling donor were randomly assigned to undergo second ASCT prepared by melphalan 220 mg/m(2) and 160 mg dexamethasone with or without anti-IL-6 monoclonal antibody (IFM99-04 protocol). Two hundred eighty-four patients-65 in the IFM99-03 trial and 219 in the IFM99-04 trial-were prospectively treated and received at least one course of VAD. On an intent-to-treat basis, overall survival (OS) and event-free survival (EFS) did not differ significantly in the studies (medians 35 and 25 months in the IFM99-03 trial vs 41 and 30 months in the IFM99-04 trial, respectively). With a median follow-up time of 24 months, the EFS of the 166 patients randomly assigned in the tandem ASCT protocol was similar to the EFS of the 46 patients who underwent the entire IFM99-03 program (median, 35 vs 31.7 months), with a trend for a better OS in patients treated with tandem ASCT (median, 47.2 vs 35 months; P = .07). In patients with high-risk de novo MM, the combination of ASCT followed by dose-reduced allogeneic transplantation was not superior to tandem dose-intensified, melphalan-based ASCT.

Feasibility, safety, and efficacy of a 4-course high-dose chemotherapy (HDT) protocol including autologous stem cell transplantation (SCT) after courses 2, 3, and 4 was investigated in 110 patients, aged 18 to 60 years, with primary diagnosis of aggressive NHL (aNHL), and lactic dehydrogenase (LDH) levels above normal. At dose level 1 (DL1), course 1 consisted of cyclophosphamide 1500 mg/m2, doxorubicin (Adriamycin) 70 mg/m2, vincristine 2 mg, etoposide 450 mg/m2, and prednisone 500 mg. With courses 2 and 3 cyclophosphamide and etoposide were escalated to 4500 mg/m2 and 600 mg/m2, respectively. With course 4 cyclophosphamide and etoposide were given at 6000 mg/m2 and 1000 mg/m2, respectively. At DL2 etoposide was further increased to 600, 960, 960, and 1480 mg/m2 with courses 1 to 4, respectively. Therapy as per protocol was completed by 81.8% of patients. Overall survival at 5 years was 67.2%, freedom from treatment failure (FFTF) was 62.1%, and treatment-related mortality was 4.5%. There was a trend to better FFTF at DL2 compared to DL1 (66.9% versus 54.2%). Repetitive HDT with escalated CHOP plus etoposide is feasible and effective treatment of patients with aNHL. DL2 of this therapy is being used in an ongoing phase 3 study.

We examined whether combining all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) might be an alternative to ATRA plus chemotherapy in untreated acute promyelocytic leukemia (APL). Twenty-five low-risk patients (white blood cell [WBC] count less than 10 x 10(9)/L [10,000/microL]) received ATRA (45 mg/m(2) daily) and ATO (0.15 mg/kg daily, beginning day 10 of ATRA), and in complete remission (CR) received ATO plus ATRA, without chemotherapy, unless they were reverse transcriptase-polymerase chain reaction (RT-PCR)-positive 3 months from CR date or had molecular relapse. Nineteen high-risk patients were treated identically, but received chemotherapy, generally 9 mg/m(2) gemtuzumab ozogamycin (GO) on day 1 of induction. The CR rate was 39 of 44 (24 of 25 in low-risk, 15 of 19 in high-risk). Disease recurred at 9, 9, and 15 months, respectively, in 3 high-risk patients. The median follow-up time from CR date in the 36 patients alive in first CR is 16 months (15 months in low-risk, 20 months in high-risk), with 9 patients followed for at least 24 months. Each of the 36 patients was PCR-negative at last follow-up. Thus, none of the low-risk patients has received chemotherapy, and only 3 high-risk patients (the 3 with relapsed disease) have received chemotherapy past induction. ATRA plus ATO may serve as an alternative to chemotherapy in low-risk untreated APL (eg, in older patients) and, when combined with GO, may improve outcome in high-risk patients.

FLT3 internal tandem duplications (FLT3/ITDs) in the juxtamembrane domain are found in approximately 25% of acute myeloid leukemia (AML) patients, ranging in size from 3 to hundreds of nucleotides. We examined whether the sizes of FLT3/ITDs were associated with clinical outcomes in 151 AML patients enrolled in Southwest Oncology Group studies: S9333 and S9500. FLT3/ITDs were identified in 32% of patients (median ITD size = 39 nucleotides; range, 15-153 nucleotides). The CR rates were 35%, 67%, and 52% for patients with large (>or= 40), small (< 40), and no ITDs, respectively (P = .19). Increasing ITD size was associated with decreasing OS (estimated 5-year OS: large = 13%, small = 26%, and no ITD = 21%, P = .072) and RFS (estimated 5-year RFS: large = 13%, small = 27%, and no ITD = 34%, P = .017). These studies suggest that ITD size may have prognostic significance.

Innate CD1d-restricted natural killer T (NKT) cells are infected and lost in HIV-1-infected patients, and this could contribute to HIV-1 pathogenesis because NKT cells play an important role in directing both adaptive and innate immunity. Administration of interleukin-2 (IL-2) to HIV-1-infected patients leads to substantial and sustained CD4+ T-cell expansion, involving both naive and memory cells. We investigated whether IL-2 treatment could restore the NKT cell compartment in patients with primary HIV-1 infection. We show that IL-2 combined with effective antiretroviral therapy (ART) resulted in significant expansion of CD1d-restricted NKT cells. Expansion occurred in both the CD4- and CD4+ subsets of NKT cells, and expanded cells expressed the CD161 maturation marker while expression of the HIV coreceptor CCR5 was reduced. These data indicate that IL-2 treatment in combination with effective ART is beneficial for the restoration of innate NKT cell immunity in patients with primary HIV-1 infection.

Most deaths in beta-thalassemia major result from cardiac complications due to iron overload. Differential effects on myocardial siderosis may exist between different chelators. A randomized controlled trial was performed in 61 patients previously maintained on subcutaneous deferoxamine. The primary end point was the change in myocardial siderosis (myocardial T2(*)) over 1 year in patients maintained on subcutaneous deferoxamine or those switched to oral deferiprone monotherapy. The dose of deferiprone was 92 mg/kg/d and deferoxamine was 43 mg/kg for 5.7 d/wk. Compliance was 94% +/- 5.3% and 93% +/- 9.7% (P = .81), respectively. The improvement in myocardial T2(*) was significantly greater for deferiprone than deferoxamine (27% vs 13%; P = .023). Left ventricular ejection fraction increased significantly more in the deferiprone-treated group (3.1% vs 0.3% absolute units; P = .003). The changes in liver iron level (-0.93 mg/g dry weight vs -1.54 mg/g dry weight; P = .40) and serum ferritin level (-181 microg/L vs -466 microg/L; P = .16), respectively, were not significantly different between groups. The most frequent adverse events were transient gastrointestinal symptoms for deferiprone-treated patients and local reactions at the infusion site for deferoxamine. There were no episodes of agranulocytosis. Deferiprone monotherapy was significantly more effective than deferoxamine over 1 year in improving asymptomatic myocardial siderosis in beta-thalassemia major.

Deferasirox (ICL670) is a once-daily oral iron chelator developed for the treatment of chronic iron overload from blood transfusions. A comparative phase 3 trial was conducted to demonstrate the efficacy of deferasirox in regularly transfused patients with beta-thalassemia aged 2 years or older. Patients were randomized and received treatment with deferasirox (n = 296) or deferoxamine (n = 290), with dosing of each according to baseline liver iron concentration (LIC). The primary endpoint was maintenance or reduction of LIC; secondary endpoints included safety and tolerability, change in serum ferritin level, and net body iron balance. In both arms, patients with LIC values of 7 mg Fe/g dry weight (dw) or higher had significant and similar dose-dependent reductions in LIC and serum ferritin, and effects on net body iron balance. However, the primary endpoint was not met in the overall population, possibly due to the fact that proportionally lower doses of deferasirox relative to deferoxamine were administered to patients with LIC values less than 7 mg Fe/g dw. The most common adverse events included rash, gastrointestinal disturbances, and mild nonprogressive increases in serum creatinine. No agranulocytosis, arthropathy, or growth failure was associated with deferasirox administration. Deferasirox is a promising once-daily oral therapy for the treatment of transfusional iron overload.

We assessed safety and efficacy of rituximab in a prospective study of 36 patients, age 2.6 to 18.3 years, with severe chronic immune thrombocytopenic purpura (ITP). The primary outcome of sustained platelets above 50 x 10(9)/L (50,000/mm3) during 4 consecutive weeks, starting in weeks 9 to 12, was achieved by 11 of 36 patients (31%, confidence interval [CI], 16% to 48%). Median response time was 1 week (range, 1 to 7 weeks). Attainment of the primary outcome was not associated with age, prior pharmacologic responses, prior splenectomy, ITP duration, screening platelet count, refractoriness, or IgM reduction. First-dose, infusion-related toxicity was common (47%) despite premedication. Significant drug-related toxicities included third-dose hypotension (n = 1) and serum sickness (n = 2). Peripheral B cells were depleted in all subjects. IgM decreased 3.4% per week, but IgG did not significantly decrease. Rituximab was well tolerated, with manageable infusion-related side effects, but 6% of subjects developed serum sickness. Rituximab is beneficial for some pediatric patients with severe, chronic ITP.

Arsenic trioxide, as a single agent, has proven efficacy in inducing molecular remission in patients with acute promyelocytic leukemia (APL). There is limited long-term outcome data with single-agent As2O3 in the management of newly diagnosed cases of APL. Between January 1998 to December 2004, 72 newly diagnosed cases of APL were treated with a regimen of single-agent As2O3 at our center. Complete hematologic remission was achieved in 86.1%. At a median follow-up of 25 months (range: 8-92 months), the 3-year Kaplan-Meier estimate of EFS, DFS, and OS was 74.87% +/- 5.6%, 87.21% +/- 4.93%, and 86.11% +/- 4.08%, respectively. Patients presenting with a white blood cell (WBC) count lower than 5 x 10(9)/L and a platelet count higher than 20 x 10(9)/L at diagnosis (n = 22 [30.6%]) have an excellent prognosis with this regimen (EFS, OS, and DFS of 100%). The toxicity profile, in the majority, was mild and reversible. After remission induction, this regimen was administered on an outpatient basis. Single-agent As2O3, as used in this series, in the management of newly diagnosed cases of APL, is associated with responses comparable with conventional chemotherapy regimens. Additionally, this regimen has minimal toxicity and can be administered on an outpatient basis after remission induction.

Cytomegalovirus (CMV) infection is a major complication after allogeneic stem cell transplantation (SCT). Valganciclovir (V-GCV) is an oral prodrug hydrolyzed to the anti-CMV drug ganciclovir (GCV). A randomized, multicenter, crossover, open-label clinical trial compared exposure to GCV after V-GCV and intravenous GCV (IV-GCV) as preemptive therapy for CMV disease in SCT. The primary objective was to compare exposure to GCV in patients with CMV infection stratified for intestinal graft-versus-host disease (I-GVHD). Secondary objectives were the assessment of safety and efficacy. Patients without I-GVHD had a higher exposure to GCV after V-GCV when compared with IV-GCV (area under the concentration-time curve from drug administration to last observed concentration after 12 hours [AUC(0-12)] 53.8 +/- 17.97 microg/mL . h [mean +/- SD] vs 39.5 +/- 13.91; P < .001; ratio of V-GCV/IV-GCV was 1.4; 90% confidence interval [CI], 1.2-1.5). This was also true in patients with I-GVHD grades I-II (AUC(0-12) 52.9 +/- 21.75 vs 33.1 +/- 12.97 mug/mL . h; P = .018; ratio 1.6; 90% CI, 1.3-2.0). Absolute bioavailability of GCV after V-GCV was approximately 75% in individuals with or without I-GVHD grades I-II. No severe GCV-related toxicity was observed and efficacy and safety was comparable (84-day follow-up). This supports the use of V-GCV in SCT, even in patients with I-GVHD grades I-II. Due to higher exposure after V-GCV compared with IV-GCV, patients should be monitored carefully for safety reasons.

Patients with myeloma, treated on the thalidomide arm of total therapy 2 (TT2), had a higher complete response (CR) rate and improved event-free survival (EFS) but not overall survival (OS). To evaluate the benefit of TT2's posttandem autotransplant consolidation chemotherapy and dexamethasone maintenance, outcomes were compared on TT2 without thalidomide (n = 345; median follow-up, 3.5 years) and on predecessor trial TT1 (n = 231; median follow-up, 11.5 years). CR rates were similar (43% vs 41%); however, 5-year estimates of continuous CR (45% vs 32%, P < .001) and 5-year EFS (43% vs 28%, P < .001) were superior with TT2, with a trend for improved OS (62% vs 57%; P = .11). OS was also superior among patients achieving CR and receiving the second transplantation early after the first transplantation. Superior EFS and OS with TT2 versus TT1 was noted in the two thirds presenting without cytogenetic abnormalities (CAs); 4-year posttandem transplantation OS for patients with CAs was 47% with TT1 and 76% with TT2 when combination chemotherapy rather than DEX was applied for consolidation (P = .040). Thus, TT2 (without thalidomide) improved OS of patients without CAs; those with CAs benefited from posttransplantation consolidation chemotherapy. The favorable effects of CR and rapidly sequenced second transplantation attest to the validity of a melphalan dose-response effect in myeloma.

Innate immunity is involved in the biology of graft versus host disease and common airway diseases. We screened 15 genes in this pathway using a linkage disequilibrium-based approach to identify potential candidate genes that may be involved in the development of airflow obstruction after hematopoietic cell transplantation. Sixty-nine single-nucleotide polymorphisms were selected for assessment in a discovery cohort (n = 363). Significant associations were validated in a validation cohort (n = 209). Expression of the candidate gene was demonstrated by detecting gene transcript and protein in malignant and normal small airway epithelial cells. In the discovery cohort, 133 patients developed significant airflow decline. Four patient and donor bactericidal/permeability-increasing (BPI) haplotypes were associated with a 2-fold to 3-fold increased risk of developing significant airflow decline (P values, .004-.038). This association was confirmed in the validation cohort, which had 66 patients with significant airflow decline, with 9 significant haplotypes (P values, .013-.043). BPI gene transcript and protein were detected in airway epithelial cells. These results suggest mutations in the BPI gene significantly influence the risk of developing rapid airflow decline after hematopoietic cell transplantation and may represent a novel therapeutic target for this form of airway disease.

Interleukin-2 (IL-2) is historically known as a T-cell growth factor. Accumulating evidence from knockout mice suggests that IL-2 is crucial for the homeostasis and function of CD4+ CD25+ regulatory T cells in vivo. However, the impact of administered IL-2 in an immune intact host has not been studied in rodents or humans. Here, we studied the impact of IL-2 administration on the frequency and function of human CD4+ CD25(hi) T cells in immune intact patients with melanoma or renal cancer. We found that the frequency of CD4+ CD25(hi) T cells was significantly increased after IL-2 treatment, and these cells expressed phenotypic markers associated with regulatory T cells. In addition, both transcript and protein levels of Foxp3, a transcription factor exclusively expressed on regulatory T cells, were consistently increased in CD4 T cells following IL-2 treatment. Functional analysis of the increased number of CD4+ CD25(hi) T cells revealed that this population exhibited potent suppressive activity in vitro. Collectively, our results demonstrate that administration of high-dose IL-2 increased the frequency of circulating CD4+ CD25(hi) Foxp3+ regulatory T cells. Our findings suggest that selective inhibition of IL-2-mediated enhancement of regulatory T cells may improve the therapeutic effectiveness of IL-2 administration.

Chk1 and Akt signaling facilitate survival of cells treated with nucleoside analogues. Activation of Chk1 in response to cytarabine (ara-C) induced an S-phase checkpoint characterized by the inhibition of Cdk2, cell cycle arrest, no change in constitutively active Akt, or low-stress kinase signaling in ML-1 cells. However, inhibition of Chk1 by UCN-01 in S-phase-arrested cells resulted in an abrogation of the checkpoint, inhibition of Akt, activation of JNK, and a rapid induction of apoptosis. Similarly, primary acute myelogenous leukemia (AML) blasts exposed to ara-C and UCN-01 demonstrated a selective loss in cloning potential when compared with normal progenitors. Therefore, we evaluated a pilot clinical trial of ara-C in combination with UCN-01 in patients with relapsed AML. Blasts from some patients demonstrated a previously activated Chk1-Cdk2 DNA damage response pathway that decreased during therapy. Constitutively phosphorylated Akt kinase declined on addition of UCN-01 to the ara-C infusion, an action accompanied by an activation of JNK and reduction in absolute AML blast counts. Thus, use of UCN-01 in combination with ara-C decreases Chk1 phosphorylation, inhibits the Akt survival pathway, and activates JNK during the course of therapy, offering a rationale for the cytotoxic action of this combination during AML treatment.

This 2-part, double-blind, placebo-controlled study was conducted to determine the safety and efficacy of etoricoxib, a COX-2 selective inhibitor, for the treatment of hemophilic arthropathy. In part 1 (6 weeks), 102 patients (> or = 12 years old) with hemophilic arthropathy were randomized to receive 90 mg etoricoxib once daily or placebo (1:1 ratio). In part 2 (6 months), 51 patients taking placebo in part 1 were randomized to receive 90 mg etoricoxib or 25 mg rofecoxib once daily; patients taking etoricoxib in part 1 continued the same treatment. Efficacy end points included Patient Assessment of Arthropathy Pain, Patient Global Assessment of Arthropathy Disease Status, and Investigator Global Assessment of Arthropathy Disease Status. Safety was evaluated at each study visit. Etoricoxib provided significant improvement in all end points versus placebo (P < .001). Fewer patients taking etoricoxib discontinued due to a lack of efficacy versus placebo (P = .048). During part 2, efficacy was maintained; etoricoxib and rofecoxib demonstrated similar results. The most common adverse experiences were upper respiratory infection and headache. The incidence of joint bleeding during part 1 was similar between etoricoxib (66.7%) and placebo (72.6%) and during part 2 between etoricoxib (77.0%) and rofecoxib (78.9%). We conclude that etoricoxib provided superior efficacy versus placebo for the treatment of hemophilic arthropathy and was generally safe and well tolerated.

Varicella-zoster virus (VZV) disease occurs in 30% of allogeneic hematopoietic cell transplant recipients who had a history of VZV infection. A safe and effective prevention strategy has not been established. In a double-blind controlled trial, 77 hematopoietic cell transplant recipients at risk for VZV reactivation were randomized to acyclovir 800 mg twice daily or placebo given from 1 to 2 months until 1 year after transplantation. VZV disease at 1 year was the primary end point; VZV disease after discontinuation of prophylaxis, VZV-specific T-cell immunity, herpes simplex virus (HSV) infection, cytomegalovirus (CMV) disease, survival, and safety were secondary end points. Acyclovir significantly reduced VZV infections at 1 year after transplantation (HR, 0.16; 95% CI, 0.035-0.74; P = .006). In the post-intervention observation period, this difference was not statistically significant (2 years: HR, 0.52; 95% CI, 0.21-1.3; 5 years: HR, 0.76; 95% CI, 0.36-1.6). There was no statistically significant difference in reconstitution of VZV-specific T-helper cell responses, HSV infections, CMV disease, chronic graft-versus-host disease, and overall survival between the groups. Acyclovir was well tolerated. Post-study VZV disease predominantly occurred in patients with continued need for systemic immunosuppression. In conclusion, acyclovir effectively and safely prevents VZV disease during the first year after hematopoietic cell transplantation. Periods of prophylaxis longer than 12 months may be beneficial for those hematopoietic cell transplant recipients on continued immune suppression.

Donor lymphocyte infusions (DLIs) induce potent graft versus tumor (GVT) effects for relapsed chronic myelogenous leukemia (CML) after allogeneic stem cell transplantation (SCT) but are disappointing for other diseases. Disease resistance can occur if donor T cells are not appropriately activated in vivo. Ex vivo T-cell activation might overcome disease-induced anergy and augment GVT activity. We performed a phase 1 trial of ex vivo-activated DLI (aDLI) for 18 patients with relapse after SCT. Activated donor T cells are produced through costimulation with anti-CD3- and anti-CD28-coated beads. Patients with aggressive malignancies received induction chemotherapy, and all patients received conventional DLI (median, 1.5 x 10(8) mononuclear cells/kg) followed 12 days later by aDLI. Activated DLI was dose escalated from 1 x 10(6) to 1 x 10(8) CD3+ cells per kilogram in 5 levels. Seven patients developed acute graft versus host disease (GVHD) (5 grade I-II, 2 grade III), and 4 developed chronic GVHD. Eight patients achieved complete remission, including 4 of 7 with acute lymphocytic leukemia (ALL), 2 of 4 with acute myelogenous leukemia (AML), 1 with chronic lymphocytic leukemia (CLL), and 1 of 2 with non-Hodgkin lymphoma (NHL). Four complete responders relapsed while 4 remain alive in remission a median 23 months after aDLI. Overall, 10 of 18 remain alive 11 to 53 months after aDLI. Adoptive transfer of costimulated activated allogeneic T cells is feasible, does not result in excessive GVHD, and may contribute to durable remissions in diseases where conventional DLI has been disappointing.

Relapse is a major obstacle in the cure of acute myeloid leukemia (AML). The Pediatric Oncology Group AML Study 9421 tested 2 different strategies to improve event-free survival (EFS) and overall survival (OS). Patients were randomized to receive standard-dose DAT (daunorubicin, cytarabine, and thioguanine) or high-dose DAT during induction. To interfere with P-glycoprotein (P-gp)-dependent drug efflux, the second randomization tested the benefit of cyclosporine (CsA) added to consolidation chemotherapy. Of the 282 children randomly assigned to receive standard DAT induction, 248 (87.9%) achieved remission compared to 253 (91%) of the 278 receiving high-dose DAT (P = ns). Children with HLA-identical sibling donors who achieved a complete remission received an allogeneic bone marrow transplant as consolidation. For the 83 patients receiving a matched related donor bone marrow transplantation (BMT), the 3-year disease-free survival (DFS) is 67%. Of the 418 children who achieved remission and went on to consolidation with and without CsA, the DFS was 40.6% and 33.9%, respectively (P = .24). Overexpression of P-gp was infrequent (14%) in this pediatric population. In this study, intensifying induction with high-dose DAT and the addition of CsA to consolidation chemotherapy did not prolong the durations of remission or improve overall survival for children with AML.

B-cell posttransplantation lymphoproliferative disorder (B-PTLD) is a rare but severe complication of transplantation, with no consensus on best treatment practice. This prospective trial, the first to test a treatment for PTLD, was designed to evaluate the efficacy and safety of rituximab in patients with B-PTLD after solid organ transplantation (SOT). Forty-six patients were included and 43 patients were analyzed. Patients were eligible if they had untreated B-PTLD that was not responding to tapering of immunosuppression. Treatment consisted of 4 weekly injections of rituximab at 375 mg/m2. At day (d) 80, 37 (86%) patients were alive, and the response rate was 44.2%, including 12 complete response/unconfirmed complete response (CR/CRu). The only factor predictive of a response at d80 was a normal lactate dehydrogenase level (P = .007, odds ratio [OR] = 6.9). At d360, responses were maintained in 68% of patients, and 56% of patients were alive. The overall survival rate at 1 year was 67%. We conclude that rituximab is effective and safe in PTLD, with stable responses at 1 year. The response rate and overall survival might be improved by combining rituximab with other treatments.