Tacrolimus and minidose methotrexate for prevention of acute graft-versus-host disease after HLA-mismatched marrow or blood stem cell transplantation

Elevation of tacrolimus concentration after administration of methotrexate for treatment of graft-versus-host disease in pediatric patients received allogeneic hematopoietic stem cell transplantation

BACKGROUND

Methotrexate (MTX) is used to treat graft-versus-host disease (GVHD) following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Recently, a case was encountered in which the blood concentration of tacrolimus (TCR) at steady state increased after intravenous MTX administration for GVHD treatment (therapeutic IV-MTX administration). Therefore, this study aimed to investigate the effect of therapeutic IV-MTX administration on the pharmacokinetics of TCR.

METHODS

This single-center, retrospective, observational study included patients who underwent allo-HSCT and received therapeutic IV-MTX administration during immunosuppressive therapy with continuous intravenous infusion (CIV) of TCR from April 2004 to December 2021. Here, each therapeutic IV-MTX administration was defined as a case and independently subjected to subsequent analyses. The blood concentration of TCR at steady state (Css), ratio of Css to daily TCR dose (C/D), and clinical laboratory data were compared before and after therapeutic IV-MTX administration. In addition, dose changes in the TCR after therapeutic IV-MTX administration were evaluated.

RESULTS

Ten patients (23 cases) were included in this study. The C/D value significantly increased after therapeutic IV-MTX administration (median: 697 vs. 771 (ng/mL)/(mg/kg), 1.16-fold increase, P < 0.05), indicating a reduction in the apparent clearance of TCR. Along with the increase in C/D, significant increases were observed in aspartate transaminase level (median: 51.0 vs. 92.9 U/L, P < 0.01) and alanine aminotransferase level (median: 74.5 vs. 99.4 U/L, P < 0.01) indicating that liver injury after therapeutic IV-MTX administration contributes to the observed C/D increase. In addition, the daily dose of TCR was reduced in 11 cases (47.8%) after therapeutic IV-MTX administration, and the relative frequency of dose reduction tended to be higher than that of dose increase (median: 37.5% vs. 0.0%, P = 0.0519, permuted Brunner-Munzel test). The magnitude of dose reduction was 18.8% (7.4-50.0%) in the 11 cases with dose reduction.

CONCLUSIONS

Therapeutic IV-MTX administration cause a significant increase in C/D, which requires TCR dose reduction. Careful therapeutic drug monitoring of TCR is needed after therapeutic IV-MTX administration in patients receiving immunosuppressive therapy with TCR after allo-HSCT.

Tacrolimus/methotrexate vs tacrolimus/reduced-dose methotrexate/mycophenolate for graft-versus-host disease prevention

Tacrolimus (Tac)/methotrexate (MTX) is standard graft-versus-host disease (GVHD) prophylaxis; however, is associated with several toxicities. Tac, reduced-dose MTX (mini-MTX), and mycophenolate mofetil (MMF) have been used but never compared with standard MTX. We performed a randomized trial comparing Tac/MTX (full-MTX) with Tac/mini-MTX/MMF (mini-MTX/MMF) for GVHD prevention after allogeneic hematopoietic cell transplantation (HCT). Patients (pts) receiving first myeloablative HCT using an 8/8 HLA-matched donor were eligible. Primary end points were incidence of acute GVHD (aGVHD), mucositis, and engraftment. Secondary end points included chronic GVHD (cGVHD), organ toxicity, infection, relapse, nonrelapse mortality (NRM), and overall survival (OS). Ninety-six pts were randomly assigned to full-MTX (N = 49) or mini-MTX (N = 47). The majority (86%) used bone marrow grafts. There was no significant difference in grade 2-4 aGVHD (28% mini-MTX/MMF vs 27% full-MTX; P = .41); however higher incidence of grade 3-4 aGVHD (13% vs 4%; P = .07) with mini-MTX/MMF. Pts receiving mini-MTX/MMF had lower grade 3 or 4 mucositis and faster engraftment. There were no differences in moderate-to-severe cGVHD at 1 year or infections. Pts receiving mini-MTX/MMF experienced less nephrotoxicity and respiratory failure. There was no difference in the 1-year relapse (19% vs 21%; P = .89) and OS (72% vs 71%; P = .08), and mini-MTX/MMF was associated with lower but nonsignificant NRM (11% vs 22%; P = .06). Compared with full-MTX, mini-MTX/MMF was associated with no difference in grade 2-4 aGVHD and a more favorable toxicity profile. The higher severe aGVHD warrants further study to optimize this regimen. The trial was registered at www.clinicaltrials.gov as #NCT01951885.

Significance of Omitting Day 11 Mini-Dose Methotrexate for GVHD Prophylaxis After Unrelated Bone Marrow Transplantation

The combination of calcineurin inhibitors and short-term methotrexate has been used as a standard graft-versus-host-disease (GVHD) prophylaxis in allogeneic hematopoietic stem cell transplantation. Mini-dose methotrexate (mini-MTX), consisting of 5 mg/m²/d on days 1, 3, 6, and 11, is occasionally selected as an alternative considering toxicity. The significance of day 11 administration remains unclear. We performed a retrospective study of 135 cases of unrelated bone marrow transplantation at our institute between 2006 and 2019 and compared the outcomes between day 11 MTX dose omitted (n = 72) and full-doses of mini-MTX (n = 63). In total cohort, the 4-year overall survival (OS) was 58.7 %, and the omitted group showed poor GVHD/relapse-free-survival (P = .01) with comparable OS (P = .11) and relapse-free survival (P = .11). Human leukocyte antigen (HLA) mismatch is a major risk factor for severe GVHD. We analyzed the impact of omitting day 11 MTX in 2 cohorts from HLA matched or mismatched donors. In both cohorts, the omitted group had a higher risk of severe acute and chronic GVHD. In conclusion, the omission of day 11 MTX was associated with a higher risk of severe GVHD. Therefore the omission of the day 11 dose is not recommended.

Influence of Germline Genetics on Tacrolimus Pharmacokinetics and Pharmacodynamics in Allogeneic Hematopoietic Stem Cell Transplant Patients

Tacrolimus exhibits high inter-patient pharmacokinetics (PK) variability, as well as a narrow therapeutic index, and therefore requires therapeutic drug monitoring. Germline mutations in cytochrome P450 isoforms 4 and 5 genes (CYP3A4/5) and the ATP-binding cassette B1 gene (ABCB1) may contribute to interindividual tacrolimus PK variability, which may impact clinical outcomes among allogeneic hematopoietic stem cell transplantation (HSCT) patients. In this study, 252 adult patients who received tacrolimus for acute graft versus host disease (aGVHD) prophylaxis after allogeneic HSCT were genotyped to evaluate if germline genetic variants associated with tacrolimus PK and pharmacodynamic (PD) variability. Significant associations were detected between germline variants in CYP3A4/5 and ABCB1 and PK endpoints (e.g., median steady-state tacrolimus concentrations and time to goal tacrolimus concentration). However, significant associations were not observed between CYP3A4/5 or ABCB1 germline variants and PD endpoints (e.g., aGVHD and treatment-emergent nephrotoxicity). Decreased age and CYP3A5*1/*1 genotype were independently associated with subtherapeutic tacrolimus trough concentrations while CYP3A5*1*3 or CYP3A5*3/*3 genotypes, myeloablative allogeneic HSCT conditioning regimen (MAC) and increased weight were independently associated with supratherapeutic tacrolimus trough concentrations. Future lines of prospective research inquiry are warranted to use both germline genetic and clinical data to develop precision dosing tools that will optimize both tacrolimus dosing and clinical outcomes among adult HSCT patients.

Tacrolimus Concentration after Letermovir Initiation in Hematopoietic Stem Cell Transplantation Recipients Receiving Voriconazole: A Retrospective, Observational Study

Letermovir (LMV) is a new antiviral drug used to prevent cytomegalovirus infection in hematopoietic stem cell transplantation (HSCT) recipients. It has been reported to increase tacrolimus (TAC) exposure and decrease voriconazole (VRCZ) exposure in healthy participants. However, VRCZ inhibits the metabolism of TAC. Thus, the effects of LMV on TAC exposure in patients receiving VRCZ are unknown. This retrospective, observational, single-center study was conducted between May 2018 and April 2019. The TAC concentration/dose (C/D) ratio, VRCZ concentration, and VRCZ C/D ratio for 7 days before and for the first and second 7-day periods after the initiation of LMV administration were evaluated. Fourteen HSCT recipients receiving VRCZ were enrolled. There was no significant difference in the TAC C/D ratio for 7 days before and for the first and second 7-day periods after initiating LMV administration (median: 866 [IQR: 653-953], 842 [IQR: 636-1031], and 906 [IQR: 824-1210] [ng/mL]/[mg/kg], respectively). In contrast, the VRCZ C/D ratio and concentration for the first and second 7-day periods after LMV initiation were significantly lower than those before initiating LMV administration (mean 1.11 ± 0.07, 0.12 ± 0.08, and 0.22 ± 0.12 [μg/mL]/[mg/kg] and 0.7 ± 0.5, 0.8 ± 0.5, and 1.3 ± 0.7 μg/mL, respectively; n = 12). This can be explained by the increase in TAC concentration caused by CYP3A4 inhibition due to LMV and by the decrease in TAC concentration ascribed to the decrease in VRCZ concentration by CYP2C19 induction due to LMV. These results suggest that it is unnecessary to adjust the dose of TAC based on LMV initiation; however, it is necessary to adjust the dose of TAC based on conventional TAC concentration measurements.

Impact of CYP3A5, POR, and CYP2C19 Polymorphisms on Trough Concentration to Dose Ratio of Tacrolimus in Allogeneic Hematopoietic Stem Cell Transplantation

Single nucleotide polymorphisms in drug-metabolizing genes may affect tacrolimus pharmacokinetics. Here, we investigated the influence of genotypes of CYP3A5, CYP2C19, and POR on the concentration/dose (C/D) ratio of tacrolimus and episodes of acute graft-versus-host disease (GVHD) in Japanese recipients of allogeneic hematopoietic stem cell transplantation (HSCT). Thirty-six patients receiving the first HSCT using tacrolimus-based GVHD prophylaxis were enrolled with written informed consent. During continuous intravenous infusion, HSCT recipients carrying the CYP3A5*1 allele, particularly those with at least one POR*28 allele, had a significantly lower tacrolimus C/D ratio throughout all three post-HSCT weeks compared to that in recipients with POR*1/*1 (p < 0.05). The CYP3A5*3/*3 genotype and the concomitant use of voriconazole were independent predictors of an increased tacrolimus C/D ratio during the switch from continuous intravenous infusion to oral administration (p < 0.05). In recipients receiving concomitant administration of voriconazole, our results suggest an impact of not only CYP3A5 and CYP2C19 genotypes, but also plasma voriconazole concentration. Although switching from intravenous to oral administration at a ratio of 1:5 was seemingly appropriate in recipients with CYP3A5*1, a lower conversion ratio (1:2-3) was appropriate in recipients with CYP3A5*3/*3. Our results suggest that CYP3A5, POR, and CYP2C19 polymorphisms are useful biomarkers for individualized dosage adjustment of tacrolimus in HSCT recipients.

Reduced intensity vs. myeloablative conditioning with fludarabine and PK-guided busulfan in allogeneic stem cell transplantation for patients with AML/MDS

Conditioning regimens contribute significantly to outcomes following allogeneic stem cell transplantation (allo-SCT). Reduced-intensity conditioning (RIC) regimens provide lower toxicity at the cost of reduced efficacy compared with myeloablative conditioning (MAC) regimens. However, because pre-transplant prognostic variables often determine the conditioning regimen, studies of RIC vs. MAC have been inconclusive. We present a retrospective analysis of 242 acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) patients, 112 of whom were in 56 pairs matched using propensity scores, to account for variation that may confound clinical outcomes. The uniform conditioning regimens consisted of fludarabine with pharmacokinetic (PK)-guided intravenous busulfan (Bu). The RIC and MAC regimens were dosed at the average daily area under the concentration-vs-time curve (AUC) of 4000 µMol min and 5000-6000 µMol min, or total course AUC of 16,000 µMol min and 20,000-24,000 µMol min, respectively; PK-guided dosing removes overlap in systemic Bu exposure. When patients' data were propensity-matched, there was a trend toward significantly increased full donor chimerism and decreased chronic graft vs. host disease in RIC, and no significant differences in progression free survival and overall survival between RIC and MAC. Our results also elucidate the efficacy of PK-guided-dosing in the setting of allo-SCT for AML and MDS.

Fludarabine with pharmacokinetically guided IV busulfan is superior to fixed-dose delivery in pretransplant conditioning of AML/MDS patients

We hypothesized that IV Busulfan (Bu) dosing could be safely intensified through pharmacokinetic (PK-) dose guidance to minimize the inter-patient variability in systemic exposure (SE) associated with body-sized dosing, and this should improve outcome of AML/MDS patients undergoing allogeneic stem cell transplantation (allo-HSCT). To test this hypothesis, we treated 218 patients (median age 50.7 years, male/female 50/50%) with fludarabine (Flu) 40 mg/m² once daily ×4, each dose followed by IV Bu, randomized to 130 mg/m² (N=107) or PK-guided to average daily SE, AUC of 6,000 µM-min (N=111), stratified for remission-status, and allo-grafting from HLA-matched donors. Toxicity and graft vs. host disease (GvHD) rates in the groups were similar; the risk of relapse or treatment-related mortality remained higher in the fixed-dose group throughout the 80-month observation period. Further, PK-guidance yielded safer disease-control, leading to improved overall and progression-free survival, most prominently in MDS-patients and in AML-patients not in remission at allo-HSCT. We conclude that AML/MDS patients receiving pretransplant conditioning treatment with our 4-day regimen may benefit significantly from PK-guided Bu-dosing. This could be considered an alternative to fixed dose delivery since it provides the benefit of precise dose delivery to a predetermined SE without increasing risk(s) of serious toxicity and/or GvHD.

Long-Term Outcomes after Treatment with Clofarabine ± Fludarabine with Once-Daily Intravenous Busulfan as Pretransplant Conditioning Therapy for Advanced Myeloid Leukemia and Myelodysplastic Syndrome

Pretransplant conditioning regimens critically determine outcomes in the setting of allogeneic stem cell transplantation (allo-SCT). The use of nucleoside analogs such as fludarabine (Flu) in combination with i.v. busulfan (Bu) has been shown to be highly effective as a pretransplant conditioning regimen in acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and myelodysplastic syndrome (MDS). Because leukemia relapse remains the leading cause of death after allo-SCT, we studied whether clofarabine (Clo), a nucleoside analog with potent antileukemia activity, can be used to complement Flu. In a preliminary report, we previously showed the safety and efficacy of Clo ± Flu with i.v. Bu in 51 patients with high-risk AML, CML, and MDS. The study has now been completed, and we present long-term follow-up data on the entire 70-patient population, which included 49 (70%), 8 (11%), and 13 (19%) patients with AML, MDS, and CML, respectively. Thirteen patients (19%) were in complete remission, and 41 patients (59%) received matched unrelated donor grafts. Engraftment was achieved in all patients. Sixty-three patients (90%) achieved complete remission. There were no deaths reported at day +30, and the 100-day nonrelapse mortality rate was 4% (n = 3). Thirty-one percent of patients (n = 22) developed grades II to IV acute graft-versus-host disease, and the median overall survival and progression-free survival times were 2.4 years and .9 years, respectively. Our results confirm the safety and overall and progression-free survival advantage of the arms with higher Clo doses and lower Flu doses, which was most prominent in the AML/MDS group.

Optimal graft source for allogeneic hematopoietic stem cell transplant: bone marrow or peripheral blood?

Peripheral blood (PB), compared with bone marrow graft, has higher stem cell content, leads to faster engraftment and is more convenient for collection. Consequently, the use of PB graft has significantly increased in recent years. Although the use of PB graft is acceptable or even preferred to bone marrow graft in matched related donor allogeneic transplant due to a possibility of improved survival, PB graft increases the risk of chronic graft-versus-host disease and associated long-term toxicities in the setting of matched unrelated donor allogeneic transplant. In haploidentical transplant, mitigation of graft-versus-host disease with the use of post-transplant cyclophosphamide is a hypothesis-generating possibility; however, available studies have significant limitations to draw any definite conclusion.

Circulating CD14(+) HLA-DR(-/low) myeloid-derived suppressor cells in leukemia patients with allogeneic hematopoietic stem cell transplantation: novel clinical potential strategies for the prevention and cellular therapy of graft-versus-host disease

Myeloid‐derived suppressor cells (MDSCs) are a heterogeneous cell population that includes immature myeloid cells and the progenitor cells of macrophages, dendritic cells (DCs), monocytes, and neutrophils. The expansion and functional importance of MDSCs in patients with cancer and noncancer pathogenic conditions has been recognized. As a result, there has been growing interest in understanding their roles in acute graft‐versus‐host disease (aGVHD) after allogenetic hematopoietic stem cell transplantation (allo‐HSCT). In order to evaluate possible effects of MDSCs on aGVHD development and clinical outcomes, this study systematically detected the dynamic changes of MDSCs accumulation in patients during the first 100 days after allo‐HSCT, and investigated the levels of other cell types and relative cytokines during MDSCs accumulation. Results showed that accumulation of MDSCs in the graft and in peripheral blood when engraftment might contribute to patients' overall immune suppression and result in the successful control of severe aGVHD and long‐term survival without influence on risk of recurrence after allo‐HSCT. But MDSCs levels in the graft had more favorable predictive abilities. Furthermore, MDSCs proportion significantly increased in patients developing aGVHD after allo‐HSCT. It might be caused by secondary inflammatory response, especially related to high concentrations of IL‐6 and TNF‐α. But this accumulation would not be able to counterbalance the aggravation of aGVHD and would not have influence on clinical outcomes and risk of relapse. Overall, MDSCs might be considered as potential new therapeutic option for aGVHD and achieve long‐term immunological tolerance and survival.

Once-daily i.v. BU-based conditioning regimen before allogeneic hematopoietic SCT: a study of influence of GST gene polymorphisms on BU pharmacokinetics and clinical outcomes in Chinese patients

I.v. BU has been proven to have better bioavailability, reliable systemic drug exposure with more predictable blood levels and lower toxicity than oral BU when used as part of conditioning regimens before hematopoietic SCT (HSCT). Some studies have shown that once-daily i.v. BU had the same clinical efficacy as i.v. BU administered four times daily. To observe the clinical efficacy and pharmacokinetics (PK) of once-daily i.v. BU and to evaluate the influence of glutathione S-transferase (GST) gene polymorphisms on once-daily i.v. BU PK in adult Chinese patients with allogeneic HSCT, we analyzed 25 patients receiving related or unrelated donor transplant conditioned with i.v. BU-based regimens. With a median follow-up of 32.7 months, the 2-year OS and EFS were 64 and 63.8% for all the patients, respectively, and the 2-year cumulative incidence of relapse for all patients was 18.3%. On the basis of HPLC analysis, the mean clearance and mean daily area under the curve (AUC) of i.v. BU were calculated as 4.02 mL/min per kg and 3380.77 μM/min, respectively. The estimated Cmax was 1.031±0.0325 μg/mL. The estimated t1/2 and Vd values were 3.618±0.1932 h and 1.212±0.0352 L/kg. The once-daily i.v. BU-based conditioning regimen was very well tolerated with minor toxicity in patients, most likely because of dose assurance with predictable PK. There was no GSTA1 *B/*B homozygous patient in our Chinese patients. A significant association between BU metabolism and GSTA1 polymorphism was observed. The GSTA1 *A/*B genotype group showed a significantly higher AUC (P<0.0001), higher Cmax (P=0.0003) and lower clearance (P=0.0007) than the GSTA1 *A/*A genotype group. AUC was lower in GSTP1 *A/*A genotypes compared with*A/*G (P=0.0283) and *G/*G genotypes (P=0.0111). The BU clearance in GSTP1 *A/*A genotype was shown to be higher than *A/*G (P=0.0255) and *G/*G genotypes (P=0.0111). In addition, the differences of PK in BU among different ethnic groups existed because of the different distribution frequencies of GST gene polymorphism in Chinese patients and Caucasian patients.

The graft-versus-myeloma effect: chronic graft-versus-host disease but not acute graft-versus-host disease prolongs survival in patients with multiple myeloma receiving allogeneic transplantation

We conducted a study of patients with multiple myeloma (MM) undergoing allogeneic transplantation to evaluate outcome parameters. Fifty-seven consecutive patients with MM received an allogeneic transplantation between 2004 and 2011 at our institution. Patients who had received at least 1 prior autologous transplantation were included. Twenty-six patients underwent allogeneic transplantation for consolidation after a response to their first autograft, and 30 patients received an allogeneic transplantation as salvage therapy. Donor source was evenly distributed between related and unrelated. The median follow-up was 52 months. Thirty-two (57.1%) patients achieved a complete response (CR). At 5 years, 49.2% of all patients were in CR. Sixteen patients received either donor lymphocyte infusions or immune suppression withdrawal for disease progression, with a 62.5% response rate. The 5-year overall survival (OS) for all patients was 59%. The 5-year OS for the 30 patients in the consolidation group was 82% compared with 38% for those in the salvage group. In multivariate analysis, 3 factors remained significantly associated with OS. These include being in the salvage group (hazard ratio [HR], 4.05; P = .0196), acute graft-versus-host disease (aGVHD) (HR, 2.99; P = .034), and chronic graft-versus-host disease (cGVHD), which was highly protective, with a 5-year OS of 78.8% for patients with cGVHD versus 42.6% for patients without cGVHD (HR .17, P = .008). Our data show that allogeneic transplantation for MM can lead to sustained remissions. aGVHD is significantly deleterious to OS and progression-free survival, whereas cGVHD is strongly favorable, supporting an important role for the graft-versus-myeloma effect.

A randomized phase II trial of fludarabine/melphalan 100 versus fludarabine/melphalan 140 followed by allogeneic hematopoietic stem cell transplantation for patients with multiple myeloma

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is a potentially curative treatment for multiple myeloma (MM); however, because of high treatment-related mortality (TRM), its role is not well defined. Patients with newly diagnosed, relapsed, or primary refractory myeloma were enrolled in a randomized phase II trial of 2 reduced-intensity conditioning regimens: fludarabine 120 mg/m(2) + melphalan 100 mg/m(2) (FM100) versus fludarabine 120 mg/m(2) + melphalan 140 mg/m(2) (FM140) before allo-HCT from related or unrelated donors. Fifty patients underwent allo-HCT using FM100 (n = 23) or FM140 (n = 27) conditioning between April 2002 and 2011. There were no significant differences between FM100 and FM140 in time to neutrophil engraftment (P = .21), acute grade II to IV graft-versus-host disease (GVHD) (P = 1.0), chronic GVHD (P = .24), response rate (P = 1.0), TRM (13% versus 15%, P = 1.0), median progression-free survival (PFS), 11.7 versus 8.4 months, P = .12, and median overall survival (OS), 35.1 versus 19.7 months, P = .38. Cumulative incidence of disease progression in FM100 and FM140 was 43% and 70%, respectively (P = .08). Recurrent disease was the most common cause of death for both FM100 (26%) and FM140 (44%), P = .24. On multivariate analysis, disease status at allo-HCT, complete response or very good partial response (VGPR) was significantly associated with longer PFS (15.6 versus 9.6 months in patients with <VGPR, P = .05). OS was similar across all variables. We conclude that FM100 and FM140 may result in similar patient outcomes after allo-HCT for MM.

Randomized trial of myeloablative conditioning regimens: busulfan plus cyclophosphamide versus busulfan plus fludarabine

PURPOSE

We conducted a phase III randomized clinical trial to compare two myeloablative conditioning regimens for allogeneic hematopoietic cell transplantation (HCT) in patients with leukemia and myelodysplastic syndrome.

PATIENTS AND METHODS

After randomization, 64 patients received busulfan (3.2 mg/kg per day × 4 days) plus cyclophosphamide (60 mg/kg per day × 2 days; BuCy), and 62 patients received busulfan (same dose and schedule) plus fludarabine (30 mg/m(2) per day × 5 days; BuFlu).

RESULTS

The median age was 41 years (range, 17 to 59 years). Five patients in the BuFlu arm experienced graft failure (primary, n = 1; secondary, n = 4). At 4 weeks after HCT, the median percentage of recipient hematopoietic chimerism was significantly greater in the BuFlu arm (0% v 5.5%; P < .001), and complete donor chimerism was greater in the BuCy arm (97.2% v 44.4%; P < .001). Severe (grade 3 or higher) infection and gastrointestinal adverse events were significantly more common in the BuCy arm, but the frequencies of hepatic adverse events were similar in the two arms. Nonrelapse mortality was similar in the two arms, but the BuCy arm had better overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS; OS at 2 years, 67.4% v 41.4%, P = .014; RFS, 74.7% v 54.9%, P = .027; EFS, 60.7% v 36.0%, P = .014).

CONCLUSION

Our results indicate that the BuFlu regimen is not a suitable replacement for the BuCy regimen in young adults who are eligible for myeloablative conditioning therapy for allogeneic HCT.

The effectiveness of tacrolimus and minidose methotrexate in the prevention of acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation in children: a single-center study in Korea

Background

Knowledge of the roles of tacrolimus and minidose methotrexate (MTX) in the prevention of acute graft-versus-host disease (aGVHD) in pediatric allogeneic hematopoietic stem cell transplantation (HSCT) is limited. We retrospectively evaluated the engraftment status, incidence of aGVHD and chronic GVHD (cGVHD), and toxicities of tacrolimus and minidose MTX in aGVHD prophylaxis in children undergoing allogeneic HSCT.

Methods

Seventeen children, who underwent allogeneic HSCT and received tacrolimus and minidose MTX as GVHD prophylaxis from March 2003 to February 2011, were reviewed retrospectively. All the patients received tacrolimus since the day before transplantation at a dose of 0.03 mg/kg/day and MTX at a dose of 5 mg/m² on days 1, 3, 6, and 11.

Results

Of the 17 patients, 9 received human leukocyte antigen (HLA)-matched related donor transplants, and 8 received HLA-matched, or partially mismatched unrelated donor transplants. The median time for follow-up was 55 months. The incidence of aGVHD in the related and unrelated donor groups was 22.2% and 42.9%, respectively. cGVHD was not observed. To maintain therapeutic blood levels of tacrolimus, the younger group (<8 years of age) required an increased mean dose compared to the older group (≥8 years) (P=0.0075). The adverse events commonly associated with tacrolimus included hypomagnesemia (88%), nephrotoxicity (23%), and hyperglycemia (23%).

Conclusion

Tacrolimus and minidose MTX were well tolerated and effective in GVHD prophylaxis in pediatric patients undergoing allogeneic HSCT. Children <8 years of age undergoing HSCT required increased doses of tacrolimus to achieve therapeutic levels.

Randomized phase II trial comparing two dose levels of thymoglobulin in patients undergoing unrelated donor hematopoietic cell transplant

The optimal dose and schedule of thymoglobulin (ATG) for graft-versus-host disease prevention (GVHD) is unknown. We compared two doses of ATG (4.5 mg/kg and 7.5 mg/kg) in a Bayesian adaptively randomized fashion, and assessed whether ATG levels measured on days 0, 7, 14 and 28 were associated with clinical outcomes. Treatment success was defined as the patient being alive, engrafted, in remission and without acute GVHD at day 100. Twenty patients received ATG 4.5 mg/kg (n = 15) or 7.5 mg/kg (n = 5) with reduced-intensity conditioning followed by unrelated donor hematopoietic cell transplant. The first 10 patients were fairly randomized, but the next 10 patients were adaptively randomized to the arm with higher success rate (4.5 mg/kg arm in this trial). The posterior mean treatment success rates for the ATG 4.5 mg/kg and ATG 7.5 mg/kg arms were 0.73 and 0.45, respectively. The posterior probability that the success rate was greater in the 4.5 mg/kg arm than in the 7.5 mg/kg arm was 0.93. There was no difference in the overall survival (p = 0.607), relapse-free survival (p = 0.607), treatment-related mortality (p = 0.131) or incidence of acute (p = 0.303) or chronic GVHD (p = 0.999) between the two doses. ATG levels were not associated with clinical outcomes. Thus, our results favor the use of ATG 4.5 mg/kg over ATG 7.5 mg/kg in patients undergoing unrelated donor hematopoietic cell transplant with reduced-intensity conditioning regimens.

Myeloablative reduced-toxicity i.v. busulfan-fludarabine and allogeneic hematopoietic stem cell transplant for patients with acute myeloid leukemia or myelodysplastic syndrome in the sixth through eighth decades of life

The optimal pretransplant regimen for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) in patients ≥ 55 years of age remains to be determined. The myeloablative reduced-toxicity 4-day regimen i.v. busulfan (Bu) (130 mg/m(2)) and i.v. fludarabine (Flu) (40 mg/m(2)) is associated with low morbidity and mortality. We analyzed 79 patients ≥ 55 years of age (median, 58 years) with AML (n = 63) or MDS (n = 16) treated with i.v. Bu-Flu conditioning regimens between 2001 and 2009 (median follow-up, 24 months). The patients who received this regimen had a good performance status. The 2-year overall survival (OS) rates for patients in first complete remission (CR1), second CR (CR2), or refractory disease and for all patients at time of transplantation were 71%, 44%, 32%, and 46%, respectively; 2-year event-free survival (EFS) rates for patients in CR1, CR2, or refractory disease at time of transplantation and for all patients were 68%, 42%, 30%, and 44%, respectively. One-year transplant-related mortality (TRM) rates for patients who were in CR or who had active disease at the time of transplantation were 19% and 20%, respectively. Grade II-IV acute graft-versus-host (aGVHD) disease was diagnosed in 40% of the patients. Our results suggest that age alone should not be the primary reason for exclusion from receiving myeloablative reduced-toxicity conditioning with i.v. Bu-Flu preceding transplantation in patients with AML/MDS.

A prospective dose-finding trial using a modified continual reassessment method for optimization of fludarabine plus melphalan conditioning for marrow transplantation from unrelated donors in patients with hematopoietic malignancies

BACKGROUND

Because of the less graft-facilitating effect by bone marrow (BM), we need to assess a dosage of conditioning more accurately particularly in combination with reduced-intensity conditioning. Thus we examined that modified continual reassessment method (mCRM) is applicable for deciding appropriate conditioning of allogeneic BM transplantation.

PATIENTS AND METHODS

The conditioning regimen consisted of i.v. fludarabine (125 mg/m2) plus an examination dose of i.v. melphalan. The primary endpoint was a donor-type T-cell chimerism at day 28 with successful engraftment defined as >90% donor cells. Five patients per dose level were planned to be accrued and chimerism data were used to determine the next dose.

RESULTS

Seventeen patients were enrolled at doses between 130 and 160 mg/m2. The dose was changed from 160 to 130 mg/m(2) (second level) after five full-donor chimerisms. With one patient of 0% chimera in the second level, the dose was increased to 135 mg/m2 (third level). Following five full-donor chimerisms in the third level, the study was complete as projected.

CONCLUSIONS

mCRM was shown to be a relevant method for dose-finding of conditioning regimen. The melphalan dose of 135 mg/m2 was determined as the recommended phase II dose to induce initial full-donor chimerism.

Unrelated donor transplantation for acute myelogenous leukemia in first remission

We retrospectively analyzed the outcomes of all acute myelogenous leukemia (AML) patients in first remission (n = 44; median age = 48 years; high-risk cytogenetics = 59%) who received unrelated donor hematopoietic cell transplantation (HCT) with myeloablative conditioning regimen of i.v. busulfan, fludarabine, and antithymocyte globulin (ATG) between January 2002 and November 2009 at our institution. Donor-recipient pairs were matched by high-resolution HLA-A, -B, -C, -DRB1, and -DQB1 typing (10/10 matches, n = 41; 9/10 matches, n = 3). With a median follow-up of 34 months, actuarial 3-year event-free survival (EFS) and overall survival (OS) is 70% and 78%, respectively. The 3-year EFS and OS in patients with and without poor risk cytogenetics is similar (63% versus 82%, P = 0.43 and 78% versus 82%, P = .89, respectively). The 3-year EFS and OS is also similar in patients above age 55 year versus patients age 55 year or younger (80% versus 67%, P = .47 and 80% versus 78%, P = .81, respectively). The 100-day and 3-year cumulative incidence of transplant-related mortality is 5% and 15%, respectively. Six patients have relapsed, and 3 of them are alive and in remission after salvage therapy, with a median follow-up of 23 months. These results indicate that the majority of AML patients eligible for this treatment can achieve long-term disease control.

Clofarabine ± fludarabine with once daily i.v. busulfan as pretransplant conditioning therapy for advanced myeloid leukemia and MDS

Although a combination of i.v. busulfan (Bu) and fludarabine (Flu) is a safe, reduced-toxicity conditioning program for acute myelogenous leukemia/myelodysplastic syndromes (AML/MDS), recurrent leukemia posttransplantation remains a problem. To enhance the conditioning regimen's antileukemic effect, we decided to supplant Flu with clofarabine (Clo), and assayed the interactions of these nucleoside analogs alone and in combination with Bu in Bu-resistant human cell lines in vitro. We found pronounced synergy between each nucleoside and the alkylator but even more enhanced cytotoxic synergy when the nucleoside analogs were combined prior to exposing the cells to Bu. We then designed a 4-arm clinical trial in patients with myeloid leukemia undergoing allogeneic stem cell transplantation (allo-SCT). Patients were adaptively randomized as follows: Arm I-Clo:Flu 10:30 mg/m(2), Arm II-20:20 mg/m(2), Arm III-30:10 mg/m(2), and Arm IV-single-agent Clo at 40 mg/m(2). The nucleoside analog(s) were/was infused over 1 hour once daily for 4 days, followed on each day by Bu, infused over 3 hours to a pharmacokinetically targeted daily area under the curve (AUC) of 6000 μMol-min ± 10%. Fifty-one patients have been enrolled with a minimum follow-up exceeding 100 days. There were 32 males and 19 females, with a median age of 45 years (range: 6-59). Nine patients had chronic myeloid leukemia (CML) (BC: 2, second AP: 3, and tyrosine-kinase inhibitor refractory first chronic phase [CP]: 4). Forty-two patients had AML: 14 were induction failures, 8 in first chemotherapy-refractory relapse, 7 in untreated relapse, 3 in second or subsequent relapse, 4 were in second complete remission (CR), and 3 in second CR without platelet recovery (CRp), 2 were in high-risk CR1. Finally, 1 patient was in first CRp. Graft-versus-host disease (GVHD) prophylaxis was tacrolimus and mini-methorexate (MTX), and those who had an unrelated or 1 antigen-mismatched donor received low-dose rabbit-ATG (Thymoglobulin™). All patients engrafted. Forty-one patients had active leukemia at the time of transplant, and 35 achieved CR (85%). Twenty of the 42 AML patients and 5 of 9 CML patients are alive with a projected median overall survival (OS) of 23 months. Marrow and blood (T cell) chimerism studies at day +100 revealed that both in the lower-dose Clo groups (groups 1+2) and the higher-dose Clo groups (groups 3+4), the patients had a median of 100% donor (T cell)-derived DNA. There has been no secondary graft failure. In the first 100 days, 1 patient died of pneumonia, and 1 of liver GVHD. We conclude that (1) Clo ± Flu with i.v. Bu as pretransplant conditioning is safe in high-risk myeloid leukemia patients; (2) clofarabine is sufficiently immunosuppressive to support allo-SCT in myeloid leukemia; and (3) the median OS of 23 months in this high-risk patient population is encouraging. Additional studies to evaluate the antileukemic efficacy of Clo ± Flu with i.v. Bu as pretransplant conditioning therapy are warranted.

Total parenteral nutrition associated with severe insulin resistance following hematopoietic stem cell transplantation in patients with hemophagocytic syndrome: report on two cases

Hyperglycemia secondary to total parenteral nutrition (TPN) is reported in adults. In addition, insulin resistance and type 2 diabetes as late consequences of hematopoietic stem cell transplantation (HSCT) are well described. Both situations are generally manageable with traditional insulin dosing. We present two children who developed severe insulin resistance requiring intravenous insulin therapy at doses up to 13 units/kg/h. Both children were on TPN after undergoing HSCT for hemophagocytic syndrome. We believe that our report will alert physicians to such a condition and help with early recognition that is a key to successful intervention. These cases aim to increase awareness and stimulate research to unravel the associated underling mechanisms.

Once daily i.v. busulfan and fludarabine (i.v. Bu-Flu) compares favorably with i.v. busulfan and cyclophosphamide (i.v. BuCy2) as pretransplant conditioning therapy in AML/MDS

We postulated that fludarabine (Flu) instead of cyclophosphamide (Cy) combined with i.v. busulfan (Bu) as preconditioning for allogeneic hematopoietic stem cell transplantation (HSCT) would improve safety and retain antileukemic efficacy. Sixty-seven patients received BuCy2, and subsequently, 148 patients received Bu-Flu. We used a Bayesian method to compare outcomes between these nonrandomized patients. The groups had comparable pretreatment characteristics, except that Bu-Flu patients were older (46 versus 39 years, P < .01), more often had unrelated donors (47.3% versus 20.9%, P < .0003), and had shorter median follow-up (39.7 versus 74.6 months). To account for improved supportive care and other unidentified factors that may affect outcome ("period" effects), 78 acute myelogenous leukemia (AML) patients receiving Melphalan-Flu (MF), treated in parallel during this time (1997-2004) were used to estimate the period effect. The MF patients' outcomes worsened during this period. Therefore, the period effect is unlikely to explain the greatly improved outcome with Bu-Flu. Patients transplanted with Bu-Flu in the first complete remission (CR1) had a 3-year overall survival and event-free-survival (EFS) of 78% and 74%, respectively, whereas CR1 patients younger than age 41 had a 3-year EFS of 83%. These results support replacing BuCy +/- ATG with Bu-Flu +/- rabbit-antithymocyte globulin (ATG), and warrant a prospective comparison between allogeneic HSCT and conventional induction/consolidation chemotherapy for AML in CR1.

Sirolimus in combination with cyclosporine or tacrolimus plus methotrexate for prevention of graft-versus-host disease following hematopoietic cell transplantation from unrelated donors

In 2 consecutive prospective clinical trials, we evaluated the efficacy of sirolimus together with a calcineurin inhibitor (cyclosporine or tacrolimus) and low-dose methotrexate for prevention of graft-versus-host disease (GVHD) after unrelated hematopoietic cell transplantation (HCT). Nine patients received sirolimus with cyclosporine, and 17 received sirolimus with tacrolimus. The incidence of grade II-IV GVHD was 77%, with the median onset at day 7 after HCT. Because of toxicity, administration of sirolimus was discontinued earlier than planned in 11 patients, but after the onset of GVHD. Three patients developed renal failure requiring hemodialysis. Accrual in both studies was terminated because of lack of efficacy. In these studies, the addition of sirolimus to regimens containing a calcineurin inhibitor and methotrexate appeared to cause toxicity and provided no detectable improvement in preventing GVHD.

Targeting mycophenolate mofetil for graft-versus-host disease prophylaxis after allogeneic blood stem cell transplantation

As low trough levels of mycophenolic acid (MPA) have been measured in recipients of allo-SCTs, we performed a pilot study targeting mycophenolate mofetil (MMF) doses according to the MPA area under the concentration (AUC) levels. Twenty-nine patients were transplanted from matched sibling (n=7) and unrelated donors (n=22). Tacrolimus was given orally from day -1 to achieve trough blood levels of 5-10 ng/ml. MMF was started on day 0 at 1500 mg intravenously b.i.d. AUC measurements of MPA by HPLC were scheduled on days 3, 7 and 11 after transplantation. The MMF dose was modified to achieve an MPA AUC of 35-60 microg/ml/h. With the respective adjustments 66 and 75% surpassed the lower AUC target on days 7 and 11, respectively. The cumulative incidence of grade III-IV acute GVHD was 28% (8/29). Eight out of 24 evaluable patients (33%) suffer from limited (n=3) or extensive (n=5) chronic GVHD. Overall, the results of this study suggest that targeting of MPA exposure is feasible early after transplantation. A simplified MMF targeting strategy based on MPA C(max) or C(2h) levels seems to be warranted in future trials involving more patients at later time points in the outpatient setting.

Phase I/II study of gemtuzumab ozogamicin added to fludarabine, melphalan and allogeneic hematopoietic stem cell transplantation for high-risk CD33 positive myeloid leukemias and myelodysplastic syndrome

We investigated the hypothesis that gemtuzumab ozogamicin (GO), an anti-CD33 immunotoxin would improve the efficacy of fludarabine/melphalan as a preparative regimen for allogeneic hematopoietic stem cell transplantation (HSCT) in a phase I/II trial. Toxicity was defined as grades III-IV organ damage, engraftment failure or death within 30 days. 'Response' was engraftment and remission (CR) on day +30. We sought to determine the GO dose (2, 4 or 6 mg m(-2)) giving the best trade-off between toxicity and response. All patients were not candidates for myeloablative regimens. Treatment plan: GO (day -12), fludarabine 30 mg m(-2) (days -5 to -2), melphalan 140 mg m(-2) (day -2) and HSCT (day 0). GVHD prophylaxis was tacrolimus and mini-methotrexate. Diagnoses were AML (n=47), MDS (n=4) or CML (n=1). Median age was 53 years (range, 13-72). All but three patients were not in CR. Donors were related (n=33) or unrelated (n=19). Toxicity and response rates at 4 mg m(-2) were 50% (n=4) and 50% (n=4). GO dose was de-escalated to 2 mg m(-2): 18% had toxicity (n=8) and 82% responded (n=36). 100-day TRM was 15%; one patient had reversible hepatic VOD. Median follow-up was 37 months. Median event-free and overall survival was 6 and 11 months. GO 2 mg m(-2) can be safely added to fludarabine/melphalan, and this regimen merits further evaluation.

Randomized comparison of four-times-daily versus once-daily intravenous busulfan in conditioning therapy for hematopoietic cell transplantation

Sixty patients were randomized to receive intravenous busulfan (iBU) either as 0.8 mg/kg, over 2 hours 4 times a day (BU4 arm) or 3.2 mg/kg, over 3 hours once a day (BU1 arm) in conditioning therapy for hematopoietic cell transplantation. The complete pharmacokinetic parameters for the first busulfan dose were obtained from all patients and were comparable between the 2 arms: for the BU4 and BU1 groups, elimination half-life (mean+/-SD) was 2.75+/-0.22 versus 2.83+/-0.21 hours, estimated daily AUC was 6058.0+/-1091.9 versus 6475.5+/-1099.4 microM.min per day, and clearance was 2.05+/-0.36 versus 1.91+/-0.31 mL/min/kg, respectively. Times to engraftment after transplantation were similar between the 2 arms. No significant differences were evident in the occurrence of acute graft-versus-host disease (aGVHD) and hepatic veno-occlusion disease (VOD). Moreover, other toxicities observed within 100 days after transplantation were not significantly different between the 2 arms. The cumulative incidence of nonrelapse mortality was 20.8% in BU4 arm and 13.3% in BU1 arm. In conclusion, our randomized study demonstrates that the pharmacokinetic profiles and posttransplant complications are similar for once-daily iBU and traditional 4-times-daily iBU.

Risk factors associated with late cytomegalovirus reactivation after allogeneic stem cell transplantation for hematological malignancies

We analyzed the clinical factors associated with late cytomegalovirus (CMV) reactivation in a group of 269 consecutive recipients of allogeneic stem cell transplant (SCT) for hematological malignancies. Eighty-four subjects (31%) experienced late CMV reactivation, including 64 with prior early reactivation and 20 with isolated late reactivation. Multivariate analyses were conducted in patients with early CMV reactivation to identify factors associated with late recurrence. Important risk factors included lymphoid diagnosis, occurrence of graft-versus-host disease (GVHD), greater number of episodes of early reactivation, persistent day 100 lymphopenia and the use of a CMV-seronegative donor graft. We combined these risk factors in a predictive model to identify those at relatively low, intermediate and high risk. The low-risk group (15% cumulative incidence, CI) encompassed patients without early CMV reactivation, and subjects transplanted for a myeloid malignancy from a matched-related (MR) donor without subsequent acute GVHD. The high-risk patients (73% CI) met all of the following criteria: (1) received an MR graft but developed GVHD, or received a non-MR graft irrespective of GVHD; (2) had more than two episodes of early reactivation; and (3) received a CMV-seronegative graft and/or remained persistently lymphopenic at day 100 after SCT. The remaining patients had an intermediate incidence of 32%.

Sirolimus and thrombotic microangiopathy after allogeneic hematopoietic stem cell transplantation

Thrombotic microangiopathy (TMA) may occur after allogeneic hematopoietic stem cell transplantation (HSCT) and is related in part to calcineurin inhibitor toxicity. We observed a higher-than-expected rate of TMA when calcineurin inhibitors were combined with sirolimus. To determine the incidence of and risk factors for TMA after HSCT, we performed a retrospective cohort analysis of myeloablative allogeneic HSCT recipients between 1997 and 2003. TMA diagnosis required the simultaneous occurrence of (1) creatinine increase >2 mg/dL or >50% above baseline, (2) schistocytosis, (3) increased lactate dehydrogenase, and (4) no evidence of disseminated intravascular coagulopathy. A total of 111 sirolimus-exposed subjects were compared with 216 nonexposed subjects after HSCT. TMA occurred in 10.8% of the sirolimus group and 4.2% in the nonsirolimus group (odds ratio, 2.79; P=.03). Sirolimus exposure was associated with TMA earlier than in nonsirolimus patients (25 versus 58 days; P=.04). Only the use of sirolimus (exact odds ratio, 3.49; P=.02) and grade II to IV acute graft-versus-host disease (exact odds ratio, 6.60; P=.0002) were associated with TMA in regression analyses. Treatment of TMA varied among affected individuals. Renal recovery was complete in 92% of sirolimus-treated patients. Overall survival after TMA diagnosis was better for sirolimus subjects than for nonsirolimus subjects (58.3% versus 11.1%; P=.02). Sirolimus seems to potentiate the effects of calcineurin inhibitors on TMA after HSCT. TMA associated with sirolimus seems reversible and has a favorable prognosis when compared with TMA associated with calcineurin inhibitors alone. A careful monitoring strategy for TMA should be used with a sirolimus-containing graft-versus-host disease prophylaxis regimen.

Non-total body irradiation containing preparative regimen in alternative donor bone marrow transplantation for severe aplastic anemia

Using non-total body irradiation (TBI) containing preparative regimens, 13 patients with severe aplastic anemia (SAA) were transplanted from an alternative donor in a single institute. In total, 12 donors were unrelated volunteers and one was an HLA one-locus mismatched sibling. Median time from diagnosis of SAA to bone marrow transplantation (BMT) was 10.1 months (range, 1.6-180.1). Nine patients had received immunosuppressive treatment with ATG before BMT, while four had not. Preparative regimens consisted of cyclophosphamide plus ATG in nine patients, cyclophosphamide plus fludarabine in two patients, and cyclophosphamide plus fludarabine plus ATG in two patients. All patients received non-T-cell depleted bone marrow from the donor. Cyclosporine plus methotrexate were given for GVHD prophylaxis. All patients engrafted on a median of day 21 (range, 15-27). Grade III-IV acute GVHD developed in three (23%) of 13 patients and extensive chronic GVHD in four (31%) of 12 evaluable patients. With a median follow-up duration of 1138 days (range, 118-1553), 10 patients are alive with durable engraftment showing 74.6% (95% confidence interval, 49.5-99.7%) of survival rate. Cause of the deaths was CNS bleeding in one and chronic GVHD in two. In conclusion, non-TBI containing preparative regimen could ensure durable engraftment in alternative donor BMT for SAA and showed promising results.

Modification of the Bu/Cy myeloablative regimen using daily parenteral busulfan: reduced toxicity without the need for pharmacokinetic monitoring

Pharmacokinetic and clinical outcome measures among three groups of patients undergoing hematopoietic transplant were assessed: group A: Parenteral busulfan (Bu) 3.2 mg/kg i.v. given qd, n=20; group B: parenteral Bu 0.8 mg/kg i.v. given every 6 h, n=11; group C: Bu 1 mg/kg p.o. given every 6 h, n=25. All groups received Bu over 4 days followed by Cy 60 mg/kg i.v. qd over 2 days; followed by an infusion of allogeneic stem cells. Median Bu clearance was 3.21 ml/min/kg and median daily AUC was 4071 micromol/min for the group A patients. The dosing formula for Bu i.v. qd was highly predictive of the AUC for patients whose mass < or =IBW+20%. For patients of greater mass, the dosing formula uniformly resulted in lower-than-predicted AUC. Neurologic toxicity, hepatic toxicity, hematologic engraftment, and relapse at 100 days were comparable across all three groups. Severe AGVHD was least among group A, followed by group B when compared with group C. Bu i.v. qd is a safe and effective regimen for allogeneic transplantation and is at least clinically equivalent to every 6 h dosing schemes using either oral or parenteral Bu.

Sirolimus and tacrolimus without methotrexate as graft-versus-host disease prophylaxis after matched related donor peripheral blood stem cell transplantation

Methotrexate in combination with a calcineurin inhibitor is a standard graft-versus-host disease (GVHD) prophylactic regimen in allogeneic stem cell transplantation. However, methotrexate is associated with delayed engraftment, mucositis, idiopathic pneumonia syndrome, and other transplant-related complications. Sirolimus, a novel immunosuppressant without methotrexate's toxicities, has been used successfully in solid organ transplantation. We hypothesized that replacing methotrexate with sirolimus would preserve effective prophylaxis of GVHD while minimizing transplant-related toxicity after allogeneic peripheral blood stem cell transplantation. We enrolled 30 patients in a phase II study to test the efficacy of tacrolimus in combination with sirolimus in lieu of methotrexate in preventing GVHD after allogeneic peripheral blood stem cell transplantation from HLA-matched related donors. Grade II GVHD occurred in 3 patients (10%), and no patient developed grade III or IV GVHD. Neutrophil and platelet engraftment were prompt, occurring on days 14 and 13, respectively. All patients survived to hospital discharge (median, 18 days), and peritransplantation toxicity was mild. Four patients developed thrombotic microangiopathy, and 3 patients developed hepatic veno-occlusive disease. Chronic GVHD occurred in 11 patients. Relapse-free and overall survival at 100 days were 93% and 97%, respectively, and were 71% and 67% at 1 year. Causes of death included relapse (n = 6), veno-occlusive disease (n = 1), and late pulmonary toxicity (n = 1). Sirolimus in combination with tacrolimus is a promising alternative to methotrexate-based regimens for GVHD prophylaxis after matched related donor peripheral blood stem cell transplantation. Mucositis was modest, engraftment was prompt, and transplant-related toxicity was modest. Methotrexate-free, sirolimus-based GVHD prophylactic regimens should be tested in randomized trials against the current standard of care.

Severe metabolic abnormalities after allogeneic hematopoietic cell transplantation

Severe metabolic abnormalities occurring within 100 days after allogeneic hematopoietic cell transplantation (HCT) were investigated in 311 patients. The metabolic abnormalities included hyper- and hypocalcemia, hypophosphatemia, hyper- and hypokalemia, hyper- and hyponatremia, hyper- and hypomagnesemia, hypercholesterolemia, hyper- and hypoglycemia, and hyperuricemia. Severe abnormalities, defined as grades III-V by NCI CTCAE v3.0, occurred in 269 patients (86.5%). Multivariate analysis revealed that patients with moderate-to-severe hepatic veno-occlusive disease had significantly higher risk for the occurrence of severe metabolic abnormalities. Grades III-IV acute graft-versus-host disease was the most frequently associated with individual metabolic abnormalities. Patients with at least one severe metabolic abnormality had significantly higher day 100 nonrelapse mortality (P=0.015) and lower 5-year overall survival (P=0.002) than those without severe abnormalities. The number of metabolic abnormalities also stratified the patients with different clinical outcomes. In conclusion, severe metabolic abnormalities occurring within 100 days after allogeneic HCT were common, and their occurrence was significantly associated with inferior clinical outcomes. These results indicate that metabolic parameters should be monitored in patients undergoing allogeneic HCT and that the occurrence of severe metabolic abnormalities should be considered an important toxicity parameter in prospective clinical trials regarding allogeneic HCT.

Acute graft-versus-host disease: Pathophysiology, clinical manifestations, and management

Hematopoietic stem cell transplantation has evolved as a central treatment modality in the management of different hematologic malignancies. Despite adequate posttransplantation immunosuppressive therapy, acute graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality in the hematopoietic stem cell transplantation setting, even in patients who receive human leukemic antigen (HLA) identical sibling grafts. Up to 30% of the recipients of stem cells or bone marrow transplantation from HLA-identical related donors and most patients who receive cells from other sources (matched-unrelated, non-HLA-identical siblings, cord blood) will develop > Grade 2 acute GVHD despite immunosuppressive prophylaxis. Thus, GVHD continues to be a major limitation to successful hematopoietic stem cell transplantation. In this review, the authors summarize the most current knowledge on the pathophysiology, clinical manifestations, and management of this potentially life-threatening transplantation complication.

Dose modification protocol using intravenous busulfan (Busulfex) and cyclophosphamide followed by autologous or allogeneic peripheral blood stem cell transplantation in patients with hematologic malignancies

We evaluated the safety and toxicity through a 5-cohort dose-modification model of once-daily administration of IV busulfan (Bu) in combination with high-dose cyclophosphamide (Cy) as preparative therapy for stem cell transplantation. Twenty-one adult patients with hematologic malignancies were evaluated. Eleven patients underwent autologous and 10 patients underwent HLA-matched sibling allogeneic transplantation. Patients were sequentially enrolled into 5 cohorts. Cohort 1 received intravenous (IV) Bu 1.6 mg/kg every 12 hours for 2 doses and then 0.8 mg/kg every 6 hours for 12 doses; cohort 2 received IV Bu 1.6 mg/kg every 12 hours for 4 doses and then 0.8 mg/kg every 6 hours for 8 doses; cohort 3 received IV Bu 3.2 mg/kg for 1 dose and then 1.6 mg/kg every 12 hours for 2 doses and 0.8 mg/kg every 6 hours for 8 doses; cohort 4 received IV Bu 3.2 mg/kg every 24 hours for 2 doses and then 0.8 mg/kg every 6 hours for 8 doses; and cohort 5 received IV Bu 3.2 mg/kg every 24 hours for 4 doses. In all groups, Bu was administered on day -7 through day -4 and was followed at least 6 hours after the last Bu dose by Cy 60 mg/kg daily for 2 doses on days -3 and -2. Blood samples were collected for pharmacokinetic analysis on the first and last day of IV Bu administration. All patients were alive and had engrafted at day 30. Five patients developed grade 3 or 4 toxicities. Four patients developed hepatic abnormalities, and 3 exhibited evidence of veno-occlusive disease. Two of 3 patients in cohort 5 with a Bu area under the curve >6000 micromol/min developed autopsy-confirmed veno-occlusive disease. Interpatient variability in AUCs was observed in patients within and between cohorts, but no statistically significant interpatient differences were observed in Bu half-life, volume of distribution, clearance, or dose-adjusted area under the curve. Further, minimal variability in Bu pharmacokinetics was observed between the 2 evaluations performed in each patient, thus reflecting the stability of Bu disposition within individual patients. On the basis of the dosing guidelines and schedule outlined in this study, our data suggest that administration of IV Bu 3.2 mg/kg IV every 24 hours for 4 doses in combination with Cy may result in excessive toxicity.

Hydroxychloroquine for the prevention of acute graft-versus-host disease after unrelated donor transplantation

Hydroxychloroquine (HCQ) is an immunosuppressive agent that interferes with antigen presentation and with activity against graft-versus-host disease (GVHD). In a phase II trial assessing the GVHD prophylactic effects of HCQ, 51 consecutive unrelated donor transplant recipients received HCQ in addition to cyclosporin A, methylprednisolone, and methotrexate. HCQ was initiated on pretransplantation day -21 at 800 mg/d and continued until day +100 after transplantation. HCQ was extremely well tolerated and was not associated with side effects. Pharmacokinetic analyses demonstrated large inter- and intrapatient variability. The addition of HCQ did not affect posttransplantation immune recovery. Grade II to IV acute GVHD was observed in 56% of patients, and grade III and IV GVHD was observed in 17%. Day +100 mortality was 22%. When compared with a matched cohort of patients reported to the International Bone Marrow Transplant Registry, patients receiving HCQ had comparable cumulative incidences of grade II to IV acute GVHD. However, lower incidences of grades III and IV GVHD and better GVHD-free survival were observed in HCQ-treated patients (P =.01). We conclude that prophylactic HCQ is well tolerated and associated with a low incidence of severe acute GVHD. An ongoing placebo-controlled randomized trial will further determine what role HCQ plays in preventing GVHD after allografting.

Tacrolimus as monotherapy or combined with minidose methotrexate for graft-versus-host disease prophylaxis after allogeneic peripheral blood stem cell transplantation: long-term outcomes

We report long-term outcomes for allogeneic peripheral blood stem cell (PBSC) recipients, evaluating cumulative incidence (CI) of acute and chronic graft-versus-host disease (GVHD), after use of tacrolimus with or without minidose methotrexate for GVHD prophylaxis. From April 1996 to April 1998, 97 adults underwent allogeneic PBSC transplantation. The first 49 received tacrolimus monotherapy as GVHD prophylaxis and the subsequent 48 received combination therapy. The median follow-up for survivors was 67 months. Compared to combination therapy, tacrolimus monotherapy resulted in enhanced neutrophil engraftment, shortened hospitalization, comparable rates of GVHD, and equivalent 100-day survival. The CI of grades II-IV acute GVHD was 35% with tacrolimus and 23% with the combination (P=0.19). The CI of III-IV GVHD was 22% for tacrolimus and 19% for the combination. CI of chronic GVHD was similar between the two groups (P=0.5). Patients with good-risk disease had superior overall survival (OS) when compared to those with poor-risk features (P<0.001). Within the good-risk disease category, patients receiving methotrexate had a trend towards improved OS (P=0.07). Multivariate analysis indicated good-risk disease status and methotrexate were independently associated with improved OS, progression-free survival (PFS), and relapse. In addition, patients developing chronic GVHD had a significantly reduced risk of relapse and improved PFS.

Once-daily intravenous busulfan and fludarabine: clinical and pharmacokinetic results of a myeloablative, reduced-toxicity conditioning regimen for allogeneic stem cell transplantation in AML and MDS

Postulating favorable antileukemic effect with improved safety, we used intravenous busulfan and fludarabine as conditioning therapy for allogeneic hematopoietic stem cell transplantation (HSCT) for acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). Fludarabine 40 mg/m2 and intravenous busulfan 130 mg/m2 were given once daily for 4 days, with tacrolimus-methotrexate as graft-versus-host disease (GVHD) prophylaxis. We treated 74 patients with AML and 22 patients with MDS; patients had a median age of 45 years (range, 19-66 years). Only 20% of the patients were in first complete remission (CR) at transplantation. Donors were HLA-compatible related (n = 60) or matched unrelated (n = 36). The CR rate for 54 patients with active disease was 85%. At a median follow-up of 12 months, 1-year regimen-related and treatment-related mortalities were 1% and 3%, respectively. Two patients had reversible hepatic veno-occlusive disease. Actuarial 1-year overall survival (OS) and event-free survival (EFS) were 65% and 52% for all patients, and 81% and 75% for patients receiving transplants in CR. Recipient age and donor type did not influence OS or EFS. Median busulfan clearance was 109 mL/min/m2 and median daily area-under-the-plasma-concentration-versus-time-curve was 4871 micromol-min, with negligible interdose variability in pharmacokinetic parameters. The results suggest that intravenous busulfan-fludarabine is an efficacious, reduced-toxicity, myeloablative-conditioning regimen for patients with AML or MDS undergoing HSCT.

Acute and chronic graft-versus-host disease after ablative and nonmyeloablative conditioning for allogeneic hematopoietic transplantation

In this study, we evaluated the influence of nonmyeloablative and ablative conditioning regimens on the occurrence of acute and chronic graft-versus-host disease (GVHD). One hundred thirty-seven patients undergoing matched-related sibling transplantations received the same GVHD prophylaxis. Myeloablative regimens included intravenous busulfan/cyclophosphamide (n=45) and fludarabine/melphalan (n=29). Patients in the nonmyeloablative group (n=63) received fludarabine/idarubicin/cytarabine, cisplatin/fludarabine/idarubicin, and fludarabine/cyclophosphamide. The actuarial rate of grade II to IV acute GVHD was significantly higher (hazard ratio, 3.6; 95% confidence interval, 1.5-8.8) in patients receiving ablative regimens (36%) compared with the nonmyeloablative group (12%). The cumulative incidence of chronic GVHD was higher in the ablative group (40%) compared with the nonmyeloablative group (14%). The rates were comparable within the first 200 days and were significantly higher in the ablative group beyond day 200 (hazard ratio, 5.2; 95% confidence interval, 1.2-23.2). Nonrelapse and GVHD-related mortality were relatively low in both groups. The use of the described nonmyeloablative preparative regimens was associated with a reduced incidence of grade II to IV acute GVHD and chronic GVHD compared with the busulfan/cyclophosphamide and fludarabine/melphalan transplant regimens. It is interesting to note that nonrelapse mortality with nonmyeloablative regimens in older and more debilitated patients was low (14%) and comparable to that achieved with standard high-dose regimens in younger patients.

CD25 expression on donor CD4+ or CD8+ T cells is associated with an increased risk for graft-versus-host disease after HLA-identical stem cell transplantation in humans

Graft-versus-host disease (GVHD) occurs in an unpredictable fashion after 30% to 50% of matched-related transplantations. The presence of increased frequencies of CD4(+)CD25(+) regulatory T cells in donor grafts has been shown to ameliorate GVHD after allogeneic transplantation in murine models. To determine whether a similar relationship exists in humans, we quantitated the coexpression of CD25 on CD4(+) and CD8(+) T cells within 60 donor grafts infused into matched siblings and examined GVHD incidence in the respective recipients. Recipients in whom GVHD developed received donor grafts containing significantly higher frequencies of CD4(+) T cells coexpressing CD25 than those who did not (median, 9.26% vs 2.22%; P =.004). Frequencies of donor graft CD8(+) T cells coexpressing CD25 were also higher (0.65% vs 0.14%; P =.002). Furthermore, transplant recipients who received grafts containing fewer CD4(+)CD25(+) and CD8(+)CD25(+) T cells were less likely to acquire acute GVHD, even though these donor-recipient pairs were similar to others with respect to relevant clinical variables. These data suggest that the coexpression of CD4 and CD25 may be insufficient to identify regulatory T cells in humans and that increased frequencies and numbers of CD25(+) T cells in donor grafts is associated with GVHD in transplant recipients.

Sirolimus, tacrolimus, and low-dose methotrexate for graft-versus-host disease prophylaxis in mismatched related donor or unrelated donor transplantation

We studied the feasibility and activity of adding sirolimus to tacrolimus and low-dose methotrexate as graft-versus-host disease (GVHD) prophylaxis in recipients of alternative donor transplants. Forty-one patients with hematologic malignancies were conditioned with cyclophosphamide and total body irradiation. Marrow stem cells were from an HLA-A, -B, and -DR compatible, unrelated donor (n = 26, 68%), from a 5 of 6 antigen-matched unrelated donor (n = 8, 20%), or from a 5 of 6 antigen-matched family member (n = 5, 12%). Therapeutic serum levels of sirolimus were attained in most patients. All evaluable patients engrafted. An absolute neutrophil count of 500/microL was achieved on day +18 (range, 11-32 days). Sustained platelet counts of more than 20 000/ microL were attained on day +29 (range, 14-98 days). Grades 0-I acute GVHD occurred in 75% of patients. Grades II, III, and IV acute GVHD occurred in 13%, 8%, and 5%, respectively (total grades II-IV GVHD, 26%). Median survival is 366 days (95% CI 185, not estimable) and actuarial survival at 1 year is 52%. Oral sirolimus is tolerable, adequate blood levels are achievable, and there is a low rate of acute GVHD compared with historical data in this high-risk population. This novel agent is worthy of further study in allogeneic transplantation.

Regimen-related toxicity after fludarabine-melphalan conditioning: a prospective study of 31 patients with hematologic malignancies

A total of 31 consecutive patients with hematologic malignancies who were considered poor candidates for TBI underwent allogeneic stem cell transplantation after conditioning with fludarabine and melphalan. A total of 25 matched sibling recipients received fludarabine 25 mg/m(2) x 5 days and melphalan 70 mg/m(2) x 2 days. For unrelated and haploidentical donor recipients, fludarabine was increased to 30 mg/m(2) and ATG 30 mg/kg x 4 days was added. Graft-versus-host disease prophylaxis consisted of tacrolimus and mini methotrexate. All patients engrafted. Regimen-related toxicity was considerable and included mainly renal, hepatic and mucosal toxicity. There were seven regimen-related-deaths including two VOD, two pulmonary, one renal, one cardiac and one mucosal toxicity. One case of fatal pulmonary toxicity death could be attributed to pre-existing pulmonary damage. Progression-free survival at 12 months was 44% (90% CI: 30-58%) for recipients of HLA-identical sibling transplants and 33% (90% CI: 21-45%) for all patients. In conclusion, the fludarabine-melphalan regimen leads to consistent engraftment. The regimen-related toxicity is considerable and cannot be explained solely by patient selection. Cardiac toxicity is emerging as a unique toxicity of this regimen. Despite toxicity, fludarabine-melphalan has considerable activity and leads to durable remission in a proportion of patients.

Non-T-cell-depleted HLA haploidentical stem cell transplantation in advanced hematologic malignancies based on the feto-maternal michrochimerism

Feto-maternal microchimerism suggests that immunologic tolerance exists between mother and fetus. Based on this hypothesis, we performed haploidentical stem cell transplantation (SCT) without T-cell depletion (TCD) in 5 patients with advanced hematologic malignancies. HLA incompatibilities for graft-versus-host disease (GVHD) direction included 3-loci mismatches in 4 patients, and 2-loci mismatches in one patient. Recipient chimeric cells were detected in all patients. The prophylaxis against GVHD was tacrolimus with minidose methotrexate. Engraftment was obtained in all patients. An acute GVHD of less than or equal to grade 2 developed in all patients except one who developed tacrolimus encephalopathy. Two patients died, 1 from fungal pneumonia and 1 from disease progression. The other 3 patients survived, with one patient in complete remission. These observations suggest that haploidentical SCT based on the feto-maternal microchimerism without TCD is possible.

Patients with acute lymphoblastic leukaemia allografted with a matched unrelated donor may have a lower survival with a peripheral blood stem cell graft compared to bone marrow

We analysed data for 213 patients with ALL and AML who received either peripheral blood stem cells (PBSC) (n=74) or bone marrow (BM) (n=139) from an HLA-matched unrelated donor (EBMT acute leukaemia registry; January 1994 to January 1999). The two groups of patients (by cell source) were comparable with respect to age, sex, disease status, year at transplant and graft T cell depletion. Engraftment was achieved in about 90% regardless of stem cell source or leukaemia type. Kinetics of neutrophil and platelet recovery, similar for both sources in ALL patients, were faster for PBSC in AML patients. The incidence of acute graft-versus-host disease was similar for both sources in AML patients, but higher for PBSC in ALL patients (74 vs 54%, P=0.05). The 1-year probability of chronic graft-versus-host disease was 40 and 45% (P=0.66) in ALL patients compared to 49 and 35% (P=0.13) in AML patients (PBSC vs BM). In AML patients, none of the following differed significantly with cell source: transplant-related mortality, relapse incidence, leukaemia-free survival and overall survival. In ALL patients, the transplant-related mortality for PBSC vs BM was 61 vs 47% (P=0.13), the relapse incidence was 47 vs 39% (P=0.17), the leukaemia-free survival was 21 vs 32% (P=0.04) and the overall survival was 24 vs 34% (P=0.04). These data suggest that the short-term outcome of allogeneic PBSC is not significantly different from that of BM in AML patients who underwent a transplant from a matched unrelated donor but, conversely, that survival with PBSC may be decreased in ALL patients. In conclusion, the source of transplant cells needs to be evaluated by disease, especially when dealing with unrelated donors.