Omission of day +11 methotrexate after allogeneic bone marrow transplantation is associated with increased risk of severe acute graft-versus-host disease

Clinical effects of tacrolimus blood concentrations early after allogeneic hematopoietic stem cell transplantation

BACKGROUND AIMS

Tacrolimus (TAC) plus short-term methotrexate (stMTX) is used for graft-versus-host disease (GVHD) prophylaxis after allogeneic hematopoietic stem cell transplantation (allo-HSCT). TAC blood concentrations are frequently adjusted to enhance the graft-versus-leukemia/lymphoma effect or attenuate severe GVHD. Limited information is available on the clinical impact of these adjustments and the optimal time to perform them in order to achieve good clinical outcomes.

METHODS

We retrospectively analyzed 211 patients who underwent allo-HSCT at our institutes.

RESULTS

Higher TAC concentrations in week 3 correlated with a significantly higher cumulative incidence of relapse (CIR) (P = 0.03) and lower nonrelapse mortality (P = 0.04). The clinical impact of high TAC concentrations in week 3 on CIR was detected in the refined disease risk index: low/intermediate (P = 0.04) and high (P < 0.01), and conditioning regimens other than cyclophosphamide/total body irradiation and busulfan/cyclophosphamide (P = 0.07). Higher TAC concentrations in week 1 correlated with a lower grade 2-4 acute GVHD rate (P = 0.01). Higher TAC concentrations in weeks 2 and 3 correlated with slightly lower (P = 0.05) and significantly lower (P = 0.02) grade 3-4 acute GVHD rates, respectively. Higher TAC concentrations in weeks 1 and 3 were beneficial for severe acute GVHD in patients with a human leukocyte antigen-matched donor (P = 0.03 and P < 0.01, respectively), not treated with anti-thymocyte globulin (P = 0.02 and P = 0.02, respectively), and receiving three stMTX doses (P = 0.03 and P = 0.02, respectively).

CONCLUSIONS

The clinical impact of TAC concentrations varied according to patient characteristics, including disease malignancy, conditioning regimens, donor sources, and GVHD prophylaxis. These results suggest that TAC management needs to be based on patient profiles.

Hepatic graft-versus-host disease: what we know, when to biopsy, and how to diagnose

Graft-versus-host disease (GVHD) is one of the serious complications that may develop after hematopoietic cell transplantation (HCT), for hematologic malignancies, solid organ transplantation, and other hematologic disorders. GVHD develops due to T lymphocytes present in the graft attacking the host antigens, which results in tissue damage. A significant number of HCT patients develop acute or chronic GVHD, which may affect multiple organs including the liver. The diagnosis of hepatic GVHD (hGVHD) is challenging as many other conditions in HCT patients may lead to liver dysfunction. Particularly challenging among the various conditions that give rise to liver dysfunction is differentiating sinusoidal obstruction syndrome and drug-induced liver injury (DILI) from hGVHD on clinical grounds and laboratory tests. Despite the minimal risks involved in performing a liver biopsy, the information gleaned from the histopathologic changes may help in the management of these very complex patients. There is a spectrum of histologic features found in hGVHD, and most involve histopathologic changes affecting the interlobular bile ducts. These include nuclear and cytoplasmic abnormalities including dysmorphic bile ducts, apoptosis, and cholangiocyte necrosis, among others. The hepatitic form of hGVHD typically shows severe acute hepatitis. With chronic hGVHD, there is progressive bile duct loss and eventually fibrosis. Accurate diagnosis of hGVHD is paramount so that timely treatment and management can be initiated. Techniques to prevent and lower the risk of GVHD from developing have recently evolved. If a diagnosis of acute GVHD is made, the first-line of treatment is steroids. Recurrence is common and steroid resistance or dependency is not unusual in this setting. Second-line therapies differ among institutions and have not been uniformly established. The development of GVHD, particularly hGVHD, is associated with increased morbidity and mortality.

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.

Impact of omitting post-transplant minidose-methotrexate doses in allogeneic hematopoietic cell transplantation

Given prophylactic methotrexate (MTX) is often held in the setting of toxicity we investigated the impact of omitting minidose-MTX dose(s). Outcomes were compared between patients who had 1-3 doses omitted and those who received all four planned doses of minidose-MTX. Of 370 consecutive patients, 50 had MTX dose(s) omitted. When MTX was omitted, initial management was mycophenolate mofetil (MMF; 36/50 patients) with or without corticosteroids (14/50 patients). Rates of grade 3-4 acute GVHD were similar between groups. Omission of minidose-MTX resulted in an increased risk of chronic GVHD (cGVHD; HR 2.27; p = .024) and decreased overall survival (HR 1.61; p = .024). However, other transplant-related outcomes were comparable. In summary, omission of minidose-MTX doses was not associated with an increased risk of acute GVHD when an alternative was added (e.g. MMF ± corticosteroids). This did not abrogate the increased risk of cGVHD or decreased overall survival.

Omission of day +11 methotrexate dose and allogeneic hematopoietic cell transplantation outcomes: results of a systematic review/meta-analysis

Allogeneic hematopoietic cell transplantation (allo-HCT) is potentially curative for patients with malignant and benign hematologic conditions. Graft-versus-host disease (GVHD) is a known complication of allo-HCT that results in significant morbidity and mortality. A common GVHD prophylaxis strategy combines a calcineurin inhibitor with methotrexate. When mucositis and organ toxicity develop, the day +11 dose is frequently omitted to limit further organ damage. The potential impact of this practice on allo-HCT outcomes is unclear as published data show conflicting results. Thus, we performed a systematic review/meta-analysis of the available literature to assess the impact of omitting day +11 methotrexate on allo-HCT recipients. Data were extracted in relation to benefits (overall survival [OS], progression-free survival [PFS]) and harms (acute and chronic GVHD, non-relapse mortality [NRM], and relapse). Pooled OS rate favored those who received day +11 methotrexate vs. those who did not (HR = 1.21; 95% CI = 1.02-1.43; p = 0.03). There was no significant difference in pooled rates of PFS (HR = 0.96; 95% CI = 0.60-1.52; p = 0.85), acute GVHD (HR = 1.03; 95% CI = 0.35-2.98; p = 0.96), chronic GVHD (HR = 0.83; 95% CI = 0.44-1.57; p = 0.57), NRM (HR = 0.86; 95% CI = 0.67-1.11; p = 0.25), and relapse (HR = 0.97; 95% CI = 0.75-1.26; p = 0.83) between the two groups. Large prospective multicenter studies are needed to better define the significance of day +11 methotrexate omission.

Efficacy of folinic acid rescue following MTX GVHD prophylaxis: results of a double-blind, randomized, controlled study

The use of methotrexate (MTX) for graft-versus-host disease (GVHD) prophylaxis is associated with increased rates of organ-specific toxicities. Despite limited data, the European Society for Blood and Marrow Transplantation-European LeukemiaNet working group recommend the use of folinic acid (FA) rescue to reduce MTX toxicity after allogeneic hematopoietic cell transplantation (allo-HCT). In a multicenter, double-blind, randomized, controlled trial, we explored whether FA rescue reduces MTX-induced toxicity. We enrolled patients undergoing allo-HCT with myeloablative conditioning with peripheral blood stem cell grafts, with GVHD prophylaxis consisting of cyclosporine and MTX. Patients were randomized to receive FA or placebo starting 24 hours after each MTX dose and continuing over 24 hours in 3 to 4 divided doses. The primary end point was the rate of grades 3 and 4 oral mucositis. After enrollment of 52 patients (FA, n = 28; placebo, n = 24), preplanned interim analysis revealed similar rates of grade 3 and 4 (46.6% vs 45.8%; P = .97) and grades 1 to 4 (83.3% vs 77.8%; P = .65) oral mucositis. With a median follow-up of 17 (range, 4.5-50) months, there was no difference in the rates of acute and chronic GVHD, disease relapse, nonrelapse mortality, and overall survival. These interim results did not support continuation of the study. We conclude that FA rescue after MTX GVHD prophylaxis does not decrease regimen-related toxicity or affect transplantation outcomes. This study was registered at clinicaltrials.gov as #NCT02506231.

Leucovorin Rescue After Methotrexate Graft-Versus-Host Disease Prophylaxis Shortens the Duration of Mucositis, Time to Neutrophil Engraftment, and Hospital Length of Stay

Oropharyngeal mucositis (OPM) is common following conditioning for allogeneic hematopoietic cell transplantation (alloHCT) and results in pain, functional status decline, need for nutritional support, infections, and prolonged length of stay (LOS). Methotrexate (MTX) graft-versus-host disease (GVHD) prophylaxis exacerbates OPM and slows hematopoietic engraftment, which may prolong LOS. Previous studies have demonstrated reduced OPM and more rapid engraftment when leucovorin (LCV) is added following MTX GVHD prophylaxis, yet this practice is controversial. The primary objective of this study was to determine if the routine addition of LCV to MTX GVHD prophylaxis impacted the duration of grade 2 to 4 OPM. Secondary objectives included determination of the incidence of grade 2 to 4 and grade 3 to 4 OPM, time to engraftment, ability to receive all four planned MTX doses, use of total parenteral nutrition (TPN), use of patient-controlled analgesia (PCA), LOS, incidence of acute or chronic GVHD, relapse-free survival (RFS), and overall survival (OS). This single-center, retrospective cohort study compared alloHCT outcomes for 46 adult patients who received MTX 15 mg/m² day +1; MTX 10 mg/m² days +3, +6, and +11 (15-10-10-10); and LCV following days +3, +6, and +11 MTX compared to historical controls who did not. Patients who received myeloablative conditioning (MAC) and matched related donor (MRD) or matched unrelated donor (MUD) alloHCT were included. The addition of LCV resulted in significant reductions in the duration of grade 2 to 4 OPM (median, 6 days versus 10.5 days; P = .0004), duration of TPN (7 days versus 16 days; P = .001), PCA use (16% versus 39%; P = .0001), time to neutrophil engraftment (median, 18 versus 20 days; P = .008), and LOS (median, 27.5 versus 31 days; P = .017) compared to historical controls. Patients who received routine LCV had similar incidences of grade 2 to 4 acute GVHD (30% versus 28%; relative risk [RR], 1.08; 95% confidence interval [CI], .57 to 2.03; P = 1.0), grade 3 or 4 acute GVHD (2% versus 7%; RR, .33; 95% CI, .04 to 3.09; P = .62) and chronic GVHD (37% versus 30%; RR, 1.21; 95% CI, .67 to 2.16; P = .66) compared to historical controls. Graft failure occurred in 2% of patients in each group. In a multivariable logistic regression analysis, RFS was similar in the LCV group compared to historical controls (HR, .86; 95% CI, .24 to 1.2; P = .13); however, OS was improved in patients who received LCV (HR, .33; 95% CI, .13 to .83; P = .01). In patients undergoing MAC MRD/MUD alloHCT with four planned doses of MTX GVHD prophylaxis (15-10-10-10), LCV was associated with reduced duration of grade 2 to 4 OPM, faster neutrophil engraftment, reduced utilization of TPN and PCA, and shortened LOS compared to historical controls not receiving routine LCV. These benefits were apparent without an increased risk of acute or chronic GVHD or adverse effect on RFS. LCV improved OS; however, it is unclear if this was due to the intervention or an unmeasured confounder. A randomized, prospective trial of LCV prophylaxis in patients receiving MAC alloHCT and MTX 15-10-10-10 GVHD prophylaxis is warranted to confirm our findings.

Graft-versus-host disease prophylaxis: Pathophysiology-based review on current approaches and future directions

Graft-versus-host disease (GvHD) was first described in 1959, since then major efforts have been made in order to understand its physiopathology and animal models have played a key role. Three steps, involving different pathways, have been recognised in either acute and chronic GvHD, identifying them as two distinct entities. In order to reduce GvHD incidence and severity, prophylactic measures were added to transplant protocols. The combination of a calcineurin inhibitor (CNI) plus an antimetabolite remains the standard of care. Better knowledge of GvHD pathophysiology has moved this field forward and nowadays different drugs are being used on a daily basis. Improving GvHD prophylaxis is a major goal as it would translate into less non-relapse mortality and better overall survival. As compared to CNI plus methotrexate the combination of CNI plus mycophenolate mophetil (MMF) allows us to obtain similar results in terms of GvHD incidence but a lower toxicity rate in terms of neutropenia or mucositis. The use of ATG has been related to a lower risk of acute and chronic GvHD in prospective randomized trials as well as the use of posttransplant Cyclophosphamide, with no or marginal impact on overall survival but with an improvement in GvHD-relapse free survival (GRFS). The use of sirolimus has been related to a lower risk of acute GvHD and significantly influenced overall survival in one prospective randomized trial. Other prospective trials have evaluated the use of receptors such as CCR5 or α4β7 to avoid T-cells trafficking into GvHD target organs, cytokine blockers or immune check point agonists. Also, epigenetic modifiers have shown promising results in phase II trials. Attention should be paid to graft-versus-leukemia, infections and immune recovery before bringing new prophylactic strategies to clinical practice. Although the list of novel agents for GvHD prophylaxis is growing, randomized trials are still lacking for many of them.

The Impact of Methylenetetrahydrofolate Reductase C677T Polymorphism on Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation with Methotrexate Prophylaxis

Pharmacogenomics can explain the inter-individual differences in response to drugs, including methotrexate (MTX) used for acute graft-versus-host disease (aGVHD) prophylaxis during hematopoietic stem cell transplantation (HSCT). In real-world practice, preplanned MTX dose is arbitrarily modified according to observed toxicity which can lead to unexpected and severe aGVHD development. We aimed to validate the influence of MTHFR C677T polymorphism on the outcomes of allogenic HSCT in a relatively under-represented homogenous Asian population. A total of 177 patients were divided into 677TT group versus 677C-carriers (677CT+677CC), and clinical outcomes along with baseline characteristics were analyzed and compared. Although there was a tendency towards increased peak liver function test results and accordingly greater delta values between the highest and the baseline in 677TT group, we found no associations between genotypes and hepatotoxicity. However, the incidence of acute liver GVHD (≥ grade 2) was significantly higher in the 677TT group than in the 677CC + 677CT group (P = 0.016). A total of 25 patients (14.1%) expired due to transplantation related mortality (TRM) during the first 180 days after HSCT. Patients carrying 677TT genotype were more likely to experience early TRM than 677C-carriers. The same pattern was observed in the cumulative TRM rate, and 677TT genotype patients were more prone to cumulative TRM (P = 0.010). This translated into shorter OS for patients with 677TT compared to 677C-carriers (P = 0.010). The 3-year survival after HSCT was 29.9% for 677TT cases and 47.1% for 677C-carriers. The multivariate analysis identified 677TT genotype (HR = 1.775. 95% CI 1.122–2.808, P = 0.014) and non-CR state (HR = 2.841. 95% CI 1.627–4.960, P<0.001) as predictors for survival. In conclusion, the MTHFR 677TT genotype appears to be associated with acute liver GVHD, and represent a risk factor for TRM and survival in patients undergoing HSCT with MTX as GVHD prophylaxis.

Cyclosporine Plus Methotrexate or Cyclosporine Plus Mycophenolate Mofetil as Graft Versus Host Disease Prophylaxis in Acute Leukemia Transplant: Comparison of Toxicity, Engraftment Kinetics and Transplant Outcome

We sought to compare two graft-versus-host disease (GVHD) prophylaxis regimen, cyclosporine and methotrexate (CsA+MTX) with CsA+mycophenolate mofetil (MMF) in 77 acute leukemia patients who underwent hematopoietic stem cell transplant (HSCT) between January 2008 and March 2013. Fifty-three patients received CsA+MTX while 24 received CsA+MMF. The incidence of grade 3-4 mucositis and grade 3-4 diarrhea was 74 and 6 % with CsA+MTX compared to 33 % and 21 % with CsA+MMF (P = 0.001 and 0.09 respectively). Forty-two (79 %) patients in CsA+MTX group required total parenteral nutrition compared to 14 (58 %) in CsA+MMF group (P = 0.09). The incidence of engraftment fever was 17 % with CsA+MTX and 41 % with CsA+MMF (P = 0.02). The median time to neutrophil and platelet engraftment was 14 days and 13 days with CsA+MTX compared to 12 days and 10 days with CsA+MMF (P = 0.003 and 0.08 respectively). The incidence of any grade and grade II-IV acute GVHD was 45 and 13 % with CsA+MTX compared to 42 and 29 % with CsA+MMF (P = NS). Incidence of overall and extensive chronic GVHD was 57 and 38 % with CsA+MTX compared to 42 and 17 % with CsA+MMF (P = NS). Incidence of relapse was 38 % with CsA+MTX compared to 33 % with CsA+MMF (P = NS). TRM was 6 % with CsA+MTX and 21 % with CsA+MMF (P = NS). At 2 years, overall survival (OS) was 64 % in CsA+MTX group compared to 46 % in CsA+MMF group (P = NS). We conclude that CsA+MMF is associated with lesser toxicity, faster myeloid engraftment and similar rates of acute and chronic GVHD, TRM, relapse and OS compared to CsA+MTX in acute leukemia transplant.

Substitution of methotrexate with corticosteroid for acute graft-versus-host disease prevention in transplanted patients who develop methotrexate toxicity

Methotrexate (MTX) toxicity can hamper the administration of all planned doses in acute graft-versus-host disease (GVHD) prophylaxis following allogeneic hematopoietic stem cell transplantation. Reduction or omission of MTX doses results in an increased risk of acute GVHD. In this prospective observational study, we compared the incidence of GVHD and the transplant outcomes between patients who received the full treatment course of MTX (group 1), patients in whom MTX doses were omitted if MTX toxicity developed (group 2), and patients receiving corticosteroid instead of MTX if MTX toxicity developed (group 3). The cumulative incidence of grades II-IV acute GVHD at 100 days post-transplantation was 22.2 % in group 1, 43.6 % in group 2, and 25.0 % in group 3 (P = 0.132). The risk of grades II-IV acute GVHD in group 2 was higher than that in group 1 (hazard ratio (HR) 3.262, P = 0.016), but the risk in group 3 was similar to that in group 1 (HR 0.960, P = 0.890). Group 3 also showed a trend towards a lower risk of chronic GVHD compared to the other groups. The cumulative risk of chronic GVHD at 2 years was 73.9, 71.6, and 33.3 % in groups 1, 2, and 3, respectively (P = 0.084). However, a likely higher relapse incidence and infection-related mortality in group 3 produced a trend towards the lowest relapse-free survival (2-year RFS, 46.3, 49.3, and 25.0 % in groups 1, 2, and 3, respectively; P = 0.329) and overall survival (2-year OS, 45, 52.3, and 25 %, respectively; P = 0.322) in group 3. Although the substitution of MTX with corticosteroid ameliorates the increased risk of GVHD in patients in which it is imperative to omit its dose, its negative impact on relapse and infection risk does not result in favorable transplant outcomes.

Tacrolimus versus Cyclosporine after Hematopoietic Cell Transplantation for Acquired Aplastic Anemia

Combinations of cyclosporine (CSP) with methotrexate (MTX) have been widely used for immunosuppression after allogeneic transplantation for acquired aplastic anemia. We compared outcomes with tacrolimus (TAC)+MTX versus CSP+MTX after transplantation from HLA-identical siblings (SIB) or unrelated donors (URD) in a retrospective cohort of 949 patients with severe aplastic anemia. Study endpoints included hematopoietic recovery, graft failure, acute graft-versus-host disease (GVHD), chronic GVHD, and mortality. TAC+MTX was used more frequently in older patients and, in recent years, in both SIB and URD groups. In multivariate analysis, TAC+MTX was associated with a lower risk of mortality in URD recipients and with slightly earlier absolute neutrophil count recovery in SIB recipients. Other outcomes did not differ statistically between the 2 regimens. No firm conclusions were reached regarding the relative merits of TAC+MTX versus CSP+MTX after hematopoietic cell transplantation for acquired aplastic anemia. Prospective studies would be needed to determine whether the use of TAC+MTX is associated with lower risk of mortality in URD recipients with acquired aplastic anemia.

Cyclosporine in combination with mycophenolate mofetil versus methotrexate for graft versus host disease prevention in myeloablative HLA-identical sibling donor allogeneic hematopoietic cell transplantation

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality in allogeneic hematopoietic cell transplantation (HCT) despite current prophylaxis. Methotrexate (MTX) with a calcineurin inhibitor (CNI) is the current standard, however, has several toxicities. Mycophenolate mofetil (MMF) is frequently used in reduced-intensity HCT, but data in myeloablative transplants is limited. We thus retrospectively identified 241 patients who underwent myeloablative HCT from an HLA-identical sibling donor; 174 patients received cyclosporine (CSA) + MMF and 67 received CSA+MTX. Patients receiving MMF + CSA had rapid neutrophil (median 11 vs. 19 days with MTX+CSA), and platelet recovery (median 19 vs. 25 days), lower incidence of severe mucositis by OMAS (19% vs. 53%), and shorter length of hospital stay (median 25 vs. 36 days) (P < 0.001 for all comparisons). There were no significant differences in incidence of grade 2-4 (MMF+CSA 37% vs. MTX+CSA 39%) or 3-4 acute GVHD (17% vs. 12%), chronic GVHD (46% vs. 56%), relapse (28% vs. 27%), non-relapse mortality (20% vs. 27%), or overall survival (47% vs. 44%) (P = NS for all). However, in multivariable analysis, the use of MMF+CSA was associated with an increased risk of severe grade 3-4 acute GVHD (HR 2.92, 95% CI 1.2-7.15, P = 0.019). There were no differences between the two regimens in multivariable analyses for other survival outcomes. This analysis demonstrates that the use of MMF in myeloablative sibling donor transplantation is well tolerated. However, there may be an increased risk of severe GVHD with MMF+CSA compared to MTX+CSA. Further studies evaluating optimal dosing strategies are needed.

Evaluation of risk for graft-versus-host disease in children who receive less than the full doses of mini-dose methotrexate for graft-versus-host disease prophylaxis in allogeneic hematopoietic stem cell transplantation

PURPOSE

The use of cyclosporine and mini-dose methotrexate (MTX) is a common strategy for graft-versus-host disease (GVHD) prophylaxis in allogeneic transplants. We investigated whether patients who receive fewer than the planned MTX doses are at increased risk for GVHD.

METHODS

The study cohort included 103 patients who received allogeneic transplants at the Department of Pediatrics of The Catholic University of Korea College of Medicine, from January 2010 to December 2011. MTX was administered on days 1, 3, 6, and 11 after transplant at a dose of 5 mg/m(2) each. Within the cohort, 76 patients (74%) received all 4 doses of MTX [MTX(4) group], while 27 patients (26%) received 0-3 doses [MTX(0-3) group].

RESULTS

Although there was no difference in neutrophil engraftment between the 2 groups, platelet engraftment was significantly faster in the MTX(4) group (median, 15 days), compared to the MTX(0-3) group (median, 25 days; P=0.034). The incidence of grades II-IV acute GVHD was not different between the MTX(4) and MTX(0-3) groups (P=0.417). In the multivariate study, human leukocyte antigen mismatch was the most significant factor causing grades II-IV acute GVHD (P=0.002), followed by female donor to male recipient transplant (P=0.034). No difference was found between the MTX(4) and MTX (0-3) groups regarding grades III-IV acute GVHD, chronic GVHD, and disease-free survival.

CONCLUSION

Our results indicate that deviations from the full dose schedule of MTX for GVHD prophylaxis do not lead to increased incidence of either acute or chronic GVHD.

ABCB1 C3435T genetic polymorphism on population pharmacokinetics of methotrexate after hematopoietic stem cell transplantation in Korean patients: a prospective analysis

BACKGROUND

Methotrexate (MTX) is often used to prevent graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). However, MTX has great pharmacokinetic variability and its use can result in fatal complications and/or infections after HSCT.

OBJECTIVES

The purposes of this study were to build a population pharmacokinetic model of MTX treatment in Korean patients who have undergone HSCT and to identify covariates, including genetic polymorphisms, that affect the pharmacokinetic properties of MTX.

METHODS

Clinical characteristics and MTX concentration data for 20 post-HSCT patients were collected. For each patient, ABCB1, ABCC2, ATIC, GGH, MTHFR, and TYMS genotyping was performed. Population pharmacokinetic analysis was performed using the NONMEM program. Analysis of MTX pharmacokinetic properties was accomplished using a 2-compartment pharmacokinetic model that incorporated first-order conditional estimation methods with interaction. The effects of a variety of demographic and genetic factors on MTX disposition were investigated.

RESULTS

The study population consisted of 12 men (60%) and 8 women (40%). Median age and body weight were 28 years (range, 18-49 years) and 55.6 kg (range, 44.8-80.8 kg), respectively. Within the study population, the estimated mean MTX clearance (CL) was 7.08 L/h, whereas the mean central compartment volume (V(1)) of MTX distribution was 19.4 L. MTX CL was significantly affected by glomerular filtration rate (GFR), penicillin use, and the ABCB1 3435 genotype. Interindividual variabilities for CL and V(1) were 21.6% and 73.3%. A 10-mL/min GFR increase was associated with a 32% increase in mean MTX CL, whereas penicillin use was associated with a decrease in MTX CL of 61%. MTX CL was significantly greater (by ∼21%) in patients with the ABCB1 3435 CC and CT genotype than in those with the ABCB1 3435 TT genotype (P < 0.001).

CONCLUSIONS

There was great interindividual variation in MTX pharmacokinetic properties in patients who had undergone HSCT. GFR, concurrent penicillin use, and the presence of the ABCB1 3435 C<T genotypes significantly affected MTX CL. The MTX population pharmacokinetic model developed here may provide useful information for individualizing MTX therapy after HSCT.

Should methotrexate plus calcineurin inhibitors be considered standard of care for prophylaxis of acute graft-versus-host disease?

In a rapidly developing field, one can always anticipate that different interpretations of similar data will coexist. Stem cell transplanters can be a contentious lot, especially in the absence of controlled randomized trials. Thus, although improvements in the basic understanding of acute graft-versus-host disease (aGVHD) has led to many testable hypotheses in the management of GVHD, there remains little consensus regarding the most effective and least toxic approach to GVHD prevention. In the 1980s, the comparison would have been between cyclosporine-based regimens and ex vivo T cell depletion (TCD). Although ex vivo TCD is still used in some settings, pharmacologic-based therapy and in vivo TCD with serotherapy now predominate. This review is meant to highlight the advantages and disadvantages of the "standard of care" and assess the prospects for future regimens that may be more effective.

Cotransplantation of HLA-identical sibling culture-expanded mesenchymal stem cells and hematopoietic stem cells in hematologic malignancy patients

Mesenchymal stem cells (MSCs) are found in a variety of tissues, including human bone marrow; secrete hematopoietic cytokines; support hematopoietic progenitors in vitro; and possess potent immunosuppressive properties. We hypothesized that cotransplantation of culture-expanded MSCs and hematopoietic stem cells (HSCs) from HLA-identical sibling donors after myeloablative therapy could facilitate engraftment and lessen graft-versus-host disease (GVHD); however, the safety and feasibility of this approach needed to be established. In an open-label, multicenter trial, we coadministered culture-expanded MSCs with HLA-identical sibling-matched HSCs in hematologic malignancy patients. Patients received either bone marrow or peripheral blood stem cells as the HSC source. Patients received 1 of 4 study-specified transplant conditioning regimens and methotrexate (days 1, 3, and 6) and cyclosporine as GVHD prophylaxis. On day 0, patients were given culture-expanded MSCs intravenously (1.0-5.0 x 10(6)/kg) 4 hours before infusion of either bone marrow or peripheral blood stem cells. Forty-six patients (median age, 44.5 years; range, 19-61 years) received MSCs and HLA-matched sibling allografts. MSC infusions were well tolerated, without any infusion-related adverse events. The median times to neutrophil (absolute neutrophil count > or = 0.500 x 10(9)/L) and platelet (platelet count > or = 20 x 10(9)/L) engraftment were 14.0 days (range, 11.0-26.0 days) and 20 days (range, 15.0-36.0 days), respectively. Grade II to IV acute GVHD was observed in 13 (28%) of 46 patients. Chronic GVHD was observed in 22 (61%) of 36 patients who survived at least 90 days; it was extensive in 8 patients. Eleven patients (24%) experienced relapse at a median time to progression of 213.5 days (range, 14-688 days). The probability of patients attaining disease- or progression-free survival at 2 years after MSC infusion was 53%. Cotransplantation of HLA-identical sibling culture-expanded MSCs with an HLA-identical sibling HSC transplant is feasible and seems to be safe, without immediate infusional or late MSC-associated toxicities. The optimal MSC dose and frequency of administration to prevent or treat GVHD during allogeneic HSC transplantation should be evaluated further in phase II clinical trials.

Life-threatening graft-vs-host disease

Hematopoietic stem cell transplant (SCT) is considered standard therapy for a variety of malignant and nonmalignant diseases. Graft-versus-host disease (GVHD) still represents today a major complication of hematopoietic SCT. Two types of GVHD have traditionally been recognized on the basis of the time of onset following transplantation, distinct pathobiological pathways, and different clinical presentations. The acute form commonly breaks out 2 to 6 weeks after transplantation, affecting up to 60% of patients receiving allogeneic transplants from HLA identical donors. Transfer of immunocompetent donor T cells contained in the graft may undergo alloreactivity against recipient cells because of major or minor histocompatibility antigens disparities between the donor and the immunosuppressed host. Target specificity in acute GVHD involves preferential injury to epithelial surfaces of the skin and mucous membranes, biliary ducts of the liver, and crypts of the intestinal tract. Chronic GVHD affects approximately 30% to 80% of patients surviving 6 months or longer after stem cell transplantation and is the leading cause of nonrelapse deaths occurring more than 2 years after transplantation. Chronic GVHD is a multiorgan syndrome with clinical features suggesting some autoimmune diseases, and possibly both alloreactive and autoreactive T cell clones are involved in its pathophysiology. Although GVHD may convey beneficial graft-versus-leukemia/lymphoma effects, it also entails a significant risk of morbidity and mortality. Patients with mild GVHD need only minimal, if any, immunosuppressive treatment, whereas prognosis of patients with extensive disease or resistant to standard immunosuppressive treatment may be dismal. Early recognition of GVHD followed by prompt therapeutic intervention may prevent the progression to higher-grade disease and improve the outcome for patients receiving hematopoietic SCT.

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.

A novel reduced intensity regimen for allogeneic hematopoietic stem cell transplantation associated with a reduced incidence of graft-versus-host disease

SUMMARY

In all, 55 patients at high risk or ineligible for a conventional allogeneic hematopoietic stem cell transplant (HSCT) received a regimen consisting of extracorporeal photopheresis, pentostatin, and reduced dose total body irradiation. The median age was 49 years (18-70 years); 44 received a sibling and 11 an unrelated HSCT; 44% were over the age of 50 years and 31% had undergone a prior HSCT. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate. Full donor chimerism was documented in 98% by day +100. The 1000-day nonrelapse mortality was 11%. The median follow-up is 502 days (154-1104 days). The 1- and 2-year overall survival (OS) and event-free survival (EFS) are 67, 58 and 55%, and 47%, respectively. Patients who had not received a prior HSCT or had less than three prior chemotherapy regimens had a 71% OS and 67% EFS at 1 year. Greater than grade II aGVHD developed in 9% and chronic GVHD (cGVHD) in 43%, and extensive in 12% and limited in 31%. Of the patients, 86% who engrafted had a disease response, 72% had complete and 14% partial responses. This novel reduced intensity preparative regimen was well tolerated and associated with a low incidence of transplant-related mortality and serious acute and cGVHD.

27. Transplantation immunology: organ and bone marrow

The discovery of the human MHC in 1967 launched the field of organ and tissue transplantation. More than 800,000 such transplants have been performed during this time. Although matching of donor and recipient for MHC antigens was shown to be of great importance and continues to be so, the development of pharmacologic agents and antilymphocyte antibodies that interfere with the process of graft rejection has had a crucial role in the success of organ transplantation during the past 2 decades. Enormous progress has been made in understanding the immunologic mechanisms of graft rejection and of graft-versus-host disease. The roles of antibodies, antigen-presenting cells, helper and cytotoxic T cells, immune cell surface molecules, and signaling mechanisms and the cytokines they release have been clarified. This understanding is leading to the development of newer immunosuppressive agents targeting various components of the rejection process. Combinations of these agents work synergistically, leading to lower doses and reduced toxicity. Similarly, the development of effective T-cell depletion techniques has been of great importance for bone marrow transplantation when an HLA-identical sibling is not available. The major obstacle to the performance of solid organ transplantation currently is the shortage of donor organs.