Mycophenolate mofetil: fully utilizing its benefits for GvHD prophylaxis

Development of a nomogram to predict the risk of secondary failure of platelet recovery in patients with β-thalassemia major after hematopoietic stem cell transplantation: a retrospective study

Background

Secondary failure of platelet recovery (SFPR) is a common complication that influences survival and quality of life of patients with β-thalassemia major (β-TM) after hematopoietic stem cell transplantation (HSCT).

Objectives

A model to predict the risk of SFPR in β-TM patients after HSCT was developed.

Design

A retrospective study was used to develop the prediction model.

Methods

The clinical data for 218 β-TM patients who received HSCT comprised the training set, and those for another 89 patients represented the validation set. The least absolute shrinkage and selection operator regression algorithm was used to identify the critical clinical factors with nonzero coefficients for constructing the nomogram. Calibration curve, C-index, and receiver operating characteristic curve assessments and decision curve analysis (DCA) were used to evaluate the calibration, discrimination, accuracy, and clinical usefulness of the nomogram. Internal and external validation were used to test and verify the predictive model.

Results

The nomogram based on pretransplant serum ferritin, hepatomegaly, mycophenolate mofetil use, and posttransplant serum albumin could be conveniently used to predict the SFPR risk of thalassemia patients after HSCT. The calibration curve of the nomogram revealed good concordance between the training and validation sets. The nomogram showed good discrimination with a C-index of 0.780 (95% CI: 70.3-85.7) and 0.868 (95% CI: 78.5-95.1) and AUCs of 0.780 and 0.868 in the training and validation sets, respectively. A high C-index value of 0.766 was reached in the interval validation assessment. DCA confirmed that the nomogram was clinically useful when intervention was decided at the possibility threshold ranging from 3% to 83%.

Conclusion

We constructed a nomogram model to predict the risk of SFPR in patients with β-TM after HSCT. The nomogram has a good predictive ability and may be used by clinicians to identify SFPR patients early and recommend effective preventive measures.

A Limited Sampling Strategy for Therapeutic Drug Monitoring of Mycophenolate Mofetil for Prophylaxis of Acute Graft-Versus-Host Disease in Allogeneic Stem Cell Transplantation

A universally accepted strategy for therapeutic drug monitoring (TDM) of mycophenolate mofetil (MMF) in the prevention of acute graft-versus-host disease (aGVHD) in allogenic hematopoietic stem cell transplantation (alloHSCT) does not exist. We explored the feasibility of developing a limited sampling strategy (LSS) for TDM of MMF in this setting. Patients undergoing alloHSCT received standard MMF-cyclosporine prophylaxis, with MMF administered twice daily (BD) for matched transplant recipients or thrice daily (TID) in haploidentical transplantation. Intensive blood sampling was carried out on day 7 and area under the concentration–time curve (AUC) of mycophenolic acid (MPA), the active metabolite, was estimated using noncompartmental analysis. The ability of MPA exposure defined by AUC_0-12 to discriminate between responders (patients who did not develop GVHD) and nonresponders (patients who developed GVHD) was determined by receiver operating characteristic curve analysis. Patients were divided into training and validation sets within BD and TID groups. Mathematical equations were developed from the training set to predict AUC_0-12 from an abbreviated AUC involving a limited number of sampling points. The equations were validated in the validation set by comparing the MPA AUC_0-12 predicted from LSS with the observed AUC_0-12. It was observed that patients with AUC_0-12 ≤18.99 mg*h/L had a higher risk of developing aGVHD [odds ratio (OR) = 2.63 (1.17 to 5.87), P = 0.06]. The benefit was more in matched transplant recipients [OR = 3.5 (1.30 to 9.49), P = 0.05] as compared to haploindentical transplant [OR = 2.8 (0.49 to 15.91), P = NS]. Using the mathematical equations, the observed AUC_0-12 was predicted with 92.31% accuracy in the BD subset and 100% accuracy in the TID subset for a combined accuracy of 94.76%. A set of just three samples that constituted the abbreviated AUC_1-4 was used to develop the predictive models. The LSS could be employed for the therapeutic monitoring of MMF particularly in patients undergoing matched hematopoietic stem cell transplantation.

Favorable Outcomes after Single Cord Blood Transplantation for Patients with High-Risk Hematologic Diseases: A Single-Institute Retrospective Analysis

The donor selection algorithm for cord blood (CB) with regards to matched related and unrelated donors has not been fully investigated. To assess the potential of CB transplantation (CBT) in patients with hematologic malignancies, especially for high-risk patients, we performed a single-institute retrospective analysis and compared the clinical outcomes of CBT with those of HLA-matched sibling and unrelated donor transplantation. We included 394 patients aged 16 years and older with hematologic diseases who received their first allogeneic hematopoietic cell transplantation between 1990 and 2018 at Kyoto University Hospital. These included 394 recipients of single unrelated cord blood units (UCB, n = 108), HLA-matched sibling donors (MSDs, n = 143), or HLA-matched unrelated donors (MUDs, n = 143). There was no significant difference in relapse-free survival (RFS) between UCB, MSD, and MUD recipients (P = .975). However, we found a significant interaction between transplant year and CBT outcomes (P = .010), with significantly better outcomes observed in the more recent years. Furthermore, we found that CBT showed better RFS than matched donor transplantation (hazard ratio [HR], 0.50; 95% confidence interval [CI], 0.30 to 0.84). This impact was more prominent in high-risk patients (HR, 0.35; 95% CI, 0.16 to 0.77), with lower relapse rates (HR, 0.25; 95% CI, 0.11 to 0.54), and comparable non-relapse mortality (NRM) compared to matched donor transplantation. Extensive chronic graft-versus-host disease was less frequently observed in CBT (HR, 0.58; 95% CI, 0.26 to 1.28). CBT associated with favorable outcomes, particularly in high-risk patients, with good RFS and low relapse rates without an increase in NRM in the single-institute study. Although the findings should be externally validated, CBT might serve as a reasonable donor choice, particularly in high-risk patients.

Area-under-the-Curve-Based Mycophenolate Mofetil Dosage May Contribute to Decrease the Incidence of Graft-versus-Host Disease after Allogeneic Hematopoietic Cell Transplantation in Pediatric Patients

Acute graft-versus-host disease (GvHD) remains the second leading cause of death, after disease relapse, in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). The medical records of 112 pediatric patients who underwent allo-HSCT from matched unrelated and haploidentical donors were analyzed. Patients were divided into two groups, according to the GvHD prophylactic regimen used. In the control group, GvHD prophylaxis consisted of cyclosporine A (CsA) and methotrexate (MTX) or CsA and mycophenolate mofetil (MMF) at a standard daily dose of 30 mg/kg. All subjects in the study group received tacrolimus (FK506) and MMF. In this group, MMF was subjected to therapeutic drug monitoring (TDM) through mycophenolic acid (MPA) area under the curve AUC_0–12. We found a statistically significant difference in both overall acute GvHD (p < 0.0001) and overall chronic GvHD (p < 0.05) incidence between the study and the control group. The initial daily MMF dose and the age at transplant in the study group proved to be inversely correlated (r = −0.523, p < 0.0001). The children under six years of age required a significantly higher daily MMF dose (p < 0.008). This study showed that pharmacological monitoring of MPA AUC_0–12 concentration allowed a reduction in the incidence of acute and chronic GvHD. MMF showed age-dependent pharmacokinetics due to greater drug clearance in younger children.

Pharmacokinetics of mycophenolic acid after haplo-hematopoietic stem cell transplantation in Japanese recipients

PURPOSE

Mycophenolate mofetil (MMF), a mycophenolic acid (MPA) prodrug, is used to prevent graft-versus-host disease (GVHD) in hematopoietic stem cell transplantation (HSCT). Although previous studies have reported that enterohepatic circulation (EHC) of MPA, which is usually observed in MMF-treated patients, does not occur in HSCT patients, it is unclear what happens in haploidentical-HSCT (haplo-HSCT) patients, who are using post-transplant cyclophosphamide. This study was conducted to investigate MPA pharmacokinetics in haplo-HSCT patients.

METHODS

Seventeen haplo-HSCT patients, who received MMF for GVHD prophylaxis, were enrolled in this study. We collected blood samples on days 14 and 28, and plasma MPA concentrations were measured by high-performance liquid chromatography; pharmacokinetic parameters such as area under the curve (AUC), mean residence time (MRT), and apparent oral clearance (CL/F) were measured with moment analysis. We also evaluated EHC as AUC_6-12h/AUC_0-12h.

RESULTS

There was no significant difference in MPA pharmacokinetic parameters between days 14 and 28. There was also no difference between the pharmacokinetic parameter changes and diarrhea. Additionally, varying plasma MPA concentrations suggested that MPA EHC did not occur.

CONCLUSION

In this study, we revealed the pharmacokinetics of MMF in Japanese haplo-HSCT recipients. Additionally, our study demonstrated that MPA EHC might not occur in Japanese haplo-HSCT recipients.

Use of unapproved or off-label drugs in Japan for the treatment of graft-versus-host disease and post-transplant viral infection

Many drugs are used for unapproved indications in Japan for post hematopoietic stem cell transplant (HCT) complications. To investigate unapproved or off-label drug usage for graft-versus-host disease (GVHD) and virus infections after allogeneic HCT, we analyzed the data of Japanese HCT registry. Between 2006 and 2017, 39,941 adults and children received HCT for a variety of disease and their transplant data were captured in the registry. Among them, 14,687 and 8914 patients receiving treatment for acute and/or chronic GVHD, 24,828 patients with cytomegalovirus (CMV) infection or receiving therapies for CMV, and 4943 who received treatment for other viral infections were included in the analyses of off-label or unapproved drugs. For GVHD, mycophenolate mofetil was the most frequently used off-label drug, followed by beclomethasone, infliximab, and etanercept. For viral infections other than CMV, foscarnet was the most frequently used off-label drug. Cidofovir, which is not approved for use in Japan, was mainly used for adenovirus infection. This study demonstrated that numerous off-label and unapproved drugs have been used as key drugs for GVHD and post-transplant viral infection, and the real world date in the transplant registry may serve as an important asset to regulatory purposes.

[Impact of mycophenolate mofetil prophylaxis duration on acute graft-versus-host disease after haploidentical stem cell transplantation]

Objective: To investigate the impact of mycophenolate mofetil (MMF) prophylaxis duration on acute graft-versus-host disease (aGVHD) after haploidentical stem cell transplantation (haplo-HSCT) using 'Beijing Protocol'. Methods: Adult patients (≥14 years) received haplo-HSCT in Peking University Institute of Hematology from Sep, 2016 to Mar, 2017 were retrospectively reviewed if they fulfilled the criterias: ①diagnosed with hematological maligancies; ②standard-risk status at haplo-HSCT. A total of 237 patients [including 102 patients with long MMF duration (defined as started on day -9 with 100 mg/d, adjusted to 500 mg/d from day +30 and discontinued on day +45 to +60 or occurrence of CMV/EBV reactivation or late-onset hemorrhagic cytitis), and 135 patients with short MMF duration (defined as started on day -9 with 500 mg/d and discontinued on the day achieved neutrophil engraftment)] were reviewed. The incidence of aGVHD, virus infection and overall survival (OS) were compared between the two groups. Results: The median durations of MMF prophylaxis of long and short duration groups were 27(7-71) and 15(9-24) days, respectively after haplo-HSCT. There were no differences of baseline characteristics (including sex, patient age, disease, mismatched HLA loci, donor-recipient relation, donor-recipient sex and donor age) between the two groups. The incidences of the grade Ⅱ-Ⅳ and Ⅲ/Ⅳ aGVHD in long and short duration groups were 31.1% versus 17.6% (P=0.018) and 7.4% verus 7.8% (P=0.900), respectively. The duration of MMF prophylaxis was not found to be associated with gradeⅡ-Ⅳ aGVHD by the multivariate analysis. There were no significant differences in terms of CMV viremia, EBV viremia, hemorrhagic cytitis and OS between the two groups. Conclusion: Prophylaxis with short duration MMF in the setting of 'Beijing protocol' haplo-SCT was not associated with increased acute GVHD with no impact on OS, which indicated that short duration MMF might be a feasible GVHD prophylaxis regimen.

Mucosal Biopsy After Bone Marrow Transplantation

Gastrointestinal mucosal biopsies in the hematopoietic stem cell transplantation setting are challenging because histologic features of graft-versus-host disease (GVHD), which is treated by increasing immunosuppression, overlap with those of other conditions, such as infection, which can get worse with GVHD treatment. More than one condition can occur at the same time. It is important to understand the histologic features of GVHD, drug toxicity, infection, and clinical factors surrounding patients, including timing of biopsy in relation to transplantation, medication history, and laboratory data. Rendering a correct diagnosis and generating a pathology report with standard language that can direct clinical management ensure proper management.

Pharmacokinetic Variability of Mycophenolic Acid in Pediatric and Adult Patients With Hematopoietic Stem Cell Transplantation

The aim of this study was to evaluate the pharmacokinetic variations of mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil (MMF), in both pediatric and adult patients following hematopoietic stem cell transplantation (HSCT). Twenty pediatric patients with a median age of 3 years (range 0.2-12 years) and 13 adult patients with a median age of 54 years (range 18-63 years) were enrolled. Blood samples were collected on days 0, 7, 14, 21, and 30 after allogeneic HSCT. Total and free (unbound) MPA as well as MPA 7-O-glucuronide (MPAG) were quantified using a validated LC-MS/MS assay. The plasma protein binding of MPA and MPAG did not change significantly in pediatric patients over the 1-month sampling period post-HSCT. However, it increased in adult patients from day 7 to day 30 post-HSCT, from 97.3 ± 0.8% to 98.3 ± 0.6% for MPA (P < .05), and 74.6 ± 9.4% to 82.9 ± 8.1% for MPAG (P < .05). The plasma protein binding of MPA was significantly higher in males compared to females in both pediatric (98.3 ± 1.1% vs 97.4 ± 1.1%) and adult (98.1 ± 0.7% vs 97.4 ± 1.2%) patients (P < .05). The MPAG/MPA ratios on a milligram-per-kilogram dose basis in adult patients were significantly higher than those in pediatric patients (4.3 ± 3.4 vs 2.4 ± 2.6; P < .05). Time-dependent plasma protein binding and age-related differences in MPA metabolism at least in part impact the reported large intra- and interindividual variability in MPA pharmacokinetics. These patient and pharmacologic factors, if incorporated into MMF regimen design and modification, may contribute to the rational dose selection of MMF in HSCT patients.

Clinical Pharmacokinetics of Mycophenolic Acid in Hematopoietic Stem Cell Transplantation Recipients

Mycophenolate mofetil (MMF), an ester prodrug of mycophenolic acid (MPA), is widely used as a maintenance immunosuppressive regimen in solid organ transplant patients. It is increasingly used for the prophylaxis and treatment of graft-versus-host disease (GVHD) in hematopoietic stem cell transplantation (HSCT) patients. MPA displays extensive binding to serum albumin and glucuronidation to the inactive MPA-7-O-glucuronide (MPAG). Here, we review and discuss the pertinent information regarding the clinical pharmacokinetics of MPA in HSCT patients. The pharmacokinetics of MPA are altered in HSCT patients with lower oral bioavailability, shorter half-life and higher clearance than those in healthy volunteers and renal transplant recipients. Moreover, clearance may be increased in young pediatric patients. The optimal MMF dosing and preferred targets are still under investigation in HSCT patients due to the substantial intra- and inter-individual pharmacokinetic variability of MPA and broad range of transplants (malignant vs. nonmalignant, related vs. unrelated donor, and human leukocyte antigen mismatch). The complex pharmacokinetics of MPA have partly hampered the efficient use of MMF, and pharmacokinetic studies in HSCT patients have been limited in size and mostly inconclusive. Future research should be multi-institutional and focus on developing clinical decisions with adequate statistical power to improve clinical care of HSCT recipients.

Mycophenolate-based graft versus host disease prophylaxis is not inferior to methotrexate in myeloablative-related donor stem cell transplantation

We retrospectively reviewed 242 patients who received related donor myeloablative peripheral blood hematopoietic cell transplantation. We compared patients who received mycophenolate (MMF)/cyclosporine (CSA) (n = 71), to historical controls who received methotrexate (MTX)/CSA (n = 172). There were no differences in overall survival, nonrelapse mortality, and relapse. The MMF/CSA group had significantly faster neutrophil and platelet engraftment: medians of 13 versus 18 days and 10 versus 14 days, respectively (P = 0.001). The cumulative incidence of acute graft versus host disease (GVHD) (Grades, 2-4) was significantly lower in the MMF/CSA group (45.1 vs. 74.4%, P < 0.001). The MMF/CSA group showed a lower incidence of skin (51.5 vs. 72.1%, P < 0.001) and liver acute GVHD (11.3 vs. 54.2%, P < 0.001) and a higher incidence of lung (42.2 vs. 19.0%, P = 0.045), eye (59.7 vs. 30.1%, P < 0.001), and mouth (72.8 vs. 56.4%, P = 0.001) chronic GVHD but only eye chronic GVHD was confirmed in propensity score matching (PSM) analysis. The incidence of cytomegalovirus (CMV) viremia was higher in the MMF/CSA group (55.8 vs. 39.6%, P < 0.001) but this was not confirmed in PSM analysis. MMF/CSA was identified as an independent favorable factor for acute GVHD (P < 0.001, hazard ratio, 0.41) but as a possible adverse risk factor for CMV viremia as this was not found to be statistically significant in PSM analysis. MMF/CSA in myeloablative matched related donor peripheral blood stem cell transplant is not inferior as GVHD prophylaxis in comparison with MTX/CSA and is associated with faster engraftment but a potentially higher risk of CMV viremia.

Mycophenolate mofetil use after unrelated hematopoietic stem cell transplantation for prophylaxis and treatment of graft-vs.-host disease in adult patients in Japan

Our previous study of 301 patients who received hematopoietic stem cell transplantation (HSCT) from related donors demonstrated the efficacy of mycophenolate mofetil (MMF) for prophylaxis and treatment of graft-vs.-host disease (GVHD). In this study, we investigated the safety and efficacy of MMF in 716 adult patients who received unrelated HSCT. The incidences of Grade II-IV and III-IV acute GVHD in the prophylactic administration group were 38.3% and 14.3%, respectively. These rates were not statistically significant when evaluating the MMF dosage and graft source. The incidences of limited and extensive chronic GVHD were 16.6% and 11.1%, respectively. In the therapeutic administration group, 69.1% of the subjective symptoms for both acute and chronic GVHD improved. With respect to the adverse events, 75 infections and 50 cases of diarrhea were observed, and the frequency of these events increased with increasing MMF dose. The overall survival rate was 36.4% after a median follow-up period of three yr. This study shows that MMF is safe and effective for the prevention and treatment of GVHD in patients who have received HSCT from unrelated donors.

Clinical outcomes of allogeneic stem cell transplantation for relapsed or refractory follicular lymphoma: a retrospective analysis by the Fukuoka Blood and Marrow Transplantation Group

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is considered the only curative treatment for relapsed or refractory follicular lymphoma (FL), but it has a high treatment-related mortality rate. Only a few reports, however, have described the efficacy of allo-SCT for FL in the Japanese population. We retrospectively analyzed the outcome of allo-SCT in 30 patients with FL. Seventeen (56.7 %) patients were chemorefractory, whereas 13 (43.3 %) were chemosensitive. An estimated 2-year overall survival rate (OS) and relapse rate of all patients was 46.7 and 20.0 %, respectively. There were no significant differences in the estimated 2-year OS rate between patients who received myeloablative conditioning and those who received reduced-intensity conditioning (P = 0.98), and among the recipients of related bone marrow (BM)/peripheral blood stem cell, unrelated BM and umbilical cord blood (P = 0.20). In patients who were either chemosensitive or chemorefractory at allo-SCT, the 2-year OS rate was 69.2 and 29.4 % (P = 0.06). Patients with mild-to-moderate acute GVHD had better 2-year PFS rate compared with patients who had severe acute GVHD (P = 0.01), but not better PFS compared with patients who had no acute GVHD (P = 0.12). Our results suggest that the graft-versus-lymphoma effects of allo-SCT may provide survival benefits even in patients with chemorefractory FL.

Influence of pharmacological immunomodulatory agents on CD4(+)CD25(high)FoxP3(+) T regulatory cells in humans

T regulatory cells (Tregs) play a critical role in the immunologic tolerance to the graft in transplantation. Thus, due to their immunosuppressive capability, ex vivo expanded Tregs may be used as a cellular therapy and an attractive novel strategy to control chronic rejection and eliminate need for lifelong pharmacological immunosuppression. Since Treg therapy is still in its infancy, initially Tregs still need to be applied in combination with pharmacological agents to prevent rejection. Fortunately, some of the medications have been shown to enhance the function and number of Tregs. In the clinic, different immunosuppressive regimens are used for individual patients for different types of organ transplantation. In this review, we present the most commonly used pharmacological agents for immunosuppression and discuss how they affect the Treg population. It is extremely difficult to dissect the effect of single agent on Tregs population in clinical settings since usually the combination of several medications is applied at the same time for graft protection. Nevertheless, experimental and clinical data indicate that thymoglobulin as immunosuppressive induction and mTOR inhibitors as immunosuppressive maintenance agents have the most beneficial effect on Treg population in the blood. Among supplemental agents promoting Tregs, anti-TNFα preparations have been in clinical use (in autoimmune diseases) for many years, so they are optimal candidates for testing in transplant settings in combination with Treg based cellular therapy.