Impact of melphalan day -1 vs day -2 on outcomes after autologous stem cell transplant for multiple myeloma

Background

Melphalan is the most common conditioning regimen used prior to autologous stem cell transplant (ASCT); however, there are varying data on optimal melphalan timing prior to transplant for best safety and efficacy. Historically, ASCT conditioning consisted of melphalan 200 mg/m2 on day 2 (D-2) (48 h prior to ASCT), but many institutions have since adopted a melphalan protocol with administration on day 1 (D-1) (24 h prior to SCT) or split dosing over the 2 days. The optimal timing of melphalan has yet to be determined.

Methods

In this single-center retrospective study, we analyzed transplant outcomes for patients between March 2011 and September 2020 admitted for high-dose, single-agent melphalan 200 mg/m2 on D-1 vs. D-2. The primary outcomes were time to neutrophil and platelet engraftment. Secondary outcomes include incidence of hospital readmission within 30 days, 2-year progression-free survival, and 2-year overall survival.

Results

A total of 366 patients were studied (D-2 n = 269 and D-1 n = 97). The incidence of high-risk cytogenetics was similar between the two groups (37% vs. 40%). Median days to absolute neutrophil count engraftment was similar at 11 days in the D-2 and D-1 cohort (n = 269, range 0-14, IQR 11-11 vs. n = 97, range 0-14, IQR 11-12). Median days to platelet engraftment >20,000/mcL was 18 days for D-2 melphalan (range: 0-28, IQR 17-20) versus 19 days for D-1 melphalan (range: 0-32, IQR 17-21). Overall survival at 2 years post-transplant was similar in both cohorts (94%; p = 0.76), and PFS was 70% in D-2 compared with 78% in D-1 (p = 0.15). In a multivariable model including age and performance status, hospital readmission within 30 days of transplant was higher in the D-1 cohort (odds ratio 1.9; p = 0.01).

Conclusion

This study demonstrates similar neutrophil and platelet engraftment in D-1 and D-2 melphalan cohorts with similar 2-year PFS and OS. Either D-2 or D-1 melphalan dosing schedule is safe and effective.

Higher Fludarabine and Cyclophosphamide Exposures Lead to Worse Outcomes in Reduced-Intensity Conditioning Hematopoietic Cell Transplantation for Adult Hematologic Malignancy

Reduced-intensity conditioning regimens using fludarabine (Flu) and cyclophosphamide (Cy) have been widely used in hematopoietic cell transplantation (HCT) recipients. The optimal exposure of these agents remains to be determined. We aimed to delineate the exposure-outcome associations of Flu and Cy separately and then both combined on HCT outcomes. This is a single-center, observational, pharmacokinetic (PK)-pharmacodynamic (PD) study of Flu and Cy in HCT recipients age ≥18 years who received Cy (50 mg/kg in a single dose), Flu (150 to 200 mg/m² given as 5 daily doses), and total body irradiation (TBI; 200 cGy). We measured trough concentrations of 9-β-D-arabinosyl-2-fluoradenine (F-ara-A), an active metabolite of Flu, on days -5 and -4 (F-ara-A_Day-5 and F-ara-A_Day-4, respectively), and measured phosphoramide mustard (PM), the final active metabolite of Cy, and estimated the area under the curve (AUC). The 89 enrolled patients had a nonrelapse mortality (NRM) of 9% (95% confidence interval [CI], 3% to 15%) at day +100 and 15% (95% CI, 7% to 22%) at day +180, and an overall survival (OS) of 73% (95% CI, 63% to 81%) at day +180. In multivariate analysis, higher PM area under the curve (AUC) for 0 to 8 hours (PM AUC_{0-8 hr}) was an independent predictor of worse NRM (P < .01 at both day +100 and day +180) and worse day +180 OS (P < .01), but no associations were identified for F-ara-A trough levels. We observed lower day +100 NRM in those with both high F-ara-A_Day-4 trough levels (≥40 ng/mL; >25th percentile) and low PM AUC_{0-8 hr} (<34,235 hr ng/mL; <75th percentile), compared with high exposures to both agents (hazard ratio, 0.06; 95% CI, 0.01 to 0.48). No patients with low F-ara-A_Day-4 (<40 ng/mL; <25th percentile) had NRM by day +100, regardless of PM AUC. The interpatient PK variability was large in F-ara-A_Day-4 trough and PM AUC_{0-8 hr} (29-fold and 5.0-fold, respectively). Flu exposure alone was not strongly associated with NRM or OS in this reduced Flu dose regimen; however, high exposure to both Flu and Cy was associated with a >16-fold higher NRM. These results warrant further investigation to optimize reduced-intensity regimens based on better PK-PD understanding and possible adaptation to predictable factors influencing drug clearance.

High incidence of thromboembolism in patients with chronic GVHD: association with severity of GVHD and donor-recipient ABO blood group

Chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic cell transplantation (HCT) is associated with systemic inflammation and endothelial dysfunction, increasing risk for thromboembolic events (TEE). In 145 adult recipients who developed cGVHD after a matched sibling or umbilical cord blood donor HCT from 2010 to 2018, 32(22%) developed at least 1 TEE event, and 14(10%) developed 2 TEE events. The 5-year cumulative incidence of TEE was 22% (95% CI, 15–29%) with a median time from cGVHD to TEE of 234 days (range, 12–2050). Median time to the development of LE DVT or PE was 107 (range, 12–1925) compared to 450 days (range, 158–1300) for UE DVT. Cumulative incidence of TEE was 9% (95% CI, 0–20%), 17% (95% CI, 9–25%), and 38% (95% CI, 22–55%) in those with mild, moderate, and severe GVHD, respectively. Higher risk for TEE was associated with cGVHD severity (hazard ratio [HR] 4.9, [95% CI, 1.1–22.0]; p = 0.03), non-O-donor to recipient ABO match compared to O-donor to O-recipient match (HR 2.7, [95% CI, 1.0–7.5]; p = 0.053), and personal history of coronary artery disease (HR 2.4, [95% CI, 1.1–5.3]; p = 0.03). TEE was not associated with 2-year non-relapse mortality or 5-year overall survival.

Patients with chronic GVHD after allogeneic hematopoietic cell transplantation are at high risk for thromboembolic events occurring years after diagnosis.

More severe chronic GVHD, non-O donor-recipient ABO compared to O-O match and personal history of coronary artery disease are associated with higher risk of thromboembolic events.

Effect of Keratinocyte Growth Factor on Hospital Readmission and Regimen-Related Toxicities after Autologous Hematopoietic Cell Transplantation for Lymphoma

Regimen-related toxicities with high-dose therapy followed by hematopoietic cell rescue leads to considerable patient distress, morbidity, and high readmission rates. Palifermin is a recombinant keratinocyte growth factor that is Food and Drug Administration-approved to decrease severe oral mucositis (OM) associated with autologous hematopoietic cell transplantation (ASCT) for hematologic malignancies. We added palifermin as a supportive care measure for patients with lymphoma undergoing ASCT with BEAM conditioning. We compared patients receiving palifermin (n = 35) with historical controls (n = 38) for toxicity and readmission outcomes. The cumulative incidence of OM of any grade was 23% in the palifermin-treated patients and 42% in the control group. Patients receiving palifermin were less likely to be readmitted (57% versus 82%; P = .04), had fewer hospital readmission days (median, 4 days versus 7 days; P < .01), and had fewer total days in the hospital through day +30 after ASCT (median, 12 days versus 15 days; P = .05). Fewer patients in the palifermin group had >20 days in the hospital through day +30 (9% in the palifermin group versus 23% of controls). Adverse events associated with palifermin were mild and transient. The addition of palifermin limits severe regimen-related toxicities and decreases readmissions and duration of hospital stay. This and other measures are needed to identify comprehensive and cost-effective approaches, possibly including palifermin, to prevent severe regimen-related toxicities and decrease health care resource utilization.

Weight-based mycophenolate mofetil dosing predicts acute GVHD and relapse after allogeneic hematopoietic cell transplantation

OBJECTIVES

Higher MMF dose can reduce acute GVHD risk after allogeneic hematopoietic cell transplantation (HCT). We examined the effect of MMF dose, relative to patient actual body weight (mg/kg/day), on outcomes of 680 adults after HCT.

METHODS

MMF was combined with cyclosporine (n = 599) or sirolimus (n = 81). We divided MMF dose/kg/day in quartiles.

RESULTS

The median time to grade II-IV acute GVHD was 32 days. The incidence of grade II-IV acute GVHD at day 30 was 30% in 1st (<29), 20% in 2nd (29-34), 16% in 3rd (35-41), and 19% in 4th (≥42) quartile (P < .01). Corresponding relapse incidence at 1 year was 16%, 25%, 27%, and 31%, respectively (P = .01). In multivariate analysis, as compared to 1st quartile, higher dose of weight-based MMF reduced grade II-IV acute GVHD (HR = 0.64 for 2nd, HR = 0.48 for 3rd, and HR = 0.55 for 4th quartile), but increased the risk of relapse (HR = 1.63 for 2nd, HR = 1.75 for 3rd, and HR = 2.31 for 4th quartile).

CONCLUSIONS

Weight-based MMF dose had no significant impact on engraftment, chronic GVHD, or survival. These data suggest that higher weight-based MMF dose reduces the risk of acute GVHD at the expense of increased relapse and supports conducting prospective studies to optimize MMF dosing after HCT.

Comparison of continuous versus intermittent infusion cyclosporine and impact on transplant related outcomes in allogeneic transplant recipients

INTRODUCTION

Continuous infusion (CIVI) cyclosporine (CsA) is an alternative for allograft recipients intolerant of twice daily infusions (TDI). The importance of achieving therapeutic levels of CsA early after allogeneic HCT has been demonstrated in previous studies. Our study evaluated the incidence of acute graft versus host disease (GVHD) and survival among patients receiving CIVI vs. TDI CsA during their first allogeneic HCT.

METHODS

A retrospective study of adult patients undergoing first allogeneic HCT at the University of Minnesota Medical Center between 2011 and 2017. Patients were grouped according to the administration method. The primary outcome was the occurrence of acute grade II-IV GVHD by day +180. Secondary outcomes included the 1-year incidence of chronic GVHD, relapse, and overall survival.

RESULTS

42 patients intolerant of TDI CsA received CsA via CIVI for >48 hours for a median of 9 days (range, 3-32 days). CsA concentrations were similar between groups. We found no difference between the rates of grade II-IV acute (45% vs 53%, p = 0.59) or chronic (17% vs 30%, p = 0.20) GVHD or overall survival (57% vs 67%, p = 0.10). Subgroup analysis of patients that received myeloablative conditioning or umbilical cord blood did not reveal significant differences in GVHD or overall survival. Cumulative incidence of relapse was higher among the continuous infusion group (39% vs. 23%, p < 0.01).

CONCLUSION

Due to the finding of increased risk of relapse, cyclosporine should be administered as traditional twice daily infusion unless necessary. A prospective clinical trial is needed to confirm these results.

Prophylactic Foscarnet for Human Herpesvirus 6: Effect on Hematopoietic Engraftment after Reduced-Intensity Conditioning Umbilical Cord Blood Transplantation

The high incidence of human herpesvirus-6 (HHV-6) reactivation, potentially interfering with engraftment after umbilical cord blood (UCB) hematopoietic cell transplantation (HCT), remains a major challenge. To potentially address this problem, we evaluated the effect of prophylactic foscarnet administered twice daily beginning on day +7 and continuing through engraftment in 25 patients. To determine the impact of foscarnet on HHV-6, engraftment, and other transplantation outcomes, we compared results in 61 identically treated patients with hematologic malignancies. Treatment and control groups underwent reduced-intensity conditioning UCB HCT with a conditioning regimen of fludarabine, cyclophosphamide, and total body irradiation 200 cGy with or without antithymocyte globulin (ATG), using sirolimus plus mycophenolate mofetil immune suppression. The treatment and control groups were similar in terms of age, disease risk, use of ATG, Hematopoietic Cell Transplantation Comorbidity Index, and graft CD34 cell dose; however, foscarnet-treated patients were less likely to receive a double UCB graft and to be treated more recently (2016 to 2018). The cumulative incidence of HHV-6 reactivation by day +100 was 63% for all patients (95% confidence interval [CI], 51% to 75%) and was not significantly different between the 2 groups. HHV-6 reactivation occurred at a median of 34 days in the foscarnet group and 25.5 days in the control group. The incidence of neutrophil engraftment at day 42 was higher in the foscarnet group compared with the control group (96%; [95% CI, 83% to 100%] versus 75% [95% CI, 64% to 85%]; P< .01). The cumulative incidence of platelet engraftment by 6 months was 92% (95% CI, 69% to 100%) for the foscarnet group versus 75% (95% CI, 60% to 90%) for the control group (P= .08), and multivariate analysis identified the use of foscarnet as an independent predictor of better platelet engraftment. No patients died as a result of graft failure in recipients of foscarnet, whereas 5 patients died from graft failure in the control group. Six-month overall survival (OS) and nonrelapse mortality (NRM) were better in the foscarnet group (96% versus 72% [P= .02] and 4% versus 18% [P= .07], respectively). Even though foscarnet prophylaxis did not prevent HHV-6 viremia, we observed a delay in time to HHV-6 reactivation, a trend toward differences in engraftment, NRM, and OS compared with historical controls.

CD33-Targeted Therapies: Beating the Disease or Beaten to Death?

CD33 is a transmembrane protein that is found on cells of myeloid lineage. It is also intensely expressed on acute myeloid leukemia (AML) progenitor cells but not on normal stem cells. It internalizes on binding and dimerization, making it a specific and ideal target for AML therapeutics and drug delivery. Several targeted therapies have been tested and many are still currently in development. Gemtuzumab ozogamicin was the first and only CD33-directed antibody-drug conjugate to be US Food and Drug Administration approved for AML. Other targeted agents have not achieved such success. Promising new strategies include cellular therapy mechanisms and linker molecules. This is an exciting target that requires a considerable amount of precision to yield clinical benefit.

Effect of Conditioning Regimen Dose Reduction in Obese Patients Undergoing Autologous Hematopoietic Cell Transplantation

Data are limited on whether to adjust high-dose chemotherapy before autologous hematopoietic cell transplant (autoHCT) in obese patients. This study explores the effects of dose adjustment on the outcomes of obese patients, defined as body mass index (BMI) ≥ 30 kg/m². Dose adjustment was defined as a reduction in standard dosing ≥20%, based on ideal, reported dosing and actual weights. We included 2 groups of US patients who had received autoHCT between 2008 and 2014. Specifically, we included patients with multiple myeloma (MM, n = 1696) treated with high-dose melphalan and patients with Hodgkin or non-Hodgkin lymphomas (n = 781) who received carmustine, etoposide, cytarabine, and melphalan conditioning. Chemotherapy dose was adjusted in 1324 patients (78%) with MM and 608 patients (78%) with lymphoma. Age, sex, BMI, race, performance score, comorbidity index, and disease features (stage at diagnosis, disease status, and time to transplant) were similar between dose groups. In multivariate analyses for MM, adjusting for melphalan dose and for center effect had no impact on overall survival (P = .894) and treatment-related mortality (TRM) (P = .62), progression (P = .12), and progression-free survival (PFS; P = .178). In multivariate analyses for lymphoma, adjusting chemotherapy doses did not affect survival (P = .176), TRM (P = .802), relapse (P = .633), or PFS (P = .812). No center effect was observed in lymphoma. This study demonstrates that adjusting chemotherapy dose before autoHCT in obese patients with MM and lymphoma does not influence mortality. These results do not support adjusting chemotherapy dose in this population.

Catheter-Related Thrombosis in Patients with Lymphoma or Myeloma Undergoing Autologous Stem Cell Transplantation

Catheter-related thrombosis (CRT) occurs frequently during autologous hematopoietic cell transplantation (AHCT) and data regarding the incidence, risk factors, and management are understudied. We evaluated 789 consecutive patients with lymphoma and myeloma that underwent AHCT over 10 years (2006 to 2016) and detected the incidence of CRT was 6.3%; only 32% of CRT were symptomatic. The majority occurred within 100 days of AHCT (86%) and median time from tunneled line placement to CRT was 44 days (range, 11 to 89 days). Outcomes of these 50 patients with CRT were compared with age- and disease-matched AHCT control subjects to identify risk factors. History of prior venous thromboembolism (VTE) (20.9% versus 7.0%, P = .02) was the only significant risk factor. Treatment with low-molecular-weight heparin was tolerated with rare minor bleeding (4%), although CRT recurrence or extension (10%) and subsequent VTE (12%) were common. CRT did not impact on nonrelapse mortality or risk of relapse; 2-year progression-free survival was 55% in CRT cases versus 54% in control subjects (P = .42). CRT appears to be common in patients with lymphoma and myeloma undergoing AHCT and significantly contributes to morbidity. Further study to determine mitigating strategies and modify risk factors for CRT is warranted.

Sirolimus and Mycophenolate Mofetil as Calcineurin Inhibitor-Free Graft-versus-Host Disease Prophylaxis for Reduced-Intensity Conditioning Umbilical Cord Blood Transplantation

The use of calcineurin inhibitors (CNIs) to reduce the risk of graft-versus-host disease (GVHD) after hematopoietic cell transplantation (HCT) requires intensive post-transplantation toxicity monitoring. Sirolimus-based GVHD prophylaxis is associated with a favorable toxicity profile and requires less intensive monitoring. However, the efficacy of sirolimus-based regimen compared with CNI-based regimen has not been evaluated in the setting of reduced-intensity conditioning (RIC) double umbilical cord blood (UCB) HCT. We compared outcomes of patients receiving sirolimus/mycophenolate mofetil (MMF) (n = 37) or cyclosporine (CSA)/MMF (n = 123) in an ongoing phase II study of RIC UCB transplantation. In multiple regression analysis, sirolimus/MMF did not influence the risk of grades II to IV or grades III and IV acute GVHD. In addition, there was no association between type of GVHD prophylaxis and hematopoietic engraftment. Infection density analysis found a significantly lower risk of infections with sirolimus/MMF between days +46 and +180 after HCT compared with CSA/MMF (3.4 versus 6.3 per 1000 patient-days, P = .03); however, no difference was observed before day +45. Sirolimus/MMF use resulted in no thrombotic microangiopathy, fewer instances of elevated serum creatinine >2 mg/dL (14% versus 45%; P <.01), and similar rates of sinusoidal obstruction syndrome (2.7% versus 4%; P = .68), compared with CSA/MMF. Disease-free survival at 1 year was 51% for sirolimus/MMF and 41% for CSA/MMF (P = .41), and sirolimus/MMF use did not influence the risk of nonrelapse mortality or survival. In conclusion, sirolimus/MMF GVHD prophylaxis was better tolerated and resulted in similar rates of GVHD and survival as compared to CSA/MMF after RIC double UCB transplantation.

Hemorrhagic cystitis after allogeneic hematopoietic cell transplantation: risk factors, graft source and survival

Although hemorrhagic cystitis (HC) is a common complication of allogeneic hematopoietic cell transplantation (alloHCT), its risk factors and effects on survival are not well known. We evaluated HC in a large cohort (n=1321, 2003-2012) receiving alloHCT from all graft sources, including umbilical cord blood (UCB). We compared HC patients with non-HC (control) patients and examined clinical variables at HC onset and resolution. Of these 1321 patients, 219 (16.6%) developed HC at a median of 22 days after alloHCT. BK viruria was detected in 90% of 109 tested HC patients. Median duration of HC was 27 days. At the time of HC diagnosis, acute GVHD, fever, severe thrombocytopenia and steroid use were more frequent than at the time of HC resolution. In univariate analysis, male sex, age <20 years, myeloablative conditioning with cyclophosphamide and acute GVHD were associated with HC. In multivariate analysis, HC was significantly more common in males and HLA-mismatched UCB graft recipients. Severe grade HC (grade III-IV) was associated with increased treatment-related mortality but not with overall survival at 1 year. HC remains hazardous and therefore better prophylaxis, and early interventions to limit its severity are still needed.

Higher Dose of Mycophenolate Mofetil Reduces Acute Graft-versus-Host Disease in Reduced-Intensity Conditioning Double Umbilical Cord Blood Transplantation

Mycophenolate mofetil (MMF) is frequently used in hematopoietic cell transplantation (HCT) for graft-versus-host disease (GVHD) prophylaxis and to facilitate engraftment. We previously reported that a higher level of mycophenolic acid can be achieved with an MMF dose of 3 g/day than with 2 g/day. Here, we retrospectively compared clinical outcomes of reduced-intensity conditioning (RIC) double umbilical cord blood (dUCB) HCT recipients receiving cyclosporine A with MMF 2 g (n = 93) versus 3 g (n = 175) daily. Multiple regression analysis adjusted for antithymocyte globulin in the conditioning revealed that MMF 3 g/day led to a 49% relative risk (RR) reduction in grade II to IV acute GVHD rate (RR, .51; 95% confidence interval, .36 to .72; P < .01). However, the higher MMF dose was not protective for chronic GVHD. Additionally, MMF dose was not an independent predictor of neutrophil engraftment or treatment-related mortality at 6 months or 2-year post-transplantation disease relapse, disease-free survival, or overall survival. Higher MMF dose did not increase risk of infectious complications, and infection-related mortality was similar for both MMF doses. Our data indicate that MMF 3 g/day reduces the risk of acute GVHD without affecting other clinical outcomes and should be used for GVHD prophylaxis after RIC dUCB transplantation.

Highly Variable Mycophenolate Mofetil Bioavailability Following Nonmyeloablative Hematopoietic Cell Transplantation

This study determined the oral bioavailability of mycophenolic acid, the active metabolite of mycophenolate mofetil, in patients undergoing nonmyeloablative hematopoietic cell transplantation. Eighteen adults receiving a preparative regimen containing fludarabine, cyclophosphamide, and total body irradiation were studied. Immune suppression consisted of cyclosporine and mycophenolate 1 g twice daily. Pharmacokinetic variability was high after intravenous and oral dosing. Intravenous dosing resulted in a median area under the curve (AUC) of 28.3 microg x h/mL (range, 9.96-70.4) and an oral AUC of 16.7 microg x h/mL (range, 9.38-35.3). Cmax after intravenous and oral dosing was 12.18 and 5.29 microg/mL, respectively. The median oral bioavailability was 72.3% (20.5%-172%), with 8-fold variability. Five patients (28%) had an oral bioavailability < or = 50%. At time of oral pharmacokinetics, 15 patients (83%) had an AUC(0-12) < 30 microg x h/mL. The initial oral dose should be at least 25% greater than the intravenous dose with follow-up assessment of plasma concentrations.

Comparison of two mycophenolate mofetil dosing regimens after hematopoietic cell transplantation

Mycophenolic acid (MPA) is the active component of mycophenolate mofetil (MMF). Low MPA exposure is associated with a higher incidence of acute GVHD and possibly worse engraftment. Therapeutic plasma targets have been proposed in hematopoietic cell transplantation (HCT), however, are difficult to achieve in adult patients with MMF doses of 2 g/day. Mycophenolate pharmacokinetics was prospectively studied in adults undergoing nonmyeloablative HCT who received MMF 3 g/day with CYA. The first 15 individuals received 1.5 g every 12 h and the second 15 received 1 g every 8 h. Sampling was performed in each patient with i.v. and oral administration. There were no differences in total or unbound MPA 24-h cumulative area under the curves (AUCs), concentrations at steady state (Css) or troughs between the two dosing regimens (all P>0.01). The previously proposed total MPA Css target of 3 microg/ml and trough >or=1 micro/ml were achieved in only 13-27% and 20-53% of patients, respectively, on 3 g/day. However, the 3 g/day regimens readily achieved satisfactory unbound 24-h cumulative AUC targets of 0.600 microg(*)h/ml in 87-100% of subjects. There appears to be no significant difference in daily MPA exposure when MMF of 3 g/day is divided into two or three equal doses.

A limited sampling model for estimation of total and unbound mycophenolic acid (MPA) area under the curve (AUC) in hematopoietic cell transplantation (HCT)

OBJECTIVES

Renal transplant patients with suboptimal mycophenolic acid (MPA) areas under the curves (AUCs) are at greater risk of acute rejection. In hematopoietic cell transplantation, a low MPA AUC is also associated with a higher incidence of acute graft versus host disease. Therefore, a limited sampling model was developed and validated to simultaneously estimate total and unbound MPA AUC0-12 in hematopoietic cell transplantation patients.

METHODS

Intensive pharmacokinetic sampling was performed at steady state between days 3 to 7 posttransplant in 73 adult subjects while receiving prophylactic mycophenolate mofetil 1 g per 12 hours orally or intravenously plus cyclosporine. Total and unbound MPA plasma concentrations were measured, and total and unbound AUC0-12 was determined using noncompartmental analysis. Regression analysis was then performed to build IV and PO, total and unbound AUC0-12 models from the first 34 subjects. The predictive performance of these models was tested in the next 39 subjects.

RESULTS

Trough concentrations poorly estimate observed total and unbound AUC0-12 (r<0.48). A model with 3 concentrations (2-, 4-, and 6-hour post start of infusion) best estimated observed total and unbound AUC0-12 after IV dosing (r>0.99). Oral total and unbound AUC0-12 was more difficult to estimate and required at least 4 concentrations (0-, 1-, 2-, and 6-hour post dose) in the model (r>0.85). The predictive performance of the final models was good. Eighty-three percent of IV and 70% of PO AUC0-12 predictions fell within +/-20% of the observed values without significant bias.

CONCLUSION

Trough MPA concentrations do not accurately describe MPA AUC0-12. Three intravenous (2-, 4-, 6-hour post start of infusion) or 4 oral (0-, 1-, 2-, and 6-hour post dose) MPA plasma concentrations measured over a 12-hour dosing interval will estimate the total and unbound AUC0-12 nearly as well as intensive pharmacokinetic sampling with good precision and low bias. This approach simplifies AUC0-12 targeting of MPA post hematopoietic cell transplantation.

Suppressor function of umbilical cord blood-derived CD4+CD25+ T-regulatory cells exposed to graft-versus-host disease drugs

BACKGROUND

This study examines the effects of the most commonly used graft-versus-host disease (GVHD) prophylactic drugs on inducing apoptosis and suppressor cell function of human umbilical cord blood (UCB) CD4+25+ Treg and CD4+25- cells.

METHODS

Cyclosporin A (CSA), methylprednisolone (MP), methotrexate (MTX), and mycophenolic acid (MPA) were added to the final 6 days of expansion cultures of Treg or CD4+25- T-cells isolated from the same donor and each concurrently cultured under the same conditions. Cell viability was measured for CD4+25+ as compared to CD4+25- T-cells and Treg function was assessed. The effects of these immunosuppressive drugs, Treg cells, or both also were tested in a primary allogeneic mixed lymphocyte response (MLR) response.

RESULTS

The cell viability percentages were lower for CD4+25- cells than for Treg cells when MP, MTX, or MPA was added for the last 6 days of an expansion culture. Under these interleukin (IL)-2 based expansion conditions, CSA had no effect. The addition of any of the four GVHD prophylactic agents to the expansion phase of culture did not reduce the MLR suppressive capacity of Treg cells. Overall MLR suppression was increased when Treg cells were added along with CSA and MP to a primary MLR culture, whereas MTX modestly reduced Treg suppression.

CONCLUSION

These data indicate a general resistance of expanded UCB Treg cells to GVHD immune suppressive agents and support trials to test UCB Treg infusions under the cover of GVHD prophylactic drugs in hematopoietic cell transplantation.

Relationship of mycophenolic acid exposure to clinical outcome after hematopoietic cell transplantation

Mycophenolate mofetil is used increasingly to provide immunosuppression after nonmyeloablative allogeneic hematopoietic cell transplantation. There is wide variability in the pharmacokinetics of mycophenolic acid (MPA), the active metabolite, and low concentrations are associated with rejection after organ transplantation. We hypothesized that low MPA was associated with poorer engraftment and a higher incidence of acute graft versus host disease. We evaluated the pharmacokinetics in 87 adult subjects undergoing nonmyeloablative-related and nonmyeloablative-unrelated hematopoietic cell transplantation who were receiving 1 g mycophenolate mofetil orally or intravenously every 12 hours plus cyclosporine (INN, ciclosporin). Subjects with an unbound MPA area under the curve (AUC) from 0 to 6 hours of less than 150 ng . h/mL had a higher cumulative incidence of grade II-IV acute graft versus host disease than subjects with a greater AUC (68% versus 40%, P = .02). An unbound AUC from 0 to 12 hours of less than 300 ng . h/mL was also associated with more frequent acute graft versus host disease (58% versus 35%, P = .05). There was no association between graft versus host disease and trough concentrations (P < or = .62). A higher cumulative incidence of engraftment was associated with total MPA trough concentrations greater than 1 microg/mL (P < .01). All engraftment failures occurred in the cord blood recipients. About one half of subjects were below the unbound AUC target after oral dosing with nearly a 5-fold variability in AUC. Intravenous dosing achieved unbound targets better than oral dosing. The current practice of dosing with 1 g twice daily provides inadequate plasma concentrations in many patients, and doses of at least 3 g/d are likely necessary. Therapeutic monitoring of MPA concentrations with dose adjustment into the therapeutic target appears to be necessary for the most effective use of mycophenolate mofetil.

Posttransplant day significantly influences pharmacokinetics of cyclosporine after hematopoietic stem cell transplantation

Cyclosporine-based immunosuppression is common after allogeneic hematopoietic stem cell transplantation (HSCT). Elevated cyclosporine concentrations are associated with significant toxicity and often result in the temporary cessation or discontinuation of cyclosporine. Low blood concentrations also result in significant immunologic risks, primarily graft-versus-host disease and loss of stem cell graft. The pharmacokinetics of cyclosporine are highly complex, and maintaining therapeutic and safe cyclosporine concentrations are challenging. Several clinical factors are known to independently influence in vivo cyclosporine pharmacokinetic behavior. However, in the critically ill patient, several of these clinical factors are generally present simultaneously. Unfortunately, there are no studies that have evaluated the combined effects of these clinical factors on cyclosporine disposition in HSCT. The objective of our study is to determine the population pharmacokinetic parameters of intravenous and oral cyclosporine, evaluate the effects of clinical covariates on cyclosporine pharmacokinetics, and develop a model that estimates clearance (Cl) and dose requirements for an individual HSCT patient with these clinical covariates. The authors analyzed 740 cyclosporine steady-state whole blood concentrations in 129 adult patients obtained between day 0 and discharge or 60 days posttransplant, whichever came first. Patients received intravenous cyclosporine at 2.5 mg/kg every 12 hours if body weight was greater than 50 kg, 2.5 mg/kg every 8 hours if less than 50 kg, or 5 to 7.5 mg/kg/d given as a continuous infusion, beginning on day-3. Patients were converted to oral therapy as tolerated. The influence of clinical covariates on the Cl of cyclosporine was tested with a nonlinear mixed effects model (NONMEM). The tested clinical covariates were age, height, body weight on admission, body surface area, sex, type of hematologic malignancy, transplant type, preparative regimen, baseline serum creatinine, T-cell depletion of graft, number of methotrexate doses, day of onset, and maximum grade of acute graft-versus-host disease. The route and frequency of cyclosporine administration, day posttransplant, total bilirubin level, serum creatinine level, actual body weight, presence of concurrent CYP450 enzyme inhibitors and inducers, or nephrotoxins on the day of the cyclosporine blood measurement were also evaluated. Cyclosporine Cl significantly decreased each week posttransplant. The authors found no significant effect of any of the other tested covariates including total bilirubin on Cl. The final regression model for the estimation of Cl is: Cl (L/hr) = ([body weight in kg - 70] * 0.183 + 22.3) * (day posttransplant factor). The corresponding day posttransplant factor estimates are 1.46, 1.32, 1.20, and 1.0 during days 0 to 7, 8 to 14, 15 to 21 and greater than 21 posttransplant, respectively. The interindividual variability in Cl was 27.7%. The dose of intravenous or oral cyclosporine can be calculated using the estimated Cl. Understanding cyclosporine pharmacokinetics and the clinical events that lead to alterations in Cl and exposure is critical in optimizing immunosuppressive therapy. The authors found that cyclosporine Cl significantly decreased posttransplant until day 21. A pharmacokinetics model was developed that incorporates the day posttransplant to predict cyclosporine Cl. Cyclosporine dose requirements in an individual HSCT patient to achieve the desired therapeutic blood target can be estimated using this model.

A prospective randomized trial of the anti-emetic efficacy of ondansetron and granisetron during bone marrow transplantation

To determine the comparative anti-emetic efficacy of ondansetron and granisetron in patients undergoing bone marrow transplantation, we performed a double-blind, randomized trial in pediatric and adult patients receiving transplants at the University of Minnesota. The results in 187 patients stratified by age (<18 years, n = 51; > or =18 years, n = 136) were analyzed. The average number of emetic episodes in the entire group from day -7 to 2 was 0.86/day for patients receiving ondansetron and 0.73/day for those receiving granisetron (p = 0.32). No differences were noted between the two drugs in total days of complete or major control of emesis or in the number of requests for additional drugs to alleviate symptoms of nausea. The use of total-body irradiation-containing conditioning regimens was associated with a decreased number of emetic episodes compared with regimens of chemotherapy alone. Perceived nausea was evaluated using a nausea scoring system, and no differences were apparent between the granisetron and ondansetron groups; however, reported nausea was significantly higher in females (p<0.01) and in the adult population (p = 0.05). We conclude that both ondansetron and granisetron provide good control of nausea and vomiting experienced with conditioning regimens for bone marrow transplantation. The relative cost of the drugs within an institution must be considered in developing standard anti-emetic regimens for bone marrow transplantation.

Effect of low-dose oral glutamine on painful stomatitis during bone marrow transplantation

Painful oral mucositis is a common complication after bone marrow transplantation (BMT). Glutamine is a nutrient for rapidly dividing cells and the major energy source for intestinal epithelium. This study tested whether an oral glutamine preparation could decrease the severity of oral mucositis in patients undergoing BMT. Glutamine or a placebo (glycine) were administered from admission until day +28 in 193 BMT patients in a randomized, double-blind, placebo-controlled study at a dose of 1.0 g amino acid/m2/dose swish and swallow four times a day. In autologous BMT patients (n = 87) glutamine was associated with significantly less mouth pain by self report and by opiate use (5.0+/-6.2 days of morphine for glutamine vs 10.3+/-9.8 days for placebo; P= 0.005). Matched sibling BMT patients had no effect by self report and an increased duration of opiate use (23.2+/-5.7 days for glutamine vs 16.3+/-8.3 days for placebo) (P = 0.002). However, day 28 survival of allogeneic patients was improved by glutamine. No significant differences in TPN use, rate of relapse or progression of malignancy, parenteral antibiotic use, acute or chronic GVHD, or days of hospitalization were observed in either autologous or allogeneic recipients. No toxicity of glutamine was observed. We conclude that oral glutamine can decrease the severity and duration of oropharyngeal mucositis in autologous BMT patients but not in allogeneic BMT patients, possibly due to interaction with methotrexate.

Extrapyramidal symptoms in a BMT recipient with hyperintense basal ganglia and elevated manganese

Neurologic syndromes attributed to conditioning or medications have been reported in BMT recipients. A patient is presented who developed extrapyramidal symptoms on day +56 after allogeneic BMT. Brain magnetic resonance images of this patient demonstrated hyperintense basal ganglia, which has been associated with manganese (Mn) toxicity. The patient had received total parenteral nutrition (TPN) with standard trace element supplementation and had been cholestatic. Serum Mn was elevated, and continued to be so 5 months after BMT, long after discontinuation of TPN. Cholestatic patients and those on long-term TPN have been found to have high blood or serum levels of Mn, but generally are asymptomatic. When other cholestatic BMT patients were reviewed, all had elevated serum Mn. Manganese supplementation in TPN requires evaluation for BMT recipients.

Use of a somatostatin analogue, octreotide acetate, in the management of acute gastrointestinal graft-versus-host disease

PURPOSE

Because the secretory diarrhea of acute graft-versus-host disease (GvHD) of the gut induces serious metabolic and nutritional disturbances, this study was initiated to assess the use of a somatostatin analogue, octreotide acetate, as adjunctive therapy for severe GvHD of the gut with massive diarrhea.

PATIENTS AND METHODS

In a pilot study, six patients with biopsy-confirmed acute gut GvHD after allogeneic bone marrow transplantation received octreotide 50 to 250 micrograms three times a day subcutaneously.

RESULTS

Three of the six treated patients had a prompt and dramatic reduction in stool volume within 1 to 3 days of initiation of octreotide therapy.

CONCLUSIONS

Somatostatin and its analogues have been used successfully in diarrheal states by antagonism of neuropeptide overproduction, although other potential therapeutic mechanisms include inhibition of fluid secretion, enhanced salt absorption, and inhibition of gut motility. Somatostatin and its analogues may be promising adjunctive agents in the treatment of gastrointestinal GvHD, although assessment in a controlled trial will be required to confirm their therapeutic efficacy.