Conditioning intensity and peritransplant flow cytometric MRD dynamics in adult AML.

In acute myeloid leukemia (AML), measurable residual disease (MRD) before or after allogeneic hematopoietic cell transplantation (HCT) is an established independent indicator of poor outcome. To address how peri-HCT MRD dynamics could refine risk assessment across different conditioning intensities, we analyzed 810 adults transplanted in first or second remission after myeloablative conditioning (MAC; n = 515) or non-MAC (n = 295) who underwent multiparameter flow cytometry-based MRD testing before as well as 20 to 40 days after allografting. Patients without pre- and post-HCT MRD (MRDneg/MRDneg) had the lowest risks of relapse and highest relapse-free survival (RFS) and overall survival (OS). Relative to those patients, outcomes for MRDpos/MRDpos and MRDneg/MRDpos patients were poor regardless of conditioning intensity. Outcomes for MRDpos/MRDneg patients were intermediate. Among 161 patients with MRD before HCT, MRD was cleared more commonly with a MAC (85 of 104; 81.7%) than non-MAC (33 of 57; 57.9%) regimen (P = .002). Although non-MAC regimens were less likely to clear MRD, if they did, the impact on outcome was greater. Thus, there was a significant interaction between conditioning intensity and "MRD conversion" for relapse (P = .020), RFS (P = .002), and OS (P = .001). Similar findings were obtained in the subset of 590 patients receiving HLA-matched allografts. C-statistic values were higher (indicating higher predictive accuracy) for peri-HCT MRD dynamics compared with the isolated use of pre-HCT MRD status or post-HCT MRD status for prediction of relapse, RFS, and OS. Across conditioning intensities, peri-HCT MRD dynamics improve risk assessment over isolated pre- or post-HCT MRD assessments in patients with AML.

Sirolimus with CSP and MMF as GVHD prophylaxis for allogeneic transplantation with HLA antigen-mismatched donors.

This trial aimed to evaluate the efficacy of sirolimus in addition to cyclosporine (CSP) and mycophenolate mofetil (MMF) for graft-versus-host disease (GVHD) prophylaxis after nonmyeloablative conditioning for HLA class I or II mismatched hematopoietic cell transplantation (HCT). Eligible patients had hematologic malignancies treatable by allogeneic HCT. Conditioning consisted of fludarabine (90 mg/m2) and 2 to 3 Gy total body irradiation. GVHD prophylaxis comprised cyclosporine, mycophenolate mofetil, and sirolimus. The primary objective was to determine whether the cumulative incidence of grade 2 to 4 acute GVHD could be reduced to <70% in HLA class I or II mismatched HCT. The study was closed on December 20, 2018. Seventy-seven participants were recruited between April 14, 2011, and December 12, 2018, of whom 76 completed the study intervention. Median follow-up was 47 months (range, 4-94 months). The cumulative incidence of grade 2 to 4 acute GVHD at day 100 was 36% (95% confidence interval [CI], 25-46), meeting the primary end point. The cumulative incidence of nonrelapse morality, relapse/progression, and overall survival was 18% (95% CI, 9-27), 30% (interquartile range, 19-40), and 62% (95% CI, 50-73) after 4 years. In conclusion, the addition of sirolimus to cyclosporine and mycophenolate mofetil resulted in a lower incidence of acute GVHD, thus translating into superior overall survival compared with historical results. This trial was registered at www.clinicaltrials.gov as #NCT01251575.

Total body irradiation dose and risk of subsequent neoplasms following allogeneic hematopoietic cell transplantation.

We examined the impact of total body irradiation (TBI) dose and fractionation on risk of subsequent malignant neoplasms (SMNs) in the era of reduced-intensity and nonmyeloablative conditioning regimens for hematopoietic cell transplantation (HCT). Among 4905 1-year survivors of allogeneic HCT for hematologic malignancies (N = 4500) or nonmalignant disorders (N = 405) who received transplants between 1969 and 2014, we identified 581 SMNs (excluding squamous and basal cell of skin) in 499 individuals. With a median length of follow-up of 12.5 years, the cumulative incidence of SMNs by 30 years after HCT was 22.0%. Compared with age-, sex-, and calendar year-matched Surveillance, Epidemiology, and End Results (SEER) population rates, the standardized incidence ratio (SIR) of SMNs was increased 2.8-fold. The highest SIRs were for SMNs of bones (SIR, 28.8), oral cavity (SIR, 13.8), skin (SIR, 7.3), central nervous system (SIR, 6.0), and endocrine organs (SIR, 4.9). The highest excess absolute risks (EARs) were seen with breast cancer (EAR, 2.2) and cancers of the oral cavity (EAR, 1.5) and skin (EAR, 1.5) per 1000 person-years. The highest incidence of SMNs was in survivors exposed to unfractionated (600-1000 cGy) or high-dose fractionated (1440-1750 cGy) TBI. For patients receiving low-dose TBI, the incidence was comparable to myeloablative chemotherapy alone, although still twofold higher than in the general population. These data demonstrate a strong effect of TBI dose, dose fractionation, and risk of SMNs after HCT. The cumulative incidence of SMNs increases with follow-up time; thus, HCT survivors require lifetime monitoring for early detection and effective therapy of SMNs.

Allogeneic hematopoietic cell transplantation with non-myeloablative conditioning for patients with hematologic malignancies: Improved outcomes over two decades.

We have used a non-myeloablative conditioning regimen for allogeneic hematopoietic cell transplantation for the past twenty years. During that period, changes in clinical practice have been aimed at reducing morbidity and mortality from infections, organ toxicity, and graft-versus-host disease. We hypothesized that improvements in clinical practice led to better transplantation outcomes over time. From 1997-2017, 1,720 patients with hematologic malignancies received low-dose total body irradiation +/- fludarabine or clofarabine before transplantation from HLA-matched sibling or unrelated donors, followed by mycophenolate mofetil and a calcineurin inhibitor ± sirolimus. We compared outcomes in three cohorts by year of transplantation: 1997 +/- 2003 (n=562), 2004 +/- 2009 (n=594), and 2010 +/- 2017 (n=564). The proportion of patients ≥60 years old increased from 27% in 1997 +/- 2003 to 56% in 2010-2017, and with scores from the Hematopoietic Cell Transplantation Comborbidity Index of ≥3 increased from 25% in 1997 +/- 2003 to 45% in 2010 +/- 2017. Use of unrelated donors increased from 34% in 1997 +/- 2003 to 65% in 2010-2017. When outcomes from 2004 +/- 2009 and 2010-2017 were compared to 1997 +/- 2003, improvements were noted in overall survival (P=.0001 for 2004-2009 and P <.0001 for 2010-2017), profression-free survival (P=.002 for 2004-2009 and P <.0001 for 2010 +/- 2017), non-relapse mortality (P<.0001 for 2004 +/- 2009 and P <.0001 for 2010 +/- 2017), and in rates of grades 2 +/- 4 acute and chronic graft-vs.-host disease. For patients with hematologic malignancies who underwent transplantation with non-myeloablative conditioning, outcomes have improved during the past two decades. Trials reported are registered under ClinicalTrials.gov identifiers: NCT00003145, NCT00003196, NCT00003954, NCT00005799, NCT00005801, NCT00005803, NCT00006251, NCT00014235, NCT00027820, NCT00031655, NCT00036738, NCT00045435, NCT00052546, NCT00060424, NCT00075478, NCT00078858, NCT00089011, NCT00104858, NCT00105001, NCT00110058, NCT00397813, NCT00793572, NCT01231412, NCT01252667, NCT01527045.

Survival, Nonrelapse Mortality, and Relapse-Related Mortality After Allogeneic Hematopoietic Cell Transplantation: Comparing 2003-2007 Versus 2013-2017 Cohorts.

Background: Allogeneic hematopoietic cell transplantation is indicated for refractory hematologic cancer and some nonmalignant disorders. Survival is limited by recurrent cancer and organ toxicity. Objective: To determine whether survival has improved over the past decade and note impediments to better outcomes. Design: The authors compared cohorts that had transplants during 2003 to 2007 versus 2013 to 2017. Survival outcome measures were analyzed, along with transplant-related complications. Setting: A center performing allogeneic transplant procedures. Participants: All recipients of a first allogeneic transplant during 2003 to 2007 and 2013 to 2017. Intervention: Patients received a conditioning regimen, infusion of donor hematopoietic cells, then immunosuppressive drugs and antimicrobial approaches to infection control. Measurements: Day-200 nonrelapse mortality (NRM), recurrence or progression of cancer, relapse-related mortality, and overall mortality, adjusted for comorbidity scores, source of donor cells, donor type, patient age, disease severity, conditioning regimen, patient and donor sex, and cytomegalovirus serostatus. Results: During the 2003-to-2007 and 2013-to-2017 periods, 1148 and 1131 patients, respectively, received their first transplant. Over the decade, decreases were seen in the adjusted hazards of day-200 NRM (hazard ratio [HR], 0.66 [95% CI, 0.48 to 0.89]), relapse of cancer (HR, 0.76 [CI, 0.61 to 0.94]), relapse-related mortality (HR, 0.69 [CI, 0.54 to 0.87]), and overall mortality (HR, 0.66 [CI, 0.56 to 0.78]). The degree of reduction in overall mortality was similar for patients who received myeloablative versus reduced-intensity conditioning, as well as for patients whose allograft came from a matched sibling versus an unrelated donor. Reductions were also seen in the frequency of jaundice, renal insufficiency, mechanical ventilation, high-level cytomegalovirus viremia, gram-negative bacteremia, invasive mold infection, acute and chronic graft-versus-host disease, and prednisone exposure. Limitation: Cohort studies cannot determine causality, and current disease severity criteria were not available for patients in the 2003-to-2007 cohort. Conclusion: Improvement in survival and reduction in complications were substantial after allogeneic transplant. Relapse of cancer remains the largest obstacle to better survival outcomes. Primary Funding Source: National Institutes of Health.

Impact of Rituximab and Host/Donor Fc Receptor Polymorphisms after Allogeneic Hematopoietic Cell Transplantation for CD20+ B Cell Malignancies.

We previously reported a 24% 1-year relapse rate in 93 older or medically unfit patients with CD20+ B cell malignancies after allogeneic hematopoietic cell transplantation (HCT) with low-intensity conditioning. The current prospective study tested the hypothesis that disease relapse could be reduced and overall survival (OS) improved by peritransplantation administration of rituximab (RTX). Sixty-three patients received RTX (375 mg/m2/day) on days -3, +10, +24, and +38 along with 2 to 3 Gy total body irradiation with or without fludarabine (30 mg/m2 for 3 days). Median RTX levels of >25 µg/mL were achieved through day +84 after transplantation, but RTX level was not correlated with relapse or graft-versus-host disease (GVHD). HCT recipients with F/F and V/F FCγRIIIa polymorphisms showed a trend toward a higher relapse rate compared with those with V/V polymorphism (P= .15). No difference in outcome was found based on V/V donor pairing. Five-year relapse rates were similar between RTX-treated patients and historical controls (32% versus 28%; P = .94). RTX-treated patients had greater 5-year OS (47% versus 38%; P = .13) and progression-free survival (41% versus 32%; P = .12) compared with historical controls who underwent HCT without RTX, although the difference was not statistically significant. The incidence of acute GVHD was similar in the 2 groups (grade II-IV, 57% versus 56%; grade III-IV, 13% versus 17%), but the 5-year incidence of chronic GVHD was higher among RTX-treated patients (62% versus 47%). In patients with relapsed or refractory non-Hodgkin lymphoma, peritransplantation RTX neither reduced relapse nor improved GVHD. The role of donor-recipient pairing by FCγRIIIa polymorphisms in outcomes remains to be determined.

HLA-Haploidentical Hematopoietic Cell Transplantation for Treatment of Nonmalignant Diseases Using Nonmyeloablative Conditioning and Post-Transplant Cyclophosphamide.

Allogeneic hematopoietic cell transplant (HCT) is often the only curative therapy for patients with nonmalignant diseases; however, many patients do not have an HLA-matched donor. Historically, poor survival has been seen after HLA-haploidentical HCT because of poor immune reconstitution, increased infections, graft-versus-host disease (GVHD), and graft failure. Encouraging results have been reported using a nonmyeloablative T cell-replete HLA-haploidentical transplant approach in patients with hematologic malignancies. Here we report the outcomes of 23 patients with various nonmalignant diseases using a similar approach. Patients received HLA-haploidentical bone marrow (n = 17) or granulocyte colony-stimulating factor-mobilized peripheral blood stem cell (n = 6) grafts after conditioning with cyclophosphamide 50 mg/kg, fludarabine 150 mg/m2, and 2 or 4 Gy total body irradiation. Postgrafting immunosuppression consisted of cyclophosphamide, mycophenolate mofetil, tacrolimus, ± sirolimus. Median patient age at HCT was 10.8 years. Day 100 transplant-related mortality (TRM) was 0%. Two patients died at later time points, 1 from intracranial hemorrhage/disseminated fungal infection in the setting of graft failure and 1 from infection/GVHD. The estimated probabilities of grades II to IV and III to IV acute GVHD at day 100 and 2-year National Institutes of Health consensus chronic GVHD were 78%, 26%, and 42%, respectively. With a median follow-up of 2.5 years, the 2-year overall and event-free rates of survival were 91% and 78%, respectively. These results are encouraging and demonstrate favorable disease-specific lineage engraftment with low TRM in patients with nonmalignant diseases using nonmyeloablative conditioning followed by T cell-replete HLA-haploidentical grafts. However, additional strategies are needed for GVHD prevention to make this a viable treatment approach for patients with nonmalignant diseases.

History of hematopoietic cell transplantation: challenges and progress.

After more than 60 years of research in allogeneic hematopoietic cell transplantation (HCT), this therapy has advanced from one that was declared dead in the 1960s to a standard treatment of otherwise fatal malignant and non-malignant blood diseases. To date, close to 1.5 million hematopoietic cell transplants have been performed in more than 1,500 transplantation centers worldwide. This review will highlight the enormous efforts by numerous investigators throughout the world who have brought the experimental field of HCT to clinical reality, examine ongoing challenges, and provide insights for the future.

Yttrium-90-labeled anti-CD45 antibody followed by a reduced-intensity hematopoietic cell transplantation for patients with relapsed/refractory leukemia or myelodysplasia.

Outcomes of patients with persistent high-risk leukemia or myelodysplasia prior to allogeneic hematopoietic cell transplantation are dismal. We therefore conducted a phase I trial evaluating the use of CD45-targeted radiotherapy preceding hematopoietic cell transplantation with the goal of improving outcomes for this high-risk scenario. Fifteen patients, median age 62 (range 37-76) years, were treated: ten with advanced acute myeloid leukemia, five with high-risk myelodysplastic syndrome. All patients had evidence of disease prior to treatment including nine with marrow blast counts ranging from 7-84% and six with minimal residual disease. Patients received escalating doses of yttrium-90-labeled anti-CD45 antibody followed by fludarabine and 2 Gy total body irradiation prior to human leukocyte antigen-matched, related or unrelated hematopoietic cell transplantation. Although a maximum dose of 30 Gy was delivered to the liver, no dose-limiting toxicity was observed. Therefore, the maximum-tolerated dose could not be estimated. Treatment led to complete remission in 13 patients (87%). All patients engrafted by day 28. Six patients relapsed, median of 59 (range 6-351) days, after transplantation. The 1-year estimate of relapse was 41%. Eight patients (53%) are surviving with median follow up of 1.8 (range 0.9-5.9) years. Estimated overall survival at one and two years was 66% and 46%, respectively, with progression-free survival estimated to be 46% at each time point. In conclusion, the combination of 90Y-DOTA-BC8 with an allogeneic hematopoietic cell transplantation regimen was feasible and tolerable. This approach appears promising in this high-risk leukemia/myelodysplasia patient population with active disease. (Trial registered at clinicaltrials.gov identifier: NCT01300572).

Phase I/II multisite trial of optimally dosed clofarabine and low-dose TBI for hematopoietic cell transplantation in acute myeloid leukemia.

Clofarabine is an immunosuppressive purine nucleoside analog that may have better anti-leukemic activity than fludarabine. We performed a prospective phase I/II multisite trial of clofarabine with 2 Gy total body irradiation as non-myeloablative conditioning for allogeneic hematopoietic cell transplantation in adults with acute myeloid leukemia who were unfit for more intense regimens. Our main objective was to improve the 6-month relapse rate following non-myeloablative conditioning, while maintaining historic rates of non-relapse mortality (NRM) and engraftment. Forty-four patients, 53 to 74 (median: 69) years, were treated with clofarabine at 150 to 250 mg/m2 , of whom 36 were treated at the maximum protocol-specified dose. One patient developed multifactorial acute kidney injury and another developed multiorgan failure, but no other grade 3 to 5 non-hematologic toxicities were observed. All patients fully engrafted. The 6-month relapse rate was 16% (95% CI, 5%-27%) among all patients and 14% (95% CI, 3%-26%) among high-risk patients treated at the maximum dose, meeting the pre-specified primary efficacy endpoint. Overall survival was 55% (95% CI, 40%-70%) and leukemia-free survival was 52% (95% CI, 37%-67%) at 2 years. Compared to a historical high-risk cohort treated with the combination of fludarabine at 90 mg/m2 and 2 Gy TBI, protocol patients treated with the clofarabine-TBI regimen had lower rates of overall mortality (HR of 0.50, 95% CI, 0.28-0.91), disease progression or death (HR 0.48, 95% CI, 0.27-0.85), and morphologic relapse (HR 0.30, 95% CI, 0.13-0.69), and comparable NRM (HR 0.85, 95% CI 0.36-2.00). The combination of clofarabine with TBI warrants further investigation in patients with high-risk AML.

Hematopoietic Cell Transplantation for Paroxysmal Nocturnal Hemoglobinuria in the Age of Eculizumab.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired clonal hematopoietic cell disease characterized by the destruction of hematopoietic cells through activation of the complement system with manifestations that can be life-threatening including hemolysis, thrombosis, and marrow failure. Allogeneic hematopoietic cell transplantation (HCT) remains the sole cure for PNH, but eculizumab, a terminal complement inhibitor of C5, has been used to prevent complement-mediated hemolysis in patients with PNH since its approval by the Food and Drug Administration in 2007. We examined outcomes of HCT in patients with PNH to evaluate the effects of disease subtype, conditioning intensity, and eculizumab use either pre-HCT or post-HCT. Fifty-five patients with a diagnosis of PNH underwent at least 1 HCT, with 4 patients requiring a second HCT for graft failure. The median age at the time of first HCT was 30.0 years (range, 4.2 to 66.9 years). Seventeen patients (30.9%) had classical PNH, and the remaining 38 patients had PNH associated with another marrow disorder (aplastic anemia in 26 of the 38). Indications for HCT included pancytopenia in 47.3% of the patients, myeloid malignancy (myelodysplastic syndrome, myeloproliferative neoplasm, or acute myelogenous leukemia) in 21.8%, recurrent hemolysis in 20.0%, and thrombosis in 10.9%. Of the 55 first HCTs, 26 were performed with myeloablative conditioning, 27 were performed with reduced-intensity conditioning, and 2 sets of identical twins underwent HCT without any conditioning. Donor types included HLA-matched related in 38.2%, HLA-matched unrelated in 34.5%, single HLA-allele mismatched unrelated in 16.4%, umbilical cord blood in 5.5%, syngeneic in 3.6%, and HLA-haploidentical in 1.8%. The median duration of follow-up in surviving patients was 6.1 years (range, 2.1 to 46.1 years) after first HCT. The median time to neutrophil and platelet engraftment was 17 days and 19 days, respectively; all but 2 patients (96.3%) had sustained engraftment. Overall survival was 70% at 5 years. Neither the choice of conditioning intensity nor PNH subtype affected survival. Nineteen patients died during follow-up, including 12 patients before day +365. Six patients received treatment with eculizumab before HCT, and 2 were treated after HCT. All patients treated with eculizumab were alive at a median follow-up of 2.3 years (range, .2 to 6.9 years). Both patients treated with eculizumab after HCT had minimal to no acute GVHD (aGVHD), with grade I skin aGVHD in 1 patient and no aGVHD in the other patient, and no chronic GVHD at 2.1 and 4.1 years post-HCT, respectively. With the approval of eculizumab, the indications for HCT include persistent hemolysis, persistent thrombosis, and associated marrow failure. Administration of eculizumab before and after HCT warrants further study, particularly considering our observation of minimal to no GVHD in 2 patients who received eculizumab after HCT.

Allogeneic Hematopoietic Cell Transplantation in the Outpatient Setting.

Conditioning with fludarabine and low-dose total-body irradiation before allogeneic hematopoietic cell transplantation (HCT) enabled treating older or medically infirm patients with advanced hematologic malignancies in the outpatient setting. Between December 1997 and June 2017, 1037 patients with hematologic malignancies received peripheral blood stem cell (PBSC) grafts from HLA-matched or 1 HLA antigen/allele-mismatched related or unrelated donors. Median age was 58 (range, 18 to 80) years. Serious comorbidities with Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) scores ≥3 were present in 52% of patients. We found that 47% of patients were either never hospitalized or only had an overnight hospital stay for infusion of late-arriving PBSCs while 53% were admitted for a median of 6 days. Main reasons for admission were infection, fever, graft-versus-host disease, and regimen-related toxicity. Two thirds of admissions occurred within 3 weeks of HCT. The 5-year risk of nonrelapse mortality (NRM) was 26% among hospitalized patients and 13% among nonhospitalized patients. Significant risk factors for hospitalization included unrelated transplants, 1 HLA antigen-mismatched transplant, high HCT-CI scores, and diagnosis of nonmyeloma malignancies. Significant risk factors for NRM were hospitalization, older age, unrelated transplants, and high HCT-CI scores. Ambulatory allogeneic HCT is feasible and safe.

Prognostic Performance of the Augmented Hematopoietic Cell Transplantation-Specific Comorbidity/Age Index in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation from Alternative Graft Sources.

The Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) was developed and validated to weigh the burden of pretransplantation comorbidities and estimate their impact on post-transplantation risks of nonrelapse mortality (NRM). Recently, the HCT-CI was augmented by the addition of both age and the values of 3 markers: ferritin, albumin, and platelet count. So far, research involving The HCT-CI has been limited almost exclusively to recipients of allogeneic hematopoietic cell transplantation (HCT) from HLA-matched grafts. To this end, we sought to investigate the discriminative capacity of an augmented comorbidity/age index among 724 recipients of allogeneic HCT from HLA-mismatched (n = 345), haploidentical (n = 117), and umbilical cord blood (UCB; n = 262) grafts between 2000 and 2013. In the overall cohort, the augmented comorbidity/age index had a higher c-statistic estimate for prediction of NRM compared with the original HCT-CI (.63 versus .59). Findings were similar for recipients of HLA-mismatched (.62 versus .59), haploidentical (.60 versus .54), or UCB grafts (.65 versus .61). Compared with patients with an HCT-CI score ≥4, those with a score <4 had a higher survival rate among recipients of HLA-mismatched (55% versus 39%; P < .0008), HLA-haploidentical (58% versus 38%; P = .01), or UCB (67% versus 48%; P = .004) grafts. Our results demonstrate the utility of the augmented comorbidity/age index as a valid prognostic tool among recipients of allogeneic HCT from alternative graft sources.

Total body irradiation dose escalation decreases risk of progression and graft rejection after hematopoietic cell transplantation for myelodysplastic syndromes or myeloproliferative neoplasms.

A non-myeloablative regimen of fludarabine and 200 cGy total body irradiation combined with post-grafting immunosuppression with mycophenolate mofetil and a calcineurin inhibitor facilitates allogeneic hematopoietic cell transplantation from HLA-matched related or unrelated donors in older patients and/or those with comorbidities. However, outcomes of prior studies have been disappointing in patients with myelodysplastic syndromes or myeloproliferative neoplasms due to high incidences of progression or graft failure (together termed hematopoietic cell transplantation-failure). We hypothesized that escalating the total body irradiation dose may improve the outcomes and subsequently performed a phase II total body irradiation dose-escalation trial. Patients with median age 66 years were enrolled in two arms to receive non-myeloablative conditioning followed by hematopoietic cell transplantation with total body irradiation dose escalation for excessive hematopoietic cell transplantation-failure: Arm A: myeloproliferative neoplasm/myelodysplastic syndrome low risk (n=36); and Arm B: myelodysplastic syndrome high-risk/chronic myelomonocytic leukemia (n=41). Total body irradiation dose levels were: Level-1 (300 cGy), Level-2 (400 cGy), or Level-3 (450 cGy). Patients received intravenous fludarabine 30 mg/m2 for three days. Total body irradiation was administered on day 0 followed by infusion of peripheral blood stem cells from HLA-matched related (n=30) or unrelated (n=47) donors. Post-grafting immunosuppression with mycophenolate mofetil and cyclosporine was administered. The primary end point was day 200 hematopoietic cell transplant failure, with the objective of reducing the incidence to <20%. The primary end point was reached on Arm A at dose Level-1 (300 cGy total body irradiation) with a cumulative incidence of day 200 hematopoietic cell transplant failure of 11%, and on Arm B at dose Level-3 (450 cGy) with a cumulative incidence of day 200 hematopoietic cell transplant failure of 9%. Increasing the total body irradiation dose leads to a higher success rate with non-myeloablative conditioning by reducing relapse and rejection. Further studies are necessary to decrease non-relapse mortality, especially among patients with high-risk disease. Trial registered under clinicaltrials.gov identifier: NCT00397813.

Long-term follow up of tandem autologous-allogeneic hematopoietic cell transplantation for multiple myeloma.

We previously reported initial results in 102 multiple myeloma (MM) patients treated with sequential high-dose melphalan and autologous hematopoietic cell transplantation followed by 200 cGy total body irradiation with or without fludarabine 90 mg/m2 and allogeneic hematopoietic cell transplantation. Here we present long-term clinical outcomes among the 102 initial patients and among 142 additional patients, with a median follow up of 8.3 (range 1.0-18.1) years. Donors included human leukocyte antigen identical siblings (n=179) and HLA-matched unrelated donors (n=65). A total of 209 patients (86%) received tandem autologous-allogeneic upfront, while thirty-five patients (14%) had failed a previous autologous hematopoietic cell transplantation before the planned autologous-allogeneic transplantation. Thirty-one patients received maintenance treatment at a median of 86 days (range, 61-150) after allogeneic transplantation. Five-year rates of overall survival (OS) and progression-free survival (PFS) were 54% and 31%, respectively. Ten-year OS and PFS were 41% and 19%, respectively. Overall non-relapse mortality was 2% at 100 days and 14% at five years. Patients with induction-refractory disease and those with high-risk biological features experienced shorter OS and PFS. A total of 152 patients experienced disease relapse and 117 of those received salvage treatment. Eighty-three of the 117 patients achieved a clinical response, and for those, the median duration of survival after relapse was 7.8 years. Moreover, a subset of patients who became negative for minimal residual disease (MRD) by flow cytometry experienced a significantly lower relapse rate as compared with MRD-positive patients (P=0.03). Our study showed that the graft-versus-myeloma effect after non-myeloablative allografting allowed long-term disease control in standard and high-risk patient subsets. Ultra-high-risk patients did not appear to benefit from tandem autologous/allogeneic hematopoietic cell transplantation because of early disease relapse. Incorporation of newer anti-MM agents into the initial induction treatments before tandem hematopoietic cell transplantation and during maintenance might improve outcomes of ultra-high-risk patients. Clinical trials included in this study are registered at: clinicaltrials.gov identifiers: 00075478, 00005799, 01251575, 00078858, 00105001, 00027820, 00089011, 00003196, 00006251, 00793572, 00054353, 00014235, 00003954.

Anti-Inducible Costimulator Monoclonal Antibody Treatment of Canine Chronic Graft-versus-Host Disease.

In murine model systems inducible costimulator (ICOS) signaling has been implicated in the formation of chronic graft-versus-host disease (GVHD). Previously, we showed that chronic GVHD can be reproducibly produced in the dog hematopoietic cell transplantation (HCT) model and that ICOS expression is upregulated on T cells in dogs with chronic GVHD. The goal of the present study was to determine whether administration of a short course of anti-canine ICOS mAb could alter the rapid and progressive course of chronic GVHD. Five dogs underwent HCT from dog leukocyte antigen mismatched unrelated donors after total body irradiation. Postgrafting immunosuppression consisted of methotrexate (days 1, 3, 6, and 11) and cyclosporine (days -1 through 78). Anti-ICOS mAb (3 injections, 72 hours apart) was administered upon diagnosis of GVHD. One dog failed to respond to anti-ICOS mAb therapy and succumbed to chronic GVHD in a time course similar to control untreated dogs. Overall, anti-ICOS-treated dogs experienced a significant prolongation in survival from the time of diagnosis of chronic GVHD compared with control dogs. Within the limitations of the number of study dogs we suggest that a short course of anti-ICOS mAb may be useful in the treatment of chronic canine GVHD.

Reversal of Low Donor Chimerism after Hematopoietic Cell Transplantation Using Pentostatin and Donor Lymphocyte Infusion: A Prospective Phase II Multicenter Trial.

In a multicenter, prospective, phase II study we evaluated the safety and efficacy of pentostatin followed by donor lymphocyte infusion (DLI) in patients with low donor Tcell chimerism after allogeneic hematopoietic cell transplantation (HCT). Thirty-six patients with low donor blood CD3 chimerism were enrolled in this study. Thirty-five patients received a total of 41 DLIs after a dose of pentostatin, and 1 patient received pentostatin only. Median donor CD3 chimerism prompting the initiation of pentostatin and DLI was 28% (range, 5% to 47%). Responses (defined by increases in donor CD3 chimerism ≥10% maintained to day 56 post-DLI) were seen in 16 patients (44.4%) with a median rise in CD3 donor chimerism to 64% (range, 48% to 100%). There was a trend for better responses among 21 patients who received first treatment within 100 days after transplant (57% response rate) compared with15 patients who received first treatment more than 100 days after HCT (27% response rate, P = .07). Fourteen patients (39%) developed grades II to IV acute graft-versus-host disease (GVHD) at a median of 10 days (range, 0 to 83) after DLI. Ten patients (28%) developed extensive chronic GVHD. Seventeen patients (47%) developed new grade 4 cytopenias after DLI. There was no difference in relapse between nonresponders and responders. Twenty-eight patients (78%) died, most (n = 21) because of relapse. Five of 16 responders (31%) are alive, all disease-free, at a median of 60 months (range, 21 to 132) after DLI. Six of 20 nonresponders (30%) are alive at a median of 47 months (range, 16 to 100) after DLI, 3 in complete remission. Pentostatin and DLI had acceptable toxicity and appeared to increase low donor CD3 chimerism after HCT but had no impact on mortality.

Long-Term Follow-Up of 90Y-Ibritumomab Tiuxetan, Fludarabine, and Total Body Irradiation-Based Nonmyeloablative Allogeneic Transplant Conditioning for Persistent High-Risk B Cell Lymphoma.

Nonmyeloablative allogeneic hematopoietic cell transplantation (HCT) can provide prolonged remissions in patients with advanced B cell lymphoma (B-NHL) via the graft-versus-lymphoma effect, although inferior results are seen in patients with chemoresistant, bulky, or aggressive disease. Radioimmunotherapy can safely induce responses in B-NHL with minimal nonhematologic toxicity. Initial results of 90Y-ibritumomab tiuxetan-based allografting demonstrated early safety and disease control in nonremission patients but with short follow-up. Here we report the long-term outcomes of patients treated on this study with specific emphasis on patients achieving early remissions. Eleven of 40 patients were alive at a median follow-up of 9 years (range, 5.3 to 10.2). Fourteen (35%) deaths were due to disease progression and 14 (35%) deaths to complications from HCT. One patient died of a Merkel cell carcinoma. The 5-year overall and progression-free survival for patients with indolent B-NHL was 40% and 27.5%, respectively. None of the patients with diffuse large B cell lymphoma was a long-term disease-free survivor regardless of early remission status. 90Y-ibritumomab tiuxetan-based allografting represents a viable option in patients with indolent histologies. Improved strategies are needed for aggressive B-NHL. The original trial was registered at www.clinicaltrials.gov as NCT00119392.

Posttransplantation cyclophosphamide for prevention of graft-versus-host disease after HLA-matched mobilized blood cell transplantation.

The cumulative incidence of National Institutes of Health (NIH)-defined chronic graft-versus-host disease (GVHD) requiring systemic treatment is ∼35% at 1 year after transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized blood cells from HLA-matched related or unrelated donors. We hypothesized that high-dose cyclophosphamide given after G-CSF-mobilized blood cell transplantation would reduce the cumulative 1-year incidence of chronic GVHD to 15% or less. Forty-three patients with high-risk hematologic malignancies (median age, 43 years) were enrolled between December 2011 and September 2013. Twelve (28%) received grafts from related donors, and 31 (72%) received grafts from unrelated donors. Pretransplant conditioning consisted of fludarabine and targeted busulfan (n = 25) or total body irradiation (≥12 Gy; n = 18). Cyclophosphamide was given at 50 mg/kg per day on days 3 and 4 after transplantation, followed by cyclosporine starting on day 5. The cumulative 1-year incidence of NIH-defined chronic GVHD was 16% (95% confidence interval, 5-28%). The cumulative incidence estimates of grades 2-4 and 3-4 acute GVHD were 77% and 0%, respectively. At 2 years, the cumulative incidence estimates of nonrelapse mortality and recurrent malignancy were 14% and 17%, respectively, and overall survival was projected at 70%. Of the 42 patients followed for ≥1 year, 21 (50%) were relapse-free and alive without systemic immunosuppression at 1 year after transplantation. Thus, myeloablative pretransplant conditioning can be safely combined with high-dose cyclophosphamide after transplantation, and the risk of chronic GVHD associated with HLA-matched mobilized blood cell grafts can be substantially reduced. This trial was registered at www.clinicaltrials.gov as #NCT01427881.