H. Kent Holland

Disabling Immune Tolerance by Programmed Death-1 Blockade With Pidilizumab After Autologous Hematopoietic Stem-Cell Transplantation for Diffuse Large B-Cell Lymphoma: Results of an International Phase II Trial

PURPOSE The Programmed Death-1 (PD-1) immune checkpoint pathway may be usurped by tumors, including diffuse large B-cell lymphoma (DLBCL), to evade immune surveillance. The reconstituting immune landscape after autologous hematopoietic stem-cell transplantation (AHSCT) may be particularly favorable for breaking immune tolerance through PD-1 blockade. PATIENTS AND METHODS We conducted an international phase II study of pidilizumab, an anti-PD-1 monoclonal antibody, in patients with DLBCL undergoing AHSCT, with correlative studies of lymphocyte subsets. Patients received three doses of pidilizumab beginning 1 to 3 months after AHSCT. RESULTS Sixty-six eligible patients were treated. Toxicity was mild. At 16 months after the first treatment, progression-free survival (PFS) was 0.72 (90% CI, 0.60 to 0.82), meeting the primary end point. Among the 24 high-risk patients who remained positive on positron emission tomography after salvage chemotherapy, the 16-month PFS was 0.70 (90% CI, 0.51 to 0.82). Among the 35 patients with measurable disease after AHSCT, the overall response rate after pidilizumab treatment was 51%. Treatment was associated with increases in circulating lymphocyte subsets including PD-L1E-bearing lymphocytes, suggesting an on-target in vivo effect of pidilizumab. CONCLUSION This is the first demonstration of clinical activity of PD-1 blockade in DLBCL. Given these results, PD-1 blockade after AHSCT using pidilizumab may represent a promising therapeutic strategy in this disease.

T-Cell–Replete HLA-Haploidentical Hematopoietic Transplantation for Hematologic Malignancies Using Post-Transplantation Cyclophosphamide Results in Outcomes Equivalent to Those of Contemporaneous HLA-Matched Related and Unrelated Donor Transplantation

PURPOSE T-cell-replete grafts from haploidentical donors using post-transplantation cyclophosphamide may represent a solution for patients who require allogeneic hematopoietic cell transplantation (alloHCT) but lack a conventional donor. We compared outcomes of alloHCT using haploidentical donors with those of transplantation using conventional HLA-matched sibling donors (MRDs) and HLA-matched unrelated donors (MUDs). PATIENTS AND METHODS Outcomes of 271 consecutive patients undergoing T-cell-replete first alloHCT for hematologic malignancies performed contemporaneously at a single center (53 using haploidentical donors; 117, MRDs; 101, MUDs) were compared. Overall and disease-free survival (DFS) were adjusted for effects of significant patient-, disease-, and transplantation-related covariates using a stratified Cox model. RESULTS Patient characteristics were similar between the three donor groups. For patients undergoing MRD, MUD, and haploidentical transplantation, 24-month cumulative incidences of nonrelapse mortality were 13%, 16%, and 7% and of relapse were 34%, 34%, and 33%, respectively (P not significant [NS]). Cumulative incidences of grades 3 to 4 acute graft-versus-host disease (GVHD) at 6 months were 8%, 11%, and 11%, respectively (P NS); extensive chronic GVHD occurred in 54%, 54%, and 38% of patients, respectively (P < .05 for those undergoing haploidentical donor v MRD or MUD transplantation). Adjusted 24-month probabilities of survival were 76%, 67%, and 64% and of DFS were 53%, 52%, and 60%, respectively; these were not significantly different among the three donor groups. CONCLUSION Haploidentical transplantation performed using T-cell-replete grafts and post-transplantation cyclophosphamide achieves outcomes equivalent to those of contemporaneous transplantation performed using MRDs and MUDs. Such transplantation represents a valid alternative for patients who lack a conventional donor.

CTLA4 blockade with ipilimumab to treat relapse of malignancy after allogeneic hematopoietic cell transplantation

Relapse of malignancy after allogeneic hematopoietic cell transplantation (allo-HCT) remains a therapeutic challenge. Blockade of the CTLA4 molecule can effectively augment antitumor immunity mediated by autologous effector T cells. We have assessed the safety and preliminary efficacy of a neutralizing, human anti-CTLA4 monoclonal antibody, ipilimumab, in stimulating the graft-versus-malignancy (GVM) effect after allo-HCT. Twenty-nine patients with malignancies that were recurrent or progressive after allo-HCT, received ipilimumab as a single infusion at dose cohorts between 0.1 and 3.0 mg/kg. Dose-limiting toxicity was not encountered, and ipilimumab did not induce graft-versus-host disease (GVHD) or graft rejection. Organ-specific immune adverse events (IAE) were seen in 4 patients (grade 3 arthritis, grade 2 hyperthyroidism, recurrent grade 4 pneumonitis). Three patients with lymphoid malignancy developed objective disease responses following ipilimumab: complete remission (CR) in 2 patients with Hodgkin disease and partial remission (PR) in a patient with refractory mantle cell lymphoma. At the 3.0 mg/kg dose, active serum concentrations of ipilimumab were maintained for more than 30 days after a single infusion. Ipilimumab, as administered in this clinical trial, does not induce or exacerbate clinical GVHD, but may cause organ-specific IAE and regression of malignancy. This study is registered at (http://clinicaltrials.gov) under NCI protocol ID P6082.

Haploidentical Transplantation Using T Cell Replete Peripheral Blood Stem Cells and Myeloablative Conditioning in Patients with High-Risk Hematologic Malignancies Who Lack Conventional Donors is Well Tolerated and Produces Excellent Relapse-Free Survival: Results of a Prospective Phase II Trial

Haploidentical hematopoietic stem cell transplant (HSCT) provides an opportunity for nearly all patients to benefit from HSCT. We conducted a trial of haploidentical T cell replete allografting using a busulfan-based myeloablative preparative regimen, peripheral blood stem cells (PBSCs) as the graft source, and posttransplantation cyclophosphamide (Cy). Eligibility was limited to patients at high risk of relapse after nonmyeloablative haploidentical bone marrow transplant (BMT). Twenty patients were enrolled in the study (11 with relapsed/refractory disease and 9 who underwent transplantation while in remission and considered standard risk). Donor engraftment occurred in all 20 patients with full donor T cell and myeloid chimerism by day +30. The cumulative incidence of grades II-IV and III-IV acute graft-versus-host disease (aGVHD) was 30% and 10%, respectively. The cumulative incidence of chronic GVHD (cGVHD) was 35%. Nonrelapse mortality (NRM) at 100 days and 1 year was 10% for all patients and 0% for standard-risk patients. With a median follow-up of 20 months, the estimated 1-year overall survival (OS) and disease-free survival (DFS) was 69% and 50%, respectively, for all patients, and 88% and 67% for standard-risk patients. Myeloablative haploidentical HSCT is associated with excellent rates of engraftment, GVHD, NRM, and DFS, and is a valid option in patients with high-risk malignancies who lack timely access to a conventional donor.

Total Body Irradiation-Based Myeloablative Haploidentical Stem Cell Transplantation Is a Safe and Effective Alternative to Unrelated Donor Transplantation in Patients Without Matched Sibling Donors.

We enrolled 30 patients on a prospective phase II trial utilizing a total body irradiation (TBI)-based myeloablative preparative regimen (fludarabine 30 mg/m2/day × 3 days and TBI 150 cGy twice per day on day -4 to -1 [total dose 1200 cGy]) followed by infusion of unmanipulated peripheral blood stem cells from a haploidentical family donor (haplo). Postgrafting immunosuppression consisted of cyclophosphamide 50 mg/kg/day on days 3 and 4, mycophenolate mofetil through day 35, and tacrolimus through day 180. Median patient age was 46.5 years (range, 24 to 60). Transplantation diagnosis included acute myelogenous leukemia (n = 16), acute lymphoblastic leukemia (n = 6), chronic myelogenous leukemia (n = 5), myelodysplastic syndrome (n = 1), and non-Hodgkins lymphoma (n = 2). Using the Dana Farber/Center for International Blood and Marrow Transplant Research/Disease Risk Index (DRI), patients were classified as low (n = 4), intermediate (n = 12), high (n = 11), and very high (n = 3) risk. All patients engrafted with a median time to neutrophil and platelet recovery of 16 and 25 days, respectively. All evaluable patients achieved sustained complete donor T cell and myeloid chimerism by day +30. Acute graft-versus-host disease (GVHD) grades II to IV and III and IV was seen in 43% and 23%, respectively. The cumulative incidence of chronic GVHD was 56% (severe in 10%). After a median follow-up of 24 months, the estimated 2-year overall survival (OS), disease-free survival (DFS), nonrelapse mortality, and relapse rate were 78%, 73%, 3%, and 24%, respectively. Two-year DFS and relapse rate in patients with low/intermediate risk disease was 100% and 0%, respectively, compared with 39% and 53% for patients with high/very high risk disease. When compared with a contemporaneously treated cohort of patients at our institution receiving myeloablative HLA-matched unrelated donor (MUD) transplantation (acute myelogenous leukemia [n = 17], acute lymphoblastic leukemia [n = 15], chronic myelogenous leukemia [n = 7], myelodysplastic syndrome [n = 7], non-Hodgkin lymphoma [n = 1], chronic lymphoblastic leukemia [n = 1]), outcomes were statistically similar, with 2-yr OS and DFS being 78% and 73%, respectively after haplo transplantation versus 71% and 64%, respectively, after MUD transplantation. In patients with DRI low/intermediate risk disease, 2-yr DFS was superior after haplo compared with MUD transplantations (100% versus 74%, P = .032), whereas there was no difference in DFS in patients with high/very high risk disease (39% versus 37% for haplo and MUD respectively, P = .821). Grade II to IV acute GVHD was seen less often after haplo compared with MUD transplantation (43% versus 63%, P = .049), as was moderate-to-severe chronic GVHD (22% versus 58%, P = .003). Myeloablative haplo transplantation using this regimen is a valid option for patients with advanced hematologic malignancies who lack timely access to a conventional donor. Outcomes appear at least equivalent to those seen in contemporaneous patients who underwent transplantation from MUD.

Comparison of Outcomes of Hematopoietic Cell Transplants from T-Replete Haploidentical Donors Using Post-Transplantation Cyclophosphamide with 10 of 10 HLA-A, -B, -C, -DRB1, and -DQB1 Allele-Matched Unrelated Donors and HLA-Identical Sibling Donors: A Multivariable Analysis Including Disease Risk Index

Outcomes of 475 consecutive patients undergoing first allogeneic transplantation for hematologic malignancy performed using T-replete HLA-haploidentical donors and post-transplantation cyclophosphamide (HIDT; n = 116) were compared with contemporaneous patients transplanted from 10 of 10 HLA allele-matched unrelated donors (MUDT; n = 178) or HLA-identical sibling donors (MRDT; n = 181). Uniform supportive care measures and assessments were used. Median follow-up was 45 months. HIDT patients were more likely than MUDT patients to be black (44% versus 2%; P < .001). At 2 years after transplantation, estimates of overall survival were 57% for HIDT, 59% for MUDT, and 72% for MRDT (P not significant [NS] for HIDT versus MUDT; P = .02 for HIDT versus MRDT); corresponding disease-free survival rates were 54%, 50%, and 56% (P NS for both comparisons). The respective cumulative incidences (CIs) of nonrelapse mortality were 17%, 16%, 14%, and those of relapse were 29%, 34%, and 30% (P NS for all). The respective CIs of acute graft-versus-host disease (GVHD) grade II-IV were 41%, 48%, and 28% (P = NS for HIDT versus MUDT; P = .005 for HIDT versus MRDT). At 2 years, the respective CIs of moderate/severe chronic GVHD were 31%, 47%, and 44% (P = .004 for HIDT versus MUDT; P = .032 for HIDT versus MRDT) and 19% of HIDT recipients, 42% of MUDT recipients, and 35% of MRDT recipients were on systemic immunosuppressive treatment (P = .007 for HIDT versus MUDT). In recipients of peripheral blood stem cell grafts, the incidence of moderate-severe chronic GVHD was significantly lower in HIDT recipients compared with MUDT recipients (2-year CI, 25% versus 48%; P = .002). In a multivariate analysis incorporating Disease Risk Index and other significant covariates, survival (hazard ratio [HR], 1.31; P = .15) and disease-free survival (HR, 0.96; P = .79) were not significantly different between HIDT and MUDT recipients, but the incidence of chronic GVHD was lower in HIDT recipients (moderate-severe, HR, 0.59; P = .007). HIDT produced similar long-term survival with lower rates of chronic GVHD than optimally matched MUDT. HIDT should be considered a standard of care option for patients lacking a matched sibling donor.

Corticosteroid-Free Primary Treatment of Chronic Extensive Graft-versus-Host Disease Incorporating Rituximab

Chronic graft-versus-host disease (cGVHD) is a significant determinant of overall outcome and quality of life in survivors of allogeneic hematopoietic cell transplantation. Standard initial therapy of cGVHD is based on prolonged use of corticosteroids and a calcineurin inhibitor and has not changed for over 3 decades, despite limited efficacy and long-term toxicity. Rituximab is an attractive agent for the upfront treatment of cGVHD because of its favorable toxicity profile, efficacy in steroid-refractory cGVHD, and ability to serve as a steroid-sparing agent in autoimmune diseases. We hypothesized that a corticosteroid-free regimen incorporating rituximab would result in improved outcomes when used for the initial treatment of cGVHD. Twenty-five patients (median age, 56 years; range, 29 to 77) with extensive cGVHD were enrolled on a prospective phase II trial. Enrollment was limited to patients with first onset extensive cGVHD requiring systemic immunosuppression and without residual or concurrent acute graft-versus-host disease. cGVHD was classified as de novo, interrupted, and progressive in 12, 11, and 2 patients, respectively. cGVHD severity (National Institutes of Health grade) was mild, moderate, and severe in 3, 14, and 8 patients, respectively. All patients received rituximab 375 mg/m(2) × 4 weekly doses, then 1 dose every 3 months × 4 doses, in addition to mycophenolate mofetil and either tacrolimus or sirolimus. No other systemic immunosuppression was permitted, and only a short-course of steroids (≤4 weeks) was allowed at physician discretion; otherwise, treatment was deemed a failure and patients were treated off study. Twenty-two of 25 patients (88%) responded to treatment. Of the 22 responding patients, the median time to maximum response was 161 days (range, 35 to 300 days) with maximum response being complete in 21 of 22 patients and partial in 1 patient. Excluding the 3 patients taken off study for treatment failure, corticosteroids were used sparingly, with only 2 patients receiving any steroids for a median of 15 days (range, 13 to 18 days). Immunosuppression was discontinued in 17 of 22 evaluable patients (77%) with a median time to discontinuation of 300 days (range, 138 to 488 days). After immunosuppression discontinuation, cGVHD did recur in 7 patients after a median of 166 days (range, 21 to 393 days), requiring reinstitution of systemic immunosuppression (estimated cGVHD recurrence rate of 37%). With a median follow-up of 27 months, estimated 2-year overall survival is 82%. This regimen utilizing rituximab in the initial therapy of cGVHD is effective and avoids the use of corticosteroids in the majority of patients. In permitting early discontinuation of immunosuppression while obviating the need for prolonged exposure to systemic corticosteroids, this regimen may result in reduced treatment-related morbidity and mortality associated with cGVHD and its treatment.

Does Total Body Irradiation Conditioning Improve Outcomes of Myeloablative Human Leukocyte Antigen–Identical Sibling Transplantations for Chronic Lymphocytic Leukemia?

An allogeneic hematopoietic cell transplantation from an HLA-identical donor after high-dose (myeloablative) pretransplantation conditioning is an effective therapy for some people with chronic lymphocytic leukemia (CLL). Because CLL is a highly radiosensitive cancer, we hypothesized that total body irradiation (TBI) conditioning regimens may be associated with better outcomes than those without TBI. To answer this, we analyzed data from 180 subjects with CLL receiving myeloablative doses of TBI (n = 126) or not (n = 54), who received transplants from an HLA-identical sibling donor between 1995 and 2007 and reported to the Center for International Blood & Marrow Transplant Research. At 5 years, treatment-related mortality was 48% (95% confidence interval [CI], 39% to 57%) versus 50% (95% CI, 36% to 64%); P = NS. Relapse rates were 17% (95% CI, 11% to 25%) versus 22% (95% CI, 11% to 35%); P = NS. Five-year progression-free survival and overall survival were 34% (95% CI, 26% to 43%) versus 28% (95% CI, 15% to 42%); P = NS and 42% (95% CI, 33% to 51%) versus 33% (95% CI, 19% to 48%); P = NS, respectively. The single most common cause of death in both cohorts was recurrent/progressive CLL. No variable tested in the multivariate analysis was found to significantly affect these outcomes, including having failed fludarabine. Within the limitations of this study, we found no difference in HLA-identical sibling transplantation outcomes between myeloablative TBI and chemotherapy pretransplantation conditioning in persons with CLL.

Impact of Donor Type on Outcome after Allogeneic Hematopoietic Cell Transplantation for Acute Leukemia

Allogeneic hematopoietic cell transplantation (alloHCT) is considered the most potent postremission antileukemic therapy in adults with acute leukemia. We analyzed 172 consecutive acute leukemia patients transplanted in complete remission after a T cell-replete alloHCT from either a matched related (MRD, n = 54), unrelated (MUD, n = 67), or haploidentical (haplo, n = 51) donor to look for patient-, disease-, and transplant-related factors associated with post-transplant outcomes. Patients included 123 acute myeloid leukemia patients (first complete remission [CR], n = 94; second CR, n = 28; third CR, n = 1) and 49 acute lymphoblastic leukemia (ALL) patients (first CR, n = 39; second CR, n = 9; third CR, n = 1) with a median age of 50 years (range, 19 to 74). Median follow-up for surviving patients was 38 months. Cumulative incidence of nonrelapse mortality at 1 and 3 years was 6% and 17%, respectively. The estimated rates of 3-year overall survival, disease-free survival, and relapse incidence were 59%, 50%, and 33%, respectively. In multivariate analysis, risk factors for inferior survival included diagnosis of ALL, high risk disease risk index, and use of a female donor for a male recipient. Donor type (MRD, MUD, haplo) had no impact on any transplant outcome. Given the favorable outcomes associated with alloHCT in acute leukemia and lack of effect of donor type, a strong case can be made for transplanting acute leukemia patients in remission as soon as any donor becomes available.

Myeloablative Conditioning with PBSC Grafts for T Cell-Replete Haploidentical Donor Transplantation Using Posttransplant Cyclophosphamide

Relapse is the main cause of treatment failure after nonmyeloablative haploidentical transplant (haplo-HSCT). In an attempt to reduce relapse, we have developed a myeloablative (MA) haplo-HSCT approach utilizing posttransplant cyclophosphamide (PT/Cy) and peripheral blood stem cells as the stem cell source. We summarize the results of two consecutive clinical trials, using a busulfan-based (n = 20) and a TBI-based MA preparative regimen (n = 30), and analyze a larger cohort of 64 patients receiving MA haplo-HSCT. All patients have engrafted with full donor chimerism and no late graft failures. Grade III-IV acute GVHD and moderate-severe chronic GVHD occurred in 23% and 30%, respectively. One-year NRM was 10%. Predicted three-year overall survival, disease-free survival, and relapse were 53%, 53%, and 26%, respectively, in all patients and 79%, 74%, and 9%, respectively, in patients with a low/intermediate disease risk index (DRI). In multivariate analysis, DRI was the most significant predictor of survival and relapse. Use of TBI (versus busulfan) had no significant impact on survival but was associated with significantly less BK virus-associated hemorrhagic cystitis. We contrast our results with other published reports of MA haplo-HSCT PT/Cy in the literature and attempt to define the comparative utility of MA haplo-HSCT to other methods of transplantation.