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

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.

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.

Relapse of malignancy after allogeneic hematopoietic cell transplantation (allo-HCT

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.

Autotransplants increasingly are used to treat breast cancer. One-hundred-day mortality has decreased substantially. Three-year survival is better in women with earlier stage disease and in those who respond to pretransplant chemotherapy.

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.

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-Hodgkin's 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 transpl...