Alternate donor hematopoietic cell transplantation (HCT) in non-Hodgkin lymphoma using lower intensity conditioning: a report from the CIBMTR

Lower Graft-versus-Host Disease and Relapse Risk in Post-Transplant Cyclophosphamide-Based Haploidentical versus Matched Sibling Donor Reduced-Intensity Conditioning Transplant for Hodgkin Lymphoma

Classic Hodgkin lymphoma (cHL) patients with relapsed or refractory disease may benefit from allogeneic hematopoietic cell transplantation (allo-HCT), but many lack a matched sibling donor (MSD). Herein, we compare outcomes of 2 reduced-intensity conditioning (RIC) HCT platforms in cHL: T cell-replete related donor haploidentical (haplo) HCT with a post-transplant cyclophosphamide (PTCy)-based approach versus an MSD/calcineurin inhibitor (CNI)-based approach. The study included 596 adult patients who underwent a first RIC allo-HCT for cHL between 2008 and 2016 using either a haplo-PTCy (n = 139) or MSD/CNI-based (n = 457) approach. Overall survival (OS) was the primary endpoint. Secondary endpoints included acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD), nonrelapse mortality (NRM), relapse/progression, and progression-free survival (PFS). On multivariate analysis, there was no significant difference between haplo/PTCy and MDS/CNI-based approaches in terms of OS (hazard ratio [HR], 1.07; 95% confidence interval [CI], .79 to 1.45; P = .66) or PFS (HR, .86; 95% CI, .68 to 1.10; P = .22). Haplo/PTCy was associated with a significantly higher risk of grades II to IV aGVHD (odds ratio [OR], 1.73, 95% CI, 1.16 to 2.59; P = .007), but the risk of grades III to IV aGVHD was not significantly different between the 2 cohorts (OR, .61; 95% CI, .29 to 1.27; P = .19). The haplo/PTCy platform provided a significant reduction in cGVHD risk (HR, .45; 95% CI, .32 to .64; P < .001), and a significant reduction in relapse risk (HR, .74; 95% CI, .56 to .97; P = .03). There was a statistically nonsignificant trend toward higher NRM with a haplo/PTCy approach (HR, 1.65; 95% CI, .99 to 2.77; P = .06). Haplo/PTCy-based approaches are associated with lower incidences of cGVHD and relapse, with PFS and OS outcomes comparable with MSD/CNI-based approaches. There was a leaning toward higher NRM with a haplo/PTCy-based platform. These data show that haplo/PTCy allo-HCT in cHL results in survival comparable with MSD/CNI-based allo-HCT.

How ibrutinib, a B-cell malignancy drug, became an FDA-approved second-line therapy for steroid-resistant chronic GVHD

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is potentially curative for a number of hematologic conditions, both malignant and nonmalignant. However, its success can be limited by the development of acute and chronic graft-versus-host disease (GVHD). Chronic GVHD (cGVHD) is the most common long-term complication following allo-SCT, and patients who develop this condition have significantly higher morbidity and mortality and significantly lower quality of life than patients who do not. Until recently, there were no US Food and Drug Administration (FDA)-approved therapies for cGVHD treatment. In this review article, we describe how ibrutinib was identified as potential cGVHD therapy based on preclinical cGVHD models and clinical studies in B-cell malignancies and elucidation of its mechanisms of action in cGVHD. Results from a phase 2 clinical trial that was designed based on National Institutes of Health Criteria for the grading and staging of cGVHD culminated in the FDA-approval of ibrutinib as second line therapy of steroid-refractory or steroid-resistant cGVHD. Results of ibrutinib studies in phase 3 randomized studies, for cGVHD prophylaxis and as first -line testing along with steroids will be especially important in selecting the preferred indications for ibrutinib in patients at risk for or who have developed cGVHD.

Allogeneic hematopoietic cell transplantation as curative therapy for non-transformed follicular lymphomas

Allogeneic hematopoietic cell transplantation (HCT) offers the chance of cure for patients with non-transformed follicular lymphoma (FL), but is associated with the risk of non-relapse mortality (NRM). The aim of this study was to identify subgroups of FL patients who benefit from HCT. The European Society for Blood and Marrow Transplantation (EBMT) Minimum-Essential-A Data of 146 consecutive patients who received HCT for FL between 1998 and 2008 were extracted from the database of the German Registry 'DRST'. Diagnosis of FL was verified by contact with the reference pathologists. Estimated 1-, 2- and 5-year overall survivals (OS) were 67%, 60% and 53%, respectively. Day 100 NRM was 15%. Thirteen out of 33 patients (40%) with treatment-refractory disease (RD) at the time of transplantation survived long term. Univariate statistical analysis suggested limited chronic GvHD, donor age ⩽42 years and TBI-based conditioning in treatment refractory patients to correlate with favorable OS. Independent prognostic factors for OS were treatment-sensitive disease and limited chronic GvHD for the whole cohort, and additionally TBI-based conditioning for the treatment refractory subgroup. In contrast, patient age ⩾55 years had no impact on outcome. Thus, HCT for FL is associated with acceptable NRM, and offers a substantial chance of cure for patients with RD or advanced age. Donors ⩽42 years should be preferred if available.

Donor HLA-specific Abs: to BMT or not to BMT?

The engraftment failure associated with Abs to donor-specific HLA (DSA) limits options for sensitized BMT candidates. Fourteen of fifteen patients with no other viable donor options were desensitized and transplanted using a regimen of plasmapheresis and low-dose i.v. Ig modified to accommodate pre-BMT conditioning. DSA levels were assessed by solid-phase immunoassays and cell-based crossmatch tests. DSA levels were monitored throughout desensitization and on day -1 to determine if there was any DSA rebound that would require additional treatment. A mean reduction in DSA level of 64.4% was achieved at the end of desensitization, with a subsequent reduction of 85.5% after transplantation. DSA in 11 patients was reduced to levels considered negative post-BMT, whereas DSA in three patients remained at low levels. All 14 patients achieved donor engraftment by day +60; however, seven patients suffered disease relapses. Four patients experienced mild, grade 1 GVHD. Factors influencing the response to desensitization include initial DSA strength, number, specificity, DSA rebound and a mismatch repeated from a prior transplant. While desensitization should be reserved for patients with limited donor options, careful DSA assessment and monitoring can facilitate successful engraftment after BMT.

Alternative donors extend transplantation for patients with lymphoma who lack an HLA matched donor

Alternative donor transplantation is increasingly used for high risk lymphoma patients. We analyzed 1593 transplant recipients (2000 to 2010) and compared transplant outcomes in recipients of 8/8 allele human leukocyte antigen (HLA)-A, -B, -C, and DRB1 matched unrelated donors (MUD; n=1176), 7/8 allele HLA-matched unrelated donors (MMUD; n=275) and umbilical cord blood donors (1 or 2 units UCB; n=142). Adjusted 3-year non-relapse mortality of MMUD (44%) was higher as compared to MUD (35%; p=0.004), but similar to UCB recipients (37%; p=0.19), although UCB had lower rates of neutrophil and platelet recovery compared to unrelated donor groups. With a median follow-up of 55 months, 3-year adjusted cumulative incidence of relapse was lower after MMUD compared with MUD (25% vs 33%, p=0.003) but similar between UCB and MUD (30% vs 33%; p=0.48). In multivariate analysis UCB recipients had lower risks of acute and chronic graft versus host disease compared with adult donor groups (UCB vs MUD: HR=0.68, p=0.05; HR=0.35; p<0.001). Adjusted 3-year overall survival was comparable (43% MUD, 37% MMUD and 41% UCB). Data highlight that patients with lymphoma have acceptable survival after alternative donor transplantation. MMUD and UCB can expand the curative potential of allotransplant to patients who lack suitable HLA-matched sibling or MUD.

Hematopoietic stem cell transplantation donor sources in the 21st century: choosing the ideal donor when a perfect match does not exist

Most patients who require allogeneic stem cell transplantation do not have a matched sibling donor, and many patients do not have a matched unrelated donor. In an effort to increase the applicability of transplantation, alternative donors such as mismatched adult unrelated donors, haploidentical related donors, and umbilical cord blood stem cell products are frequently used when a well matched donor is unavailable. We do not yet have the benefit of randomized trials comparing alternative donor stem cell sources to inform the choice of donor; however, the existing data allow some inferences to be made on the basis of existing observational and phase 2 studies. All 3 alternative donor sources can provide effective lymphohematopoietic reconstitution, but time to engraftment, graft failure rate, graft-versus-host disease, transplant-related mortality, and relapse risk vary by donor source. These factors all contribute to survival outcomes and an understanding of them should help guide clinicians when choosing among alternative donor sources when a matched related or matched unrelated donor is not available.

Allotransplantation for patients age ≥40 years with non-Hodgkin lymphoma: encouraging progression-free survival

Non-Hodgkin lymphoma (NHL) disproportionately affects older patients, who do not often undergo allogeneic hematopoietic cell transplantation (HCT). We analyzed Center for International Blood and Marrow Transplant Research data on 1248 patients age ≥40 years receiving reduced-intensity conditioning (RIC) or nonmyeloablative (NMA) conditioning HCT for aggressive (n = 668) or indolent (n = 580) NHL. Aggressive lymphoma was more frequent in the oldest cohort 49% for age 40 to 54 versus 57% for age 55 to 64 versus 67% for age ≥65; P = .0008). Fewer patients aged ≥65 had previous autografting (26% versus 24% versus 9%; P = .002). Rates of relapse, acute and chronic GVHD, and nonrelapse mortality (NRM) at 1 year post-HCT were similar in the 3 age cohorts (22% [95% confidence interval (CI), 19% to 26%] for age 40 to 54, 27% [95% CI, 23% to 31%] for age 55 to 64, and 34% [95% CI, 24% to 44%] for age ≥65. Progression-free survival (PFS) and overall survival (OS) at 3 years was slightly lower in the older cohorts (OS: 54% [95% CI, 50% to 58%] for age 40 to 54; 40% [95% CI, 36% to 44%] for age 55 to 64, and 39% [95% CI, 28% to 50%] for age ≥65; P < .0001). Multivariate analysis revealed no significant effect of age on the incidence of acute or chronic GVHD or relapse. Age ≥55 years, Karnofsky Performance Status <80, and HLA mismatch adversely affected NRM, PFS, and OS. Disease status at HCT, but not histological subtype, was associated with worse NRM, relapse, PFS, and OS. Even for patients age ≥55 years, OS still approached 40% at 3 years, suggesting that HCT affects long-term remission and remains underused in qualified older patients with NHL.

The changing landscape of peripheral T-cell lymphoma in the era of novel therapies

Peripheral T-cell lymphomas (PTCLs) are the most common sub-entity of mature T-cell lymphomas, and apart from particular presentations, share a poor prognosis with frequent short-term, agressive, and chemorefractory relapses. Because of the rarity and also the heterogeneity of the disease, we lack randomized clinical trials. However, to date, neither intensification of frontline chemotherapy or autologous transplant has led to any improvement of survival, and the standard CHOP (cyclophosphamide, doxorubicine, vincristine, and prednisone) regimen remains the most employed as induction therapy. In the past few years, new chemotherapeutic agents, with the capability to encompass the resistance to conventional chemotherapy, such as pralatrexate or bendamustine, have been evaluated. Furthermore, identification of cell surface molecular markers (CD52, CD30, CCR4) has led to the development of new monoclonal antibodies. Similarly, the better comprehension of physiopathological mechanisms and detection of deregulated intracellular pathways encouraged the use of novel therapies such as histone deacetylase inhibitors or immunomodulatory drugs. Some of these compounds have been approved for relapse, and are currently evaluated upfront in ongoing clinical trials. Despite these efforts, the global prognosis still remains much inferior to those of B-cell lymphomas, highlighting the necessity of multicenter clinical trials.

Treating B-cell cancer with T cells expressing anti-CD19 chimeric antigen receptors

Most B-cell malignancies express CD19, and a majority of patients with B-cell malignancies are not cured by current standard therapies. Chimeric antigen receptors (CARs) are fusion proteins consisting of antigen recognition moieties and T-cell activation domains. T cells can be genetically modified to express CARs, and adoptive transfer of anti-CD19 CAR T cells is now being tested in clinical trials. Effective clinical treatment with anti-CD19 CAR T cells was first reported in 2010 after a patient with advanced-stage lymphoma treated at the NCI experienced a partial remission of lymphoma and long-term eradication of normal B cells. Additional patients have subsequently obtained long-term remissions of advanced-stage B-cell malignancies after infusions of anti-CD19 CAR T cells. Long-term eradication of normal CD19(+) B cells from patients receiving infusions of anti-CD19 CAR T cells demonstrates the potent antigen-specific activity of these T cells. Some patients treated with anti-CD19 CAR T cells have experienced acute adverse effects, which were associated with increased levels of serum inflammatory cytokines. Although anti-CD19 CAR T cells are at an early stage of development, the potent antigen-specific activity observed in patients suggests that infusions of anti-CD19 CAR T cells might become a standard therapy for some B-cell malignancies.