Yi-Bin Chen

Ipilimumab for Patients with Relapse after Allogeneic Transplantation

BACKGROUND Loss of donor-mediated immune antitumor activity after allogeneic hematopoietic stem-cell transplantation (HSCT) permits relapse of hematologic cancers. We hypothesized that immune checkpoint blockade established by targeting cytotoxic T-lymphocyte-associated protein 4 with ipilimumab could restore antitumor reactivity through a graft-versus-tumor effect. METHODS We conducted a phase 1/1b multicenter, investigator-initiated study to determine the safety and efficacy of ipilimumab in patients with relapsed hematologic cancer after allogeneic HSCT. Patients received induction therapy with ipilimumab at a dose of 3 or 10 mg per kilogram of body weight every 3 weeks for a total of 4 doses, with additional doses every 12 weeks for up to 60 weeks in patients who had a clinical benefit. RESULTS A total of 28 patients were enrolled. Immune-related adverse events, including one death, were observed in 6 patients (21%), and graft-versus-host disease (GVHD) that precluded further administration of ipilimumab was observed in 4 patients (14%). No responses that met formal response criteria occurred in patients who received a dose of 3 mg per kilogram. Among 22 patients who received a dose of 10 mg per kilogram, 5 (23%) had a complete response, 2 (9%) had a partial response, and 6 (27%) had decreased tumor burden. Complete responses occurred in 4 patients with extramedullary acute myeloid leukemia and 1 patient with the myelodysplastic syndrome developing into acute myeloid leukemia. Four patients had a durable response for more than 1 year. Responses were associated with in situ infiltration of cytotoxic CD8+ T cells, decreased activation of regulatory T cells, and expansion of subpopulations of effector T cells in the blood. CONCLUSIONS Our early-phase data showed that administration of ipilimumab was feasible in patients with recurrent hematologic cancers after allogeneic HSCT, although immune-mediated toxic effects and GVHD occurred. Durable responses were observed in association with several histologic subtypes of these cancers, including extramedullary acute myeloid leukemia. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01822509.).

Selection of optimal alternative graft source: mismatched unrelated donor, umbilical cord blood, or haploidentical transplant

Only 30% of patients who require an allogeneic hematopoietic cell transplant will have an HLA-matched sibling donor. A search for an unrelated donor will be undertaken for patients without a matched family donor. However, many patients, particularly patients of diverse racial and ethnic backgrounds, may not be able to rapidly identify a suitably matched unrelated donor. Three alternative graft sources, umbilical cord blood (UCB), haploidentical (haplo)-related donor, and mismatched unrelated donor (MMUD) are available. UCB is associated with decreased GVHD, but hematologic recovery and immune reconstitution are slow. Haplo-HCT is characterized by donor availability for transplantation and after transplantation adoptive cellular immunotherapy but may be complicated by a high risk of graft failure and relapse. A MMUD transplant may also be an option, but GVHD may be of greater concern. Phase 2 studies have documented advances in HLA typing, GVHD prophylaxis, and infection prevention, which have improved survival. The same patient evaluated in different transplant centers may be offered MMUD, UCB, or haplo-HCT depending on center preference. In this review, we discuss the rationale for donor choice and the need of phase 3 studies to help answer this important question.

Immune Reconstitution after Double Umbilical Cord Blood Stem Cell Transplantation: Comparison with Unrelated Peripheral Blood Stem Cell Transplantation

Double umbilical cord blood (DUCB) transplantation is an accepted transplantation strategy for patients without suitable human leukocyte antigen (HLA) matched donors. However, DUCB transplantation is associated with increased morbidity and mortality because of slow recovery of immunity and a high risk of infection. To define the differences in immune reconstitution between DUCB transplantation and HLA matched unrelated donor (MUD) transplantation, we performed a detailed, prospective analysis of immune reconstitution in 42 DUCB recipients and 102 filgrastim-mobilized unrelated peripheral blood stem cell recipients. Reconstitution of CD3 T cells was significantly delayed in the DUCB cohort compared with the MUD cohort for 1 to 6 months posttransplantation (P < .001), including naive (CD45RO-) and memory (CD45RO+) CD4 T cells, regulatory (CD4CD25) T cells, and CD8 T cells. In contrast, CD19 B cells recovered more rapidly in the DUCB cohort and numbers remained significantly greater from 3 to 24 months after transplantation (P = .001). CD56CD16 natural killer (NK) cells also recovered more rapidly in DUCB recipients and remained significantly greater from 1 to 24 months after transplantation. B cell activating factor (BAFF) levels were higher in the DUCB cohort at 1 month (P < .001), were similar in both cohorts at 3 and 6 months, and were lower in the DUCB cohort at 12 months (P = .002). BAFF/CD19 B cell ratios were lower in the DUCB cohort at 3 (P = .045), 6 (P = .02), and 12 months (P = .002) after transplantation. DUCB recipients had more infections within the first 100 days after transplantation (P < .001), and there was less chronic graft-versus-host disease (P < .001), but there were no differences in cumulative incidence of relapse, nonrelapse death, progression-free survival, or overall survival between the 2 groups. These results suggest that increased risk of infections is specifically associated with delayed reconstitution of all major T cell subsets, but the increased risk is limited to the first 3 months after DUCB transplantation. There is no increased risk of relapse, suggesting that graft-versus-leukemia activity is maintained. Early reconstitution of B cells and NK cells may, in part, account for these findings.

Prospective serial evaluation of 2-hydroxyglutarate, during treatment of newly diagnosed acute myeloid leukemia, to assess disease activity and therapeutic response

Mutations of genes encoding isocitrate dehydrogenase (IDH1 and IDH2) have been recently described in acute myeloid leukemia (AML). Serum and myeloblast samples from patients with IDH-mutant AML contain high levels of the metabolite 2-hydroxyglutarate (2-HG), a product of the altered IDH protein. In this prospective study, we sought to determine whether 2-HG can potentially serve as a noninvasive biomarker of disease burden through serial measurements in patients receiving conventional therapy for newly diagnosed AML. Our data demonstrate that serum, urine, marrow aspirate, and myeloblast 2-HG levels are significantly higher in IDH-mutant patients, with a correlation between baseline serum and urine 2-HG levels. Serum and urine 2-HG, along with IDH1/2-mutant allele burden in marrow, decreased with response to treatment. 2-HG decrease was more rapid with induction chemotherapy compared with DNA-methyltransferase inhibitor therapy. Our data suggest that serum or urine 2-HG may serve as noninvasive biomarkers of disease activity for IDH-mutant AML.

Hematopoietic Stem Cell Transplantation for Multiple Myeloma: Guidelines from the American Society for Blood and Marrow Transplantation.

Therapeutic strategies for multiple myeloma (MM) have changed dramatically over the past decade. Thus, the role of hematopoietic stem cell transplantation (HCT) must be considered in the context of this evolution. In this evidence-based review, we have critically analyzed the data from the most recent clinical trials to better understand how to incorporate HCT and when HCT is indicated. We have provided our recommendations based on strength of evidence with the knowledge that ongoing clinical trials make this a dynamic field. Within this document, we discuss the decision to proceed with autologous HCT, factors to consider before proceeding to HCT, the role of tandem autologous HCT, post-HCT maintenance therapy, and the role of allogeneic HCT for patients with MM.

Efficacy, durability, and response predictors of low-dose interleukin-2 therapy for chronic graft-versus-host disease.

Chronic graft-versus-host disease (cGVHD) is associated with inadequate reconstitution of tolerogenic CD4(+)CD25(+)FOXP3(+) regulatory T cells (Tregs). Previous phase 1 studies identified a low daily dose of interleukin-2 (IL-2) that was well tolerated, did not exacerbate alloimmunity, augmented Treg in vivo, and was associated with improvement of active cGVHD. In the current phase 2 study, 35 adults with steroid-refractory cGVHD received daily IL-2 (1 × 10(6) IU/m(2)) for 12 weeks. Median time from transplantation and cGVHD onset was 616 days (range, 270-2145 days) and 317 days (range, 28-1880 days), respectively. Two patients withdrew and 5 required IL-2 dose reductions due to side effects. Twenty of 33 evaluable patients (61%) had clinical responses at multiple cGVHD sites (liver, skin, gastrointestinal tract, lung, joint/muscle/fascia). Three patients (9%) had progressive cGVHD. Compared with pretreatment levels, Treg and natural killer cell counts rose >fivefold (P < .001) and >fourfold (P < .001), respectively, without significant change in conventional CD4 T cells (Tcons) or CD8 T cells. The Treg:Tcon ratio rose >fivefold (P < .001). Clinical responders initiated IL-2 earlier (508 vs 917 days after transplantation, P = .005; 249 vs 461 days after cGVHD onset; P = .03). Treg:Tcon ratios ≥0.07 at baseline and ≥0.2 at week 1 also predicted clinical response (P = .003; P = .0003, respectively). After a 4-week treatment hiatus, clinical responders were eligible to continue IL-2 therapy indefinitely. During 2 years of extended IL-2 therapy, clinical and Treg immune responses persisted, while Tcon count and Treg:Tcon ratio gradually normalized. Low-dose IL-2 provides durable clinical improvement in active cGVHD and extended therapy is well-tolerated.

Autologous Stem Cell Transplantation with Thiotepa, Busulfan, and Cyclophosphamide (TBC) Conditioning in Patients with CNS Involvement by Non-Hodgkin Lymphoma

Primary central nervous system non-Hodgkin lymphoma (PCNSL) carries a poor prognosis and, although it responds to chemotherapy, fewer than 20% of patients are long-term disease-free survivors. Secondary CNS non-Hodgkin lymphoma (SCNSL) has an even worse prognosis with a median survival of only months and very few reported long-term survivors. For both of these groups of patients, there has been interest in using high-dose chemotherapy with autologous stem cell transplantation (ASCT) following conditioning with thiotepa, busulfan, and cyclophosphamide (TBC). We performed a retrospective review (from 2006-2010) of 32 patients from the Dana-Farber Cancer Institute and Massachusetts General Hospital with PCNSL or SCNSL who underwent ASCT with TBC conditioning. Of the 32 patients, 56% received TBC/ASCT after achieving brain magnetic resonance imaging (MRI) and/or cerebrospinal fluid complete response in brain, and 44% of patients were treated with TBC/ASCT in the setting of measurable CNS disease. The 100-day transplant-related mortality rate was only 3%. The most common nonhematologic grade 3 or 4 toxicity was mucositis, which occurred in 73% of patients. Notably, there was only 1 patient with prolonged significant neurologic toxicity that manifested as ataxia and dysphagia. The 1-year OS estimate is 93% (95% confidence interval [CI]: 75%-98%), and the 1-year progression-free survival (PFS) estimate is 90% (95% CI: 72%-96%) from the date of transplantation. Although these outcomes are encouraging, longer follow-up is required and comparison with other traditional ASCT regimens used for patients with non-Hodgkin lymphoma (NHL) is warranted.

Reduced intensity conditioning is superior to nonmyeloablative conditioning for older chronic myelogenous leukemia patients undergoing hematopoietic cell transplant during the tyrosine kinase inhibitor era

Tyrosine kinase inhibitors (TKIs) and reduced intensity conditioning (RIC)/nonmyeloablative (NMA) conditioning hematopoietic cell transplants (HCTs) have changed the therapeutic strategy for chronic myelogenous leukemia (CML) patients. We analyzed post-HCT outcomes of 306 CML patients reported to the Center for International Blood and Marrow Transplant Research aged 40 years and older undergoing RIC/NMA HCT from 2001 to 2007: 117 (38%) aged 40 to 49 years, 119 (39%) 50 to 59 years, and 70 (23%) 60 years or older. The majority (74%) had treatment with imatinib before HCT. At HCT, most patients aged 40 to 49 years were in chronic phase (CP) 1 (74%), compared with 31% aged 60 years or older. Siblings were donors for 56% aged 40 to 49 years; older cohorts had more unrelated donors. The majority received peripheral blood grafts and RIC across all age groups. 3 year overall survival (54%, 52%, and 41%), day + 100 grade II-IV acute GVHD (26%, 32%, and 32%), chronic GVHD (58%, 51%, and 43%), and 1-year treatment-related mortality (18%, 20%, and 13%) were similar across ages. The 3-year relapse incidence (36%, 43%, and 66%) and disease-free survival (35%, 32%, and 16%) were inferior in the oldest cohort. Importantly, for CP1 patients, relapse and disease-free survival were similar across age cohorts. Allogeneic RIC HCT for older patients with CML can control relapse with acceptable toxicity and survival in TKI-exposed CML, especially if still in CP1.

Increasing use of allogeneic hematopoietic cell transplantation in patients aged 70 years and older in the United States

In this study, we evaluated trends and outcomes of allogeneic hematopoietic cell transplantation (HCT) in adults ≥70 years with hematologic malignancies across the United States. Adults ≥70 years with a hematologic malignancy undergoing first allogeneic HCT in the United States between 2000 and 2013 and reported to the Center for International Blood and Marrow Transplant Research were eligible. Transplant utilization and transplant outcomes, including overall survival (OS), progression-free survival (PFS), and transplant-related mortality (TRM) were studied. One thousand one hundred and six patients ≥70 years underwent HCT across 103 transplant centers. The number and proportion of allografts performed in this population rose markedly over the past decade, accounting for 0.1% of transplants in 2000 to 3.85% (N = 298) in 2013. Acute myeloid leukemia and myelodysplastic syndromes represented the most common disease indications. Two-year OS and PFS significantly improved over time (OS: 26% [95% confidence interval (CI), 21% to 33%] in 2000-2007 to 39% [95% CI, 35% to 42%] in 2008-2013, P < .001; PFS: 22% [16% to 28%] in 2000-2007 to 32% [95% CI, 29% to 36%] in 2008-2013, P = .003). Two-year TRM ranged from 33% to 35% and was unchanged over time (P = .54). Multivariable analysis of OS in the modern era of 2008-2013 revealed higher comorbidity by HCT comorbidity index ≥3 (hazard ratio [HR], 1.27; P = .006), umbilical cord blood graft (HR, 1.97; P = .0002), and myeloablative conditioning (HR, 1.61; P = .0002) as adverse factors. Over the past decade, utilization and survival after allogeneic transplant have increased in patients ≥70 years. Select adults ≥70 years with hematologic malignancies should be considered for transplant.

Allogeneic transplantation provides durable remission in a subset of DLBCL patients relapsing after autologous transplantation

For diffuse large B‐cell lymphoma (DLBCL) patients progressing after autologous haematopoietic cell transplantation (autoHCT), allogeneic HCT (alloHCT) is often considered, although limited information is available to guide patient selection. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we identified 503 patients who underwent alloHCT after disease progression/relapse following a prior autoHCT. The 3‐year probabilities of non‐relapse mortality, progression/relapse, progression‐free survival (PFS) and overall survival (OS) were 30, 38, 31 and 37% respectively. Factors associated with inferior PFS on multivariate analysis included Karnofsky performance status (KPS) <80, chemoresistance, autoHCT to alloHCT interval <1‐year and myeloablative conditioning. Factors associated with worse OS on multivariate analysis included KPS<80, chemoresistance and myeloablative conditioning. Three adverse prognostic factors were used to construct a prognostic model for PFS, including KPS<80 (4 points), autoHCT to alloHCT interval <1‐year (2 points) and chemoresistant disease at alloHCT (5 points). This CIBMTR prognostic model classified patients into four groups: low‐risk (0 points), intermediate‐risk (2‐5 points), high‐risk (6‐9 points) or very high‐risk (11 points), predicting 3‐year PFS of 40, 32, 11 and 6%, respectively, with 3‐year OS probabilities of 43, 39, 19 and 11% respectively. In conclusion, the CIBMTR prognostic model identifies a subgroup of DLBCL patients experiencing long‐term survival with alloHCT after a failed prior autoHCT.