Amandeep Salhotra

Phase I Trial of Total Marrow and Lymphoid Irradiation Transplantation Conditioning in Patients with Relapsed/Refractory Acute Leukemia

Current conditioning regimens provide insufficient disease control in relapsed/refractory acute leukemia patients undergoing hematopoietic stem cell transplantation (HSCT) with active disease. Intensification of chemotherapy and/or total body irradiation (TBI) is not feasible because of excessive toxicity. Total marrow and lymphoid irradiation (TMLI) allows for precise delivery and increased intensity treatment via sculpting radiation to sites with high disease burden or high risk for disease involvement, while sparing normal tissue. We conducted a phase I trial in 51 patients (age range, 16 to 57 years) with relapsed/refractory acute leukemia undergoing HSCT (matched related, matched unrelated, or 1-allele mismatched unrelated) with active disease, combining escalating doses of TMLI (range, 1200 to 2000 cGy) with cyclophosphamide (CY) and etoposide (VP16). The maximum tolerated dose was declared at 2000 cGy, as TMLI simulation studies indicated that >2000 cGy might deliver doses toxic for normal organs at or exceeding those delivered by standard TBI. The post-transplantation nonrelapse mortality (NRM) rate was only 3.9% (95% confidence interval [CI], .7 to 12.0) at day +100 and 8.1% (95% CI, 2.5 to 18.0) at 1 year. The cumulative incidence of grades II to IV acute graft-versus-host disease (GVHD) was 43.1% (95% CI, 29.2 to 56.3) and for grade III and IV, it was 13.7% (95% CI, 6.9 to 27.3). The day +30 complete remission rate for all patients was 88% and was 100% for those treated at 2000 cGy. The overall 1-year survival was 55.5% (95% CI, 40.7 to 68.1). The TMLI/CY/VP16 conditioning regimen is well tolerated at TMLI doses up to 2000 cGy with a low 100-day and 1-year NRM rate and no increased risk of GVHD with higher doses of radiation.

Long-Term Results of High-Dose Therapy and Autologous Stem Cell Transplantation for Mantle Cell Lymphoma: Effectiveness of Maintenance Rituximab

High-dose therapy followed by autologous stem cell transplantation (ASCT) can improve outcomes for mantle cell lymphoma (MCL) but is associated with a high incidence of relapse. A retrospective study of 191 MCL patients who underwent ASCT at City of Hope was performed to examine prognostic factors for outcomes after ASCT. For all patients the 5-year overall survival (OS) was 71% (95% confidence interval [CI], 63% to 77%) and progression-free survival (PFS) was 53% (95% CI, 45% to 60%). The 5-year cumulative incidence of relapse was 41% (95% CI, 34% to 48%) with a continuous pattern of relapse events occurring at a median of 2.1 years (range, .2 to 13.4) after ASCT. In multivariate analysis, post-transplant maintenance rituximab was the factor most significantly associated with both OS (relative risk [RR], .17; 95% CI, .07 to .38) and PFS (RR, .25; 95% CI, .14 to .44). For the subset of patients who had positron emission tomography (PET) data available and were in a PET-negative first complete remission at ASCT (n = 105), maintenance rituximab was significantly associated with superior OS (RR, .17; 95% CI, .05 to .59) and PFS (RR, .20; 95% CI, .09 to .43). These results support a benefit with maintenance rituximab for all MCL patients treated with ASCT.

Favorable impact of allogeneic stem cell transplantation in patients with therapy-related myelodysplasia regardless of TP53 mutational status

Therapy-related myelodysplastic syndrome is a long-term complication of cancer treatment in patients receiving cytotoxic therapy, characterized by high-risk genetics and poor outcomes. Allogeneic hematopoietic cell transplantation is the only potential cure for this disease, but the prognostic impact of pre-transplant genetics and clinical features has not yet been fully characterized. We report here the genetic and clinical characteristics and outcomes of a relatively large cohort of patients with therapy-related myelodysplastic syndrome (n=67) who underwent allogeneic transplantation, comparing these patients to similarly treated patients with de novo disease (n=199). The 5-year overall survival was not different between patients with therapy-related and de novo disease (49.9% versus 53.9%; P=0.61) despite a higher proportion of individuals with an Intermediate-2/High International Prognostic Scoring System classification (59.7% versus 43.7%; P=0.003) and high-risk karyotypes (61.2% versus 30.7%; P<0.01) among the patients with therapy-related disease. In mutational analysis, TP53 alteration was the most common abnormality in patients with therapy-related disease (n=18: 30%). Interestingly, the presence of mutations in TP53 or in any other of the high-risk genes (EZH2, ETV6, RUNX1, ASXL1: n=29: 48%) did not significantly affect either overall survival or relapse-free survival. Allogeneic stem-cell transplantation is, therefore, a curative treatment for patients with therapy-related myelodysplastic syndrome, conferring a similar long-term survival to that of patients with de novo disease despite higher-risk features. While TP53 alteration was the most common mutation in therapy-related myelodysplastic syndrome, the finding was not detrimental in our case-series.

Philadelphia chromosome as a recurrent event among therapy-related acute leukemia: ALDOSS et al.

long-term outcome of NMP1 mutation positive patients transplanted after relapse. In conclusion, our single-institution experience supports the reported superior shortterm prognosis for patients with NPM1 mutated AML, but challenges the accepted notion of favorable long-term outcome in this population. Prospective clinical trials are needed to clarify long-term prognosis and optimal management of these patients.

Erythroblast macrophage protein (Emp): Past, Present and Future

This review is a journey of the landmark erythroblast macrophage protein (Emp) discovered in 1994, and it walks chronologically through the progress that has been made in understanding the biological function of this protein. Historically, Emp was the first identified cell attachment molecule and is expressed in both erythroblasts and macrophages and mediates their attachments to form erythroblastic islands. The absence of Emp erythroblasts shows defects in differentiation and enucleation. Emp‐deficient macrophages display immature morphology characterized by small sizes, round shapes, and the lack of cytoplasmic projections. Although the primary sequence of Emp has already been determined and its role in both erythroid and macrophage development is well established, there are major gaps in the understanding of its function at the molecular level. Recent studies had implicated its importance in actin cytoskeleton remodeling and cell migration, but the molecular mechanisms are still enigmatic. Previous studies have also demonstrated that downregulation of Emp affects the expression of mitogen‐associated protein kinase 1 (MAPK1) and thymoma viral protooncogene (AKT‐1) resulting in abnormal cell motility. In this review, we summarize the proposed function of Emp based on previous studies, present scenarios, and its plausible future in translational research.

Core-binding factor acute myeloid leukemia with t(8;21): Risk factors and a novel scoring system (I-CBFit)

Although the prognosis of core‐binding factor (CBF) acute myeloid leukemia (AML) is better than other subtypes of AML, 30% of patients still relapse and may require allogeneic hematopoietic cell transplantation (alloHCT). However, there is no validated widely accepted scoring system to predict patient subsets with higher risk of relapse.

Outcomes of Patients with Recurrent and Refractory Lymphoma Undergoing Allogeneic Hematopoietic Cell Transplantation with BEAM Conditioning and Sirolimus- and Tacrolimus-Based GVHD Prophylaxis

The current standard of care for patients with Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) is high-dose conditioning followed by autologous stem cell transplantation (ASCT). For some patients (ie, those with highest-risk disease, insufficient stem cell numbers after mobilization, or bone marrow involvement) allogeneic hematopoietic cell transplantation (alloHCT) offers the potential for cure. However, the majority of patients undergoing alloHCT receive reduced-intensity conditioning as a preparative regimen, and studies assessing outcomes of patients after alloHCT with myeloablative conditioning are limited. In this retrospective study, we reviewed outcomes of 22 patients with recurrent and refractory NHL who underwent alloHCT with myeloablative BEAM conditioning and received tacrolimus/sirolimus as graft-versus-host disease (GVHD) prophylaxis at City of Hope between 2005 and 2018. With a median follow-up of 2.6 years (range, 1.0 to 11.2 years), the probabilities of 2-year overall survival and event-free survival were 58.3% (95% confidence interval [CI], 35.0% to 75.8%) and 45.5% (95% CI, 24.4% to 64.3%), respectively. The cumulative incidence of grade II to IV acute GVHD was 45.5% (95% CI, 23.8% to 64.9%), with only 1 patient developing grade IV acute GVHD. However, chronic GVHD was seen in 55% of the patients (n = 12). Of the 22 eligible patients, 2 had undergone previous ASCT and 2 had undergone previous alloHCT. Both patients with previous ASCT developed severe regimen-related toxicity. Patients who underwent alloHCT with chemorefractory disease had lower survival rates, with 1-year OS and EFS of 44.4% and 33.0%, respectively. In conclusion, alloHCT with a BEAM preparative regimen and tacrolimus/sirolimus-based GVHD should be considered as an alternative option for patients with highest-risk lymphoma whose outcomes are expectedly poor after ASCT.

Pathophysiology and Immunology of Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGVHD) is the leading cause of late morbidity and mortality in patients undergoing allogeneic hematopoietic stem cell transplant (HSCT) [1, 2].Chronic GVHD and its associated complications result in increased resource utilization, poor quality of life parameters, and decreased overall survival in patients. Early detection and appropriate intervention will help in improving long-term outcomes of HCT patients. Detection of biomarkers in blood or involved tissue (skin, gut, etc.) may help in early diagnosis and risk-stratification of patients, thereby impacting the type and intensity of immunosuppressive therapy chosen. To date, early intervention and successful treatment of cGVHD patients has lagged due to difficulty in scoring organ involvement due to lack of uniform and objective scoring tools. Another major problem in the field is the absence of approved therapies in the steroid refractory setting, which is a result of the difficulties of clinical trials in this patient population due to poor standardization of scoring systems and evaluation of objective responses. There are other competing causes of death, including disease relapse and infectious complications that may confound survival data. Establishment of standardized cGVHD scoring systems has helped enormously in staging the disease and evaluating responses to new therapies, thereby helping to make objective response evaluations possible [3].

Overview of Hematopoietic Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is a form of immune therapy used to treat a variety of malignant and nonmalignant diseases. The procedure involves transfusion of multipotent hematopoietic stem cells derived from bone marrow, peripheral blood, or umbilical cord blood from a donor, usually matched in human leukocyte antigens (HLA). Immediately prior to HSCT, patients receive conditioning chemoradiotherapy to eliminate underlying hematologic malignant cells, and to sufficiently suppress the host’s immune functions for successful engraftment of donor hematopoietic cells. Following the conditioning regimen and HSCT, donor-derived hematopoietic recovery and immune reconstitution occur, during which patients require intensive supportive care, including prevention and treatment of complications such as infections and acute or chronic graft-versus-host disease (GVHD).

Hyperfractionated Cyclophosphamide, Vincristine, Doxorubicin, and Dexamethasone Chemotherapy in Mantle Cell Lymphoma Patients Is Associated with Higher Rates of Hematopoietic Progenitor Cell Mobilization Failure despite Plerixafor Rescue

Induction regimens for mantle cell lymphoma (MCL) can be categorized into highly intensive regimens containing cytarabine and less intense regimens, such as rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone (R-CHOP) or rituximab with bendamustine (R-bendamustine). Prior publications have shown rituximab and hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (R-hyperCVAD) can be associated with stem cell mobilization failures. However, those studies did not include the use of plerixafor as rescue for stem cell mobilization failure. We examined our database of 181 consecutive MCL patients who received upfront therapy from 2005 to 2015 with either R-hyperCVAD or less intense chemotherapy (R-bendamustine and R-CHOP only) regimens to assess impact of frontline chemotherapy on collection of hematopoietic cell progenitors before autologous stem cell transplantation (ASCT). In the preplerixafor era (before August 16, 2009), a significant difference in peripheral blood stem cell (PBSC) collection failure between the R-hyperCVAD (12%) and other chemotherapy (11%) groups was not established. However, in the postplerixafor era, use of R-hyperCVAD chemotherapy was associated with significantly higher rates of hematopoietic progenitor cell collection failures (17%) compared with that observed in the other chemotherapy group (4%; P = .04). The rates of mobilization failure declined to 4% in the postplerixafor era from 11% in the preplerixafor era for patients receiving less intensive chemotherapy. Conversely, the rate of mobilization failure increased in the R-hyperCVAD group from 12% in the preplerixafor era to 17% in the postplerixafor era. Plerixafor does not overcome the negative impact of R-hyperCVAD on PBSC mobilization, and caution is warranted in using R-hyperCVAD in patients with newly diagnosed MCL who are candidates for ASCT.