Celebrating the registration of 9.000 patients treated with CAR T cells in the EBMT registry: Collection of real-world data in the context of hematopoietic cellular therapies.

The European society for Blood and Marrow Transplantation (EBMT) has a long-standing interest in the evaluation of hematopoietic cell transplantation. More than three decades ago, its members established a continental registry. Today, more than 700,000 patients have been registered, and information has been gathered on more than 800,000 transplants. This huge amount of information has allowed conducting multiple retrospective studies, evaluating changes in practices over time and for different categories of diseases, benchmarking outcome across EBMT affiliated centers, and increasingly serves to build synthetic comparators to evaluate the introduction of therapeutic innovations in the field of hematology. CAR-T cells therapies draw on human and technical resources that are also used to deliver HCT; they elicit side effects that require the implementation of risk mitigation plans; they are living drugs that persist in the body of the recipient and thus deserve prolonged follow-up; the introduction of CAR-T cells in the pharmacopeia is likely to significantly impact on the practice of BMT; for all these reasons and even before the first approvals of CAR-T Cells in Europe, EBMT engaged in a project aiming at complementing the EBMT Registry with a Cellular Therapy Form, with the objective to register CAR-T cells treated patients and collect information on their short-, middle- and long-term outcome. The goal is to provide EBMT investigators with a tool for primary analyses of the collected information and to support secondary use of data transferred at the individual level to Marketing Authorization Holders and other interested parties, to fulfill their obligations to health authorities and further evaluate the actual medical values of CAR-T Cells in different contexts and indications. The EBMT Registry received a positive opinion from the European Medicines agency in 2019, and five years later contains information on more than 9.000 treated patients. This article describes the journey to start this new activity, lessons to be drawn in view of improving the collection of real-world data, and what existing information tells us in terms of patient access.

Clinical Practice Recommendations for Hematopoietic Cell Transplantation and Cellular Therapies in Follicular Lymphoma: A Collaborative Effort on Behalf of the American Society for Transplantation and Cellular Therapy and the European Society for Blood and Marrow Transplantation.

Follicular lymphoma (FL) is the most common indolent B-cell non-Hodgkin lymphoma (NHL), accounting for nearly one-third of all NHL. The therapeutic landscape for patients with FL has significantly expanded over the past decade, but the disease continues to be considered incurable. Hematopoietic cell transplantation (HCT) is potentially curative in some cases. Recently, the emergence of chimeric antigen receptor T-cell therapy (CAR-T) for patients with relapsed/refractory (R/R) FL has yielded impressive response rates and long-term remissions, but definitive statement on the curative potential of CAR-T is currently not possible due to limited patient numbers and relatively short follow up. A consensus on the contemporary role, optimal timing, and sequencing of HCT (autologous or allogeneic) and cellular therapies in FL is needed. As a result, the American Society of Transplantation and Cellular Therapy (ASTCT) Committee on Practice Guidelines endorsed this effort to formulate consensus recommendations to address this unmet need. The RAND-modified Delphi method was used to generate 15 consensus statements/recommendations. These clinical practice recommendations will help guide clinicians managing patients with FL. Of note, the use of bispecific antibodies in R/R FL was not in the scope of this project.

Hematopoietic stem cell transplantation for DLBCL: a report from the European Society for Blood and Marrow Transplantation on more than 40,000 patients over 32 years.

Autologous(auto-) and allogeneic(allo-) hematopoietic stem cell transplantation (HSCT) are key treatments for relapsed/refractory diffuse large B-cell lymphoma (DLBCL), although their roles are challenged by CAR-T-cells and other immunotherapies. We examined the transplantation trends and outcomes for DLBCL patients undergoing auto-/allo-HSCT between 1990 and 2021 reported to EBMT. Over this period, 41,148 patients underwent auto-HSCT, peaking at 1911 cases in 2016, while allo-HSCT saw a maximum of 294 cases in 2018. The recent decline in transplants corresponds to increased CAR-T treatments (1117 cases in 2021). Median age for auto-HSCT rose from 42 (1990-1994) to 58 years (2015-2021), with peripheral blood becoming the primary stem cell source post-1994. Allo-HSCT median age increased from 36 (1990-1994) to 54 (2015-2021) years, with mobilized blood as the primary source post-1998 and reduced intensity conditioning post-2000. Unrelated and mismatched allo-HSCT accounted for 50% and 19% of allo-HSCT in 2015-2021. Three-year overall survival (OS) after auto-HSCT improved from 56% (1990-1994) to 70% (2015-2021), p < 0.001, with a decrease in relapse incidence (RI) from 49% to 38%, while non-relapse mortality (NRM) remained unchanged (4%). After allo-HSCT, 3-year-OS increased from 33% (1990-1999) to 46% (2015-2021) (p < 0.001); 3-year RI remained at 39% and 1-year-NRM decreased to 19% (p < 0.001). Our data reflect advancements over 32 years and >40,000 transplants, providing insights for evaluating emerging DLBCL therapies.

Long-term outcome of peripheral T-cell lymphomas: Ten-year follow-up of the International Prospective T-cell Project.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of haematological cancers with generally poor clinical outcomes. However, a subset of patients experience durable disease control, and little is known regarding long-term outcomes. The International T-cell Lymphoma Project (ITCLP) is the largest prospectively collected cohort of patients with PTCLs, providing insight into clinical outcomes at academic medical centres globally. We performed a long-term outcome analysis on patients from the ITCLP with available 10-year follow-up data (n = 735). The overall response rate to first-line therapy was 68%, while 5- and 10-year overall survival estimates were 49% and 40% respectively. Most deaths occurred prior to 5 years, and for patients alive at 5 years, the chance of surviving to 10 years was 84%. However, lymphoma remained the leading cause of death in the 5- to 10-year period (67%). Low-risk International Prognostic Index and Prognostic Index for T-cell lymphoma scores both identified patients with improved survival, while in multivariate analysis, age >60 years and Eastern Cooperative Oncology Group performance status 2-4 were associated with inferior outcomes. The favourable survival seen in patients achieving durable initial disease control emphasizes the unmet need for optimal front-line therapeutic approaches in PTCLs.

Graft-versus-host-disease prophylaxis with ATG or PTCY in patients with lymphoproliferative disorders undergoing reduced intensity conditioning regimen HCT from one antigen mismatched unrelated donor.

Post-transplant cyclophosphamide (PTCY) has been introduced as graft-versus-host disease (GvHD) prophylaxis in mismatched and matched unrelated hematopoietic cell transplant (HCT). However, data comparing outcomes of PTCY or ATG in patients undergoing a 1 antigen mismatched HCT for lymphoproliferative disease are limited. We compared PTCY versus ATG in adult patients with lymphoproliferative disease undergoing a first 9/10 MMUD HCT with a reduced intensity conditioning regimen from 2010 to 2021. Patients receiving PTCY were matched to patients receiving ATG according to: age, disease status at transplant, female to male matching, stem cell source and CMV serology. Grade II-IV acute GvHD at 100 day was 26% and 41% for the ATG and PTCY group, respectively (p = 0.08). Grade III-IV acute GvHD was not significantly different between the two groups. No differences were observed in relapse incidence, non-relapse mortality, progression-free survival, overall survival and GvHD-relapse-free survival at 1 year. The cumulative incidence of 1-year extensive chronic GvHD was 18% in the ATG and 5% in the PTCY group, respectively (p = 0.06). In patients with lymphoproliferative diseases undergoing 9/10 MMUD HCT, PTCY might be a safe option providing similar results to ATG prophylaxis. Due to the limited number of patients, prospective randomized trials are needed.

The influence of immunodeficiency, disease features, and patient characteristics on survival in plasmablastic lymphoma.

ABSTRACT: Plasmablastic lymphoma (PBL) is a rare and aggressive non-Hodgkin lymphoma associated with immunodeficiency, characterized by uncertain treatment approaches and an unfavorable prognosis. We conducted a multicenter, international, retrospective cohort study, aiming to characterize the clinical features, risk factors, and outcomes of patients with PBL. Data were collected from 22 institutions across 4 countries regarding patients diagnosed with PBL between 1 January 1999 and 31 December 2020. Survival risk factors were analyzed using both univariate and multivariate regression models. Overall survival (OS) was calculated using Kaplan-Meier statistics. First-line treatment regimens were stratified into standard- and higher-intensity regimens, and based on whether they incorporated a proteasome inhibitor (PI). A total of 281 patients (median age, 55 years) were included. Immunodeficiency of any kind was identified in 144 patients (51%), and 99 patients (35%) had HIV-positive results. The 5-year OS for the entire cohort was 36% (95% confidence interval, 30%-42%). In multivariate analysis, inferior OS was associated with Epstein-Barr virus-negative lymphoma, poor performance status, advanced stage, and bone marrow involvement. In an independent univariate analysis, the international prognostic index was associated with OS outcomes. Neither immunosuppression nor HIV infection, specifically, influenced OS. Among patients treated with curative intent (n = 234), the overall response rate was 72%. Neither the intensity of the treatment regimen nor the inclusion of PIs in first-line therapy was associated with OS. In this large retrospective study of patients with PBL, we identified novel risk factors for survival. PBL remains a challenging disease with poor long-term outcomes.

Retrospective analysis of hematopoietic cell transplantation for blastic plasmacytoid dendritic cell neoplasm: conditioning intensity matters.

Blastic plasmacytoid dendritic cell neoplasia (BPDCN) is a rare myeloid malignancy with a generally poor prognosis. Although preliminary evidence suggests that hematopoietic cell transplantation (HCT) could improve outcome in patients with BPDCN, the individual contributions of conditioning and graft-versus-tumor (GVT) effects to HCT success are undefined. We present a retrospective study of 162 adult patients who underwent a first HCT (allogeneic 146, autologous 16) between 2009 and 2017, and were registered with the EBMT. Median age was 57 (range 20-73) years, and disease status at HCT was first complete remission (CR1) in 78%. Among patients receiving allogeneic HCT (alloHCT), myeloablative conditioning (MAC), reduced intensity conditioning (RIC) and in-vivo T-cell depletion (TCD) were used in 54%, 46%, and 59% respectively. Total body irradiation (TBI) was the conditioning backbone in 61% of MAC and 26% of RIC transplants. One-year overall survival (OS) and progression-free survival (PFS) rates were comparable after alloHCT and autologous HCT (autoHCT). Among alloHCT recipients, MAC with TBI significantly improved OS and PFS, independently of CR1, age, Karnofsky index and TCD. Accordingly, MAC (ideally based on TBI) should be preferred for alloHCT recipients with BPDCN. In patients who are not elegible for MAC alloHCT, autoHCT could be considered.

The EBMT Immune Effector Cell Nursing Guidelines on CAR-T Therapy: A Framework for Patient Care and Managing Common Toxicities.

Chimeric antigen receptor T-cell (CAR T) therapy is a new and rapidly developing field. Centers across the world are gaining more experience using these innovative anti-cancer treatments, transitioning from the 'bench' to the 'bedside', giving benefit to an increasing number of patients. For those with some refractory hematological malignancies, CAR-T may offer a treatment option that was not available a few years ago.CAR-T therapy is an immune effector cell and precision/personalized medicine treatment which is tailored to the individual patient and associated with a variety of unique adverse events and toxicities that necessitate specialist nursing/medical vigilance in an appropriate clinical setting. Subtle unrecognized signs and symptoms can result in rapid deterioration and, possibly, life threatening cardiorespiratory and/or neurological sequelae.These guidelines have been prepared for nurses working in cellular therapy in inpatient, outpatient and ambulatory settings. Many nurses will encounter cellular therapy recipients indirectly, during the referral process, following discharge, and when patients are repatriated back to local centers. The aim of these guidelines is to provide all nurses with a practice framework to enable recognition, monitoring and grading of CAR-T therapy-associated toxicities, and to support and nurse these highly complex patients with confidence.They have been developed under the auspices of several bodies of the European society for Blood and Marrow Transplantation (EBMT), by experienced health professionals, and will be a valuable resource to all practitioners working in cellular therapy.

Access to and affordability of CAR T-cell therapy in multiple myeloma: an EBMT position paper.

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapeutic approach in the treatment of multiple myeloma, and the recent approval of the first two CAR T-cell products could result in improved outcomes. However, it remains a complex and expensive technology, which poses challenges to health-care systems and society in general, especially in times of crises. This potentially accelerates pre-existing inequalities as access to CAR T-cell therapy varies, both between countries, depending on the level of economic development, and within countries, due to structural disparities in access to quality health care-a parameter strongly correlated with socioeconomic status, ethnicity, and lifestyle. Here, we identify two important issues: affordability and access to CAR T-cell treatment. This consensus statement from clinical investigators, clinicians, nurses, and patients from the European Society for Blood and Marrow Transplantation (EBMT) proposes solutions as part of an innovative collaborative strategy to make CAR T-cell therapy accessible to all patients with multiple myeloma.

Genetic and phenotypic characterisation of HIV-associated aggressive B-cell non-Hodgkin lymphomas, which do not occur specifically in this population: diagnostic and prognostic implications.

The frequency of aggressive subtypes of B-cell non-Hodgkin lymphoma (B-NHL), such as high-grade B-cell lymphomas (HGBL) with MYC and BCL2 and/or BCL6 rearrangement (HGBL-DH/TH) or Burkitt-like lymphoma (BL) with 11q aberration, is not well known in the HIV setting. We aimed to characterise HIV-associated aggressive B-NHL according to the 2017 WHO criteria, and to identify genotypic and phenotypic features with prognostic impact. Seventy-five HIV-associated aggressive B-NHL were studied by immunohistochemistry (CD10, BCL2, BCL6, MUM1, MYC, and CD30), EBV-encoded RNAs (EBERs), and fluorescence in situ hybridisation (FISH) to evaluate the status of the MYC, BCL2, and BCL6 genes and chromosome 11q. The 2017 WHO classification criteria and the Hans algorithm, for the cell-of-origin classification of diffuse large B-cell lymphomas (DLBCL), were applied. In DLBCL cases, the frequencies of MYC and BCL6 rearrangements (14.9 and 27.7%, respectively) were similar to those described in HIV-negative patients, but BCL2 rearrangements were infrequent (4.3%). MYC expression was identified in 23.4% of DLBCL cases, and coexpression of MYC and BCL2 in 13.0%, which was associated with a worse prognosis. As for BL cases, the expression of MUM1 (30.4%) conferred a worse prognosis. Finally, the prevalence of HGBL-DH/TH and BL-like with 11q aberration are reported in the HIV setting. The phenotypic and genotypic characteristics of HIV-associated aggressive B-NHL are similar to those of the general population, except for the low frequency of BCL2 rearrangements in DLBCL. MYC and BCL2 coexpression in DLBCL, and MUM-1 expression in BL, have a negative prognostic impact on HIV-infected individuals.

Characteristics and clinical outcomes of patients with ALK-positive anaplastic large cell lymphoma: Report from the prospective international T-cell lymphoma project.

The T-cell Lymphoma Project is an international registry prospective study that enrolled patients with newly diagnosed peripheral T-cell and NK-cell lymphomas (PTCL). The main objective was to define the clinical features and outcomes, establishing a robust benchmark for future clinical trials. Seventy-four institutions from 14 countries in North America, South America, Europe, and Asia collected data on patients diagnosed and treated at their respective centers between September 2006 and February 2018. Among 1553 PTCL patients, 131 (8.4% of the total cohort) were confirmed to have anaplastic large cell lymphoma - kinase positive (ALCL, ALK+). The median age of the patients was 39 years (18-84). Sixty-five patients (66%) had advanced-stage disease, although majority (45 patients, 54%) had a low-risk International Prognostic Index (IPI) score (0-1). Of 97 patients treated with chemotherapy, 97% received anthracycline-containing regimens. The overall response rate was 81%, with 69 patients (70%) achieving complete remission. Estimated OS and PFS at 3 years were 77% (95% CI: 54%-99%) and 68% (95% CI: 46%-90%), respectively, and at 5 years were very similar, 77% of OS (95% CI: 62%-92%) and 64% of PFS (95% CI: 34%-94%). Multivariate analysis for PFS showed advanced stage (hazard ratios [HR]: 4.72, 95% CI: 1.43-23.9, p = 0.015), elevated lactate dehidrogenade (LDH) (HR 4.85; 95% CI: 1.73-13.60, p = 0.001), and Eastern Cooperative Oncology Group Performance Status scale (ECOG-PS) ≥2 (HR: 5.25; 95% CI: 1.68-16.4, p = 0.024). For OS, elevated LDH (HR: 3.77; 95% CI: 1.98-14.17, p = 0.014) and ECOG-PS ≥2 (HR: 4.59; 95% CI: 1.46-14.39, p = 0.004) were identified. In summary, although the outcome of ALK+ ALCL is superior to that of other PTCLs, it remains sufficiently favorable, given the young median age of the patients. Our results confirm the usefulness of both IPI and Prognostic Index for T-cell Lymphoma (PIT) in identifying groups of patients with different outcomes. Clinical Trials ID: NCT01142674.

Complications of Autologous Stem Cell Transplantation in Multiple Myeloma: Results from the CALM Study.

Background: The main goal of this post hoc analysis of the Collaboration to Collect Autologous Transplant Outcomes in Lymphoma and Myeloma (CALM) study was to evaluate the rate of short- and long-term infectious and non-infectious complications occurring after ASCT in patients with multiple myeloma (MM). Methods: The analysis included all patients with MM from the CALM study who underwent ≥1 ASCT. The primary endpoint of the analysis was to determine the rate of infectious and non-infectious complications after ASCT and to compare them in three time periods: 0−100 days, 101 days−1 year, and >1 year after the first transplant. Results: The analysis included a total of 3552 patients followed up for a median of 56.7 months (range 0.4−108.1). Complication rates decreased with the time from ASCT with 24.85 cases per 100 patient-years from day 0 to 100 days after the transplant, and <2.31 cases per 100 patient-years from the 101st day. At 100 days after ASC T, 45.7% of patients had complications, with infectious events being twice as frequent as non-infectious complications. Bacterial infections (6.5 cases per 100 patient-years, 95% CI: 6.1−7.0) and gastrointestinal complications (4.7 cases per 100 patient-years, 95% CI: 4.3−5.1) were the most common early events. The pattern of complications changed with time from ASCT. The presence of complications after ASCT was not associated with overall survival. Conclusions: Our data provide a solid basis for comparing ASCT-related complications to those caused by emerging treatments in multiple myeloma, such as CAR T-cell therapy and other immunotherapies.

The outcome of patients with Hodgkin lymphoma and early relapse after autologous stem cell transplant has improved in recent years.

Hodgkin lymphoma (HL) patients who relapse after autologous-stem-cell- transplantation (auto-SCT) have traditionally had a poor prognosis. We analyzed 1781 adult HL patients who relapsed between 2006 and 2017 after a first auto-SCT. The 4-year overall survival (OS) after relapse continuously increased from 32% for patients relapsing in 2006-2008, to 63% for patients relapsing in 2015-2017 (p = 0.001). The improvement over time was predominantly noted in patients who had an early relapse (within 12 months) after auto-SCT (p = 0.01). On multivariate analysis, patients who relapsed in more recent years and those with a longer interval from transplant to relapse had a better OS, whereas increasing age, poor performance status, bulky disease, extranodal disease and presence of B symptoms at relapse were associated with a worse OS. Brentuximab vedotin (BV), checkpoint inhibitors (CPI) and second transplant (SCT2; 86% allogeneic) were used in 233, 91 and 330 patients respectively. The 4-year OS from BV, CPI, and SCT2 use was 55%, 48% and 55% respectively. In conclusion, the outcome after post-transplant relapse has improved significantly in recent years, particularly in the case of early relapse. These large-scale real-world data can serve as benchmark for future studies in this setting.

Outcome of allogeneic transplantation for mature T-cell lymphomas: impact of donor source and disease characteristics.

Mature T-cell lymphomas constitute the most common indication for allogeneic hematopoietic cell transplantation (allo-HCT) of all lymphomas. Large studies evaluating contemporary outcomes of allo-HCT in mature T-cell lymphomas relative to commonly used donor sources are not available. Included in this registry study were adult patients who had undergone allo-HCT for anaplastic large cell lymphoma, angioimmunoblastic T-cell lymphoma (AITL), or peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) between 2008 and 2018. Hematopoietic cell transplantation (HCT) platforms compared were posttransplant cyclophosphamide-based haploidentical (haplo-)HCT, matched sibling donor (MSD) HCT, matched unrelated donor HCT with in vivo T-cell depletion (MUD TCD+), and matched unrelated donor HCT without in vivo T-cell depletion (MUD TCD-). Coprimary end points were overall survival (OS) and progression-free survival (PFS); secondary end points included nonrelapse mortality (NRM), and relapse/progression incidence (RI). A total of 1942 patients were eligible (237 haplo-HCT; 911 MSD; 468 MUD TCD+; 326 MUD TCD-). Cohorts were comparable for baseline characteristics with the exception of higher proportions of patients with decreased performance status (PS) and marrow graft recipients in the haplo-HCT group. Using univariate and multivariate comparisons, OS, PFS, RI, and NRM were not significantly different among the haplo-HCT, MSD, MUD TCD+, and MUD TCD- cohorts, with 3-year OS and PFS of 60%, 63%, 59%, and 64%, respectively, and 50%, 50%, 48%, and 52%, respectively. Significant predictors of inferior OS and PFS on multivariate analysis were active disease status at HCT and decreased PS. AITL was associated with significantly reduced relapse risk and better PFS compared with PTCL-NOS. Allo-HCT can provide durable PFS in patients with mature T-cell lymphoma (TCL). Outcomes of haplo-HCT were comparable to those of matched donor allo-HCT.

Improved outcome of patients with graft-versus-host disease after allogeneic hematopoietic cell transplantation for hematologic malignancies over time: an EBMT mega-file study.

Acute graft-versus-host disease (aGvHD) remains a major threat to successful outcome following allogeneic hematopoietic cell transplantation though advances in prophylaxis and supportive care have been made. The aim of this study is to test whether the incidence and mortality of aGvHD have decreased over time. 102,557 patients with a median age of 47.6 years and with malignancies after first allogeneic sibling or unrelated donor (URD) transplant were studied in the following periods: 1990-1995, 1996-2000, 2001-2005, 2006-2010 and 2011-2015. Findings: 100-day incidences of aGvHD grades II-IV decreased from 40% to 38%, 32%, 29% and 28%, respectively, over calendar time (P<0.001). In multivariate analysis URD, not in complete remission (CR) at transplant or untreated, and female donor for male recipient were factors associated with increased risk whereas the use of ATG/alemtuzumab decreased aGvHD incidence. Median follow-up was 214, 169, 127, 81 and 30 months, respectively, for the periods analyzed. Three-year-survival after aGvHD grades II-IV increased significantly from 38% to 40%, 43%, 44%, and 45%, respectively. In multivariate analysis URD, not in CR at transplant, peripheral blood as stem cell source, female donor for male recipient, and the use of ATG/alemtuzumab were associated with increased mortality whereas reduced-intensity conditioning was linked to lower mortality. Mortality increased with increasing patient age but decreased in the recent cohorts. Our analysis demonstrates that aGvHD has decreased over recent decades and also that the survival rates of patients affected with aGvHD has improved.

Primary refractory follicular lymphoma: a poor outcome entity with high risk of transformation to aggressive B cell lymphoma.

BACKGROUND: Primary refractory (PREF) follicular lymphoma (FL) has a completely different clinical course from that of FL that responds to front-line treatments. In addition to having poor responses to salvage therapies, it seems that patients with PREF are at increased risk of histological transformation (HT). The Aristotle consortium presented the opportunity of investigating the risk of HT in a very large series of cases. Thus, we investigated the risk of HT in patients with PREF FL compared with that of responding patients or in stable disease and ultimately their outcome. METHODS: Six thousand three hundred thirty-nine patients from the Aristotle database were included in the analysis. These patients had a histologically confirmed grade 1, 2 or 3a FL diagnosed between 1997 and 2013. The primary end-points were the cumulative incidence (CI) of HT at the first progression or relapse and the survival after transformation. FINDINGS: The 5-year CI of HT among patients with PREF was 34% (95% confidence interval (CI): 27-43), whilst it was 7.1% (95% CI: 6.0-8.5) in the group of patients with partial response (PR) or stable disease (SD) (PR + SD) and 3.5% (95% CI: 3.0-4.2) in the group of patients achieving complete response (CR). The 5-year survival after relapse (SAR) was 33% (95% CI: 28-39) for the PREF group, 57% (95% CI 54-61) in patients with PR, 51% (95% CI 43-58) in the SD group after first-line therapy and 63% (95% CI: 66-72) in patients with CR after initial treatment (p-value <0.001). The 5-year SAR for those patients with PREF who developed HT was 21% (95% CI: 12-31), clearly diminished when compared with those patients with PREF who did not experience HT (38% [95% CI: 31-44]) (p-value = 0.001). INTERPRETATION: Patients with PREF FL have a dismal outcome and an associated very high rate of HT that further worsens their poor prognosis.