International Registry for Patients with Hereditary Thrombotic Thrombocytopenic Purpura (TTP) – Upshaw-Schulman Syndrome
Abstract Abstract 4654 Background: Hereditary TTP, also known as Upshaw-Schulman syndrome (USS), is a rare disorder and the result of recessively inherited ADAMTS13 gene (located on chromosome 9q34) mutations. The clinical presentation is variable and may vary from mild isolated thrombocytopenia to recurrent severe TTP episodes leading to organ damage or even death. The first acute TTP episode may occur during the neonatal period up to older age. The same variety applies to the treatment requirements as some patients need regular plasma infusion every two to three weeks to prevent recurrent episodes while others only need plasma therapy in situations of increased risk, such as pregnancy or during infections. Due to the rareness of USS evidence based guidelines are lacking as are knowledge of long-term outcome which emphasizes the need of a multicenter cooperation. Aim: We have established a long-term observational study with an electronic database system for hereditary TTP patients (www.ttpregistry.net, ClinicalTrials.gov NCT01257269) to gather as much information as possible about the clinical courses and laboratory investigations performed. We aim at the identification of triggers that set about acute TTP bouts and of factors influencing the clinical course with the goal to possibly elucidated the underlying causes of the variable clinical presentation of this rare monogenic disorder eventually leading to optimization of therapy and evidence based recommendations. The study is open to any patient diagnosed with hereditary TTP and his/her interested family members. Eligibility criteria are as follows: • ADAMTS13 activity ≤10% on two separate occasions at least 1 month apart; and • Absence of a functional ADAMTS13 inhibitor and • ≥2 ADAMTS13 gene mutations and/or full recovery and normal half-life of infused plasma ADAMTS13); or • Being a family members of a confirmed patient Clinical information and laboratory investigations are collected retrospectively up to enrollment as well as prospectively every 12 months following enrollment. Analysis of ADAMTS13 related parameters including molecular analysis of ADAMTS13 gene are offered free of charge to patients and all family members. Conclusion: Our long-term goal is to establish an international network and knowledge platform to exchange information and experience on USS, that helps to improve diagnosis, treatment and prevention of acute episodes with risk of permanent organ damage for affected patients. Physicians treating USS patients are invited to contact us for diagnostics of suspected patients or enroll their confirmed patients. Disclosures: Fujimura: Baxter BioScience: Membership on an entity's Board of Directors or advisory committees; Alexion Pharma: Membership on an entity's Board of Directors or advisory committees. George:Baxter, Inc.: Consultancy; Alexion, Inc.: Consultancy; Amgen, Inc.: Consultancy, PI for clinical trial involving romiplostim, PI for clinical trial involving romiplostim Other, Research Funding. Kremer Hovinga Strebel:Baxter: Consultancy, Research Funding.
Abstract Introduction Cancer associated thrombosis (CAT) is the second leading cause of death in cancer patients after death from cancer. Despite multiple available guidelines for CAT management, there remains variability in treatment practices. In order to gain insight on this variability in Canada, a survey was conducted to identify the perceived importance of managing CAT, identify differences in the pharmacological management of CAT, highlight the main barriers to optimal extended treatment and prevention of recurrent venous thromboembolism (VTE), outline challenges associated with long term treatment adherence, and identify predictors of patient non-adherence. Methods A survey was designed targeting physicians involved in the management of CAT. The questionnaire included queries on physician practice, 37 items related to beliefs and attitudes about extended treatment for prevention of recurrence of VTE, and a 30-item patient-specific profile. Results Responses were obtained from 21 professionals from four Canadian provinces (Nova Scotia, Quebec, Ontario, and Alberta); 76% were hematologists and/or oncologists, 14% were internists and 10% were pharmacists. Community and academic centers were well represented. Specific management profiles were obtained for 131 patients. Most care givers felt that VTE recurrence was an important issue deserving extended therapy for most patients. Although more than 90% believed bleeding and recurrent VTE risk should influence the length of treatment, only 62% believe that VTE recurrence risk should modify the type of treatment and 52% were concerned of the risk of bleeding with long term therapy (≥6 months). 71% of respondents believed patients’ lack of awareness of the risk of recurrent VTE reduces adherence to anticoagulant therapy for extended treatment of VTE. Although 100% of respondents detailed giving verbal patient counseling, only 19% provided written information to patients. 95% stated they assessed compliance verbally; less than 20% used more objective measures (pharmacy records, laboratory monitoring). Participants admitted to using results of clinical trials (95%) more than clinical guidelines (48%) as most felt that the published guidelines contained conflicting recommendations. The main drivers of treatment choice were clinical evidence, efficacy, and personal experience. No respondents indicated they preferred to use oral anticoagulants for extended therapy of CAT and 43% believed that LMWHs should not be used interchangeably. Most (95%) stated they follow-up with patients directly to reassess therapy after 3-6 months of treatment. The patient profile information showed the median age of patients was 62 years and 60% were female. Lung cancer, colon cancer, breast cancer, and lymphoma were the most common tumor sites and accounted for 50% of described cases. Cases of deep vein thrombosis (DVT) and pulmonary embolism (PE) were evenly represented and 82% were symptomatic. Most events were temporally related to cancer therapy (69%), presence of a central venous catheter (18%), and recent surgery (17%). Less than 5% of these cases presented with a contraindication to anticoagulation therapy (severe thrombocytopenia, active bleeding) at CAT diagnosis. Most patients were treated in the outpatient setting. Nonetheless, hospitalization was required in 33% of cases with an average patient stay of 10.8 days. Hospitalized patients were preferentially treated with LMWH (84%) and usually stayed on the same regimen upon discharge (8.3 ± 6.4 months). Long term treatment was largely managed with LMWHs (most frequently dalteparin – 80% of all treated patients) while few were managed with vitamin K antagonists (6%) or novel direct antithrombotics (2%). Anticoagulant therapy for outpatients was prescribed for 9.0 ± 7.7 months after the most recent VTE episode. Conclusion In Canada, CAT is believed to be an important complication of cancer. Extended therapy is indicated for most patients with CAT. Although bleeding risk is perceived as an important reason to modify therapy, contraindications to LMWHs were rare in the reported cases. Uptake of outpatient therapy of CAT is widespread in this country, yet hospitalization is still frequently required at diagnosis and is associated with prolonged inpatient stays. Even if non-adherence to antithrombotic therapy was believed to be rare among patients with CAT, this was rarely rigorously monitored. Disclosures: Blais: Pfizer: Consultancy; Sanofi: Consultancy; Leo: Consultancy. Butts:Pfizer: Consultancy, Honoraria, Speakers Bureau. Crowther:Pfizer: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Merck: Consultancy; Leo Pharma: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; CSL Behring: Speakers Bureau; Boehringer Ingelheim: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Baxter: Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Asahi Kasai: Membership on an entity’s Board of Directors or advisory committees; Sanofi-Aventis: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Viropharma: Membership on an entity’s Board of Directors or advisory committees. Cox-Kennett:Pfizer: honorarium as a speaker Other. Martineau:Pfizer: honorarium as a speaker Other; Boehringer: honorarium as a speaker, honorarium as a speaker Other; Bayer: honorarium as a speaker, honorarium as a speaker Other; Sanofi: honorarium as a speaker and participated in clinical trial, honorarium as a speaker and participated in clinical trial Other; BMS: honorarium as a speaker Other.
Quantification of Humoral Immune Response to Influenza Vaccination in MDS
Background: Patients with myelodysplastic syndromes (MDS) present across a clinical spectrum from mild disease to profound bone marrow failure and transformation to acute myeloid leukemia (AML). Those with lower risk disease are generally managed with watchful waiting and best supportive care (growth factors, blood and platelet transfusions and iron chelation; BSC), while those with higher risk disease are treated with repeated cycles of low dose "hypomethylating" chemotherapy (such as azacitidine or decitabine; HMA). A majority of patients with MDS, even those with lower risk disease, are likely to die of complications related to their diagnosis, mostly infections and bleeding but also leukemic transformation. As part of our standard approach to infection prevention, current clinical guidelines suggest annual vaccination against influenza. Patients with these disorders and their family members are advised to receive inactivated protein based vaccines rather than live vaccination approaches to limit infection risk. Most will receive high dose trivalent vaccination due to age. Despite these recommendations, limited data exist on the ability of patients with MDS across the spectrum of risk groups to respond to standard seasonal influenza vaccination. In light of the growing literature suggesting that patients with MDS have an altered immune environment, we hypothesized that they would show inferior response to standard vaccination. We sought to determine the response to influenza vaccination in patients with MDS receiving standard therapeutic management. Methods: A non-randomized study is currently ongoing at the Roswell Park Comprehensive Cancer Center for patients with MDS. Age-relevant family members are enrolled as a comparator population for vaccine response. Cohorts were stratified into 3 groups: healthy volunteers (Cohort 1), MDS patients receiving BSC (Cohort 2) and MDS patients actively receiving HMA (Cohort 3; Table 1). All participants are administered the yearly preparation of Sanofi Pasteur's Fluzone High-Dose Vaccine (containing trivalent inactivated strains: Influenza virus A (H1N1 and H3N2) and Influenza virus B). Baseline blood samples were collected prior to vaccination (day 0), and between days 25-90 and 115-185 post-vaccination. Serological responses to vaccination were determined by viral-neutralizing activity analyzed via microneutralization assay. Neutralizing antibody titers for the first year of the study were measured against seasonal influenza vaccine strains based upon the 2017-2018 vaccine product. Samples from the 2018-19 flu season are being analyzed. Results: To date 56 individuals have been recruited to the study over 2 years. Neutralizing antibody titers following vaccination are available for 20 individuals vaccinated in the 2017-18 flu season. Humoral immune responses to vaccination against different strains of Influenza virus A (H1N1 and H3N2) and Influenza virus B were observed across all cohorts (Figure 1). Response was deemed adequate if the titer for any vaccine component increased by >4 fold comparing the baseline to the day 25-90 time point. Cohort 1: 4/4 responded (100%); cohort 2: 4/4 responded (100%); cohort 3: 11/12 responded (92%). To better understand the effect of standard treatment for MDS on influenza vaccine response we are currently profiling immune cells pre and post vaccination using multi-parameter flow cytometry. Additional analyses are planned based on the number of HMA cycles received (<6, or ≥6) and cycle timing relative to vaccination. Conclusion: Patients with MDS respond to vaccination with Fluzone High Dose. Responses in patients with MDS were not statistically different from those seen in an age-relevant population of healthy family members. Additional individuals are being enrolled in order to assess whether standard HMA therapy impacts the response to influenza vaccination. These data suggest that MDS patients receiving BSC respond adequately to viral vaccination. Our preliminary data also show that patients receiving HMA therapy respond adequately to influenza vaccination. These data support the value of influenza vaccination in all patients with MDS and highlight the potential for anti-MDS immunotherapeutic vaccination strategies. Disclosures Vachhani: Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Astellas: Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Przespolewski:Jazz Pharmaceuticals: Other: PI on clinical trial. Thota:Incyte, Inc.: Speakers Bureau. Wang:Amgen: Other: Advisory role; Agios: Other: Advisory role; Pfizer: Other: Advisory role, Speakers Bureau; Stemline: Other: Advisory role, Speakers Bureau; Daiichi: Other: Advisory role; Astellas: Other: Advisory role, Speakers Bureau; celyad: Other: Advisory role; Jazz: Other: Advisory role; Abbvie: Other: Advisory role; Kite: Other: Advisory role. Griffiths:Boston Scientific: Consultancy; Genentech, Inc.: Research Funding; Abbvie, Inc.: Consultancy; Boston Scientific: Consultancy; Novartis Inc.: Consultancy; Astex Phramaceuticals/Otsuka Pharmaceuticals: Consultancy, Research Funding; Astex Phramaceuticals/Otsuka Pharmaceuticals: Consultancy, Research Funding; New Link Genetics: Consultancy; Genentech, Inc.: Research Funding; Onconova Therapeutics: Other: PI on a clinical trial; Appelis Pharmaceuticals: Other: PI on a clinical trial; Abbvie, Inc.: Consultancy, PI on a clinical trial; Onconova Therapeutics: Other: PI on a clinical trial; Persimmune: Consultancy; Partner Therapeutics: Consultancy; Persimmune: Consultancy; Novartis Inc.: Consultancy; Celgene, Inc: Consultancy, Research Funding; Celgene, Inc: Consultancy, Research Funding; Appelis Pharmaceuticals: Other: PI on a clinical trial; Partner Therapeutics: Consultancy; New Link Genetics: Consultancy.
Introduction: About 2 to 10% of patients (pts) diagnosed with Chronic Lymphocytic Leukemia (CLL) develop diffuse large B-cell lymphoma (DLBCL, so-called Richter transformation (RT)) over long-term follow-up. The outcomes of pts with RT are variable and poorly understood and there is no consensus on the best therapeutic approach. The aim of this study was to analyze the clinical characteristics, outcomes and factors predictive of survival in a large series of RT from the French Innovative Leukemia Organization (FILO). Methods: Biopsy-confirmed RT (limited to DLBCL and excluding Hodgkin lymphoma) diagnosed from 2001 to 2018 were identified from eight FILO centers. Clinical and biological characteristics of CLL and RT at diagnosis, including cytogenetics, clonal relation with the pre-existing CLL, Epstein-Barr virus (EBV) status, cell of origin (COO) analyzed by immunohistochemistry and RT score (Tsimberidou AM et al, J Clin Oncol, 2006) were analyzed as well as treatment and outcomes. Overall survivals (OS) were defined as time from CLL and RT diagnosis to death from any cause and analyzed using the Kaplan-Meier method. Statistical analyses were performed with SAS version 9.4. Results: A total of 70 CLL pts who developed RT were identified. The median age at CLL diagnosis was 62 years old (range 35-82), and 50 (71.4 %) were male. The median time to transformation was 5.5 years (range 0 to 22 years), with 12 simultaneous diagnosis of CLL and RT. Prior to RT, 20 (29%) pts had not been treated for CLL, 50 received one (n=21) or more (n= 29) line of treatment ; 6 pts had received a novel agent (ibrutinib, idelalisib or venetoclax). The median age at RT diagnosis was 68 years old (range 42-88). All biopsies were centrally reviewed; 38/58 pts (66%) had elevated LDH (>1.5N) ; 35/65 pts (54 %) had bulky disease (≥ 5 cm); 10/54 (18.5%) pts had del(17p) or TP53 mutation ; 9/42 pts (21%) had a complex karyotype (at least 3 abnormalities). The CLL and RT were clonally related in 27/27 (100%) tested pts. COO by Hans algorithm was non germinal center B cell-like (GCB) in 26/28 pts (93%). EBV was positive or detected in 5/40 (12.5%) pts. The median of Ki67 positivity was 70% (range 30% to 100%). The RT score (based at RT diagnosis on ECOG performance status 2-4, LDH >1.5 x normal, platelets<100 x 109/L, tumor size >5 cm and >1 prior therapy for CLL) was : low risk in 17 pts (31%), low-intermediate risk in 10 pts (19%), high-intermediate risk in 14 pts (25%) and high risk in 14 pts (25%). The most common first-line treatment of RT was immunochemotherapy (n=57, 87%) including R-CHOP-like regimen (n=48, 73%). Autologous or allogeneic transplantation was performed for 7 pts (11%). Response to first-line treatment was complete or partial response in 26 pts (40%), and stable disease or progression in 39 pts (60%). After a median follow-up of 8 years, 51/64 pts (80%) have died. The main causes of death were progressive DLBCL (n=36, 71%), infection (n=8, 16%) or progressive CLL (n=2, 4%). The median OS of the cohort from CLL and RT diagnosis (Figure 1) were 7.8 years and 9.5 months, respectively. In univariate analysis, patients with TP53 disruption at CLL stage, low platelets count, elevated LDH, elevated beta2-microglobulin, high ECOG score, high RT score, EBV positivity and absence of response to first-line RT treatment had worse OS. The ECOG score, platelets count and TP53 disruption remain significant in multivariate Cox-regression. Last, we compared the clinical and biological parameters of two Richter groups defined as: (i) short-term survivors (<12 months, n = 34) and (ii) long-term survivors (>48 months, n = 18). Long survival was significantly associated with elevated platelets count, low LDH, low ECOG, low RT score and response to RT first-line treatment. Discussion: The clinical outcomes of RT patients is poor and novel treatment options are needed. However, a group of long-term survivors was identified, characterized by elevated platelets count, low LDH, low ECOG, low RT score and response to immunochemotherapy. Disclosures Leblond: Astra Zeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Honoraria, Speakers Bureau. Thieblemont:Roche: Honoraria, Research Funding; Gilead: Honoraria; Novartis: Honoraria; Kyte: Honoraria; Janssen: Honoraria; Celgene: Honoraria; Cellectis: Membership on an entity's Board of Directors or advisory committees. Cymbalista:Janssen: Honoraria; Gilead: Honoraria; AstraZeneca: Honoraria; Sunesis: Research Funding; Roche: Research Funding; Abbvie: Honoraria. Guièze:Abbvie: Honoraria; Janssen: Honoraria; Gilead: Honoraria; Roche: Honoraria. Broseus:Janssen: Honoraria; Gilead: Honoraria; Novartis: Research Funding. Feugier:gilead: Honoraria, Research Funding, Speakers Bureau; janssen: Honoraria, Research Funding, Speakers Bureau; abbvie: Honoraria, Research Funding, Speakers Bureau; roche: Honoraria, Research Funding, Speakers Bureau.
Background:Treatment options are limited for patients (pts) with hematologic malignancies who relapse after allogeneic stem cell transplantation (allo-SCT). We hypothesized that checkpoint inhibitors may offer a novel approach for maintaining remission after allo-SCT. Data from pre-clinical studies have suggested a potential role for PD-1/PD-L1 inhibitors in acute myeloid leukemia (AML) (Zhang et al., Blood 2009), so it is possible that immunomodulation with checkpoint inhibitors could stimulate the donor anti-leukemia immune response and prevent disease relapse. However, the safety of checkpoint blockade early after allografting remains to be established. Methods:We conducted a pilot study to assess the tolerability and efficacy of Nivolumab, a PD-1 inhibitor, as maintenance therapy after allo-SCT (NCT02985554). Pts were eligible if they were post allo-SCT without evidence of relapse or active graft-vs-host disease (GVHD) or history of prior greater than stage I skin acute GVHD. Nivolumab was to be administered intravenously at 1mg/kg every 2 weeks for 4 doses followed by dosing every 12 weeks. Treatment started 4 weeks after routine immunosuppression was discontinued until 2 years after the transplant. The primary objective was to determine the tolerability of Nivolumab on this schedule. Secondary objectives were evaluation of adverse events, relapse, and overall survival. Results:Four pts were enrolled from December 2017 through November 2018. (Table 1)All pts experienced immune-related adverse events (irAE) from Nivolumab, and 2 (50%) pts experienced serious adverse events. (Table 2)One pt developed grade (G) 4 neutropenia soon after the first dose. (Figure 1)The absolute neutrophil count nadired at 20 cells/µL, at which point pegfilgrastim was administered. An interim bone marrow biopsy (BMBx) confirmed no evidence of relapsed disease. Full neutrophil recovery occurred approximately 3 months after the initial dose, and no subsequent toxicities occurred. Another pt developed G3 autoimmune encephalopathy concurrently with G2 transaminitis and G2 thrombocytopenia after one dose of Nivolumab. (Figure 2)Intravenous methylprednisolone (1mg/kg daily for 3 days) and immunoglobulin (2g/kg in 4 divided doses) were administered, followed by a 7-week steroid taper with full resolution of symptoms. Relapsed disease was ruled out by a BMBx. A third pt developed G2 skin rash approximately 10 days after the first dose of Nivolumab. Skin biopsy demonstrated drug hypersensitivity reaction vs GVHD, and the pt was treated with a 3-week prednisone course (starting at 1mg/kg followed by a taper). A mild flare recurred 2 weeks later, which was treated with topical steroids only. However, Nivolumab was not resumed. The fourth pt developed G2 elevated TSH approximately 2 months into therapy and after 4 doses of Nivolumab. Thyroid hormone replacement was initiated with subsequent symptom improvement and normalization of TSH over a 4-month period. As a result of these unexpected severe toxicities, the study was closed to further enrollment, and further Nivolumab administration ceased. Thus far, one pt (#1) relapsed after a total remission duration of 530 days; the remission duration after starting Nivolumab was 318 days. One pt has mild chronic skin GVHD. All 4 patients remain alive with a median overall survival of 2.3 years (range, 1.9-4.7). Conclusions:Even at low doses, the use of Nivolumab as maintenance therapy in the post allo-SCT setting was not tolerable at the current dosing and schedule due to an unexpected number of high grade irAEs. Additional studies of dose and timing after allo-SCT are needed to improve safety and tolerability, in conjunction with correlative studies to better understand the immunomodulatory processes in the post-transplant setting. Disclosures Kline: Merck: Honoraria; Merck: Research Funding. Stock:Kite, a Gilead Company: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Daiichi: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; UpToDate: Honoraria; Research to Practice: Honoraria. Artz:Miltenyi: Research Funding. Larson:Agios: Consultancy; Novartis: Honoraria, Other: Contracts for clinical trials; Celgene: Consultancy. Riedell:Novartis: Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Honoraria, Speakers Bureau; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau. Bishop:CRISPR Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Juno: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Liu:Arog: Other: PI of clinical trial; BMS: Research Funding; Agios: Honoraria; Novartis: Other: PI of clinical trial; Karyopharm: Research Funding. OffLabel Disclosure: Nivolumab used as maintenance therapy in the post-transplant setting
T-cell large granular lymphocyte leukemia (T-LGLL) is a clonal proliferation of cytotoxic T lymphocytes (CTL). T-LGLL mainly manifest in elderly and is associated with autoimmune diseases including rheumatoid arthritis (RA), B cell dyscrasias, non-hematologic cancers and immunodeficiency (e.g., hypogammaglobulinemia). LGL manifestations often resemble reactive immune processes leading to the dilemmas that LGLs act like CTL expansion during viral infections (for example EBV associated infectious mononucleosis). While studying a cohort of 246 adult patients with T-LGLL seen at Cleveland Clinic over the past 10 years, we encountered 15 cases of overt T-LGLL following transplantation of solid organs (SOT; n=8) and hematopoietic stem cell transplantation (HSCT; n=7). Although early studies reported on the occurrence of LGL post-transplant, these studies focused on the analysis of oligoclonality skewed reactive CTL responses rather than frank T-LGLL. We aimed to characterize post-transplantation T-LGLL in SOT and HSCT simultaneously and compare them to a control group of 231 de novo T-LGLL (cases with no history of SOT or HSCT). To characterize an unambiguous "WHO-defined T-LGLL" we applied stringent and uniform criteria. All cases were diagnosed if 3 out of 4 criteria were fulfilled, including: 1) LGL count >500/µL in blood for more than 6 months; 2) abnormal CTLs expressing CD3, CD8 and CD57 by flow cytometry; 3) preferential usage of a TCR Vβ family by flow cytometry; 4) TCR gene rearrangement by PCR. In addition, targeted deep sequencing for STAT3 mutations was performed and charts of bone marrow biopsies were reviewed to exclude other possible conditions. Diagnosis was made 0.2-27 yrs post-transplantation (median: 4 yrs). At the time of T-LGLL diagnosis, relative lymphocytosis (15-91%), T lymphocytosis (49-99%) and elevated absolute LGL counts (>500 /µL; 93%) were also seen. Post-transplantation T-LGLL were significantly younger than de novo T-LGLL, (median age: 48 vs. 61 yr; P<.0001). Sixty% of post-transplantation T-LGLL patients were males. Fifteen% of patients had more cytogenetic abnormalities compared to de novo T-LGLL, had a lower absolute LGL count (median: 4.5 vs. 8.5 k/µL) and had less frequent neutropenia, thrombocytopenia and anemia (27 vs. 43%, 33 vs. 35% and 20% vs. 55%; P=.01). TCR Vb analysis identified clonal expansion of ≥1 of the Vb proteins in 60% (n=9) of the patients; the remaining 40% (n=6) of the cases had either a clonal process involving a Vb protein not tested in the panel (20%; n=3) or no clear expansion (20%; n=3). Signs of rejection were observed in 20% (n=3/15) and GvHD in 13% (n=2/15) of the patients. Post-transplantation, 27% of cases presented with neutropenia (absolute neutrophil count <1.5 x109/L; n=4), 33% with thrombocytopenia (platelet count <150 x109/L; n=5) and 25% with anemia (hemoglobin <10 g/dL; n=3). T-LGLL evolved in 10 patients (67%; 10/15) despite IST including cyclosporine (n=5), tacrolimus (n=4), mycophenolate mofetil (n=5), cyclophosphamide (n=1), anti-thymocyte globulin (n=1), and corticosteroids (n=6). Lymphadenopathy and splenomegaly were seen in 13% (n=2) and 33% (n=5) of the patients. Other conditions observed were MGUS (20%; n=3) and RA (7%; n=1). Conventional cytogenetic showed normal karyotype in 89% (n=11, tested individuals 13/15). Somatic STAT3 mutations were identified in 2 patients. Sixty% of cases (n=9) were seropositive for EBV when tested at different time points after transplant. Similarly, 53% (n=8) were seropositive for CMV, of which, 5 were positive post-transplantation and 3 pre-/post-transplantation. The complexity of T-LGLL expansion post-transplantation might be due to several mechanisms including active viral infections, latent oncogenic viral reactivation and graft allo-antigenic stimulation. However, in our cohort graft rejection or GvHD was encountered in a few patients (2 allo-HSCT recipients). Autoimmune conditions were present in 50% of SOT recipients (n=4/ 8, including RA, ulcerative colitis, systemic lupus erythematosus). Some of our patients also had low immunoglobulin levels. Overt EBV (post-transplant lymphoproliferative disorder) and CMV reactivation was diagnosed in only 27% (4/15) of the patients. In sum we report the long term follow up of a cohort of T-LGLL and emphasize the expansion of T-LGLL post-transplant highlighting the difficulty in assigning one unique origin of LGLL. Disclosures Hill: Genentech: Consultancy, Research Funding; Takeda: Research Funding; Celegene: Consultancy, Honoraria, Research Funding; Kite: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Consultancy, Honoraria; Amgen: Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; TG therapeutics: Research Funding; AstraZeneca: Consultancy, Honoraria. Majhail:Atara Bio: Consultancy; Mallinckrodt: Honoraria; Nkarta: Consultancy; Anthem, Inc.: Consultancy; Incyte: Consultancy. Sekeres:Syros: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Maciejewski:Alexion: Consultancy; Novartis: Consultancy.
Introduction: Therapy-related myeloid neoplasms (t-MN) are associated with extremely poor clinical outcomes in otherwise long-term cancer survivors. t-MN accounts for ~20% of cases of myeloid neoplasms and is expected to rise due to the increased use of chemotherapy/radiotherapy (CT/RT) and improved cancer survivorship. Historically, t-MN was considered a direct consequence of DNA damage induced in normal hematopoietic stem cells (HSC) by DNA damaging cytotoxics. However, these studies have largely ignored the bone marrow (BM) microenvironment and the effects of age and concurrent/previous cancers. Aim: We performed an exhaustive functional study of mesenchymal stromal cells (MSC) obtained from a comparatively large cohort of t-MN patients and carefully selected control populations to evaluate the long-term damage induced by cytotoxic therapy to BM microenvironment and its impact on malignant and normal haematopoiesis. Methods: Four different cohorts were used: (1) t-MN, in which myeloid malignancy occurred after CT/RT for a previous cancer (n=18); (2) patients with multiple cancer and in which a myeloid neoplasm developed following an independent cancer which was not treated with CT/RT (MC-MN; n=10); (3) primary MN (p-MN; n=7) untreated and without any prior cancer or CT/RT; (4) age-matched controls (HC; n=17). Morphology, proliferation, cellular senescence, differentiation potential and γH2AX DNA damage response was performed. Stem/progenitor supportive capacity was assessed by co-culturing haematopoietic stem cells on MSC feeder-layer in long-term culture initiating assay (LTC-IC). Cytokine measurements were performed using 38-plex magnetic bead panel (Millipore) and RNA sequencing libraries were prepared with Illumina TruSeq Total RNA protocol for 150bp paired-end sequencing on a NextSeq500 instrument. Functional enrichment analysis was performed using EnrichR software. Results: MSC cultured from t-MN patients were significantly different from HC, p-MN and MC-MN MSC according to multiple parameters. They exhibited aberrant morphology consisting of large, rounded and less adhesive cells compared to typical spindle-shaped morphology observed with controls. MSC from myeloid neoplasm also showed impaired proliferation, senescence, osteo- and adipogenic differentiation with t-MN MSC showing the greatest differences. DNA repair was dramatically impaired compared to p-MN and HC (Fig.1A). Importantly, these aberrant t-MN MSC were not able to support normal or autologous in vitro long-term haematopoiesis (Fig.1B). The biological characteristic and poor haematopoietic supportive capacity of MSC could be "cell-intrinsic" or driven by an altered paracrine inflammatory microenvironment. Interestingly, several inflammatory cytokines were higher in t-MN compared with marrow interstitial fluid obtained from p-MN patients (Fig.1Ci) and many of these including Fractalkine, IFNα2, IL-7 and G-CSF were also significantly higher in t-MN MSC conditional media (Fig.1Cii). Together, this data suggest that t-MN microenvironment is distinct from p-MN with paracrine production of pro-inflammatory milieu that may contribute to poor HSC supportive capacity. Preliminary whole transcriptome analysis revealed differential gene expression between t-MN and HC (Fig.1Di) and p-MN MSC. Importantly, the deregulated genes play critical role in cell cycle, DNA damage repair, and cellular senescence pathways explaining phenotypical characteristic of t-MN MSC (Fig.1Dii). Moreover CXCL12 expression, a key regulator of haematopoiesis, was significantly lower in t-MN compared to HC (p=0.002) and p-MN MSC (p=0.009), thus explaining poor HSC supportive capacity. The key difference between the p-MN, MC-MN and t-MN is prior exposure to CT/RT. To study this we obtained MSC from two t-MN patients for whom we had samples at the time of their primary cancer, post high-dose chemotherapy and at the time of t-MN. MSC displayed aberrant proliferation and differentiation capacity after high-dose cytotoxic therapy (2 to 4 years prior to developing t-MN) and remained aberrant at t-MN diagnosis (Fig.1E). Conclusions: BM-MSC from t-MN patients are significantly abnormal compared with age-matched controls and typical myeloid neoplasm. Importantly, prior CT/RT leads to long-term irreversible damage to the BM microenvironment which potentially contributes to t-MN pathogenesis. Disclosures Hughes: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Hiwase:Novartis Australia: Research Funding.
Introduction: The R-MegaCHOEP trial showed that dose-escalation of conventional chemotherapy necessitating autologous stem cell transplantation (ASCT) does not confer a survival benefit for younger patients (pts) with high-risk aggressive B-cell lymphoma in the Rituximab era (Schmitz et al., Lancet Oncology 2012; 13, 1250-1259). To describe efficacy and toxicity over time and document the long-term risks of relapse and secondary malignancy we present the 10-year follow-up of this study. Methods: In the randomized, prospective phase 3 trial R-MegaCHOEP younger pts aged 18-60 years with newly diagnosed, high-risk (aaIPI 2-3) aggressive B-cell lymphoma were assigned to 8 cycles of CHOEP (cyclophosphamide, doxorubcine, vincristine, etoposide, prednisone) or 4 cycles of dose-escalated high-dose therapy (HDT) necessitating repetitive ASCT both combined with Rituximab. Both arms were stratified according to aaIPI, bulky disease, and center. Primary endpoint was event-free survival (EFS). All analyses were calculated for the intention-to-treat population. This follow-up report includes molecular data based on immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) for MYC (IHC: 31/92 positive [40-100%], FISH: 14/103 positive), BCL2 (IHC: 65/89 positive [50-100%], FISH: 23/111 positive) and BCL6 (IHC: 52/86 positive [30-100%], FISH: 34/110 positive) and data on cell of origin (COO) classification according to the Lymph2CX assay (GCB: 53/88; ABC: 24/88; unclassified: 11/88). Results: 130 pts had been assigned to R-CHOEP and 132 to R-MegaCHOEP. DLBCL was the most common lymphoma subtype (~80%). 73% of pts scored an aaIPI of 2 and 27% an aaIPI of 3. 60% of pts had an initial lymphoma bulk and in 40% more than 1 extranodal site was involved. After a median observation time of 111 months, EFS at 10 years was 57% (95% CI 47-67%) in the R-CHOEP vs. 51% in the R-MegaCHOEP arm (42-61%) (hazard ratio 1.3, 95% CI 0.9-1.8, p=0.228), overall survival (OS) after 10 years was 72% (63-81%) vs. 66% (57-76%) respectively (p=0.249). With regard to molecular characterization, we were unable to detect a significant benefit for HDT/ASCT in any subgroup analyzed. In total, 16% of pts (30 pts) relapsed after having achieved a complete remission (CR). 23% of all relapses (7 pts) showed an indolent histology (follicular lymphoma grade 1-3a) and 6 of these pts survived long-term. In contrast, of 23 pts (77%) relapsing with aggressive DLBCL or unknown histology 18 pts died due to lymphoma or related therapy. The majority of relapses occurred during the first 3 years after randomization (median time: 22 months) while after 5 years we detected relapses only in 5 pts (3% of all 190 pts prior CR). 11% of pts were initially progressive (28 pts) among whom 71% (20 pts) died rapidly due to lymphoma. Interestingly, the remaining 29% (8 pts) showed a long-term survival after salvage therapy (+/- ASCT); only 1 pt received allogeneic transplantation. The frequency of secondary malignancies was very similar in both treatment arms (9% vs. 8%) despite the very high dose of etoposide (total 4g/m2)in the R-MegaCHOEP arm. We observed 2 cases of AML and 1 case of MDS per arm. In total 70 pts (28%) have died: 30 pts due to lymphoma (12%), 22 pts therapy-related (11 pts due to salvage therapy) (9%), 8 pts of secondary neoplasia (3%), 5 pts due to concomitant disease (2%) and 5 pts for unknown reasons. Conclusions: This 10-year long-term follow-up of the R-MegaCHOEP trial confirms the very encouraging outcome of young high-risk pts following conventional chemotherapy with R-CHOEP. High-dose therapy did not improve outcome in any subgroup analysis including molecular high-risk groups. Relapse rate was generally low. Pts with aggressive relapse showed a very poor long-term outcome while pts with indolent histology at relapse survived long-term. Secondary malignancies occurred; however, they were rare with no excess leukemias/MDS following treatment with very high doses of etoposide and other cytotoxic agents. Supported by Deutsche Krebshilfe. Figure Disclosures Nickelsen: Roche Pharma AG: Membership on an entity's Board of Directors or advisory committees, Other: Travel Grants; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Travel Grant; Janssen: Membership on an entity's Board of Directors or advisory committees. Hänel:Amgen: Honoraria; Celgene: Other: advisory board; Novartis: Honoraria; Takeda: Other: advisory board; Roche: Honoraria. Truemper:Nordic Nanovector: Consultancy; Roche: Research Funding; Mundipharma: Research Funding; Janssen Oncology: Consultancy; Takeda: Consultancy, Research Funding; Seattle Genetics, Inc.: Research Funding. Held:Roche: Consultancy, Other: Travel support, Research Funding; Amgen: Research Funding; Acrotech: Research Funding; MSD: Consultancy; Bristol-Myers Squibb: Consultancy, Other: Travel support, Research Funding. Dreyling:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: scientific advisory board, Research Funding, Speakers Bureau; Bayer: Consultancy, Other: scientific advisory board, Speakers Bureau; Celgene: Consultancy, Other: scientific advisory board, Research Funding, Speakers Bureau; Mundipharma: Consultancy, Research Funding; Gilead: Consultancy, Other: scientific advisory board, Speakers Bureau; Novartis: Other: scientific advisory board; Sandoz: Other: scientific advisory board; Janssen: Consultancy, Other: scientific advisory board, Research Funding, Speakers Bureau; Acerta: Other: scientific advisory board. Viardot:Kite/Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees. Rosenwald:MorphoSys: Consultancy. Lenz:Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding; Agios: Research Funding; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bayer: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Roche: Employment, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy. Schmitz:Novartis: Honoraria; Gilead: Honoraria; Celgene: Equity Ownership; Riemser: Consultancy, Honoraria.
Venetoclax (Ven) is an effective element of treatments for chronic lymphocytic leukemia (CLL) with high response rates observed in the upfront and relapsed/refractory (R/R) settings. In addition to inducing apoptosis in CLL cells, Ven also induces apoptosis within normal and malignant myeloid lineage populations (accounting for its efficacy in the treatment of acute myeloid leukemia). We investigated the effects of Ven outside the target tumor compartment in patients (pts) with CLL receiving long-term continuous Ven and make the novel observation of the development of BAX-mutated clonal hematopoiesis in this heavily pre-treated patient group. 92 pts with CLL receiving continuous non time-limited Ven have been treated at our institutions on clinical trials. Of these, 41 had sufficient (>6 mo) follow up (median 70; range 14-95 mo) and suitable samples available for further analysis. 38/41 (93%) pts had received previous treatment with alkylators and/or fludarabine. In order to assess the non-CLL compartment in these 41 pts we identified those with peripheral blood or bone marrow aspirate samples taken during deep response to Ven demonstrating either minimal (<5%) or no CLL involvement by flow cytometry (sensitivity 10-4). We initially performed unique molecular index (UMI)-based targeted next generation sequencing of apoptosis pathway genes as well a panel of 60 genes recurrently mutated in lymphoid and myeloid malignancy. From these 41 pts we identified mutations in the apoptosis effector BAX in samples from 12 (29%). 20 different BAX mutations were observed across these 12 pts at variant allele frequencies (VAF) consistent with their occurrence in the non-CLL compartment. Mutations included frameshift, nonsense, canonical splice site and missense mutations occurring in key structural elements of BAX consistent with a loss-of-function mechanism (Fig 1A). Interestingly, an enrichment of missense and truncating mutations predicted to escape nonsense mediated decay were observed at the C-terminus of the BAX protein affecting the critical α9 helix. Mutations in this region have previously been shown in cell lines to cause aberrant intracellular BAX localization and abrogation of normal BAX function in apoptosis (Fresquet Blood 2014; Kuwana J Biol Chem 2020). For comparison, NGS targeted sequencing for BAX mutations was performed on samples from cohorts of pts with (i) myeloid or lymphoid malignancy (n=80) or (ii) R/R CLL treated with BTK inhibitors (n=15) after a similar extent of preceding chemotherapy. Neither of these cohorts had previous exposure to Ven. BAX mutations were not detected in any samples from these pts. Longitudinal sampling from pts on Ven harboring BAX mutations in the non-CLL compartment was performed to further understand compartment dynamics over time (in 9 pts over 21-93 months of follow up). Multiple pts demonstrated a progressive increase in VAF of single BAX mutations over time to become clonally dominant within the non-CLL compartment and with observed VAFs consistent with their presence in the myeloid compartment. Mutations in other genes implicated in clonal hematopoiesis and myeloid malignancy including ASXL1, DNMT3A, TET2, U2AF1 and ZRSR2 were also detected in these pts samples. Targeted amplicon single cell sequencing (Mission Bio) demonstrated the co-occurrence of clonally progressive BAX mutations within the same clones as mutations in DNMT3A and ASXL1 as well as the existence of further BAX mutations at low VAF outside these dominant clones which remained non-progressive over time (Fig 1B). In addition, fluctuations in the presence and VAF of myeloid-disease associated mutations was noted with Ven exposure. In aggregate these data are consistent with the existence of a selective pressure within the myeloid compartment of these pts and an interplay of BAX with other mutations in determining survival and enrichment of these clones over time with ongoing Ven therapy. In summary, we have observed the development of BAX-mutated clonal hematopoiesis specifically in pts with CLL treated with long-term Ven. These data are consistent with a multi-lineage pharmacological effect of Ven leading to a survival advantage for clones harboring BAX mutations within the myeloid compartment during chronic Ven exposure. Finally, our data support the further investigation of BAX mutations as a potential resistance mechanism in myeloid malignancies treated with Ven. Disclosures Blombery: Invivoscribe: Honoraria; Amgen: Consultancy; Janssen: Honoraria; Novartis: Consultancy. Anderson:Walter and Eliza Hall Institute: Patents & Royalties: milestone and royalty payments related to venetoclax.. Seymour:Celgene: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy; Mei Pharma: Consultancy, Honoraria; Morphosys: Consultancy, Honoraria; Nurix: Honoraria; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Tam:Janssen: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; BeiGene: Honoraria. Huang:Servier: Research Funding; Walter and Eliza Hall Institute: Patents & Royalties: milestone and royalty payments related to venetoclax.; Genentech: Research Funding. Wei:Janssen: Honoraria, Other; Walter and Eliza Hall Institute: Patents & Royalties; AMGEN: Honoraria, Other: Advisory committee, Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau; Astellas: Honoraria, Other: Advisory committee; Pfizer: Honoraria, Other: Advisory committee; Macrogenics: Honoraria, Other: Advisory committee; Abbvie: Honoraria, Other: Advisory committee, Research Funding, Speakers Bureau; Genentech: Honoraria, Other: Advisory committee; Servier: Consultancy, Honoraria, Other: Advisory committee; Celgene: Honoraria, Other: Advisory committee, Speakers Bureau; Astra-Zeneca: Honoraria, Other: Advisory committee, Research Funding. Roberts:Janssen: Research Funding; Servier: Research Funding; AbbVie: Research Funding; Genentech: Patents & Royalties: for venetoclax to one of my employers (Walter & Eliza Hall Institute); I receive a share of these royalties.
Background: Pyruvate kinase (PK) deficiency is a congenital hemolytic anemia caused by mutations in the PKLR gene, leading to a deficiency of the glycolytic enzyme red cell PK (PK-R). Current treatments for PK deficiency are supportive only. Mitapivat (AG-348) is an oral, small-molecule, allosteric PK-R activator in clinical trials for PK deficiency. We previously described results from DRIVE PK, a phase 2, randomized, open-label, dose-ranging study in adults with PK deficiency (N=52) treated with mitapivat for a median of 6 months. Aim: To report long-term safety and efficacy of mitapivat in patients who continue treatment in the ongoing Extension period of the DRIVE PK study (ClinicalTrials.gov NCT02476916). Methods: Patients were eligible to participate if ≥18 years of age with a confirmed diagnosis of PK deficiency (enzyme and molecular testing); baseline hemoglobin (Hb) levels ≤12.0 g/dL (males) or ≤11.0 g/dL (females); and if they had not received more than 3 units of red blood cells in the prior 12 months, with no transfusions in the prior 4 months. Patients were initially randomized 1:1 to receive mitapivat 50 mg twice daily (BID) or 300 mg BID for a 6-month Core period. Dose adjustment was allowed during the Core period based on safety and efficacy. Patients experiencing clinical benefit without concerning safety issues related to mitapivat (investigator discretion) could opt to enter the Extension period, with follow-up visits every 3 months. Safety (adverse events [AEs]) and efficacy (hematologic parameters including Hb) were assessed. Protocol amendments during the Extension period required that (1) patients who did not have an increase from baseline Hb of ≥1.0 g/dL for ≥3 of the prior 4 measurements withdraw from the study, and (2) patients treated with mitapivat doses >25 mg BID undergo a dose taper and continue on the dose that maintained their Hb level no lower than 1.0 g/dL below their pre-taper Hb level. Results: Fifty-two patients enrolled in this study and were treated in the 24-week Core period; 43 (83%) patients completed the Core period and 36 (69%) entered the Extension period. Eighteen patients discontinued from the Extension period: investigator decision (n=8), AEs (n=1), consent withdrawal (n=1), noncompliance (n=1), or other (n=7). Thus, 18 patients, all of whom received ≥29 months of treatment with mitapivat (median 35.6, range 28.7-41.9) have continued treatment. Ten of these 18 patients were male, 11 had a prior splenectomy, and 5 had a history of iron chelation. Median age was 33.5 (range 19-61) years; mean baseline Hb was 9.7 (range 7.9-12.0) g/dL. All patients had ≥1 missense PKLR mutation. The doses (post-taper) at which treatment was continued were (BID): ≤25 mg (n=12), 50 mg (n=5), and 200 mg (n=1). Improvements in Hb levels and markers of hemolysis (reticulocytes, indirect bilirubin, haptoglobin) were sustained (Figure). Among the 18 patients, headache was the most commonly reported AE during both the Extension (n=7, 38.9%) and Core (n=10, 55.6%) periods. Reports of insomnia and fatigue during the Extension period (n=5, 27.8% each) were the same as or similar to those during the Core period. There were fewer reports of nausea (2 vs 6) and hot flush (0 vs 5) in the Extension period. Nasopharyngitis was reported in 5 patients in the Extension period vs 1 patient in the Core period. These data are consistent with the AE profile for the 52 patients treated overall in the Core period, in that headache (44%), insomnia (40%), and nausea (38%) were the most commonly reported AEs and were transient (generally resolved within 7 days without intervention). Conclusion: Chronic daily dosing with mitapivat for a median of 3 years was well tolerated, with no new safety signals reported. Increased Hb levels and improvements in hemolysis markers were sustained at the optimized individual doses. These long-term data support the potential of mitapivat as the first disease-altering therapy for PK deficiency. Two phase 3 trials are underway to further study the effect of mitapivat in patients with PK deficiency. Disclosures Grace: Novartis: Research Funding; Agios Pharmaceuticals, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Layton:Novartis: Membership on an entity's Board of Directors or advisory committees; Cerus Corporation: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees. Galactéros:Addmedica: Membership on an entity's Board of Directors or advisory committees. Barcellini:Novartis: Research Funding, Speakers Bureau; Alexion: Consultancy, Research Funding, Speakers Bureau; Apellis: Consultancy; Incyte: Consultancy, Other: Advisory board; Agios: Consultancy, Other: Advisory board; Bioverativ: Consultancy, Other: Advisory board. van Beers:Agios Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Research Funding; RR Mechatronics: Research Funding. Ravindranath:Agios Pharmaceuticals, Inc.: Other: I am site PI on several Agios-sponsored studies, Research Funding. Kuo:Agios: Consultancy; Alexion: Consultancy, Honoraria; Apellis: Consultancy; Bioverativ: Other: Data Safety Monitoring Board; Bluebird Bio: Consultancy; Celgene: Consultancy; Novartis: Consultancy, Honoraria; Pfizer: Consultancy. Sheth:Apopharma: Other: Clinical trial DSMB; CRSPR/Vertex: Other: Clinical Trial Steering committee; Celgene: Consultancy. Kwiatkowski:bluebird bio, Inc.: Consultancy, Research Funding; Apopharma: Research Funding; Novartis: Research Funding; Terumo: Research Funding; Celgene: Consultancy; Imara: Consultancy; Agios: Consultancy. Hua:Agios Pharmaceuticals, Inc.: Employment, Equity Ownership. Hawkins:Bristol Myers Squibb: Equity Ownership; Infinity Pharma: Equity Ownership; Agios: Employment, Equity Ownership; Jazz Pharmaceuticals: Equity Ownership. Mix:Agios: Employment, Equity Ownership. Glader:Agios Pharmaceuticals, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.
Introduction: AL amyloidosis involves deposition of abnormally folded light chains into a wide range of tissues causing end-organ dysfunction, including in the heart and kidney. Daratumumab, a CD38-targeted antibody, has recently demonstrated efficacy in producing hematologic responses in previously relapsed/refractory disease. However, data on long-term outcomes to daratumumab, including organ responses, are lacking. Here we present the largest retrospective study to date on patients with previously treated AL amyloidosis treated with daratumumab. Methods: We conducted a retrospective analysis of relapsed/refractory AL amyloidosis patients treated at Stanford University from January 2016 to January 2019. Patients treated with daratumumab, either as monotherapy with dexamethasone (DMT) or in combination with other plasma-cell directed therapies (DCT) were included. Hematologic and organ responses were assessed by consensus guidelines. Hematologic responses were based on the maximal change in the difference between involved and uninvolved free light chains (dFLC). For cardiac response, a >30% and >300 pg/mL decrease in NT-proBNP for patients with initial baseline NT-proBNP ≥650 pg/mL was considered a response. A graded cardiac response metric was also explored with partial response (PR) representing 30-59% reduction, very good partial response (VGPR) ≥60% reduction, and complete response (CR) NT-proBNP <450 pg/mL as previously reported. For renal response, a >30% decrease (by at least 0.5 g/day) in 24-hour urine protein without worsening in creatinine or creatinine clearance by more than 25% in patients with at least 0.5 g/day pretreatment was considered a response. A graded renal response metric was also explored with PR representing 30-59% reduction in proteinuria, VGPR ≥60%, and CR ≤ 200 mg per 24-hour period. Survival data was analyzed using the Kaplan-Meier method. All time-to-event outcomes, including survival and organ responses, were determined from initiation of daratumumab. Results: Eighty-four patients were identified with baseline characteristics at start of daratumumab shown in Table 1. Median duration of follow-up was 16 months. Two-year overall survival (OS) was 83% and median OS was not reached. Median time-to-next-treatment or death was 31 months. Sixty-seven out of 80 evaluable patients (84%) achieved a hematologic response, with 47 patients (59%) achieving a VGPR or better (Figure 1). Sixty-eight patients (81%) had cardiac involvement, and among the 34 evaluable patients, 18 (53%) of evaluable patients achieved a cardiac response with a median response time of 2 months among responders. In terms of a graded cardiac response, 6 patients (18%) were able to achieve cardiac CR, 5 patients (15%) cardiac VGPR, and 7 patients (21%) PR (Figure 2). The median NT-proBNP percent reduction was 64.5% (IQR: 48.3 - 81.1%) and the median absolute reduction was 2395 pg/mL (IQR 1279.5 - 4089.5 pg/mL). Cardiac responses were associated with an improvement in OS (p<0.001, Figure 3), with landmark analysis for cardiac responses at 6-month trending towards statistical significance (100% vs. 51% at 30 months, p=0.052). Fifty-three patients (63%) had renal involvement, and among the 26 evaluable patients, 12 patients (46%) achieved a renal response with a median initial response time of 6 months among responders. Using graded response, 1 patient (4%) achieved renal CR, 7 patients (27%) renal VGPR, 4 patients (15%) renal PR, and 14 patients had no response, worsening creatinine, or were subsequently started on hemodialysis (54%) (Figure 4). The median percent reduction in proteinuria was 74.1% (IQR: 49.2 - 83.1%) and the median absolute reduction in proteinuria was 3.1 g/24 hours (IQR 2.1 - 4.9 g) among responders. There were no significant differences in OS between renal responders and non-responders. Conclusion: Daratumumab is highly effective in the treatment of previously treated AL amyloidosis, and a significant proportion of patients can achieve durable hematologic responses as well as improvements in organ function. Disclosures Kaufman: Janssen: Other: travel/lodging, Research Funding. Liedtke:Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; IQVIA/Jazz: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech/Roche: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celator: Research Funding; Caelum: Membership on an entity's Board of Directors or advisory committees; BlueBirdBio: Research Funding; Amgen/Onyx: Consultancy, Honoraria, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees; Agios: Research Funding. OffLabel Disclosure: Daratumumab in AL amyloidosis