Sokol, Lubomir

Abstract Objectives Diagnosing adult T-cell leukemia/lymphoma (ATLL) remains challenging due to its clinical and histopathologic heterogeneity. While HTLV-1 serology is a key diagnostic criterion, it is often unavailable at the time of diagnosis and does not confirm viral integration in tumor cells. The HTLV-1–encoded HBZ RNA is a reliable diagnostic biomarker for ATLL. We evaluated the diagnostic performance of RNAscope in situ hybridization (ISH) for HBZ RNA in formalin-fixed, paraffin-embedded (FFPE) tissues to distinguish ATLL from other T-cell lymphomas. Methods HBZ ISH was evaluated in 72 cases, including 52 ATLLs and 20 non-ATLL T-cell lymphomas, to determine diagnostic sensitivity and specificity, interobserver agreement, interlaboratory reproducibility, and comparison with digital gene expression. Results This assay demonstrated 86.5% sensitivity and 100% specificity, with sensitivity improving to 97% when excluding bone marrow clot sections and FFPE blocks older than 5 years. Interobserver agreement among 3 pathologists was excellent (κ = 0.92, percent agreement: 94%). Interlaboratory reproducibility of HBZ ISH was high, with 93% to 95% concordance across these Clinical Laboratory Improvement Amendments–certified laboratories. HBZ RNA ISH–positive cases demonstrated significantly higher HBZ gene expression levels by digital gene expression profiling. Conclusions We established HBZ ISH as a reliable tissue-based surrogate for HTLV-1 infection in ATLL. This assay will enhance diagnostic accuracy, expedite definitive diagnosis, and improve patient selection for targeted therapies and clinical trials, particularly in regions with a high prevalence of HTLV-1.

Abstract A phase 2, international, open-label, nonrandomized, single-arm trial was conducted to evaluate the efficacy and safety of tipifarnib, a farnesyltransferase inhibitor, as monotherapy for relapsed/refractory peripheral T-cell lymphoma (PTCL) and to evaluate tumor mutation profile as a biomarker of response. Adults with relapsed/refractory PTCL received tipifarnib 300 mg orally twice daily for 21 days in a 28-day cycle. The primary end point was objective response rate (ORR); secondary end points included ORR, progression-free survival (PFS), duration of response (DOR), and adverse events (AEs) in specific subtypes. Sixty-five patients with PTCL were enrolled: n = 38 angioimmunoblastic T-cell lymphoma (AITL), n = 25 PTCL not otherwise specified, and n = 2 other T-cell lymphomas. The ORR was 39.7% (95% confidence interval [CI], 28.1-52.5) in all patients and 56.3% (95% CI, 39.3-71.8) for AITL. Median PFS was 3.5 months overall (954% CI, 2.1-4.4), and 3.6 months (95% CI, 1.9-8.3) for AITL. Median DOR was 3.7 months (95% CI, 2.0-15.3), and greatest in patients with AITL (7.8 months; 95% CI, 2.0-16.3). The median overall survival was 32.8 months (95% CI, 14.4 to not applicable). Tipifarnib-related hematologic AEs were manageable and included neutropenia (43.1%), thrombocytopenia (36.9%), and anemia (30.8%); other tipifarnib-related AEs included nausea (29.2%) and diarrhea (27.7%). One treatment-related death occurred. Mutations in RhoA, DNMT3A, and IDH2 were seen in 60%, 33%, and 27%, respectively, in the AITL tipifarnib responder group vs 36%, 9%, and 9% in the nonresponder group. Tipifarnib monotherapy demonstrated encouraging clinical activity in heavily pretreated relapsed/refractory PTCL, especially in AITL, with a manageable safety profile. This trial was registered at www.ClinicalTrials.gov as #NCT02464228.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of lymphoproliferative disorders arising from mature T cells, accounting for about 10% of non-Hodgkin lymphomas. PTCL-not otherwise specified is the most common subtype, followed by angioimmunoblastic T-cell lymphoma, anaplastic large cell lymphoma, anaplastic lymphoma kinase–positive, anaplastic large cell lymphoma, anaplastic lymphoma kinase–negative, and enteropathy-associated T-cell lymphoma. This discussion section focuses on the diagnosis and treatment of PTCLs as outlined in the NCCN Guidelines for T-Cell Lymphomas.

Abstract Background CD47 is an innate immune checkpoint that binds signal regulatory protein alpha (SIRPα) and delivers a "don't eat me" signal to suppress macrophage phagocytosis. Overexpression of CD47 can allow tumor cells to escape immune surveillance. TTI-621 (SIRPαFc) is a fusion protein consisting of the CD47 binding domain of human SIRPα linked to the Fc region of human IgG1, designed to enhance phagocytosis and antitumor activity by blocking the CD47-SIRPα interaction between malignant cells and macrophages, and engaging Fcγ receptors. Here we report updates from the dose optimization part of the first-in-human study of TTI-621 (NCT02663518), testing dose levels between 0.5-2.0 mg/kg in patients with cutaneous T-cell lymphoma (CTCL). Methods This study has been conducted in 4 parts. Part 1 tested increasing weekly intravenous doses of TTI-621 based on 3+3 escalation. The maximum tolerated dose was initially determined to be 0.2 mg/kg based on dose limiting toxicity (DLT) of thrombocytopenia [defined as Grade (Gr) 4 of any duration]. Expanded testing followed in patients with hematologic malignancies. In Part 2, most patients received 0.2 mg/kg; however, based on investigator discretion, a subset of patients received escalating doses up to 0.5 mg/kg. In Part 3, patients with T-cell lymphomas received stepwise dose escalations from 0.2 to 0.5 mg/kg over the first 5−8 weeks. Part 4 (dose optimization) of this study, is currently ongoing with weekly TTI-621 treatment escalating in a standard 3+3 manner through 5 planned dose levels including 0.5, 0.7, 1, 1.4, and 2 mg/kg. Dose optimization is being assessed in patients with CTCL. The DLT criteria was modified to require Gr 4 thrombocytopenia lasting >72 hours. Safety monitoring includes weekly clinical laboratories and assessments of adverse events (AEs) per CTCAE v 4.03. Blood samples are obtained for pharmacokinetics and disease assessments are performed per Olsen's criteria. Results In Parts 1−3 (n=214), the most common related AEs were infusion-related reaction (IRR, 43%; 3% Gr ≥3), thrombocytopenia (30%; 22% Gr ≥3), chills (22%; 0% Gr ≥3), and fatigue (16%; 1% Gr ≥3). Objective responses to single agent TTI-621 were achieved in 14/71 (20%) NHL pts including CTCL (n=42, 1 CR, 7 PRs), PTCL (n=22, 2 CRs, 2 PRs) and DLBCL (n=7, 1 CR, 1 PR). In Part 4 as of April 12, 2021, 24 patients (17M/7F, median age 65 years) have enrolled into the 5 dose cohorts including 9 patients in the 2.0 mg/kg dose level. CTCL subtypes enrolled include mycosis fungoides (MF, n=18) and Sézary syndrome (SS, n=6). Disease stage was advanced (≥IIB) in 16 (67%) patients and a median of 3 (range 1−12) prior systemic therapies were received. Related AEs occurred in 19 (79%; 33% Gr ≥3) patients including infusion-related reaction (IRR, 50%; 13% Gr ≥3), thrombocytopenia (33%; 25% Gr ≥3), and neutropenia and headache, (13%, 0% Gr ≥3, each). Thrombocytopenia generally occurred on dosing days, and typically recovered within 2-4 days. A total of 15 IRRs have occurred in 12 (50%) patients at all doses levels. Most IRRs occurred during initial infusions only and typically resolved within the day of occurrence. The occurrence of Gr 3 IRRs prompted the addition of corticosteroids to the pre-medication regimen which largely prevent their occurrence. Aside from IRRs and thrombocytopenia which was manageable, AEs were predominantly Gr ≤2. Pharmacokinetic results reveal continued dose-dependent increases in exposure. Objective responses have been observed in 4 of 20 (20%) evaluable patients to date, including 3 partial responses in 14 patients with MF and 1 complete response in 6 patients with SS. Treatment is ongoing in the patient who achieved CR (10+ months) and in 2 of 3 patients who achieved PR (3 and 4 months). A third patient who achieved PR elected to discontinue study treatment at 5 months to pursue allogeneic stem and progenitor cell transplantation. Conclusions Preliminary results from dose optimization testing indicate that weekly infusions of TTI-621 up to 2 mg/kg are generally well tolerated. In Part 4, an overall response rate of 20% has been observed thus far in patients with CTCL. Testing of TTI-621 in alternative dosing schedules is in progress. With demonstrated good tolerability and robust single agent antitumor activity in heavily pre-treated patients, additional testing of TTI-621 beyond relapsed/refractory lymphoma has started. Disclosures Horwitz: Affimed: Research Funding; ADC Therapeutics, Affimed, Aileron, Celgene, Daiichi Sankyo, Forty Seven, Inc., Kyowa Hakko Kirin, Millennium /Takeda, Seattle Genetics, Trillium Therapeutics, and Verastem/SecuraBio.: Consultancy, Research Funding; Acrotech Biopharma, Affimed, ADC Therapeutics, Astex, Merck, Portola Pharma, C4 Therapeutics, Celgene, Janssen, Kura Oncology, Kyowa Hakko Kirin, Myeloid Therapeutics, ONO Pharmaceuticals, Seattle Genetics, Shoreline Biosciences, Inc, Takeda, Trillium Th: Consultancy; Aileron: Research Funding; Celgene: Research Funding; C4 Therapeutics: Consultancy; Crispr Therapeutics: Research Funding; Daiichi Sankyo: Research Funding; Forty Seven, Inc.: Research Funding; Kura Oncology: Consultancy; Kyowa Hakko Kirin: Consultancy, Research Funding; Millennium/Takeda: Research Funding; Myeloid Therapeutics: Consultancy; ONO Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy, Research Funding; Secura Bio: Consultancy; Shoreline Biosciences, Inc.: Consultancy; Takeda: Consultancy; Trillium Therapeutics: Consultancy, Research Funding; Tubulis: Consultancy; Verastem/Securabio: Research Funding. Foran: pfizer: Honoraria; novartis: Honoraria; servier: Honoraria; bms: Honoraria; revolution medicine: Honoraria; taiho: Honoraria; syros: Honoraria; sanofi aventis: Honoraria; certara: Honoraria; gamida: Honoraria; OncLive: Honoraria; abbvie: Research Funding; boehringer ingelheim: Research Funding; takeda: Research Funding; trillium: Research Funding; aptose: Research Funding; actinium: Research Funding; kura: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Lue: Epizyme: Consultancy; TG Therapeutics: Consultancy; Kymera Therapeutics: Research Funding; AstraZeneca: Speakers Bureau; Kura Oncology: Consultancy. Sawas: Affimed: Research Funding; Roche: Current equity holder in publicly-traded company; Flat Iron Health: Current Employment; Seattle Genetics: Honoraria; Acrotech: Honoraria; Daiichi-Sankyo: Speakers Bureau; Seattle Genetics: Speakers Bureau; Gilead: Speakers Bureau. Feldman: Alexion, AstraZeneca Rare Disease: Honoraria, Other: Study investigator. Sokol: Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees; Dren Bio: Membership on an entity's Board of Directors or advisory committees. Mei: Janssen: Honoraria; EUSA: Honoraria; TG Therapeutics: Research Funding; Epizyme: Research Funding; BMS: Research Funding; Morphosys: Research Funding; Beigene: Research Funding. Flinn: AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Villa: Janssen: Honoraria; Roche: Honoraria; Lundbeck: Honoraria; Celgene: Honoraria; Seattle Genetics: Honoraria; AbbVie: Honoraria; AstraZeneca: Honoraria; Gilead: Honoraria; NanoString Technologies: Honoraria. Percival: Pfizer: Research Funding; Abbvie: Research Funding; Biosight: Research Funding; BMS/Celgene: Research Funding; Cardiff Oncology: Research Funding; Glycomimetics: Research Funding; Nohla Therapeutics: Research Funding; Oscotec: Research Funding; Trillium: Research Funding. Savage: Seattle Genetics: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Other: Institutional clinical trial funding; Merck: Consultancy, Honoraria, Other: Institutional clinical trial funding; AbbVie: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Roche: Research Funding; Takeda: Other: Institutional clinical trial funding; Beigene: Other: Institutional clinical trial funding; Genentech: Research Funding. Diefenbach: Genentech, Inc./ F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Merck Sharp & Dohme: Consultancy, Honoraria, Research Funding; Morphosys: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; MEI: Consultancy, Research Funding; Gilead: Current equity holder in publicly-traded company; IMab: Research Funding; Celgene: Research Funding; Trillium: Research Funding; Incyte: Research Funding; AbbVie: Research Funding; Perlmutter Cancer Center at NYU Langone Health: Current Employment; IGM Biosciences: Research Funding. Kim: Kyowa Kirin: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Innate: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Corvus: Membership on an entity's Board of Directors or advisory committees, Research Funding; Trillium: Research Funding; Galderma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Elorac: Research Funding; Portola: Membership on an entity's Board of Directors or advisory committees, Research Funding; Soligenix: Research Funding; Eisai: Research Funding; CRISPR: Research Funding; Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion, AstraZeneca Rare Disease: Other: Study investigator; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Horizon: Research Funding. Lin: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Catalano: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Petrova: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Uger: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Molloy: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Large: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Bruns: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding.

Abstract The T-cell non-Hodgkin lymphomas continue to be an area of unmet need for new therapies that offer novel mechanisms of action. Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). Tipifarnib inhibits farnesylation of key regulatory proteins involved in CXCL12 production (Gualberto et al, EHA 2019). CXCL12 is a chemokine that is essential for T-cell homing to lymphoid organs and bone marrow, and for the maintenance of immune cell progenitors via its receptor CXCR4 (Susek et al, Front Immunology, 2018). Angioimmunoblastic T-cell lymphoma (AITL) is associated with high levels of CXCL12 expression, which is also a negative prognostic factor (Witzig et al, Blood, 2019). Additionally, Peripheral T-Cell lymphoma Not Otherwise Specified (PTCL-NOS) patients with the CXCL12 rs2839695 A/A wildtype genotype (PTCL-CXCL12+) have also been found to have elevated levels of CXCL12. Therefore, there is strong rationale for targeting these subsets of PTCL with tipifarnib. This Phase 2 study (NCT02464228) was a multi-institutional, single-arm, open-label trial determining the efficacy, safety, and potential predictive biomarkers for tipifarnib in adult patients with relapsed or refractory (R/R) PTCL. Patients received tipifarnib 300 mg orally twice daily on Days 1-21 of 28-day treatment cycles until progression of disease or unacceptable toxicity. The primary objective of the study was to determine the antitumor activity by overall response rate (ORR) per Lugano Classification. Secondary objectives included safety, duration of response (DoR) and progression-free survival (PFS), and exploratory analyses included overall survival (OS) and identification of potential biomarkers associated with tipifarnib activity. Sixty-five R/R PTCL patients (38 AITL, 14 PTCL-NOS, 11 PTCL-CXCL12+, 2 other (1 ALCL-ALK negative, 1 PTCL-subtype not specified) were treated with tipifarnib. The population was heavily pretreated with a median of 3 prior regimens (range 1-8). All patients had at least one treatment-emergent adverse event (TEAE); most patients (87.7%) had at least one treatment-related TEAE, and 18 (27.7%) patients had at least one treatment-related serious TEAE. The most frequently observed (≥20%) treatment-related TEAEs (all grades) were hematological (neutropenia, thrombocytopenia, anemia,) and gastrointestinal (nausea, diarrhea), as well as fatigue, which is consistent with the known safety profile of tipifarnib. Fifty-eight patients were efficacy evaluable and had an associated ORR of 39.7% (23/58) with most responses observed in the AITL and PTCL-CXCL12+ cohorts. In the 32 patients with AITL, the ORR was 56.3% (18/32), including 9 complete responses (CR) and 9 partial responses (PR). In the 10 patients with PTCL-CXCL12+, the ORR was 40.0% (4/10), including 1 CR and 3 PR. The median OS for patients with AITL was 32.8 months, and the median OS had not been reached for patients with PTCL-CXCL12+. Previously, a strong association between KIR3DL2 C336R/Q386E mutation and the activity of tipifarnib was observed and reported in AITL patients (Witzig et al, EHA 2020). Extensive gene expression and gene variant analyses of samples from the study population is currently ongoing to evaluate this correlation and explore other potential predictors of response. Final data will be presented at the time of the conference. Overall, the results from this Phase 2 study with tipifarnib demonstrated very encouraging efficacy in patients with CXCL12-expressing subtypes of PTCL (AITL and PTCL-CXCL12+) and showed a tolerable safety profile. Disclosures Witzig: Karyopharm Therapeutics, Abbvie/Genentech, Seattle Genetics, Celgene/BMS, Incyte, Epizyme, Cellectar, Tessa Therapeutics, Portola Pharmaceuticals, MorphoSys, ADC Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS, Acerta Pharma, Kura Oncology, Acrotech Biopharma, Karyopharm Therapeutics: Research Funding. Sokol: Dren Bio: Membership on an entity's Board of Directors or advisory committees; Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees. Kim: IGM Biosciences: Research Funding; Kyowa Kirin: Research Funding; Roche: Research Funding; Sanofi: Research Funding; Celltrion: Research Funding; Dong-A Pharmaceutical: Research Funding; Johnson & Johnson: Research Funding; Eisai: Research Funding. de la Cruz Vicente: Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Eusapharma: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Advani: Astellas/Agensys: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Bristol Myer Squibb: Membership on an entity's Board of Directors or advisory committees; Cell Medica: Membership on an entity's Board of Directors or advisory committees; Forty Seven: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genetech Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceutical: Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding; Kyowa: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Millenium: Research Funding; Pharmacyclics: Consultancy, Research Funding; Portola Pharmaceuticals: Consultancy; Regeneron: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees. Marin Niebla: Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kiowa Kirin: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BeiGene: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Speakers Bureau; Amgen: Speakers Bureau. Terol: BMS: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Hospital Clinico Valencia: Current Employment; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Roche: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding. Eva: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Bendris: Kura Oncology: Current Employment, Current equity holder in publicly-traded company. Ahsan: Gilead: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Kura Oncology: Current Employment, Current equity holder in publicly-traded company. Leoni: Kura Oncology: Current Employment. Foss: Daiichi Sankyo: Honoraria; Mallinckrodt: Honoraria; Acrotech: Honoraria, Speakers Bureau; Seattle Genetics: Honoraria, Speakers Bureau; Kyowa: Honoraria; Kura: Honoraria.

Abstract Introduction Central nervous system (CNS) relapse (CNSr) in patients with aggressive non-Hodgkin lymphoma (NHL) occurs uncommonly (estimated incidence 5%) but carries a high morbidity and mortality. Studies have identified risk factors for CNSr such as high tumor burden and extranodal (EN) disease. However, most focus on B-cell NHL with minimal data in T-cell lymphomas (TCL), which are significantly less common and more heterogenous. The few small series of CNSr in TCL report a median overall survival (OS) less than 3 months (mo) with incidence ranging from 2.6-9%. To better define CNSr in TCL, we performed a multi-institutional retrospective analysis of TCL patients with CNSr and herein describe clinicopathologic characteristics and treatment of CNSr. Methods We performed a retrospective observational study using data from 9 US academic centers with IRB approval at individual sites. We included adult patients diagnosed with a mature T-cell neoplasm as per the 2016 WHO classification between 1/1/2009-1/1/2019, who were found to have CNSr at any time after initial diagnosis, and collected patient, disease, and treatment characteristics at time of initial diagnosis as well as at CNSr. Patients with a diagnosis of a precursor T-cell malignancy or with CNS disease identified at initial TCL diagnosis (TCLd) and/or prior to first-line systemic treatment were excluded. Results In this analysis, we report the outcomes of 75 patients (male n=45, female n=30). At TCLd, the median age was 59 years (range 20-81), and 61% of patients (n=46) had an IPI score of at least 3, 92% (n=69) had EN involvement with 37% (n=28) involving at least 2 EN sites, and 59% (n=44) had BM involvement. The most common pathologic diagnoses were peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS; 24%, n=18), angioimmunoblastic T-cell lymphoma (AITL; 17%, n=13), adult T-cell leukemia/lymphoma (ATLL; 17%, n=13), and mycosis fungoides (MF; 12%, n=9) (Figure 1A). First-line systemic therapy for TCL included anthracyclines for 72% (n=54). Autologous and allogenic transplants were performed prior to CNSr in 12% (n=9) and 8% (n=6) of patients, respectively. Prior to CNSr, 48% (n=36) had non-CNS relapse. Some form of CNS prophylaxis was used during initial systemic lymphoma therapy in 24% of patients (n=18), predominantly intrathecal methotrexate (IT MTX; n=16). Median time from TCLd to CNSr was 8.5mo, though this was significantly longer in MF (46.8mo [range 17.5-187.7]) versus PTCL, NOS (7.6mo [range 1.1-58.4], P=0.0002), AITL (21.2mo [range 2.0-61.6, P=0.008), and ATLL (7.3mo [range 0.7-46.4], P=0.0005) (Figure 1B). CNSr developed within 6mo of TCLd in 31% of patients (n=23) and within 12mo in 57% (n=43). Symptoms related to CNSr occurred in 71% of patients (n=53). CNSr patterns were 61% leptomeningeal (n=46), 21% parenchymal (n=16), and 17% both (n=13) with no significant survival difference between leptomeningeal or parenchymal disease alone (HR 1.45, 95% CI 0.78-2.70, P=0.28). Concomitant systemic relapse was observed in 59% of patients (n=44). The most common CNS-directed therapy for CNSr was IT MTX (56%; n=42), though multiple different IT and/or systemic regimens were used. Patients received a median of 1 line of CNS-directed treatment (range 0-5). The overall response rate to initial CNS directed treatment was 32% (16% CR, 16% PR). Median follow up after CNSr was 40.7mo. At last follow up, 83% had died (n=62). Median OS after CNSr was 4.6mo (range 0.1-68.7) (Figure 1C). Those with ATLL had the shortest median OS after CNSr (2.7mo) versus 6.3mo in MF (HR 3.69, 95% CI 1.44-9.42, P=0.005), 6.5mo in AITL (HR 2.16, 95% CI 0.92-5.06, P=0.054), and 4.8mo in PTCL, NOS (HR 1.49, 95% CI 0.70-3.19, P=0.27) (Figure 1D). The most common cause of death was progressive lymphoma (77%; n=48). Conclusions This is to our knowledge the largest series of CNSr in TCL to date. Most CNSr occurred within 12mo, though CNSr occurred later in patients with MF. Although the prognosis after CNSr was generally poor, we found that median OS in CNSr was longer than previously reported, perhaps reflecting more effective treatments for CNS and systemic relapse, inclusion of MF, or lead time bias. Further analysis of the impact of different treatment strategies and outcomes in CNSr was limited by the small sample size and heterogeneity within our cohort, and future analyses in a larger cohort should focus on factors associated with outcomes. Figure 1 Figure 1. Disclosures Horwitz: ADC Therapeutics, Affimed, Aileron, Celgene, Daiichi Sankyo, Forty Seven, Inc., Kyowa Hakko Kirin, Millennium /Takeda, Seattle Genetics, Trillium Therapeutics, and Verastem/SecuraBio.: Consultancy, Research Funding; Affimed: Research Funding; Aileron: Research Funding; Acrotech Biopharma, Affimed, ADC Therapeutics, Astex, Merck, Portola Pharma, C4 Therapeutics, Celgene, Janssen, Kura Oncology, Kyowa Hakko Kirin, Myeloid Therapeutics, ONO Pharmaceuticals, Seattle Genetics, Shoreline Biosciences, Inc, Takeda, Trillium Th: Consultancy; Celgene: Research Funding; C4 Therapeutics: Consultancy; Crispr Therapeutics: Research Funding; Daiichi Sankyo: Research Funding; Forty Seven, Inc.: Research Funding; Kura Oncology: Consultancy; Kyowa Hakko Kirin: Consultancy, Research Funding; Millennium/Takeda: Research Funding; Myeloid Therapeutics: Consultancy; ONO Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy, Research Funding; Secura Bio: Consultancy; Shoreline Biosciences, Inc.: Consultancy; Takeda: Consultancy; Trillium Therapeutics: Consultancy, Research Funding; Tubulis: Consultancy; Verastem/Securabio: Research Funding. Bennani: Purdue Pharma: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Vividion: Other: Advisory Board; Kymera: Other: Advisory Board; Verastem: Other: Advisory Board. Chavez: AstraZeneca: Research Funding; ADC Therapeutics: Consultancy, Research Funding; Merk: Research Funding; MorphoSys, AstraZeneca, BeiGene, Genentech, Kite, a Gilead Company, and Epizyme: Speakers Bureau; MorphoSys, Bayer, Karyopharm, Kite, a Gilead Company, Novartis, Janssen, AbbVie, TeneoBio, and Pfizer: Consultancy; BMS: Speakers Bureau. Sokol: Dren Bio: Membership on an entity's Board of Directors or advisory committees; Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees. Saeed: Nektar Therapeutics: Consultancy, Other: research investigator; MEI Pharma Inc: Consultancy, Other: investigator; Celgene Corporation: Consultancy, Other: investigator; MorphoSys AG: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb Company: Consultancy; sano-aventis U.S.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceutica Products, LP: Consultancy, Other: investigator; Kite Pharma: Consultancy, Other: investigator; Other-TG therapeutics: Consultancy, Other: investigator; Other-Epizyme, Inc.: Consultancy; Other-Secura Bio, Inc.: Consultancy; Seattle Genetics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mehta-Shah: Kiowa Hakko Kirin: Consultancy; C4 Therapeutics: Consultancy; Verastem: Research Funding; Karyopharm: Consultancy; Ono Pharmaceuticals: Consultancy; Secura Bio: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; AstraZeneca: Research Funding; Bristol Myers Squibb: Research Funding; Celgene: Research Funding; Innate Pharmaceuticals: Research Funding; Roche/Genentech: Research Funding; Corvus Pharmaceuticals: Research Funding. Olszewski: TG Therapeutics: Research Funding; PrecisionBio: Research Funding; Celldex Therapeutics: Research Funding; Acrotech Pharma: Research Funding; Genentech, Inc.: Research Funding; Genmab: Research Funding. Allen: Epizyme: Consultancy; MorphoSys: Consultancy; ADC Therapeutics: Consultancy; Secure Bio: Consultancy; Kyowa Kirin: Consultancy. Gerson: Abbvie: Consultancy; Kite: Consultancy; TG Therapeutics: Consultancy; Pharmacyclics: Consultancy. Landsburg: Triphase: Research Funding; Takeda: Research Funding; Curis: Research Funding; ADCT: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: DSMB member; Incyte: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees. Schuster: Adaptive Biotechnologies: Research Funding; Pharmacyclics: Research Funding; Merck: Research Funding; Genentech/Roche: Consultancy, Research Funding; Tessa Theraputics: Consultancy; Juno Theraputics: Consultancy, Research Funding; Loxo Oncology: Consultancy; BeiGene: Consultancy; Alimera Sciences: Consultancy; Acerta Pharma/AstraZeneca: Consultancy; Abbvie: Consultancy, Research Funding; Nordic Nanovector: Consultancy; Novartis: Consultancy, Honoraria, Patents & Royalties, Research Funding; Incyte: Research Funding; TG Theraputics: Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Svoboda: Atara: Consultancy; Adaptive: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding; Imbrium: Consultancy; Pharmacyclics: Consultancy, Research Funding; Genmab: Consultancy; Merck: Research Funding; Incyte: Research Funding; BMS: Consultancy, Research Funding; TG: Research Funding; Seattle Genetics: Consultancy, Research Funding. Barta: Kyowa Kirin: Honoraria; Acrotech: Honoraria; Daiichi Sankyo: Honoraria; Seagen: Honoraria.

Background CD47 is an innate immune checkpoint that binds signal regulatory protein alpha (SIRPα) and delivers a "do not eat" signal to suppress macrophage phagocytosis. Overexpression of CD47 can allow tumor cells to escape immune surveillance. TTI-621 (SIRPαFc) is a fusion protein consisting of the CD47 binding domain of human SIRPα linked to the Fc region of human IgG1, designed to enhance phagocytosis and antitumor activity by blocking the CD47-SIRPα interaction between malignant cells and macrophages, and engaging Fcγ receptors. Here we report updates from the first-in-human study of TTI-621 (NCT02663518) in hematologic malignancies. Methods Study Part 1 tested increasing weekly intravenous doses of TTI-621 based on 3+3 escalation. The maximum tolerated dose was initially determined to be 0.2 mg/kg based on dose limiting toxicity (DLT) of thrombocytopenia [Grade (Gr) 4 of any duration]. Expanded testing followed in patients (pts) with hematologic malignancies, including leukemia, lymphoma, and multiple myeloma. In Part 2, most pts received 0.2 mg/kg. However, based on investigator discretion, a subset of pts received escalating doses up to 0.5 mg/kg. In Part 3, pts with T-cell lymphomas received stepwise dose escalations from 0.2 to 0.5 mg/kg over the first 5−8 weeks. In over 200 pts tested in Parts 1−3, thrombocytopenia did not increase with dose, typically recovered within 2−4 days, and was not associated with clinical sequelae. Part 4 was then undertaken to optimize TTI-621 dosing and is currently escalating doses in a 3+3 manner through pre-planned dose levels (0.5, 0.7, 1, and 1.4 mg/kg) in pts with cutaneous T-cell lymphoma (CTCL). The DLT criteria was modified to require Gr 4 thrombocytopenia lasting >72 hours. Safety monitoring includes weekly clinical laboratories and assessments of adverse events (AEs) per CTCAE v 4.03. Blood samples are obtained for pharmacokinetics (PK) and for pharmacodynamic (PD) assessments of receptor occupancy (RO) on normal peripheral T cells. Disease assessments are performed per Olsen's criteria. Results In Parts 1−3 (n=214), the most common related AEs were infusion-related reaction (IRR, 43%; 3% Gr ≥3), thrombocytopenia (30%; 22% Gr ≥3), chills (21%; 0% Gr ≥3), and fatigue (15%; 1% Gr ≥3). Objective responses to single agent TTI-621 were achieved in 14/71 (20%) NHL pts including CTCL (n=42, 1 CR, 7 PRs), PTCL (n=22, 2 CRs, 2 PRs) and DLBCL (n=7, 1 CR, 1 PR). In Part 4, as of July 10, 2020, 15 pts (9M/6F, median age 67 years) have enrolled into 4 dose cohorts (0.5−1.4 mg/kg). CTCL subtypes include mycosis fungoides (MF, n=10) and Sézary syndrome (n=5) with advanced (≥IIB) disease in 9 (60%) pts who received a median of 3 (range 1−12) prior systemic therapies. Related AEs have occurred in 11 (73%) pts including IRR (n=10) and thrombocytopenia (n=3); Gr ≥3 AEs have occurred in 4 (27%) pts including thrombocytopenia (n=3), IRRs (n=2), and exfoliative dermatitis (n=1). Thrombocytopenia generally occurred on dosing days, recovered in 2-4 days, and has not worsened with increasing doses. IRRs typically occurred during initial infusions. The Gr 3 IRR events occurred in 2 pts in the 1 and 1.4 mg/kg cohorts; low Gr IRRs have occurred across doses in 8 pts. IRRs typically resolved without recurrence and low Gr events often resolved allowing for completion of infusions. For initial infusions, the Gr 3 IRRs prompted increasing infusion times from 1 hour up to 4 hours and discretional use of steroid pre-medication. The exfoliative dermatitis occurred Day 80 and led to treatment discontinuation in 1 pt with MF whose underlying disease confounded the etiology. PK results reveal dose dependent increases in exposure; PD studies indicate ~60% RO at end of infusion up to 1 mg/kg. Antitumor activity to date includes 1 PR and 1 skin CR in 6 evaluable pts in the 1 mg/kg cohort; 2 responding pts bridged to allogeneic transplantation. The mean % change in mSWAT scores were -0.4%, -27%, and -37% for 0.5, 0.7 and 1 mg/kg cohorts, respectively. 1.4 mg/kg cohort results will be presented at the meeting. Conclusions In Parts 1−3, TTI-621 doses of 0.05 to 0.5 mg/kg were well-tolerated and demonstrated single agent activity in multiple hematologic malignancies. Preliminary data from Part 4 dose optimization indicate that weekly infusions of TTI-621 up to 1.4 mg/kg are well-tolerated without dose limiting or cumulative thrombocytopenia. Antitumor activity was seen at 1 mg/kg; dose escalation is continuing at 2 mg/kg. Disclosures Horwitz: Janssen: Consultancy; Verastem: Consultancy, Research Funding; Daiichi Sankyo: Research Funding; GlaxoSmithKline: Consultancy; ASTEX: Consultancy; Portola: Consultancy, Research Funding; C4 Therapeutics: Consultancy; Beigene: Consultancy; Myeloid Therapeutics: Consultancy; Vividion Therapeutics: Consultancy; Infinity/Verastem: Research Funding; Aileron: Consultancy, Research Funding; ADCT Therapeutics: Consultancy, Research Funding; Affirmed: Consultancy; Trillium: Consultancy, Research Funding; Corvus: Consultancy; Millenium/Takeda: Consultancy, Research Funding; Kyowa Hakka Kirin: Consultancy, Research Funding; Innate Pharma: Consultancy; Forty Seven: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Kura Oncology: Consultancy; Miragen: Consultancy; Mundipharma: Consultancy. Foran:Agios: Honoraria, Research Funding; H3Biosciences: Research Funding; Xencor: Research Funding; Trillium: Research Funding; Takeda: Research Funding; Kura Oncology: Research Funding; Aptose: Research Funding; Aprea: Research Funding; Actinium: Research Funding; Boehringer Ingelheim: Research Funding; Abbvie: Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Revolution Medicine: Consultancy. Sawas:Flatiron Health: Current Employment; Gilead: Speakers Bureau; Seattle Genetics: Speakers Bureau; Daiichi Sankyo: Speakers Bureau; Affimed: Research Funding; Roche: Current equity holder in publicly-traded company. Feldman:AstraZeneca: Consultancy; Viracta: Research Funding; Trillium: Research Funding; Pfizer: Research Funding; Janssen: Speakers Bureau; Bayer: Consultancy, Honoraria; Kyowa Kirin: Consultancy, Research Funding; Eisai: Research Funding; Cell Medica: Research Funding; Amgen: Research Funding; Pharmacyclics: Honoraria, Other, Speakers Bureau; Abbvie: Honoraria; Takeda: Honoraria, Other: Travel expenses; Celgene: Honoraria, Research Funding; Kite: Honoraria, Other: Travel expenses, Speakers Bureau; BMS: Consultancy, Honoraria, Research Funding; Corvus: Research Funding; Rhizen: Research Funding; Seattle Genetics, Inc.: Consultancy, Honoraria, Other: Travel expenses, Research Funding, Speakers Bureau; Portola: Research Funding. Sokol:EUSA Pharma: Consultancy, Honoraria, Speakers Bureau; Kyowa/Kirin Inc.: Membership on an entity's Board of Directors or advisory committees; Kymera Therapeutics: Membership on an entity's Board of Directors or advisory committees. Mei:Sanofi: Consultancy; Morphosys: Membership on an entity's Board of Directors or advisory committees. Flinn:Gilead Sciences: Consultancy, Research Funding; F. Hoffmann-La Roche: Research Funding; Roche: Consultancy, Research Funding; Vincera Pharma: Consultancy; Agios: Research Funding; Iksuda Therapeutics: Consultancy; Great Point Partners: Consultancy; Genentech, Inc.: Research Funding; Forty Seven: Research Funding; Forma Therapeutics: Research Funding; ArQule: Research Funding; Kite Pharma: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Trillium Therapeutics: Research Funding; Triphase Research & Development Corp.: Research Funding; Curio Science: Consultancy; Constellation Pharmaceuticals: Research Funding; MorphoSys: Consultancy, Research Funding; Curis: Research Funding; Nurix Therapeutics: Consultancy; Novartis: Research Funding; Pfizer: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; Portola Pharmaceuticals: Research Funding; Seattle Genetics: Consultancy, Research Funding; Teva: Research Funding; Loxo: Research Funding; BeiGene: Consultancy, Research Funding; Calithera Biosciences: Research Funding; Johnson & Johnson: Other; Rhizen Pharmaceuticals: Research Funding; Yingli Pharmaceuticals ≠: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Karyopharm Therapeutics: Research Funding; AstraZeneca: Consultancy, Research Funding; Incyte: Research Funding; Takeda: Consultancy, Research Funding; IGM Biosciences: Research Funding; Infinity Pharmaceuticals: Research Funding; Unum Therapeutics: Consultancy, Research Funding; Juno Therapeutics: Consultancy, Research Funding; Acerta Pharma: Research Funding; Celgene: Research Funding; Merck: Research Funding. Villa:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; AZ: Consultancy, Honoraria, Research Funding; Kite/Gilead: Consultancy, Honoraria; Nano String: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Sandoz Canada: Consultancy, Honoraria; Immunovaccine: Consultancy, Honoraria; Purdue Pharma: Consultancy, Honoraria. Percival:Pfizer: Research Funding; Trillium: Research Funding; Nohla Therapeutics: Research Funding; Biosight: Research Funding; Oscotec: Research Funding; Cardiff Oncology: Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees; Glycomimetics: Research Funding. Jagadeesh:Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Regeneron: Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Research Funding; Debiopharm Group: Research Funding. Savage:Merck, BMS, Seattle Genetics, Gilead, AstraZeneca, AbbVie, Servier: Consultancy; Roche (institutional): Research Funding; Merck, BMS, Seattle Genetics, Gilead, AstraZeneca, AbbVie: Honoraria; BeiGene: Other: Steering Committee. Akilov:Mallinckrodt: Consultancy; Medivir: Consultancy; Seattle Genetics, Inc.: Consultancy; Kyowa Hakko Kirin: Consultancy; Soligenix: Honoraria; Pfizer: Research Funding; Actelion: Consultancy, Research Funding; Trillium Therapeutics Inc.: Consultancy, Research Funding. Diefenbach:Trillium: Research Funding; Millenium/Takeda: Research Funding; Seattle Genetics: Consultancy, Research Funding; Merck: Consultancy, Research Funding; MEI: Research Funding; LAM Therapeutics: Research Funding; Incyte: Research Funding; Genentech, Inc.: Consultancy, Research Funding; Denovo: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding. Kim:Kyowa-Kirin Pharma: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Medivir: Membership on an entity's Board of Directors or advisory committees; Horizon Pharma: Consultancy, Research Funding; Merck: Research Funding; miRagen: Research Funding; Trillium: Research Funding; Galderma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Eisai: Membership on an entity's Board of Directors or advisory committees, Research Funding; Corvus: Research Funding; Elorac: Research Funding; Forty Seven Inc: Research Funding; Neumedicine: Consultancy, Research Funding; Innate Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Solingenix: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Portola: Research Funding. Lin:Trillium Therapeutics Inc.: Current Employment. Catalano:Trillium Therapeutics Inc.: Current Employment. Petrova:Trillium Therapeutics Inc.: Current Employment. Uger:Trillium Therapeutics Inc.: Current Employment. Molloy:Trillium Therapeutics Inc.: Current Employment. Large:Trillium Therapeutics Inc.: Current Employment. Shou:Trillium Therapeutics Inc.: Current Employment. Ansell:Affimed: Research Funding; Bristol Myers Squibb: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; ADC Therapeutics: Research Funding; Seattle Genetics: Research Funding; Takeda: Research Funding; AI Therapeutics: Research Funding.

Hepatosplenic T-cell lymphoma (HSTCL) is a rare subtype of T-cell lymphoma associated with an aggressive clinical course and a worse prognosis. HSTCL develops in the setting of chronic immune suppression or immune dysregulation in up to 20% of cases and is most often characterized by spleen, liver, and bone marrow involvement. Diagnosis and management of HSTCL pose significant challenges given the rarity of the disease along with the absence of lymphadenopathy and poor outcome with conventional chemotherapy regimens. These Guidelines Insights focus on the diagnosis and treatment of HSTCL as outlined in the NCCN Guidelines for T-Cell Lymphomas.