Kharfan‐Dabaja, Mohamed A.

Immunoproliferative small intestinal disease (IPSID) is an uncommon disease with a higher prevalence in the developing world. IPSID diagnosis relies mainly on a tissue biopsy and a high index of suspicion. Treatment options are variable; however, they mainly include anthracycline-based chemotherapy with or without antibiotics in advanced stages. Because of the paucity of IPSID, our perception of the disease remains narrow, and investigating the optimal lines of therapy and prevention without a complete comprehension of the disease is challenging. In our review, we explore the expansion of knowledge about IPSID, which has been developing over the years, to help increase the detection of IPISD cases and further research the most appropriate lines of therapy and prevention.

AbstractPatients with relapsed follicular lymphoma who do not respond to CAR‐T have a poor outcome. We present a case of refractory follicular lymphoma who relapsed after two CAR‐T infusions and achieved a complete remission after treatment with obinutuzumab and lenalidomide. This represents a promising treatment option in the post‐CAR‐T setting.

SummaryThere have been no large studies comparing reduced‐intensity/non‐myeloablative conditioning (RIC/NMA) to myeloablative conditioning (MAC) regimens in T‐cell non‐Hodgkin lymphoma (T‐NHL) patients undergoing allogeneic transplant (allo‐HCT). A total of 803 adults with peripheral T‐cell lymphoma, anaplastic large cell lymphoma and angioimmunoblastic T‐cell lymphoma (age 18–65 years), undergoing allo‐HCT between 2008–2019 and reported to the Center for International Blood and Marrow Transplant Research with either MAC (n = 258) or RIC/NMA regimens (n = 545) were evaluated. There were no significant differences between the two cohorts in terms of patient sex, race and performance scores. Significantly more patients in the RIC/NMA cohort had peripheral blood grafts, haematopoietic cell transplantation‐specific comorbidity index (HCT‐CI) of ≥3 and chemosensitive disease compared to the MAC cohort. On multivariate analysis, overall survival (OS) was not significantly different in the RIC/NMA cohort compared to the MAC cohort (hazard ratio (HR) = 1.01, 95% confidence interval (CI) = 0.79–1.29; p = 0.95). Similarly, non‐relapse mortality (NRM) (HR = 0.85, 95% CI = 0.61–1.19; p = 0.34), risk of progression/relapse (HR = 1.29; 95% CI = 0.98–1.70; p = 0.07) and therapy failure (HR = 1.14; 95% CI = 0.92–1.41, p = 0.23) were not significantly different between the two cohorts. Relative to MAC, RIC/NMA was associated with a significantly lower risk of grade 3–4 acute graft‐versus‐host disease (HR = 0.67; 95% CI = 0.46–0.99, p = 0.04). Among chemorefractory patients, there was no difference in OS, therapy failure, relapse, or NRM between RIC/NMA and MAC regimens. In conclusion, we found no association between conditioning intensity and outcomes after allo‐HCT for T‐cell NHL.

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

Abstract Background: Standard of care (SOC) for second-line (2L) therapy (tx) of relapsed/refractory aggressive B-cell non-Hodgkin lymphomas (R/R aNHL) includes platinum-based chemotherapy (PCT) followed by autologous hematopoietic cell transplantation (aHCT) in responders. Outcomes are poor for patients (pts) with R/R aNHL who experience progression during or within 12 months (mo) of 1L tx. Tisagenlecleucel (tisa-cel) is an autologous chimeric antigen receptor (CAR) T-cell tx targeting CD19 approved for pts with large B-cell lymphoma (LBCL; US) and diffuse LBCL (non-US) after ≥2 lines of tx. BELINDA (NCT03570892) is a Phase III, randomized, global (18 countries) study of tisa-cel vs SOC as 2L tx for R/R aNHL. Methods: Adults with confirmed R/R aNHL within 12 mo after 1L chemo-immunotherapy were eligible. All pts underwent leukapheresis for tisa-cel production and were randomized 1:1 to receive tisa-cel (Arm A) or SOC (Arm B) and stratified by 1L duration of response, International Prognostic Index (IPI), and geographic region. Arm A received optional bridging tx (investigator choice of protocol-defined PCT regimens) followed by lymphodepletion (LD; generally, fludarabine 25 mg/m 2/day [d] + cyclophosphamide 250 mg/m 2/d for 3 d) and followed by a single tisa-cel infusion (0.6-6×10 8 CAR-T cells). Arm B received investigator choice of PCT regimen followed by aHCT in responders or a second PCT in nonresponders. Disease assessments were performed at 6 and 12 weeks (wk), then planned every 3 mo for year (y) 1 and every 6 mo for y 2. The primary endpoint was event-free survival (EFS), defined as time from randomization to stable disease (SD) or progressive disease (PD) at or after wk 12 assessment or death at any time. SD/PD at wk 6 was not considered an event on either Arm. Arm A's wk 6 assessment evaluated disease burden before tisa-cel infusion and after bridging if administered. Arm B's wk 6 assessment determined if response was sufficient for aHCT or if a second PCT regimen was needed prior to aHCT. Results: As of May 6, 2021, 322 pts were randomized: 162 to Arm A and 160 to Arm B. In Arms A and B, 33% and 29% were ≥65 y, and 66% and 67% had primary refractory disease, respectively. Baseline characteristics indicated imbalances with more high-grade B-cell lymphomas (24% vs 17%) and IPI ≥2 (65% vs 58%) in Arm A vs B. In Arm A, 47% received ≥2 cycles of bridging PCT, 36% received 1 cycle, and 17% received 0. In Arm A, 96% received tisa-cel; the median dose was 2.9×10 8 cells. In Arm B, 96% received ≥2 PCT cycles and 54% received ≥2 different PCT regimens; 33% received aHCT, including 10% requiring ≥2 different PCT regimens before aHCT. Median time from randomization to aHCT was 92 d (range, 61-158 d). Median follow-up was 10 mo (range, 2.9-23.2 mo). At wk 6 assessment, 26% had PD in Arm A vs 14% in Arm B. Median EFS in Arms A and B was 3 mo (HR 1.07; 95% CI, 0.82-1.40; P=0.69); Arm A pts with PD at wk 6 had shorter EFS. Overall response rate (ORR) at wk 12 in Arm A was 46% vs 43% in Arm B; complete response rate in both arms was 28%. Some pts responded to tisa-cel after SD/PD at wk 12 without additional tx but were counted as an event in EFS analysis. In Arm B, 81 pts (51%) crossed over to receive tisa-cel, 71 without receiving aHCT. Of 72 crossover pts with response assessment, ORR to tisa-cel was 40%. Overall survival was immature at data cutoff. In Arm A, 84% had a grade ≥3 adverse event (AE; vs 90% in Arm B), including grade ≥3 cytokine release syndrome in 5% (CRS; Lee 2014) and grade ≥3 neurologic events (NE) in 3% (CTCAE v5.0), with no grade 5 CRS/NE. Median times to CRS and NE onset were 4 and 5 d, respectively; median time to resolution was 5 and 9 d. Fifty-two (32%) and 45 (28%) pts in Arms A and B died on study, including 42 (26%) and 32 (20%) deaths due to PD, respectively. Ten pts in Arm A and 13 in Arm B died of AEs. Conclusions: Tisa-cel as 2L tx in R/R aNHL pts did not have a higher EFS vs SOC. Possible contributing factors include study design elements, such as optional PCT bridging tx in Arm A with potential delay of tisa-cel infusion until after wk 6 assessment, allowance of a different PCT regimen to reach aHCT in Arm B after inadequate response to first PCT, and imbalances in relevant pt characteristics. Insights from this randomized Phase III study will inform use of cellular tx in the 2L R/R aNHL setting and the design of future CAR-T trials. Figure 1 Figure 1. Disclosures Bishop: Arcellx, Autolus, Bristol-Myers Squibb, CRISPR, Kite/Gilead, and Novartis: Consultancy, Research Funding; Bristol-Myers Squibb and Kite/Gilead: Other: fees for non-CME/CE services . Dickinson: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Roche: Consultancy, Honoraria, Other: travel, accommodation, expenses, Research Funding, Speakers Bureau; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Takeda: Research Funding; Celgene: Research Funding; Amgen: Honoraria. Purtill: Novartis: Honoraria; Gilead: Honoraria; BMS Celgene: Honoraria. Barba: Amgen, Celgene, Gilead, Incyte, Jazz Pharmaceuticals, MSD, Novartis, Pfizer and Roche, Jazz Phar,aceuticals: Honoraria; Cqrlos III heqlth Institute, aSOCIACION espanola contra el cancer, PERIS: Research Funding. Santoro: Arqule: Consultancy, Speakers Bureau; Sanofi: Consultancy; Takeda: Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Speakers Bureau; AbbVie: Speakers Bureau; Amgen: Speakers Bureau; Celgene: Speakers Bureau; Servier: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AstraZeneca: Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Eli-Lilly: Speakers Bureau; Sandoz: Speakers Bureau; Eisai: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hamad: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Kato: Abbvie: Consultancy, Research Funding; AstraZeneca: Consultancy; Bristol-Myers Squibb: Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Chugai: Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Dainippon-Sumitomo: Honoraria; Eisai: Consultancy, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Kyowa Kirin: Honoraria, Research Funding; MSD: Honoraria; Mundi: Honoraria; Novartis: Consultancy, Research Funding; Ono: Honoraria, Research Funding. Sureda: Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite, a Gilead Company: 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; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; Bluebird: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Consultancy. Greil: Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; Merck Sharp & Dohme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Other: Travel, Accommodations, Expenses, Research Funding; Sandoz: Honoraria, Research Funding. Thieblemont: Gilead Sciences: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Bristol Myers Squibb/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses , Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Cellectis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Hospira: Research Funding; Bayer: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses . Morschhauser: F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Chugai: Honoraria; Janssen: Honoraria; Genmab: Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZenenca: Membership on an entity's Board of Directors or advisory committees; Servier: Consultancy; Incyte: Membership on an entity's Board of Directors or advisory committees. Janz: Janssen: Honoraria, Other: Meeting Fees; Novartis: Honoraria; Takeda: Honoraria, Other: Travel Accommodations, Expenses, Meeting fees; Roche: Honoraria; Gilead: Other: Travel Accommodations, Expenses, Meeting fees. Flinn: 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 equity holder in publicly-traded company; Seattle Genetics: Research Funding; Sarah Cannon Research Institute: Current Employment; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Triphase Research & Development Corp.: 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; Teva: 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; Portola Pharmaceuticals: Other: All 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; Novartis: Consultancy, Other: All consultancy and 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; Loxo: 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; Infinity Pharmaceuticals: 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; IGM Biosciences: 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; Forma Therapeutics: 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; Constellation Pharmaceuticals: 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; Calithera Biosciences: 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; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Verastem: 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; TG Therapeutics: 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; Seagen: 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; Pharmacyclics LLC, an AbbVie Company: 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; MorphoSys: 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; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Gilead Sciences: 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; BeiGene: 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; AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding. Kwong: Novartis: Consultancy, Honoraria, Research Funding. Kersten: Novartis: Consultancy, Honoraria, Other: Travel support; Takeda: Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support, Research Funding; Celgene: Research Funding; Roche: Consultancy, Honoraria, Other: Travel support, Research Funding; Miltenyi Biotec: Consultancy, Honoraria, Other: Travel support; BMS/Celgene: Consultancy, Honoraria. Minnema: Janssen: Consultancy, Honoraria; Celgene: Other: Travel expenses; BMS: Consultancy; Kite/Gilead: Consultancy; Alnylam: Consultancy. Holte: Roche: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Nanovector: Membership on an entity's Board of Directors or advisory committees, Other: lectures honorarias; Novartis: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Nordic: Membership on an entity's Board of Directors or advisory committees. Martinez-Lopez: Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees. Maziarz: Novartis: Consultancy, Other: Data and Safety Monitoring board, Research Funding; Incyte Corporation: Consultancy, Honoraria; Bristol-Myers, Squibb/Celgene,, Intellia, Kite: Honoraria; Allovir: Consultancy, Research Funding; Artiva Therapeutics: Consultancy; CRISPR Therapeutics: Consultancy; Intellia: Honoraria; Omeros: Research Funding; Athersys: Other: Data and Safety Monitoring Board, Patents & Royalties; Vor Pharma: Other: Data and Safety Monitoring Board. McGuirk: Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Allovir: Consultancy, Honoraria, Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; EcoR1 Capital: Consultancy; Novartis: Research Funding; Fresenius Biotech: Research Funding; Astelllas Pharma: Research Funding; Bellicum Pharmaceuticals: Research Funding; Novartis: Research Funding; Gamida Cell: Research Funding; Pluristem Therapeutics: Research Funding. Bachy: Kite, a Gilead Company: Honoraria; Novartis: Honoraria; Daiishi: Research Funding; Roche: Consultancy; Takeda: Consultancy; Incyte: Consultancy. Dreyling: Amgen: Speakers Bureau; Astra Zeneca: Consultancy, Speakers Bureau; Bayer: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau; Gilead Kite: Consultancy, Research Funding, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Roche: Consultancy, Research Funding, Speakers Bureau; AbbVie: Research Funding; BeiGene: Consultancy, Speakers Bureau; Genmab: Consultancy; MorphoSys: Consultancy. Harigae: Bristol Myers Squibb: Honoraria; Novartis Pharma: Honoraria, Research Funding; Chugai Pharma: Honoraria; Janssen Pharma: Honoraria; Ono pharma: Honoraria, Other: Subsidies or Donations; Astellas Pharma: Other: Subsidies or Donations; Kyowakirin: Other: Subsidies or Donations. Bond: Kite/Gilead: Honoraria. Andreadis: Merck: Research Funding; BMS: Research Funding; CRISPR Therapeutics: Research Funding; GenMAB: Research Funding; Novartis: Research Funding; Roche: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Epizyme: Honoraria; Incyte: Honoraria; TG Therapeutics: Honoraria; Kite: Honoraria; Karyopharm: Honoraria; Atara: Consultancy, Honoraria. McSweeney: Kite-Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gamida: Consultancy, Honoraria; TG Theraputics: Consultancy, Honoraria; Autolous Limited: Research Funding; Novartis: Research Funding; NKARTA: Research Funding; Allovir: Research Funding. Newsome: Novartis: Current Employment. Degtyarev: Novartis: Current Employment, Current equity holder in publicly-traded company. Del Corral: Novartis: Current Employment. Andreola: Novartis: Current Employment, Current holder of stock options in a privately-held company. Masood: Novartis: Current Employment, Current holder of stock options in a privately-held company. Schuster: AbbVie, Acerta, Celgene/Juno, DTRM Bio, Genentech, Incyte, Merck, Novartis, Portola, and TG Therapeutics: Research Funding; Acerta, AlloGene, AstraZeneca, BeiGene, Celgene/Juno, Genentech/Roche, LoxoOncology, Novartis, and Tessa Therapeutics: Consultancy; Acerta, AlloGene, AstraZeneca, BeiGene, Celgene, Genentech/Roche, LoxoOncology, Novartis, Nordic Nanovector, Pfizer, and Tessa Therapeutics;: Honoraria; Novartis: Other: Personal fees, Patents & Royalties; AbbVie, Celgene, Novartis, Juno, Nordic Nanovector, and Pfizer: Other: Steering Committee Participation. Jaeger: BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Norvartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Westin: Kite, a Gilead Company: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; MorphoSys: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; ADC Therapeutics: Consultancy, Research Funding; Umoja: Consultancy; Iksuda Therapeutics: Consultancy; Curis: Research Funding; Morphosys: Research Funding; 47 Inc: Research Funding.

Abstract Background: trALL is an important secondary primary malignancy (SPM) that has recently been appreciated. While patients (pts) with MM have an 8%-17% risk of developing an SPM while on lenalidomide (R) maintenance following autologous stem cell transplant (ASCT), trALL has been rarely observed. Little is known about the characteristics of trALL in pts with MM compared to pts who had other malignancies prior to the development of trALL. We define tALL as any prior exposure to cytotoxic chemotherapy and/or radiation for another malignancy, and herein, we report a comparative analysis of characteristics and outcomes of pts with trALL with and without MM from the Mayo Clinic Cancer Center (MCCC). Methods: We performed a systematic search in the 3-site MCCC registry and included all pts diagnosed and received at least 1 cycle of ALL-directed therapy and/or underwent allogeneic transplantation (AlloHCT) for ALL between 2007-2020. All cases of trALL in this series are B-ALL. Comparisons of characteristics between trALL patients with and without MM were made using a Wilcoxon rank sum test (continuous variables) or Fisher's exact test (categorical variables). Time-to-event variables were compared using unadjusted Cox proportional hazards regression models. Results: 70 trALL pts (14 MM [20%], 56 non-MM [80%]) were identified during the study period. The median age at trALL diagnosis was 63.9 (range 47-71) for MM pts and 63.1 (range 18.2-84) for non-MM pts. Median follow-up from trALL diagnosis was 1.42 years (range 0.02-10.6 years). The most common prior non-MM malignancies among tALL pts were breast (28.6%), lymphoma (17.9%), myeloid (17.9%), and GU/GYN (14.3%). Amongst the 14 MM pts, 100% (n=10) had ISS-I disease, 8 (57%) had IgG K MM, 1 (n=10) had high risk cytogenetics, 8 (57.1%) received R-based induction , 4 (28.6%) received CyBorD induction, 4(28.6%) received VRD induction, 3 (21.4%) received RD induction. 10 (71.4%) pts were actively on R when they developed trALL, 8 (57.1%) pts received prior ASCT. The median time to develop trALL following ASCT for MM was 46.3 months (m), (95% CI 20.4-67.6), 12 (85.7%) pts received R maintenance with a median duration of 53m (95% CI 16.9-121). The median time to develop trALL after initiation of R maintenance was 61.2m (95% CI 16.9-123.4). The most common trALL induction regimen received was HyperCVAD which was used in 71.4% of MM pts and 51.8% of non-MM pts. In comparison to non-MM pts, MM patients had a significantly lower WBC at diagnosis (Median: 2.0 vs. 5.8, P=0.005),no t(9;22) BCR/ABL1 cytogenetics (0.0% vs. 35.7%, P=0.008), a higher frequency of hypodiploid/near-triploid (Ho-Tri) cytogenetics (42.9% vs. 12.5%, P=0.009), and a lower frequency of prior radiation therapy (7.1% vs. 44.6%, P=0.012). MM pts had a higher frequency of AlloHCT for trALL (71.4% vs. 42.9%, P=0.075) and were more commonly in complete response (CR) at transplant (100.0% vs. 70.8%, P=0.078). No trALL in MM pts were Ph-like ALL. There was a statistically significant difference in time to development of trALL between previous malignancy locations (P=0.018), with GU/GYN (Median: 9 years) having the longest time and myeloid (Median: 3 years) having the shortest time; MM was 6 years. In the overall pt cohort, 56 (80%) pts achieved a complete response after induction and 60% (n=25) were minimal residual disease (MRD)+ after induction. Pts with MM had a significantly lower likelihood of being MRD+ after induction (OR=0.09, P=0.015). Overall, 24.3% of pts relapsed after induction therapy for trALL; 39 (55.5%) died after trALL diagnosis including 43% (n=35) who died after AlloHCT. Although pts with MM tended to have better outcomes compared to non-MM trALL pts in terms of overall survival after trALL diagnosis (Figure 1A), survival after AlloHCT (Figure 1B), relapse rate after trALL diagnosis and non-relapse mortality after AlloHCT, none of these findings were statistically significant in this small cohort (Figure 1C). Conclusion: trALL is a unique SPM that can occur in pts with MM. It is associated with Ho-Tri cytogenetics and is BCR/ABL1 negative. The majority of MM pts that developed trALL had undergone prior ASCT and were on R maintenance when they developed trALL. Despite being more likely to have adverse cytogenetics features, MM-associated trALL has similar survival compared to non-MM-associated trALL which speaks to the poor survival outcomes of this SPM. Further research on trALL in MM pts is merited. Figure 1 Figure 1. Disclosures Litzow: Amgen: Research Funding; Pluristem: Research Funding; AbbVie: Research Funding; Actinium: Research Funding; Astellas: Research Funding; Omeros: Other: Advisory Board; Jazz: Other: Advisory Board; Biosight: Other: Data monitoring committee. Bergsagel: Janssen: Consultancy. Fonseca: Scientific Advisory Board: Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Caris Life Sciences: Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy; Patent: Prognosticaton of myeloma via FISH: Patents & Royalties; Bayer: Consultancy; Takeda: Consultancy; Celgene: Consultancy; Amgen: Consultancy; BMS: Consultancy; Mayo Clinic in Arizona: Current Employment; Juno: Consultancy; Kite: Consultancy; Aduro: Consultancy; OncoTracker: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; Novartis: Consultancy; Merck: Consultancy; Sanofi: Consultancy; Pharmacyclics: Consultancy; Janssen: Consultancy. Dispenzieri: Takeda: Research Funding; Alnylam: Research Funding; Pfizer: Research Funding; Oncopeptides: Consultancy; Sorrento Therapeutics: Consultancy; Janssen: Consultancy, Research Funding. Murthy: CRISPR Therapeutics: Research Funding. Ailawadhi: GSK: Consultancy, Research Funding; Sanofi: Consultancy; Pharmacyclics: Consultancy, Research Funding; Takeda: Consultancy; Medimmune: Research Funding; Xencor: Research Funding; Genentech: Consultancy; Janssen: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Cellectar: Research Funding; Beigene: Consultancy; BMS: Consultancy, Research Funding; AbbVie: Consultancy; Karyopharm: Consultancy; Ascentage: Research Funding. Foran: actinium: Research Funding; taiho: Honoraria; bms: Honoraria; servier: Honoraria; pfizer: Honoraria; novartis: Honoraria; OncLive: Honoraria; abbvie: Research Funding; boehringer ingelheim: Research Funding; takeda: Research Funding; trillium: Research Funding; aptose: Research Funding; revolution medicine: Honoraria; syros: Honoraria; sanofi aventis: Honoraria; certara: Honoraria; gamida: Honoraria; kura: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding.