Citations

Abstract Introduction: Intravascular lymphoma (IVL) is an extra nodal non-Hodgkin lymphoma with tropism for vascular endothelium. It is characterized by growth of large cells within the lumen of small to medium sized blood vessels. Central nervous system (CNS) and skin are predominantly involved. This report represents a retrospective single-institution review of IVL. Methods: We identified patients (pts) with IVL evaluated at Mayo Clinic Cancer Center between January 2003 and December 2018. Demographic, clinical, radiologic, pathologic, and therapeutic data were extracted. Statistical analysis of overall survival (OS) and progression free survival (PFS)] was performed using Kaplan-Meier method. Results: Total number of pts was 55; 22% (12/55) had CNS-only IVL, 14.5% (8/55) had CNS and non-CNS IVL, and 63.6% (35/55) had non-CNS IVL. Eighty seven percent (47/54) pts were B cell type, 11% (6/54) were T cell type, one pt had NK cell type IVL and another was unknown. Four pts were diagnosed by autopsy. Median age at diagnosis was 68 years (range, 40-85). Sixty-four percent were males. ECOG performance status was <2 in 66%. The median follow-up time from diagnosis was 63 months [CI 95%, 9-NR], and 47% (26/55) were alive. The most common diagnostic biopsy sites were bone marrow (BM) 45% (25/55), skin 25% (14/55), and brain 29% (16/55). Twenty-nine patients had a PET scan. Seventy nine percent (23/29) had abnormal PET findings, with mean SUV of 8.6 (range 2.5-19.1). Of the 35 pts with non-CNS IVL, 76% (16/21) had abnormal PET; furthermore, the diagnosis was made with biopsies of the following sites: bone marrow 54% (19/35), skin 40% (14/35), lung 14% (5/35), liver 5.7% (2/35), spleen 2.8% (1/35), and omentum 2.8% (1/35). Forty-six percent (13/28) received CNS prophylaxis and ten percent (3/55) had relapse in CNS. Two out of the three pts who had CNS relapse had received CNS prophylaxis. The median time to CNS relapse in non-CNS IVL was 9 months. The most common first-line regimen was high-dose methotrexate+ rituximab containing regimen 62% (10/16) in IVL with CNS involvement and RCHOP (60%) (17/28) in non-CNS IVL. Seventeen percent of (8/48) pts received autologous stem cell transplant (ASCT) and 63% (5/8) pts were transplanted in first complete remission (CR1), and 3 pts after the first relapse. Median OS (mOS) for the whole cohort was 57 months, [CI 95%, 9-NR], and median PFS was 7 months [CI 95%, 2-NR]. There was no significant difference in mOS between groups; CNS-only IVL- 9 months (CI 95%, 1-NR), non-CNS IVL -62 months (CI 95%, 20-NR) vs combined CNS and non-CNS IVL- 4 months (CI 95%, 3-NR). mOS for those who received ASCT in CR1 was not reached (CI 95%, 10-NR) vs 51 months in non-transplant group (CI 95%, 3-NR) p=0.24. In pts with non-CNS IVL, there was no significant difference in mOS between CNS prophylaxis subgroup (NR: CI 95%, 57-NR) vs no-CNS prophylaxis subgroup (20 months: CI 95%, 0-NR), p=0.12. In those with CNS IVL mOS for early diagnosis (0-30 days from symptom onset to diagnosis was NR (CI 95%, 3-NR) vs mOS for late diagnosis (>30 days {31-14,440})-5months (CI 95% 1-NR), p=0.29]. Conclusion: 1. BM was most frequently involved in our patients. We suggest that BM biopsy should be part of diagnostic testing when IVL is suspected. 2. Most cases are of B-cell linage, consistent with reported literature. All non-B cell cases were in non-CNS locations. 3. PET scans were abnormal in more than 70% of cases indicating that this imaging modality is vital in the diagnosis due to odd location and small size of lesions. 4.Overall prognosis in the literature was poor with most patients surviving <1 year. Our cohort has mOS of 57 months. The reason(s) for better survival in our cohort could not be definitively determined. 5. CNS involvement had an overall trend towards poor prognosis; however, those diagnosed early had better outcomes; this did not reach statistical significance due to small sample size. 6. mOS was not reached for those transplanted CR1. There was a trend towards a better survival associated with CNS prophylaxis versus no prophylaxis in non-CNS IVL. 7. We suggest that CNS-centric therapeutic approach and intensive consolidation with ASCT should be considered in managing IVL. Figure 1 Figure 1. Disclosures Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees. Habermann: Incyte: Other: Scientific Advisory Board; Seagen: Other: Data Monitoring Committee; Tess Therapeutics: Other: Data Monitoring Committee; Morphosys: Other: Scientific Advisory Board; Loxo Oncology: Other: Scientific Advisory Board; Eli Lilly & Co.,: Other: Scientific Advisor. Witzig: Karyopharm Therapeutics, Celgene/BMS, Incyte, Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS, Acerta Pharma, Kura Oncology, Acrotech Biopharma, Karyopharm Therapeutics: Research Funding. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Tun: Mundipharma, Celgene, BMS, Acrotech, TG therapeutics, Curis, DTRM: Research Funding; Gossamer Bio, Acrotech: Consultancy.

Abstract Background :COVID-19 adversely affects individuals with cancer. Several studies have found that seroconversion rates among patients with hematologic malignancies are suboptimal when compared to patients without cancer. Among patients with hematologic malignancies, seroconversion rates also appear to be influenced by recent treatment and the type of treatment they have received. Patients with non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) are immunocompromised due to impaired humoral and cellular immunity in addition to prescribed immunosuppressive therapy. Chimeric antigen receptor T-cell (CAR T) therapy is now widely used for NHL and MM, but little is known about seroconversion rates after COVID-19 vaccination among these populations. Current national guidelines recommend COVID-19 vaccination to be offered to CAR T recipients as early as three months thereafter. We retrospectively evaluated SARS-CoV-2 spike-binding IgG antibody levels following COVID-19 vaccination among NHL and MM CAR T therapy recipients. Methods:This retrospective study was conducted at three Mayo Clinic sites on NHL and MM patients that received CAR T infusions from Sept 2016 to June 2021. Baseline characteristics were ascertained from medical records. All NHL and MM patients who had received CAR T at any point and were alive at the time that the COVID-19 vaccine first became available were eligible for inclusion for antibody response evaluation. For antibody response to vaccination, antibody spike values > 0.80 U/mL were considered positive. Results: Out of 104 CAR T infusions, 73 patients are alive at the time of this submission. We have had 7 patients with known COVID-19 pre-CAR T and all 7 are currently alive (5 have antibody titers and 2 have not been tested yet). Nineteen patients developed known COVID infection post-CAR T (13 alive and 6 deceased). The mortality of COVID post-CAR T in our sample was 31.5%. Furthermore, of the 13 patients that survived COVID-19, they received CAR T an average of 416 days prior to COVID-19 infection (median = 337, range = 54 - 1406); the 6 patients who died from COVID-19 had received CAR T an average of 250 days prior to COVID-19 infection (median = 164, range = 7 - 846). All 6 deceased patients did not receive COVID-19 vaccination pre-CAR T. Out of 17 CAR T patients tested for antibody spike titers post COVID-19 vaccination, 76.4% were able to mount an antibody response. More patients with MM had a higher titer response to the vaccine (>250 U/mL) compared to the NHL counterparts (0.80-249 U/mL). All patients that received the vaccine, regardless of antibody response, were alive at the time of this submission. Conclusions:The majority of CAR T recipients with NHL and MM are able to mount an antibody response following COVID-19 vaccination in our relatively small sample. The frequency of seroconversion among CAR T recipients seems to be similar to patients with hematologic malignancy who had received a hematopoietic cell transplant reported elsewhere. These findings are limited by our small sample size and may be influenced by the timing of vaccination relative to CAR T. Furthermore, almost half of our patients received IVIG post CAR T which could potentially cause false positive antibody results as pooled immunoglobulin preparations may contain COVID-19 antibodies from vaccinated healthy donors. To better understand the characteristics of the immunologic response against SARS-CoV-2 in patients post-CAR T, larger multicenter studies exploring both humoral and cellular immunity will be needed. JEWN, MI and JM are co-first authors and PV, HM and AR are co-senior authors. Figure 1 Figure 1. Disclosures Munoz: Physicians' Education Resource: Honoraria; Seattle Genetics: Honoraria; Bayer: Research Funding; Gilead/Kite Pharma: Research Funding; Celgene: Research Funding; Merck: Research Funding; Portola: Research Funding; Incyte: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Research Funding; Janssen: Research Funding; Millennium: Research Funding; Gilead/Kite Pharma, Kyowa, Bayer, Pharmacyclics/Janssen, Seattle Genetics, Acrotech/Aurobindo, Beigene, Verastem, AstraZeneca, Celgene/BMS, Genentech/Roche.: Speakers Bureau; Pharmacyclics/Abbvie, Bayer, Gilead/Kite Pharma, Pfizer, Janssen, Juno/Celgene, BMS, Kyowa, Alexion, Beigene, Fosunkite, Innovent, Seattle Genetics, Debiopharm, Karyopharm, Genmab, ADC Therapeutics, Epizyme, Beigene, Servier: Consultancy; Targeted Oncology: Honoraria; OncView: Honoraria; Kyowa: Honoraria. Bergsagel: Oncopeptides: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Patents & Royalties: human CRBN mouse; Pfizer: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Genetech: Consultancy, Honoraria; GSK: Consultancy, Honoraria. Wang: Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; InnoCare: Research Funding; Novartis: Research Funding; MorphoSys: Research Funding; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Fonseca: Juno: Consultancy; Kite: Consultancy; Aduro: Consultancy; OncoTracker: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; AbbVie: Consultancy; Patent: Prognosticaton of myeloma via FISH: Patents & Royalties; Caris Life Sciences: Membership on an entity's Board of Directors or advisory committees; Scientific Advisory Board: Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Amgen: Consultancy; Sanofi: Consultancy; Merck: Consultancy; Mayo Clinic in Arizona: Current Employment; Celgene: Consultancy; Takeda: Consultancy; Bayer: Consultancy; Janssen: Consultancy; Novartis: Consultancy; Pharmacyclics: Consultancy. Palmer: Sierra Oncology: Consultancy, Research Funding; CTI BioPharma: Consultancy, Research Funding; Protagonist: Consultancy, Research Funding; Incyte: Research Funding; PharmaEssentia: Research Funding. Dingli: Novartis: Research Funding; GSK: Consultancy; Apellis: Consultancy; Alexion: Consultancy; Sanofi: Consultancy; Janssen: Consultancy. Kapoor: Sanofi: Research Funding; AbbVie: Research Funding; Takeda: Research Funding; Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; Amgen: Research Funding; Ichnos Sciences: Research Funding; Regeneron Pharmaceuticals: Research Funding; Glaxo SmithKline: Research Funding; Karyopharm: Research Funding. Kumar: Roche-Genentech: Consultancy, Research Funding; Oncopeptides: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Beigene: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; Merck: Research Funding; Carsgen: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, 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, Research Funding; Amgen: Consultancy, Research Funding; Bluebird Bio: Consultancy; Antengene: Consultancy, Honoraria; Sanofi: Research Funding. Paludo: Karyopharm: Research Funding. Bennani: Kymera: Other: Advisory Board; Vividion: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Purdue Pharma: Other: Advisory Board; Verastem: Other: Advisory Board. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Lin: Kite, a Gilead Company: Consultancy, Research Funding; Merck: Research Funding; Gamida Cell: Consultancy; Takeda: Research Funding; Juno: Consultancy; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Janssen: Consultancy, Research Funding; Sorrento: Consultancy; Legend: Consultancy; Vineti: Consultancy. Murthy: CRISPR Therapeutics: Research Funding.

Abstract Background: Haploidentical allogeneic hematopoietic cell transplantation (haplo) has expanded applicability of the procedure to patients for whom a suitable HLA compatible donor was not available in the past. A small multicenter retrospective study of 185 patients with hematologic malignancies who received a nonmyeloablative preparative regimen followed by infusion of bone marrow (BM) hematopoietic cells from haploidentical donors showed no significant association between the number of HLA mismatches (HLA-A, -B, -C, and -DRB1 combined) and risk of acute grade 2-4 graft-versus-host disease (GVHD) (hazard ratio [HR]=0.89; P=0.68 for 3-4 mismatches vs fewer antigen mismatches). This haploidentical transplant platform has certainly evolved. Nowadays, G-CSF mobilized peripheral blood stem cells (PBSC) are commonly used owing to its increased convenience vis-à-vis performing a BM harvest. Study population: Here, we evaluate post transplant outcomes when using haploidentical donors with T-replete PBSC and PTCy in AML in CR1. A total of 494 patients (4/8 HLA mismatch (group 1)=360, 2-3/8 HLA mismatch (group 2)=134) underwent the procedure at an EBMT participating center. The primary endpoints were cumulative incidences of grade 2-4 acute GVHD and chronic (all grades) GVHD. Secondary endpoints included cumulative incidence of relapse (RI), non-relapse mortality (NRM), leukemia-free (LFS) and overall survival (OS) and GVHD-free relapse-free survival (GRFS). Results: Group 1 and group 2 were not statistically different in regards to median age at allografting (54.1 vs. 56.1 years, p=0.51), median year of haplo transplantation (2018 vs. 2018, p=0.36), incidence of de novo AML (86.4% vs. 88.1%, p=0.63), Karnofsky equal or more than 90 (77.5% vs. 79.1%, p=0.70), and use of myeloablative conditioning (MAC) (44.7% vs. 48.5%, p=0.45). Patients in group 1 had a longer time from diagnosis to haplo-transplantation (5.3 vs. 4.9 months, p=0.03). In multivariate analysis, group 1 and group 2 did not differ in cumulative incidence of grade 2-4 acute GVHD (Hazard ratio (HR)=0.89 (95%CI=0.62-1.26), p=0.51) but group 1 had a significantly higher incidence of chronic (all grades) GVHD (HR=1.49 (95%CI=1.02-2.16), p=0.04). There was no difference in RI (HR=0.73 (95%CI=0.47-1.14), p=0.17), NRM (HR=1.25 (95%CI=0.78-2.02), p=0.36), LFS (HR=0.95 (95%CI=0.69-1.31), p=0.76), OS (HR=1.09 (95%CI=0.76-1.55), p=0.64) and GRFS (HR=1.07 (95%CI=0.81-1.42), p=0.64) between the groups. Presence of adverse cytogenetics was independently associated with higher RI (HR=1.90 (95%CI=1.20-2.99), p=0.006), inferior LFS (HR=1.59 (95%CI=1.15-2.19), p=0.005), inferior OS (HR=1.48 (95%CI=1.05-2.08), p=0.03), and worse GRFS (HR=1.54 (95%CI=1.17-2.04), p=0.002). Conclusion: Results show that patients undergoing haplo-transplantation with 4/8 (vs. 2-3/8) HLA mismatches have a higher incidence of chronic GVHD (all grades) without adversely affecting acute grade 2-4 GVHD, RI, LFS, OS and GRFS. Disclosures Labopin: Jazz Pharmaceuticals: Honoraria. Bazarbachi: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Hikma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees. Blaise: Jazz Pharmaceuticals: Honoraria. McDonald: BioCryst Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Forcade: Novartis: Other: travel grant. Ciceri: IRCCS Ospedale San Raffaele: Current Employment. Mohty: Takeda: Honoraria; Astellas: Honoraria; Adaptive Biotechnologies: Honoraria; Novartis: Honoraria; Celgene: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria; Sanofi: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Jazz: Honoraria, Research Funding; Pfizer: Honoraria; Amgen: Honoraria.

Abstract Introduction Post-transplantation cyclophosphamide (PTCy) and calcineurin inhibitor (CNI) based GVHD prophylaxis has shown lower rates of acute and chronic GVHD when compared with the traditional prophylaxis of calcineurin inhibitor (CNI) and methotrexate (MTX) in matched donor (related and unrelated) allo-HCT. The combination of PTCy with sirolimus as a calcineurin inhibitor-free GVHD prophylaxis has shown promising results with cumulative rates of grade II-IV acute and chronic GVHD in the range of 15-27% and 20-27% respectively in patients undergoing matched and haploidentical allo-HCT. We report a single center, nonrandomized comparison of patients undergoing matched donor allo-HCT receiving PTCy in combination with sirolimus (PTCy/Siro) with those receiving the standard GVHD prophylaxis of tacrolimus and MTX (Tac/MTX). Methods One hundred and sixteen consecutive patients who had undergone a MRD or MUD allo-HCT between January 2018 to January 2021 and received either PTCy with sirolimus or tacrolimus with methotrexate as GVHD prophylaxis regimens were eligible for inclusion. The selection of PTCy with sirolimus or tacrolimus with methotrexate as GVHD prophylaxis regimen was based on physician choice. Primary endpoints were cumulative incidence of acute (grade II to IV) and chronic GVHD. Secondary endpoints were a) neutrophil and platelet engraftment; b) overall survival (OS); c) non-relapse mortality (NRM); d) relapse; e) clinical infections and f) time to immunosuppression (IS) withdrawal. Kaplan-Meier method was used to estimate 1-year and 2-year freedom from long term adverse events, including chronic GVHD, relapse, NRM and OS. All tests were two-sided with alpha level set at 0.05 for statistical significance. Results Out of a total of 116 patients undergoing MRD and MUD allo-HCT, 29 received PTCy/Siro and 87 Tac/MTX. Baseline characteristics were similar between the two arms except patients in PTCy/Siro were younger with median of 48 (range: 24-69) years vs. 61 (range: 20-73) years (p=0.004) in Tac/MTX. There was difference in primary indication for allo-HCT between the two arms with non-hodgkin lymphoma (NHL) being the most common in PTCy/Siro and acute myeloid leukemia (AML) in the Tac/MTX group. Patients receiving PTCy/Siro had a significantly higher median CD3 day 100 chimerism at 100 (90-100) vs. 90 (40-100) % (<0.001) and a significantly shorter median time to IS withdrawal at 138 (37-312) vs 232(66-1120) days for patients receiving Tac/MTX. There was no difference between the two arms for length of hospital stay and time to neutrophil engraftment, but PTCy/Siro had a significantly longer median time for platelet engraftment at 17.5 (12-74) vs.14 (11-38) days (p= 0.001). No significant difference was observed between the two arms for incidence of grade II to IV acute GVHD, grade III to IV acute GVHD, steroid refractory acute GVHD or clinical infections (Table 1). After a median follow up of 1.1 (range: 0-1.8) years, patients receiving PTCy/Siro were significantly less likely to have chronic GVHD with 2-year freedom from GVHD of 75% (95%CI: 58-98%) vs 20% (95%CI 10-40%), p=0.005 (Figure 1). There was no difference between the two arms for OS, disease relapse or non-relapse mortality (Table 2). Conclusion In this study, the combination of PTCy/Siro is associated with a significantly lower risk of chronic GVHD when compared against the traditional GVHD prophylaxis of CNI and methotrexate, despite significantly earlier IS withdrawal. Other long-term outcomes of interest remained comparable between the two arms. Chronic GVHD contributes to significant morbidity and mortality in patients undergoing allo-HCT. Newer strategies to limit the impact of chronic GVHD are needed. The results of our study warrant validation in a large, multicenter, randomized prospective trial. Figure 1 Figure 1. Disclosures Murthy: CRISPR Therapeutics: Research Funding. Foran: gamida: Honoraria; takeda: Research Funding; novartis: Honoraria; trillium: Research Funding; boehringer ingelheim: Research Funding; OncLive: Honoraria; abbvie: Research Funding; certara: Honoraria; sanofi aventis: Honoraria; syros: Honoraria; taiho: Honoraria; revolution medicine: Honoraria; bms: Honoraria; servier: Honoraria; pfizer: Honoraria; actinium: Research Funding; aptose: Research Funding; kura: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding.

Abstract Background Patients (pts) with aggressive B-cell non-Hodgkin lymphoma (NHL) progressing after anti-CD19 chimeric antigen receptor T (CART) cell therapy have poor prognosis and may benefit from new therapy options through clinical trials. However, in a single center report, only 12% of such pts were treated in trials (Chow et al. Am J Hematol, 2019). Identifying the reasons for this low enrollment is needed to design future studies for this population. Here, we evaluated the eligibility criteria for recent landmark trials for relapsed/refractory aggressive B-cell NHL to learn what eligibility barriers are present. Methods Pts with aggressive B-cell NHL who received FDA-approved CART cell therapy at Mayo Clinic (Rochester, Arizona, Florida) since 2018 and progressed after CART cell therapy were identified. The potential eligibility for the following key trials was evaluated: a) polatuzumab + bendamustine + rituximab, b) tafasitamab + lenalidomide, c) selinexor and d) loncastuximab. The eligibility for each trial was retrospectively assessed at the time of disease progression after CART cell therapy based on hemoglobin (Hb), absolute neutrophils count (ANC), platelet count (Plt), renal and liver function tests, ECOG performance status (PS), and central nervous system (CNS) involvement. Results Seventy-five pts had disease progression to axicabtagene ciloleucel (N=73, 97%) or tisagenlecleucel (N=2, 3%) and are included in this analysis. Median time to progression after CART was 2.1 months (IQR: 1.0 - 3.1). Thirteen (17%) pts were treated in clinical trials after progression following CART cell therapy, while 46 (61%) were treated off trials, and 16 (22%) pts never received any treatment after progression. At a median follow-up of 13.6 months (IQR: 9.1 - 26.7) from CART progression, the median overall survival (mOS) from CART progression was 5.8 months (95% CI 3.5 - 10.1) and 53 (71%) pts died. Thirty-eight pts (51%) did not meet eligibility criteria for any of the 4 recent landmark trials. Hematologic impairment was the most common barrier to inclusion of these patients in clinical trials: Hb < 9 g/dL n=23 (31%) or Hb < 10 g/dL n=36 (48%), ANC < 1.0 x 10 9/L n=19 (25%) or ANC < 1.5 x 10 9/L n=32 (43%), and Plt < 75 x 10 9/L n=30 (40%) or Plt < 90 x 10 9/L n=34 (45%). Renal (n=11, 15%) or liver dysfunction (n=5, 7%), CNS involvement (n=8, 11%) and ECOG PS > 2 (n=3, 4%) were less common reasons leading to exclusion from trials. Post CART trial ineligible pts had significantly shorter time to progression (median 1.7 months, IQR: 1.0 - 2.6 vs. 3.0 months IQR: 1.9 - 3.4, p < 0.01) and inferior overall response to CART (45% vs 67%, p = 0.06) compared to pts who met trial eligibility post CART. Baseline Hb (median Hb 9.5 g/dL, IQR: 8.5 - 10.5 vs. 10.9 g/dL, IQR: 9.7 - 12.2, p < 0.01) and Plt (median Plt 106 x 10 9/L IQR: 54 - 165 vs. 201 x 10 9/L IQR: 141 - 243, p < 0.01) were also significantly lower in pts ineligible for trials post CART. There were no significant differences between pts eligible or ineligible for trials with regards to age (median 59 vs. 60 years), number of prior therapies (median 3 vs. 3), prior autologous stem cell transplant (41% vs. 37%), bridging therapy (65% vs. 63%), baseline ANC (median 4,1 vs. 3,0 x10 9/L), or high-grade (grade ≥ 2) cytokine release syndrome (19% vs. 21%) or neurotoxicity (32%, vs. 42%), respectively. Survival after CART progression was significantly shorter (mOS 2.5 months, 95% CI: 1.6 - 5.1) for the 38 pts ineligible for trials compared to pts eligible for trials (mOS 10.6 months, 95% CI: 8.9 - NA), (p < 0.01). In the 59 pts who received therapy post CART progression, the mOS of pts treated on (n = 13) or off (n = 46) trials was 13.8 months (95% CI: 9.2 - NA) vs. 6.6 months (4.9 - 10.7), respectively (p = 0.047). Conclusion Approximately half of the pts (51%) with aggressive B-cell NHL progressing after CART cell therapy would have be excluded from landmark clinical trials. The current hematologic exclusion criteria are a major barrier to enrollment in clinical trials, which would exclude many pts who have disease progression within 3 months of CART cell therapy (ie, primary refractory disease), in whom cytopenia as a toxicity from therapy is prevalent. Given the known delayed hematologic recovery after CART cell therapy and the unmet need of pts progressing to CART cell therapy, the hematologic exclusion criteria should be adjusted to increase trial participation of this population, especially of those with primary refractory disease. Figure 1 Figure 1. Disclosures Munoz: Gilead/Kite Pharma, Kyowa, Bayer, Pharmacyclics/Janssen, Seattle Genetics, Acrotech/Aurobindo, Beigene, Verastem, AstraZeneca, Celgene/BMS, Genentech/Roche.: Speakers Bureau; Janssen: Research Funding; Pharmacyclics/Abbvie, Bayer, Gilead/Kite Pharma, Pfizer, Janssen, Juno/Celgene, BMS, Kyowa, Alexion, Beigene, Fosunkite, Innovent, Seattle Genetics, Debiopharm, Karyopharm, Genmab, ADC Therapeutics, Epizyme, Beigene, Servier: Consultancy; Seattle Genetics: Research Funding; Millennium: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; Incyte: Research Funding; Portola: Research Funding; Merck: Research Funding; Celgene: Research Funding; Gilead/Kite Pharma: Research Funding; Bayer: Research Funding; Seattle Genetics: Honoraria; Physicians' Education Resource: Honoraria; Targeted Oncology: Honoraria; OncView: Honoraria; Kyowa: Honoraria. Murthy: CRISPR Therapeutics: Research Funding. Maurer: Morphosys: Membership on an entity's Board of Directors or advisory committees, Research Funding; Nanostring: Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Genentech: Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. 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. Paludo: Karyopharm: Research Funding. Wang: Genentech: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; MorphoSys: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; InnoCare: Research Funding. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Witzig: Karyopharm Therapeutics, Celgene/BMS, Incyte, Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS, Acerta Pharma, Kura Oncology, Acrotech Biopharma, Karyopharm Therapeutics: Research Funding. Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees. Lin: Vineti: Consultancy; Takeda: Research Funding; Sorrento: Consultancy; Novartis: Consultancy; Juno: Consultancy; Legend: Consultancy; Janssen: Consultancy, Research Funding; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Merck: Research Funding; Gamida Cell: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding.

Abstract Waldenström macroglobulinemia (WM) is a rare B‐cell lymphoproliferative malignancy. Autologous hematopoietic cell transplantation (auto‐HCT) is considered in a subset of WM patients with relapsed disease. While registry data has shown a benefit for auto‐HCT in relapsed WM, there is a paucity of data on outcomes of patients relapsing after auto‐HCT. Eligibility criteria included adult patients with relapsed/refractory WM who underwent auto‐HCT between 2007 and 2017. The primary endpoint was post‐relapse overall survival (PR‐OS). Secondary endpoints were to identify factors prognostic of PR‐OS. Of the 48 patients with WM who underwent auto‐HCT, 22 (46%) experienced relapse following auto‐HCT. Median PR‐OS of relapsed WM patients after auto‐HCT ( n = 22) was not reached (NR) (95% confidence interval [CI]: 17.5 months‐NR). Among patients who relapsed <1 year versus ≥1 year from auto‐HCT, the median PR‐OS was 18.4 months (95%CI: 0.8‐NR) months and NR (95%CI: 17.5‐NR), respectively ( p = 0.06). Of note, disease status at the time of transplant, CR/VGPR versus partial remission did not appear to impact PR‐OS. The median PR‐OS was significantly longer in patients who received ibrutinib in the post‐transplant setting compared to those who did not (NR vs. 18.4 months, 95%CI: 9.1‐NR, p = 0.02). On univariable analysis, the presence of complex karyotype (RR = 4.87, 95% CI = 1.22–19.53) and a higher number of prior lines of therapy (RR = 1.81, 95% CI = 1.23–2.67) were associated with a significantly higher risk of relapse. This is the only study to date that evaluated outcomes of WM patients who relapsed following auto‐HCT and provides a benchmark for future trials evaluating survival following auto‐HCT relapse.

SummaryWe report a comparative analysis of patients with therapy‐related acute lymphoblastic leukaemia (tr‐ALL) vs de novo ALL. We identified 331 patients with B‐ALL; 69 (21%) were classified as tr‐ALL. The most common prior malignancies were breast (23·2%) and plasma cell disorders (20·3%). Patients with tr‐ALL were older (median 63·2 vs. 46·2 years, P < 0.001), more often female (66·7% vs. 43·5%, P < 0·001), and more likely to have hypodiploid cytogenetics (18·8% vs. 5·0%, P < 0·001). In multivariable analysis, patients with tr‐ALL were less likely to achieve complete remission [odds ratio (OR) = 0·16, P < 0·001] and more likely to be minimal residual disease‐positive (OR = 4·86, P = 0·01) but had similar OS after diagnosis and allo‐haematopoietic cell transplantation.

Abstract Standard initial therapy of chronic graft vs. host disease (cGVHD) with glucocorticoids results in suboptimal response. Safety and feasibility of therapy with ofatumumab (1000 mg IV on days 0 and 14) and prednisone (1 mg/kg/day) was previously established in our phase I trial (n = 12). We now report the mature results of the phase II expansion of the trial (n = 38). The overall NIH severity of cGVHD was moderate (63%) or severe (37%) with 74% of all patients affected by the overlap subtype of cGVHD and 82% by prior acute cGVHD. The observed 6 month clinician-reported and 2014 NIH-defined overall response rates (ORR = complete + partial response [CR/PR]) of 62.5% (1-sided lower 90% confidence interval=51.5%) were not superior to pre-specified historic benchmark of 60%. Post-hoc comparison of 6 month NIH response suggested benefit compared to more contemporaneous NIH-based benchmark of 48.6% with frontline sirolimus/prednisone (CTN 0801 trial). Baseline cGVHD features (organ involvement, severity, initial immune suppression agents) were not significantly associated with 6-month ORR. The median time to initiation of second-line therapy was 5.4 months (range 0.9-15.1 months). Failure-free survival (FFS) was 64.2% (95% CI 46.5-77.4%) at 6 months and 53.1% (95% CI 35.8-67.7%) at 12 months, whereas FFS with CR/PR at 12 months of 33.5% exceeded a benchmark of 15% in post-hoc analysis, and was associated with greater success in steroid discontinuation by 24 months (odds ratio 8 (95% CI 1.21-52.7). This single-arm phase II trial demonstrated acceptable safety and potential efficacy of the upfront use of ofatumumab in combination with prednisone in cGVHD. This trial was registered at www.clinicaltrials.gov as #NCT01680965.

SummaryIn young and fit patients with mantle cell lymphoma (MCL), intensive induction therapy followed by a consolidative autologous haematopoietic cell transplant (autoHCT) is the standard of care in the front‐line setting. Recently, time‐to‐event analysis has emerged as an important risk assessment tool in lymphoma, though its impact in MCL is not well defined. We utilized the Center for International Blood and Marrow Transplant Research database to evaluate the effect of post‐autoHCT time to relapse on overall survival (OS) over time in 461 patients who underwent autoHCT within 12 months of MCL diagnosis. On multivariate analysis, the impact of relapse on OS was greatest at the six‐month [hazard ratio (HR) = 7·68], 12‐month (HR = 6·68), and 18‐month (HR = 5·81) landmark timepoints. Using a dynamic landmark model we demonstrate that adjusted OS at five years following each landmark timepoint improved with time for relapsing and non‐relapsing patients. Furthermore, early relapse (<18 months) following autoHCT defines a high‐risk group with inferior post‐relapse OS. This retrospective analysis highlights the impact of time to relapse on OS in MCL patients undergoing up‐front autoHCT and emphasizes the need to consider novel therapeutic approaches for patients suffering early relapse.

Abstract The relative efficacy of autologous hematopoietic cell transplant (auto-HCT) vs chimeric antigen receptor T-cell (CAR-T) therapy in patients with diffuse large B-cell lymphoma (DLBCL) who achieve a partial remission (PR) after salvage chemotherapy is not known. Using the Center for International Blood & Marrow Transplant Research registry database, we identified adult patients with DLBCL who received either an auto-HCT (2013-2019) or CAR-T treatment with axicabtagene ciloleucel (2018-2019) while in a PR by computed tomography or positron emission tomography scan. We compared the clinical outcomes between the 2 cohorts using univariable and multivariable regression models after adjustment for relevant baseline and clinical factors. In the univariable analysis, the 2-year progression-free survival (52% vs 42%; P = .1) and the rate of 100-day nonrelapse mortality (4% vs 2%; P = .3) were not different between the 2 cohorts, but consolidation with auto-HCT was associated with a lower rate of relapse/progression (40% vs 53%; P = .05) and a superior overall survival (OS) (69% vs 47%; P = .004) at 2 years. In the multivariable regression analysis, treatment with auto-HCT was associated with a significantly lower risk of relapse/progression rate (hazard ratio = 1.49; P = .01) and a superior OS (hazard ratio = 1.63; P = .008). In patients with DLBCL in a PR after salvage therapy, treatment with auto-HCT was associated with a lower incidence of relapse and a superior OS compared with CAR-T. These data support the role of auto-HCT as the standard of care in transplant-eligible patients with relapsed DLBCL in PR after salvage therapy.