Longitudinal Changes in the Intestinal Microbiome Composition Following Gut Decontamination in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Patients: A Pilot Study

Introduction: Early preclinical studies demonstrating that eradication of intestinal bacteria could prevent the development of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT) led many adult and pediatric HSCT programs to practice "gut decontamination" (GD) with non-absorbable oral antibiotics for aGVHD prophylaxis. However, there is insufficient data supporting a clear benefit for GD in HSCT patients. Recent adult HSCT studies show that GVHD-related mortality is associated with decreased bacterial diversity in the gut microbiome, suggesting that certain bacterial species are protective against aGVHD. GD may decrease microbiome diversity and lead to worse post-HSCT outcomes. Methods: We conducted a randomized phase 2 study to examine the impact of GD on intestinal microbiome composition in pediatric allogeneic HSCT patients. 20 patients were enrolled and randomized to receive (GD) or not receive (no GD) oral vancomycin-polymyxin per our institutional standard from day -5 through engraftment. Stool samples were collected pre-transplant, weekly until neutrophil engraftment, monthly through day +100, then at 6 months and 1-year post-HSCT. Our primary endpoint is bacterial diversity, quantified by Shannon diversity index, at 2 weeks post-HSCT. Change in diversity is defined as the delta of diversity before transplantation compared to the minimum diversity seen in a single patient in a one-week window (around 14 days post-transplantation). This change in diversity was then averaged (mean) across each treatment arm. The stool microbiome was characterized using shotgun metagenomic sequencing (Nextera Tagmentation and Illumina HiSeq4000 Sequencing) for 10 patients to date, with median count of 1.4x107 reads per sample (range 1.3x106 to 3.3x107). Following quality control (FastQC, Trim Galore, Super Deduper), reads are assigned taxonomic designations using Kraken2 and GenBank (Oct. 2018) database. Secondary endpoints include the frequency of diarrhea (defined as >3 bowel movements per day in the first 7 days post-HSCT), incidence of aGVHD and bacteremia during the first 100 days post-transplant, immune reconstitution, survival, and malignant disease relapse at 2 years after study entry. Comparisons by treatment group were performed with Fisher's exact test (binary) or Wilcoxon rank-sum test (continuous). Results: Baseline patient characteristics were similar between the two arms (Table 1). At present,5 patients (25%) have completed 2 years of follow up, 4 of 15 patients with malignant disease (27%) have had relapse (3 GD, 1 No GD), and 2 patients (10%) in the No GD arm have died (1 malignant relapse, 1 refractory chronic GVHD). Microbiome analysis in the first 10 patients (4 GD, 6 No GD) demonstrates that the average change in Shannon diversity score at 2 weeks is 1.7 (SD 0.86) in GD and 0.65 (SD 0.61) in No GD (Table 2). Diarrhea occurred in 4/10 patients in GD vs 4/10 patients in no GD (p≥0.99).1/10 patients in GD and 3/10 in No GD developed aGVHD grade II or above(p=0.58). Bacteremia within the first 100 days post-HSCT occurred in 1/10 patient in GD, whereas 5/10 patients in No GD had 8 different bacteremia events (p=0.14) (Table 3). Conclusions: This is the first randomized study of gut decontamination in pediatric patients undergoing HSCT with long-term prospective post-transplant stool sample collection and immune monitoring. Though the small sample size is currently not powered to detect differences in clinical outcomes between the 2 study arms, the descriptive microbiome and immune reconstitution data will inform larger studies. There is no statistical difference in the diarrhea, aGVHD, or bacteremia incidence between the two groups but it is interesting that there was 1 vs 8 bacteremia events in GD vs No GD. Microbiota diversity results from our pilot study with 10 patients indicate a trend toward lower diversity at 2 weeks post-transplant in the GD arm. Microbiome analysis of the remaining samples from the remaining 10 patients is underway as well as longitudinal analysis of samples from all patients. Describing the changes to the microbiota composition over time in two groups will provide insight to practice of GD, potential targets for aGVHD, and will provide preliminary data to understand which microbes and microbial gene-pathways may influence immune reconstitution. Disclosures London: United Therapeutics: Consultancy; ArQule, Inc: Consultancy. Ritz:Draper Labs: Consultancy; Kite Pharma: Research Funding; Avrobio: Consultancy; LifeVault Bio: Consultancy; Merck: Research Funding; TScan Therapeutics: Consultancy; Talaris Therapeutics: Consultancy; Celgene: Consultancy; Aleta Biotherapeutics: Consultancy; Equillium: Research Funding. Bhatt:ArcBio: Other: Scientific Advisory Board; January.ai: Other: Scientific Advisory Board; Caribou Bioscience: Other: Scientific Advisory Board; Kaleido Biosciences: Consultancy, Other: Paid Consultant; Janssen Human Microbiome Institute: Consultancy, Other: Paid Consultant; Illumina: Honoraria; 10x Genomics: Other: Research collaboration without funding support; Illumina: Other: Research collaboration without funding support; Agilent: Research Funding; Global Oncology, Inc: Other: Nonprofit Board.

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Myeloablative Fractionated Busulfan Conditioning Regimen with Sorafenib in Patients with AML: Results of Phase I Clinical Trial

Blood ◽

10.1182/blood-2021-152450 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 556-556

Author(s):

Uday R. Popat ◽

Roland Bassett ◽

Peter F. Thall ◽

Amin M. Alousi ◽

Gheath Alatrash ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Conditioning Regimen ◽

Advisory Board ◽

License Agreement ◽

Advisory Committees ◽

Post Transplant ◽

Scientific Advisory Board ◽

Scientific Advisory

Abstract Background: Myeloablative conditioning can be given safely to older patients by administering busulfan over a longer period (fractionated busulfan regimen) than the standard four-day regimen. (Popat, et al Lancet Haematology 2018). This longer conditioning regimen duration allows the addition of oral targeted agents like sorafenib, which may be synergistic with conditioning chemotherapy and thus further improve disease control. Therefore, we added sorafenib to fludarabine and fractionated busulfan regimen (f-bu) in a phase 1 dose-finding trial studying 4 different doses of sorafenib with f-bu (NCT03247088). Here we report the results of this trial. Methods: Between 3/2018 and 6/2021, 24 patients with AML aged 18 to 70 years with adequate organ function and 8/8-HLA matched related or unrelated donors were enrolled prospectively. The dose of sorafenib was varied among the four values 200, 400, 600, and 800 mg administered from day -24 to -5. Dose-limiting toxicity (DLT) was defined as grade 3 or higher regimen-related non-hematologic, non-infectious, non-GVHD toxicity occurring between day -24 and day 3. The Bayesian Model Averaging Continual Reassessment Method (BMA-CRM) with target DLT probability 0.30 was used to choose doses for successive cohorts of 3 patients. The first cohort was treated at the lowest sorafenib dose 200, with all successive cohorts' doses chosen adaptively by the BMA-CRM. The doses and schedules of busulfan and fludarabine were fixed, with f-Bu dose targeting an area under the concentration vs time curve (AUC) of 20,000 ± 12% μmol.min given over 3 weeks. The first two doses of busulfan (80 mg/m2 IV each) were administered on days -20 and -13 on an outpatient basis. The last four Bu doses were calculated to give a total course AUC of 20,000 ± 12% μmol.min and were given as inpatient following each dose of Flu 40 mg/m2 on days -6 through -3. GVHD prophylaxis was post-transplant cyclophosphamide (PTCy) 50mg/kg on days 3 and 4 and tacrolimus. Recipients of unrelated donor grafts also received MMF. All patients were eligible to receive post-transplant maintenance sorafenib after engraftment. Results: The median age was 52 years (range, 30-70). Disease status was CR in 16 (66.6%) patients, CRi in 5 (20.8%), and advanced in 3 (12.5%). Adverse risk karyotype was present in 10 (41.7%) patients. MRD was present in 13 (54.2%). 9 (38%) had mutated flt3. The donor was unrelated in 14 (58%), and peripheral blood stem cells were the graft source in 21(87.5%). Due to the absence of DLTs, the BMA-CRM assigned 200mg, 400mg, 600mg, and 800mg of sorafenib, respectively, to the first 4 cohorts, and the next 4 cohorts were given 800mg. Only 2 dose-limiting skin toxicities were seen, one in cohort 3 with 600mg of sorafenib and the second in cohort 6 with 800mg of sorafenib. 800mg was the final recommended phase 2 dose. The median follow-up in 20 surviving patients was 7.6 months and 1-year progression free survival was 89% (95% CI 75-100%). Other outcomes are summarized in Table 1. Conclusion: Sorafenib can be safely added to the fractionated busulfan regimen. Early data on efficacy appear promising, with an 89% PFS at 1 year of follow up. Figure 1 Figure 1. Disclosures Popat: Bayer: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Incyte: Research Funding. Hosing: Nkarta Therapeutics: Membership on an entity's Board of Directors or advisory committees. Rezvani: Bayer: Other: Scientific Advisory Board ; AvengeBio: Other: Scientific Advisory Board ; Navan Technologies: Other: Scientific Advisory Board; GSK: Other: Scientific Advisory Board ; Virogin: Other: Scientific Advisory Board ; Affimed: Other: License agreement and research agreement; education grant, Patents & Royalties, Research Funding; Pharmacyclics: Other: Educational grant, Research Funding; Caribou: Other: Scientific Advisory Board; GemoAb: Other: Scientific Advisory Board ; Takeda: Other: License agreement and research agreement, Patents & Royalties. Qazilbash: Bristol-Myers Squibb: Other: Advisory Board; Biolline: Research Funding; Amgen: Research Funding; Oncopeptides: Other: Advisory Board; NexImmune: Research Funding; Angiocrine: Research Funding; Janssen: Research Funding. Daver: Daiichi Sankyo: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; ImmunoGen: Consultancy, Research Funding; Astellas: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Gilead Sciences, Inc.: Consultancy, Research Funding; Trillium: Consultancy, Research Funding; Glycomimetics: Research Funding; Abbvie: Consultancy, Research Funding; Hanmi: Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; FATE Therapeutics: Research Funding; Sevier: Consultancy, Research Funding; Novimmune: Research Funding; Trovagene: Consultancy, Research Funding; Novartis: Consultancy; Jazz Pharmaceuticals: Consultancy, Other: Data Monitoring Committee member; Dava Oncology (Arog): Consultancy; Celgene: Consultancy; Syndax: Consultancy; Shattuck Labs: Consultancy; Agios: Consultancy; Kite Pharmaceuticals: Consultancy; SOBI: Consultancy; STAR Therapeutics: Consultancy; Karyopharm: Research Funding; Newave: Research Funding. Ravandi: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; AstraZeneca: Honoraria; Novartis: Honoraria; Xencor: Honoraria, Research Funding; Taiho: Honoraria, Research Funding; Astex: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Agios: Honoraria, Research Funding; Prelude: Research Funding; Syros Pharmaceuticals: Consultancy, Honoraria, Research Funding. Shpall: Magenta: Consultancy; Bayer HealthCare Pharmaceuticals: Honoraria; Magenta: Honoraria; Adaptimmune: Consultancy; Novartis: Consultancy; Navan: Consultancy; Novartis: Honoraria; Takeda: Patents & Royalties; Affimed: Patents & Royalties; Axio: Consultancy. Mehta: CSLBehring: Research Funding; Kadmon: Research Funding; Syndax: Research Funding; Incyte: Research Funding.

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Allogeneic Transplantation for Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia with Post-Transplantation Cyclophosphamide: Assessing the Importance of Conditioning Regimen, Donor Choice, and Tyrosine Kinase Inhibitor Use

Blood ◽

10.1182/blood-2020-141294 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 44-45

Author(s):

Jonathan Webster ◽

Leo Luznik ◽

Hua-Ling Tsai ◽

Philip H. Imus ◽

Amy E. DeZern ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Conditioning Regimen ◽

Advisory Board ◽

Categorical Variables ◽

Advisory Committees ◽

Post Transplant ◽

Scientific Advisory Board ◽

Scientific Advisory ◽

Donor Type

Background: Contemporary trials in adult Ph+ ALL patients with TKIs continue to show improved outcomes with allogeneic blood or marrow transplantation (alloBMT) in first remission (CR1) (Chalandon. Blood. 2015 AND Ravandi. Blood Adv. 2016). These studies have relied on myeloablative conditioning (MAC) and largely required an HLA-matched donor. Post-transplant survival in Ph+ ALL has been shown to be similar between patients transplanted with reduced-intensity conditioning (RIC) and MAC, but the incidence of relapse after RIC is higher (Bachanova. Leukemia. 2014). Post-transplant TKI maintenance reduces the incidence of relapse (Brissot. Haematologica. 2015), but this strategy has not specifically been investigated after RIC. Additionally, HLA-haploidentical donor transplants using post-transplant cyclophosphamide (PTCy) as a component of graft-versus-host disease (GVHD) prophylaxis have comparable outcomes to HLA-matched transplants (McCurdy. Haematologica. 2017). We analyzed outcomes among patients who universally received PTCy and attempted post-transplant TKI prophylaxis to determine the importance of remission status (CR1 vs. later), conditioning regimen, donor type, and TKI choice. Methods: The bone marrow transplant database at Johns Hopkins was queried for adult patients with de novo Ph+ ALL who received alloBMT using PTCy between January 2008 and August 2018. Characteristics of patients were summarized and compared using the student's T test for continuous variables and Fisher's exact test for categorical variables. Estimators of OS and RFS were reported using the Kaplan-Meier method. Differences in time-to-event outcomes were estimated using Cox proportional hazards model. Results: A total of 81 transplants for Ph+ ALL were performed: 69 (85%) in CR1 and 12 (15%) in second or greater remission (CR2+). The demographics are presented in Table 1 and separated by conditioning regimen [MAC vs. nonmyeloablative (NMAC)] for transplants in CR1. The cumulative incidences of grade 2-4 and grade 3-4 aGVHD at 1 year were 33% (95% CI, 23% to 44%) and 9% (95% CI, 3% to 15%), respectively. The incidence of moderate or severe cGVHD at 2 years was 8% (95% CI, 2% to 13%). Nearly all patients (91.4%) initiated a post-transplant TKI at a median of 56 days. Overall, 44.4% of patients were able to take a TKI on ≥85% of nonrelapse days from day 31-395 post-transplant. AlloBMT in CR1 (compared to CR2+) improved RFS (HR=0.25, p=0.0002) and pre-transplant minimal residual disease (MRD) by flow cytometry (MFC) was associated with decreased RFS (HR=2.57, p=0.039). The presence of pre-transplant MRD by PCR did not confer an increased risk of relapse (HR 1.12, p=0.84). Among the 69 patients transplanted in CR1, the 5-year OS was 77.6% (95% CI, 64.8% to 86.2%) and RFS was 67% (95% CI, 52.4-76.5%). As shown in Figure 1, the use of NMAC versus MAC (HR 0.37, p=0.02) and dasatinib versus imatinib at diagnosis (HR 0.21, p=0.007) led to improved relapse-free survival (RFS) in univariate analyses. Neither donor type (with the majority being haploidentical) nor recipient age ≥60 affected RFS. Post-transplant TKI prophylaxis was discontinued prior to relapse in 20 patients among whom 12 remain in an MRD-negative remission, 4 died of non-relapse causes, 3 relapsed, and 1 developed recurrent MRD controlled by a TKI. The median duration of post-transplant TKI prophylaxis prior to discontinuation was 46.5 months in those who remain in treatment-free remission versus 15.6 months in those who relapsed (p=0.01). Eighteen relapses occurred on maintenance therapy, and 90% of tested cases were positive for a kinase domain mutation conferring resistance to the TKI in use at relapse. No significant difference in the median time to TKI initiation post-transplant was noted between those who relapsed on maintenance and those who did not (70 days vs. 55 days, p=0.6). All patients in ongoing remission were MRD-negative by PCR at their most recent evaluation. Conclusions: AlloBMT with PTCy in Ph+ ALL was most effective when performed in CR1 with negative MFC for MRD. The initiation of post-transplant TKI prophylaxis was nearly universal. Among patients transplanted in CR1, the best results were achieved in patients treated with dasatinib at diagnosis (5-year RFS 83%) and NMAC (5-year RFS 73.1%). Thus post-transplant TKI prophylaxis appeared to overcome any relapse control advantage for MAC, yielding better outcomes with NMAC. Disclosures Webster: Amgen: Consultancy; Pfizer: Consultancy. Luznik:WindMil Therapeutics: Patents & Royalties: Patent holder; Genentech: Research Funding; Merck: Research Funding, Speakers Bureau; AbbVie: Consultancy. DeZern:Abbvie: Consultancy; Astex: Research Funding; MEI: Consultancy; Celgene: Consultancy, Honoraria. Pratz:Jazz Pharmaceutical: Consultancy; Millennium: Research Funding; Daiichi Sankyo: Research Funding; Agios: Other: Scientific Advisory Board, Research Funding; Celgene: Other: Scientific Advisory Board; Boston BioMedical: Consultancy; Astellas: Other: Scientific Advisory Board, Research Funding; AbbVie: Other: Scientific Advisory Board, Research Funding. Levis:Astellas: Honoraria, Research Funding; Menarini: Honoraria; Amgen: Honoraria; FujiFilm: Honoraria, Research Funding; Daiichi-Sankyo: Honoraria. Gojo:Amgen: Research Funding; Merck: Research Funding; Genentech: Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees; Amphivena: Research Funding. Bolanos-Meade:Incyte: Other: DSMB Fees. Dalton:Eli Lilly: Research Funding; AbbVie: Research Funding. Jain:Takeda: Consultancy, Honoraria; Bristol Myer Squibb: Other: for advisory board participation; CareDx: Other: Advisory Board. Ali:Celgene: Membership on an entity's Board of Directors or advisory committees. Borrello:Celgene: Research Funding; Aduro: Patents & Royalties; WindMIL Therapeutics: Other: Founder , Research Funding. Wagner-Johnston:ADC Therapeutics, Regeneron, CALIB-R, Verastem: Membership on an entity's Board of Directors or advisory committees. Smith:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees.

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Post-Transplant Cyclophosphamide Versus Tacrolimus and Methotrexate to Prevent Graft-Versus-Host Disease in Recipients of Matched Donor Transplantation: Comparison of Sequential Cohorts in a Prospective Trial

Blood ◽

10.1182/blood-2021-146245 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1803-1803

Author(s):

Uday R. Popat ◽

Rohtesh S. Mehta ◽

Roland Bassett ◽

Amin M. Alousi ◽

Gheath Alatrash ◽

...

Keyword(s):

Research Funding ◽

Acute Gvhd ◽

Advisory Board ◽

License Agreement ◽

Research Support ◽

Post Transplant ◽

Scientific Advisory Board ◽

Gvhd Prophylaxis ◽

Scientific Advisory ◽

Matched Donor

Abstract Background: Myeloablative conditioning can be given safely to older patients by simply administering busulfan over a longer period (fractionated busulfan regimen) than our "standard" four-day fludarabine-busulfan (Flu-Bu) regimen. (Popat et al Lancet Haematology 2018). To further improve outcomes of this fractionated (f-Bu) regimen in patients undergoing matched donor hematopoietic cell transplantation (HCT), we added cladribine (Clad) to f-Bu-Flu regimen in a prospective clinical trial (NCT02250937). GVHD prophylaxis was tacrolimus and methotrexate (Tac/MTX). After enrolling the first 29 patients, the study was amended and GVHD prophylaxis was changed to post-transplant cyclophosphamide (PTCy) and tacrolimus for the next 53 patients based on very promising data observed in patients undergoing haploidentical transplantation. We hypothesized that PTCy will reduce GVHD and non-relapse mortality (NRM), thus improving survival in patients undergoing HCT from a matched donor. In this study, we compared these two sequential cohorts with reference to GVHD prophylaxis. Methods: Between 2/2015 and 12/2018, 82 patients with AML or MDS, 18-70 years of age, with adequate organ function and 8/8-HLA matched related (n=38%) or unrelated (62%) donors were enrolled. The conditioning regimen was f-Bu to target an area under the concentration vs time curve (AUC) of 20,000 ± 12% μmol.min given over a period of 2-3 weeks. The first two doses of busulfan (80 mg/m2 IV each) were administered either consecutively (days -13 and -12) or with further fractionation, one week apart (days -20 and -13) on outpatient basis. Then, inpatient fludarabine 10 mg/m 2, and cladribine 10 mg/m 2 were given followed by Bu on days -6 to -3. GVHD prophylaxis was Tac/Mtx (n=29) or PTCy 50mg/kg on days 3 and 4 followed by tacrolimus from day 5 (n=53). Results: Baseline characteristics were similar between the PTCy and Tac/Mtx cohorts. The median age was 59 (range, 18-70) and 61 (range, 24-70) years (P=0.20); 49% and 59% had primary induction failure at HCT (P=0.58); High or very-high disease risk index was present in 40% and 41%, (P=0.40); Comorbidity index score >3 was present in 42% and 40% (P=0.24); Donor was a sibling in 34% and 45% (P=0.35), and peripheral blood graft was used in 81% and 76% (P=0.58), respectively in PTCy and Tac/Mtx cohorts. Median follow up was 42.7 months. In the PTCy and Tac/Mtx cohorts, at 3-years overall survival was 69% vs 38% (P=0.0004), NRM was 8% vs 28% (P=0.009) [Table 1, Figure 1], incidence of grade 3-4 acute GVHD at day 100 was 4% vs 17% (P=0.04), and chronic GVHD was 21% vs 28% at 3 years (P=0.53). Median time to neutrophil engraftment was prolonged by 3 days with PTCy (15 vs 12 days; P<0.0001). Full donor chimerism at day 30 was noted in 81% vs 28%, in the PTCy and Tac/Mtx cohorts respectively, (P=0.005). The toxicity profile was similar except neutropenic fever (likely cytokine-related) was higher in PTCy group (60% v/s 24%, P=0.002). Likewise, the incidence of hemorrhagic cystitis was higher in the PTCy group (36% vs 14%, p-0.04). Most of the later events were grade 1 or 2. Conclusion: Compared with Tac/Mtx, PTCy reduced severe acute GVHD and NRM, and improved survival in AML/MDS patients up to the age of 70 years who received myeloablative fractionated busulfan conditioning and transplant from a matched donor. Figure 1 Figure 1. Disclosures Popat: Bayer: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Incyte: Research Funding. Mehta: CSLBehring: Research Funding; Kadmon: Research Funding; Syndax: Research Funding; Incyte: Research Funding. Hosing: Nkarta Therapeutics: Membership on an entity's Board of Directors or advisory committees. Rezvani: Navan Technologies: Other: Scientific Advisory Board; Caribou: Other: Scientific Advisory Board; GemoAb: Other: Scientific Advisory Board ; GSK: Other: Scientific Advisory Board ; Pharmacyclics: Other: Educational grant, Research Funding; Bayer: Other: Scientific Advisory Board ; Takeda: Other: License agreement and research agreement, Patents & Royalties; Affimed: Other: License agreement and research agreement; education grant, Patents & Royalties, Research Funding; Virogin: Other: Scientific Advisory Board ; AvengeBio: Other: Scientific Advisory Board . Qazilbash: Janssen: Research Funding; Biolline: Research Funding; Oncopeptides: Other: Advisory Board; NexImmune: Research Funding; Angiocrine: Research Funding; Amgen: Research Funding; Bristol-Myers Squibb: Other: Advisory Board. Kadia: Liberum: Consultancy; AstraZeneca: Other; Sanofi-Aventis: Consultancy; Genfleet: Other; Pulmotech: Other; Dalichi Sankyo: Consultancy; Genentech: Consultancy, Other: Grant/research support; Amgen: Other: Grant/research support; Astellas: Other; Jazz: Consultancy; Aglos: Consultancy; Ascentage: Other; Cellonkos: Other; Novartis: Consultancy; Pfizer: Consultancy, Other; AbbVie: Consultancy, Other: Grant/research support; BMS: Other: Grant/research support; Cure: Speakers Bureau. Kantarjian: BMS: Research Funding; Daiichi-Sankyo: Research Funding; Pfizer: Honoraria, Research Funding; KAHR Medical Ltd: Honoraria; Novartis: Honoraria, Research Funding; Jazz: Research Funding; Precision Biosciences: Honoraria; Amgen: Honoraria, Research Funding; Aptitude Health: Honoraria; Immunogen: Research Funding; Ascentage: Research Funding; AbbVie: Honoraria, Research Funding; NOVA Research: Honoraria; Ipsen Pharmaceuticals: Honoraria; Astellas Health: Honoraria; Astra Zeneca: Honoraria; Taiho Pharmaceutical Canada: Honoraria. Shpall: Adaptimmune: Consultancy; Magenta: Consultancy; Novartis: Honoraria; Affimed: Patents & Royalties; Navan: Consultancy; Magenta: Honoraria; Novartis: Consultancy; Takeda: Patents & Royalties; Bayer HealthCare Pharmaceuticals: Honoraria; Axio: Consultancy.

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Incidence and Outcomes of Toxoplasma Reactivation in Patients with Hematologic Diseases after Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood-2021-151474 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1779-1779

Author(s):

Taha Al-Juhaishi ◽

Alexandre Elias Malek ◽

Denái R. Milton ◽

Jeremy L. Ramdial ◽

May Daher ◽

...

Keyword(s):

Stem Cell ◽

Board Of Directors ◽

Research Funding ◽

Antimicrobial Prophylaxis ◽

Advisory Board ◽

License Agreement ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Scientific Advisory Board ◽

Scientific Advisory

Abstract Introduction: Toxoplasmosis is a rare complication of allogeneic hematopoietic stem cell transplantation (AlloHSCT) usually through reactivation in a previously seropositive recipient, and is associated with mortality as high as 60% (Paccoud et al. BMT 2020). Seroprevalence in the population varies ranging from 5% or lower in North America to over 50% in France. Risk factors for reactivation include immune suppression, seronegative donors, cord blood grafts, and lack of adequate antimicrobial prophylaxis (Robin et al. BBMT 2019). We sought to evaluate the outcomes of patients with toxoplasma reactivation after undergoing AlloHSCT in the modern era. Methods: This study was a retrospective single center analysis of all patients who underwent AlloHSCT between January 2012 and June 2021 at our center. Primary objectives were to assess the incidence of toxoplasma reactivation and the effects of reactivation on survival. Patients were identified in the department database and relevant demographic and clinical data were extracted. Results of toxoplasma testing [IgG serology and polymerase chain reaction (PCR)] were collected and verified by manual chart review. Patients with negative toxoplasma serology and/or missing serology or PCR data were excluded from analysis. Reactivation was defined as positive PCR in a seropositive patient. Toxoplasma reactivation associations were assessed by logistic regression models. Overall Survival (OS) was estimated using the Kaplan-Meier method and differences compared using the log-rank test. Cox proportional hazards models were used for survival associations. Cumulative incidence of non-relapse mortality (NRM) was determined using competing risks method. This study was approved by the institutional board review (IRB) committee at our center. Results: A total of 370 patients who received AlloHSCT and had a positive toxoplasma IgG were identified. Fifty-two patients had missing toxoplasma PCR and 4 did not meet eligibility criteria and were excluded. Twenty-two (7%) out of the remaining 314 seropositive patients experienced toxoplasma reactivation as confirmed by positive PCR. Median age in the reactivation group was 55 years, and patients were mostly white males with myeloid neoplasms who underwent AlloHSCT in first complete remission using nonmyeloablative conditioning and a matched unrelated donor (table 1). No significant differences in baseline characteristics were seen between the seropositive only and the reactivation groups, except for antimicrobial prophylaxis use (P <0.001). Fifty-nine percent of patients (13 out of 22) in the reactivation group were on toxoplasma prophylaxis compared to 93% (273 out of 292) in the seropositive patients without reactivation. Sixteen out of the 22 (73%) patients with reactivation developed clinical symptoms while 6 (27%) had asymptomatic reactivation. Antimicrobial prophylaxis only with either pentamidine, atovaquone, trimethoprim/sulfamethoxazole but not dapsone, was associated with lower risk of developing reactivation (table 2). With a median follow up of 15.4 months (0.3-98.9), the median OS was 9.6 months in patients with reactivation versus 58.5 months in seropositive patients without reactivation [HR, 2.06; (95% CI, 1.21 to 3.52); P=0.008] (figure 1). NRM was also higher in the reactivation group [HR, 2.61; (95% CI, 1.34 to 5.11); P=0.005] (figure 2). Specifically, day 100, 1-year and 2-year NRM were higher in the reactivation group versus (vs) seropositive patients (36% vs 10%, 41% vs 18%, and 47% vs 20% respectively). Toxoplasma reactivation was associated with worse OS and increased NRM in univariable analysis however this did not reach statistical significance in multivariable analysis. Conclusion: Toxoplasma reactivation in seropositive AlloSCT patients remains low at our center at around 7%. Toxoplasma reactivation is associated with worse outcomes after AlloHSCT and reactivation could be mitigated by improved compliance with antimicrobial prophylaxis. Figure 1 Figure 1. Disclosures Mehta: Kadmon: Research Funding; Incyte: Research Funding; CSLBehring: Research Funding; Syndax: Research Funding. Shah: Amgen: Consultancy; Bluebird Bio: Research Funding; BMS/Celgene: Research Funding; CareDx: Consultancy; CSL Behring: Consultancy; GSK: Consultancy; Indapta Therapeutics: Consultancy; Janssen: Research Funding; Karyopharm: Consultancy; Kite: Consultancy; Nektar: Research Funding; Oncopeptides: Consultancy; Poseida: Research Funding; Precision Biosciences: Research Funding; Sanofi: Consultancy; Sutro Biopharma: Research Funding; Teneobio: Research Funding. Hosing: Nkarta Therapeutics: Membership on an entity's Board of Directors or advisory committees. Rezvani: Pharmacyclics: Other: Educational grant, Research Funding; Affimed: Other: License agreement and research agreement; education grant, Patents & Royalties, Research Funding; Takeda: Other: License agreement and research agreement, Patents & Royalties; GSK: Other: Scientific Advisory Board ; Caribou: Other: Scientific Advisory Board; GemoAb: Other: Scientific Advisory Board ; AvengeBio: Other: Scientific Advisory Board ; Virogin: Other: Scientific Advisory Board ; Navan Technologies: Other: Scientific Advisory Board; Bayer: Other: Scientific Advisory Board . Qazilbash: Janssen: Research Funding; Bristol-Myers Squibb: Other: Advisory Board; Angiocrine: Research Funding; Amgen: Research Funding; Oncopeptides: Other: Advisory Board; Biolline: Research Funding; NexImmune: Research Funding. Popat: Bayer: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Incyte: Research Funding. Shpall: Takeda: Patents & Royalties; Navan: Consultancy; Novartis: Honoraria; Magenta: Honoraria; Affimed: Patents & Royalties; Novartis: Consultancy; Magenta: Consultancy; Adaptimmune: Consultancy; Axio: Consultancy; Bayer HealthCare Pharmaceuticals: Honoraria. Ahmed: Seagen: Research Funding; Xencor: Research Funding; Tessa Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding.

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Secreted Factors Determine Resistance to Idelalisib in Marginal Zone Lymphoma Models of Resistance

Blood ◽

10.1182/blood-2019-124299 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2569-2569

Author(s):

Alberto J Arribas ◽

Sara Napoli ◽

Eugenio Gaudio ◽

Luciano Cascione ◽

Alessandra Di Veroli ◽

...

Keyword(s):

B Cell ◽

Cell Lines ◽

Research Funding ◽

Advisory Board ◽

Institutional Research ◽

Rna Seq ◽

Scientific Advisory Board ◽

Scientific Advisory ◽

Erbb Signaling ◽

Travel Grant

Background . PI3Kδ is expressed in B-cells and has a central role in the B-cell receptor signaling in B-cell derived malignancies. Idelalisib was the first-in-class PI3Kδ inhibitors and several second-generation compounds are undergoing clinical investigation as single agents and in combinations. To identify modalities to overcome the resistance that develops to this class of agents, we have developed two idelalisib-resistant models derived from splenic marginal zone lymphoma (SMZL) cell lines. Materials and Methods. Cells were kept under idelalisib (IC90) until acquisition of resistance (RES) or with no drug (parental, PAR). Stable resistance was confirmed by MTT assay after 2-weeks of drug-free culture. Multi-drug resistance phenotype was ruled out. Cells underwent transcriptome and miRNA profiling by RNA-Seq, whole exome sequencing (WES), lipidomics profiling, pharmacological screening (348 compounds), and FACS analysis. Cytokines and growth factor secretion was performed by ELISA. Results. Two RES models were obtained from VL51 and Karpas1718 with 7-10 fold times higher IC50s than PAR counterparts. In both models, conditioned media from RES cells transferred the resistance in the PAR cells. While WES did not identify somatic mutations associated with resistance, RNA-Seq and lipidomics analyses showed that the two cell lines had developed resistance activating different modalities. The VL51 RES model showed an enrichment in BCR-TLR-NFkB (TLR4, CD19, SYK), IL6-STAT3 (IL6, CD44), chemokines (CXCL10, CXCR4, CXCR3) and PDGFR (PDGFRA, PRKCE) signatures, paired with increased p-AKT and p-BTK levels, decreased cardiolipins and sphingomyelins levels, and increased levels of specific triacylglycerols and glycerophosphocholines. In particular, there was an over-expression of surface expression of PDGFRA and secretion of IL6 in the medium. Silencing of both IL6and PDGFRA by siRNAs reverted the resistance, while the silencing of the individual genes had only a partial effect. These data were paired with the acquired sensitivity to the PDGFR inhibitor masitinib, identified in the pharmacologic screening. In the Karpas1718 model, we observed an increased p-AKT activity with an enrichment for B-cell activation signatures (RAG1, RAG2, TCL1A), proliferation (E2F2, MKI67), ERBB signaling (HBEGF, NRG2, ERRB4), increased levels of some triacylglycerols and repressed levels for specific glycerophosphocholines. HBEGF secretion was confirmed by ELISA. The addition of recombinant HBEGF to the medium induced resistance in the PAR cells. Combination with the pan ERBB inhibitor lapatinib was beneficial in the K1718 RES. Recombinant HBEGF also induced resistance to the BTK inhibitor ibrutinib in the PAR cells and in the mantle cell lymphoma SP-53 cell line. Specific members of the let-7 family of miRNAs were repressed in the RES lines derived from both cell lines, indicating the involvement of miRNA deregulation in the mechanism of resistance. Indeed, let-7 members are known to directly target IL6-STAT3 and cytokine signaling cascade, as well PI3K-AKT network. In solid tumors, let-7 members are also expressed at low levels in tumors with constitutive active ERBB signaling, in accordance with the activation of ERBB pathway and p-AKT we observed in our Karpas1718model. Experiments with a LIN28B inhibitor are now on-going. Finally, we validated the findings across a panel of 34 B-cell lymphoma cell lines, in which IL6, PDGFRA, HBEGF and LIN28 expression levels were negatively correlated with idelalisib sensitivity, while the latter was positively correlated with let-7 levels (P <0.05). Conclusions. We developed two distinct models derived from MZL of secondary resistance to the PI3Kδ inhibitor idelalisib. We identified treatments that might overcome resistance to idelalisib and are worth of further investigations. The two models, driven by different biologic processes, will allow the evaluation of further alternative therapeutic approaches. Disclosures Stathis: PharmaMar: Other: Renumeration; ADC Therapeutics: Other: Institutional research funding; Abbvie: Other: Renumeration; Bayer: Other: Institutional research funding; Novartis: Other: Institutional research funding; MEI-Pharma: Other: Institutional research funding; Roche: Other: Institutional research funding; Pfizer: Other: Institutional research funding; Merck: Other: Institutional research funding. Stuessi:Gilead: Speakers Bureau. Zucca:Gilead: Honoraria, Other: travel grant. Rossi:Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Other: Scientific advisory board; Janseen: Honoraria, Other: Scientific advisory board; Roche: Honoraria, Other: Scientific advisory board; Astra Zeneca: Honoraria, Other: Scientific advisory board. Bertoni:Nordic Nanovector ASA: Research Funding; Acerta: Research Funding; Jazz Pharmaceuticals: Other: travel grants; ADC Therapeutics: Research Funding; Bayer AG: Research Funding; Cellestia: Research Funding; CTI Life Sciences: Research Funding; EMD Serono: Research Funding; Helsinn: Consultancy, Research Funding; ImmunoGen: Research Funding; Menarini Ricerche: Consultancy, Research Funding; NEOMED Therapeutics 1: Research Funding; Oncology Therapeutic Development: Research Funding; PIQUR Therapeutics AG: Other: travel grant, Research Funding; HTG: Other: Expert Statements ; Amgen: Other: travel grants; Astra Zeneca: Other: travel grants.

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Conventional Immunochemotherapy (R-CHOEP) Vs High-Dose Immunochemotherapy (R-MegaCHOEP) in Younger Patients with High-Risk Aggressive B-Cell Lymphoma: 10-Year Long-Term Follow-up of a German Lymphoma Alliance (GLA) Study

Blood ◽

10.1182/blood-2019-123637 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1589-1589

Author(s):

Fabian Frontzek ◽

Marita Ziepert ◽

Maike Nickelsen ◽

Bettina Altmann ◽

Bertram Glass ◽

...

Keyword(s):

High Risk ◽

Board Of Directors ◽

Research Funding ◽

Advisory Board ◽

High Dose ◽

Advisory Committees ◽

Scientific Advisory Board ◽

Scientific Advisory

Introduction: The R-MegaCHOEP trial showed that dose-escalation of conventional chemotherapy necessitating autologous stem cell transplantation (ASCT) does not confer a survival benefit for younger patients (pts) with high-risk aggressive B-cell lymphoma in the Rituximab era (Schmitz et al., Lancet Oncology 2012; 13, 1250-1259). To describe efficacy and toxicity over time and document the long-term risks of relapse and secondary malignancy we present the 10-year follow-up of this study. Methods: In the randomized, prospective phase 3 trial R-MegaCHOEP younger pts aged 18-60 years with newly diagnosed, high-risk (aaIPI 2-3) aggressive B-cell lymphoma were assigned to 8 cycles of CHOEP (cyclophosphamide, doxorubcine, vincristine, etoposide, prednisone) or 4 cycles of dose-escalated high-dose therapy (HDT) necessitating repetitive ASCT both combined with Rituximab. Both arms were stratified according to aaIPI, bulky disease, and center. Primary endpoint was event-free survival (EFS). All analyses were calculated for the intention-to-treat population. This follow-up report includes molecular data based on immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) for MYC (IHC: 31/92 positive [40-100%], FISH: 14/103 positive), BCL2 (IHC: 65/89 positive [50-100%], FISH: 23/111 positive) and BCL6 (IHC: 52/86 positive [30-100%], FISH: 34/110 positive) and data on cell of origin (COO) classification according to the Lymph2CX assay (GCB: 53/88; ABC: 24/88; unclassified: 11/88). Results: 130 pts had been assigned to R-CHOEP and 132 to R-MegaCHOEP. DLBCL was the most common lymphoma subtype (~80%). 73% of pts scored an aaIPI of 2 and 27% an aaIPI of 3. 60% of pts had an initial lymphoma bulk and in 40% more than 1 extranodal site was involved. After a median observation time of 111 months, EFS at 10 years was 57% (95% CI 47-67%) in the R-CHOEP vs. 51% in the R-MegaCHOEP arm (42-61%) (hazard ratio 1.3, 95% CI 0.9-1.8, p=0.228), overall survival (OS) after 10 years was 72% (63-81%) vs. 66% (57-76%) respectively (p=0.249). With regard to molecular characterization, we were unable to detect a significant benefit for HDT/ASCT in any subgroup analyzed. In total, 16% of pts (30 pts) relapsed after having achieved a complete remission (CR). 23% of all relapses (7 pts) showed an indolent histology (follicular lymphoma grade 1-3a) and 6 of these pts survived long-term. In contrast, of 23 pts (77%) relapsing with aggressive DLBCL or unknown histology 18 pts died due to lymphoma or related therapy. The majority of relapses occurred during the first 3 years after randomization (median time: 22 months) while after 5 years we detected relapses only in 5 pts (3% of all 190 pts prior CR). 11% of pts were initially progressive (28 pts) among whom 71% (20 pts) died rapidly due to lymphoma. Interestingly, the remaining 29% (8 pts) showed a long-term survival after salvage therapy (+/- ASCT); only 1 pt received allogeneic transplantation. The frequency of secondary malignancies was very similar in both treatment arms (9% vs. 8%) despite the very high dose of etoposide (total 4g/m2)in the R-MegaCHOEP arm. We observed 2 cases of AML and 1 case of MDS per arm. In total 70 pts (28%) have died: 30 pts due to lymphoma (12%), 22 pts therapy-related (11 pts due to salvage therapy) (9%), 8 pts of secondary neoplasia (3%), 5 pts due to concomitant disease (2%) and 5 pts for unknown reasons. Conclusions: This 10-year long-term follow-up of the R-MegaCHOEP trial confirms the very encouraging outcome of young high-risk pts following conventional chemotherapy with R-CHOEP. High-dose therapy did not improve outcome in any subgroup analysis including molecular high-risk groups. Relapse rate was generally low. Pts with aggressive relapse showed a very poor long-term outcome while pts with indolent histology at relapse survived long-term. Secondary malignancies occurred; however, they were rare with no excess leukemias/MDS following treatment with very high doses of etoposide and other cytotoxic agents. Supported by Deutsche Krebshilfe. Figure Disclosures Nickelsen: Roche Pharma AG: Membership on an entity's Board of Directors or advisory committees, Other: Travel Grants; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Travel Grant; Janssen: Membership on an entity's Board of Directors or advisory committees. Hänel:Amgen: Honoraria; Celgene: Other: advisory board; Novartis: Honoraria; Takeda: Other: advisory board; Roche: Honoraria. Truemper:Nordic Nanovector: Consultancy; Roche: Research Funding; Mundipharma: Research Funding; Janssen Oncology: Consultancy; Takeda: Consultancy, Research Funding; Seattle Genetics, Inc.: Research Funding. Held:Roche: Consultancy, Other: Travel support, Research Funding; Amgen: Research Funding; Acrotech: Research Funding; MSD: Consultancy; Bristol-Myers Squibb: Consultancy, Other: Travel support, Research Funding. Dreyling:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: scientific advisory board, Research Funding, Speakers Bureau; Bayer: Consultancy, Other: scientific advisory board, Speakers Bureau; Celgene: Consultancy, Other: scientific advisory board, Research Funding, Speakers Bureau; Mundipharma: Consultancy, Research Funding; Gilead: Consultancy, Other: scientific advisory board, Speakers Bureau; Novartis: Other: scientific advisory board; Sandoz: Other: scientific advisory board; Janssen: Consultancy, Other: scientific advisory board, Research Funding, Speakers Bureau; Acerta: Other: scientific advisory board. Viardot:Kite/Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees. Rosenwald:MorphoSys: Consultancy. Lenz:Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding; Agios: Research Funding; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bayer: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Roche: Employment, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy. Schmitz:Novartis: Honoraria; Gilead: Honoraria; Celgene: Equity Ownership; Riemser: Consultancy, Honoraria.

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Identification of Two CAR T-Cell Populations Associated with Complete Response or Progressive Disease in Adult Lymphoma Patients Treated with Axi-Cel

Blood ◽

10.1182/blood-2019-130815 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 779-779 ◽

Cited By ~ 2

Author(s):

Zinaida Good ◽

Jay Y. Spiegel ◽

Bita Sahaf ◽

Meena B. Malipatlolla ◽

Matthew J. Frank ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Advisory Board ◽

Advisory Committees ◽

Car T Cells ◽

Scientific Advisory Board ◽

Car T ◽

Scientific Advisory

Axicabtagene ciloleucel (Axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for the treatment of relapsed or refractory diffuse large B-cell lymphoma (r/r DLBCL). Long-term analysis of the ZUMA-1 phase 1-2 clinical trial showed that ~40% of Axi-cel patients remained progression-free at 2 years (Locke et al., Lancet Oncology 2019). Those patients who achieved a complete response (CR) at 6 months generally remained progression-free long-term. The biological basis for achieving a durable CR in patients receiving Axi-cel remains poorly understood. Here, we sought to identify CAR T-cell intrinsic features associated with CR at 6 months in DLBCL patients receiving commercial Axi-cel at our institution. Using mass cytometry, we assessed expression of 33 surface or intracellular proteins relevant to T-cell function on blood collected before CAR T cell infusion, on day 7 (peak expansion), and on day 21 (late expansion) post-infusion. To identify cell features that distinguish patients with durable CR (n = 11) from those who developed progressive disease (PD, n = 14) by 6 months following Axi-cel infusion, we performed differential abundance analysis of multiparametric protein expression on CAR T cells. This unsupervised analysis identified populations on day 7 associated with persistent CR or PD at 6 months. Using 10-fold cross-validation, we next fitted a least absolute shrinkage and selection operator (lasso) model that identified two clusters of CD4+ CAR T cells on day 7 as potentially predictive of clinical outcome. The first cluster identified by our model was associated with CR at 6 months and had high expression of CD45RO, CD57, PD1, and T-bet transcription factor. Analysis of protein co-expression in this cluster enabled us to define a simple gating scheme based on high expression of CD57 and T-bet, which captured a population of CD4+ CAR T cells on day 7 with greater expansion in patients experiencing a durable CR (mean±s.e.m. CR: 26.13%±2.59%, PD: 10.99%±2.53%, P = 0.0014). In contrast, the second cluster was associated with PD at 6 months and had high expression of CD25, TIGIT, and Helios transcription factor with no CD57. A CD57-negative Helios-positive gate captured a population of CD4+ CAR T cells was enriched on day 7 in patients who experienced progression (CR: 9.75%±2.70%, PD: 20.93%±3.70%, P = 0.016). Co-expression of CD4, CD25, and Helios on these CAR T cells highlights their similarity to regulatory T cells, which could provide a basis for their detrimental effects. In this exploratory analysis of 25 patients treated with Axi-cel, we identified two populations of CD4+ CAR T cells on day 7 that were highly associated with clinical outcome at 6 months. Ongoing analyses are underway to fully characterize this dataset, to explore the biological activity of the populations identified, and to assess the presence of other populations that may be associated with CAR-T expansion or neurotoxicity. This work demonstrates how multidimensional correlative studies can enhance our understanding of CAR T-cell biology and uncover populations associated with clinical outcome in CAR T cell therapies. This work was supported by the Parker Institute for Cancer Immunotherapy. Figure Disclosures Muffly: Pfizer: Consultancy; Adaptive: Research Funding; KITE: Consultancy. Miklos:Celgene: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Kite-Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; AlloGene: Membership on an entity's Board of Directors or advisory committees; Precision Bioscience: Membership on an entity's Board of Directors or advisory committees; Miltenyi Biotech: Membership on an entity's Board of Directors or advisory committees; Becton Dickinson: Research Funding; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees. Mackall:Vor: Other: Scientific Advisory Board; Roche: Other: Scientific Advisory Board; Adaptimmune LLC: Other: Scientific Advisory Board; Glaxo-Smith-Kline: Other: Scientific Advisory Board; Allogene: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Apricity Health: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Unum Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Obsidian: Research Funding; Lyell: Consultancy, Equity Ownership, Other: Founder, Research Funding; Nektar: Other: Scientific Advisory Board; PACT: Other: Scientific Advisory Board; Bryologyx: Other: Scientific Advisory Board.

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Interaction of Mantle Cell Lymphoma with the Microenvironment Induces Phospho Akt-Mediated Resistance Against BTK Inhibition and Can be Overcome By Co-Treatment with a Specific Akt Inhibitor (MK-2206)

Blood ◽

10.1182/blood-2019-128782 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2802-2802

Author(s):

Elisabeth Silkenstedt ◽

Claudia Schwandner ◽

Johanna Deuss ◽

Natalie Mack ◽

Yvonne Zimmermann ◽

...

Keyword(s):

Western Blot ◽

Research Funding ◽

Direct Interaction ◽

Cell Interaction ◽

Advisory Board ◽

Akt Inhibitor ◽

Scientific Advisory Board ◽

Mantle Cell ◽

Scientific Advisory ◽

Btk Inhibitor

Mantle cell lymphoma (MCL) is a distinct lymphoma subtype representing 6-8% of non-Hodgkin's lymphoma (NHL). Although with current standard therapy high initial response rates can be achieved, early relapses and rapid disease progression determine the clinical course of most MCL patients. Recently, Bruton´s tyrosine Kinase (BTK) inhibitors have been introduced with highly promising clinical activity. Nevertheless, interindividual responsiveness is heterogenous and primary and secondary resistance has been reported. However, molecular mechanisms driving resistance to BTK inhibition are not well understood yet. Among other factors, interactions between the tumor and its microenvironment have been proposed to play an important role in response to targeted therapy. In this study, we investigated the influence of tumor cell interaction with its microenvironment on sensitivity to the BTK inhibitor CC292 in vitro. MCL cell lines JeKo-1, Z-138 and Granta-519 were treated with 5 µM of CC292 alone or in co-culture with human bone marrow stromal cells (HS-5) and cell death induction and proliferation were assessed. Expression of proteins involved in BCR signaling and other tumor-promoting pathways was analyzed by Western Blot. Co-cultured MCL cells settled within the stromal cell layer were separated using MACS Feeder removal microbeads prior to Western Blot analysis. In all cell lines, direct interaction with the microenvironment markedly reduced sensitivity towards CC292 treatment (by 22% (JeKo-1), 33% (Granta) and 64 % (Z-138)). Importantly, cell-cell contact was shown to play a crucial role for mediating resistance to CC292 as only those MCL cells settled within the stromal cell layer proved to be significantly less vulnerable to the inhibitor compared to MCL cells co-cultured with HS-5 but separated by a transwell insert. Western Blot analysis showed a reduction of protein levels of phBTK upon treatment with CC292 in both, mono- and co-cultured cells. Interestingly, direct interaction of MCL cells with the microenvironment strongly induced protein expression of phAkt. Accordingly, phosphorylation (inactivation) of the pro-apoptotic FoxO1, a downstream-target of phAkt, was increased and its translocation to the nucleus was decreased in those cells. We could show that the effect of microenvironment interaction on sensitivity towards CC292 is mediated by Akt as knockdown of Akt using siRNA restored sensitivity to the drug. Furthermore, co-treatment of MCL cells with CC292 and the specific Akt inhibitor MK-2206 hampered upregluation of phAkt in co-cultivated cells and prevented Akt-mediated sequestration of FoxO1 in the cytoplasm, resulting in translocation of FoxO1 to the nucleus. Thus, combination with MK-2206 could significantly overcome microenvironment-mediated protection from growth inhibition and apoptosis induction upon CC292 treatment. Moreover, combination of the BTK inhibitor CC292 and the Akt inhibitor MK-2206 proved to act synergistically in MCL cells in all dose combinations tested (Combination index 0,73-0,93 in Z-138; 0,47-0,78 in JeKo-1). Taken together, cell-cell-interaction of MCL cells with their microenvironment protected them from CC292-induced cell death. This effect was mediated by increased phAkt expression resulting in inhibition of pro-apoptotic signaling and could effectively be overcome by combination with the specific Akt inhibitor MK-2206. Furthermore, CC292 and MK-2206 acted synergistically in MCL cells. Our results indicate that co-targeting the PI3K/Akt-pathway might be a promising strategy to overcome resistance to BTK inhibition mediated by interaction with the microenvironment. Disclosures Dreyling: Sandoz: Other: Scientific advisory board; Roche: Other: Scientific advisory board, Research Funding, Speakers Bureau; Novartis: Other: Scientific advisory board; Mundipharma: Other: Scientific advisory board, Research Funding; Janssen: Other: Scientific advisory board, Research Funding, Speakers Bureau; Gilead: Other: Scientific advisory board, Speakers Bureau; Celgene: Other: Scientific advisory board, Research Funding, Speakers Bureau; Bayer: Other: Scientific advisory board, Speakers Bureau; Acerta: Other: Scientific advisory board.

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Early Immune Reconstitution after Hematopoietic Stem Cell Transplantation for Adolescents and Adults with Sickle Cell Disease

Blood ◽

10.1182/blood-2021-147133 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3907-3907

Author(s):

Loïc Vasseur ◽

Florence Morin ◽

Corinne Pondarré ◽

Florian Chevillon ◽

Aude-Marie Fourmont ◽

...

Keyword(s):

Stem Cell ◽

Research Funding ◽

Immune Reconstitution ◽

Normal Values ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Post Transplant ◽

Stem Cell Source ◽

Cell Source ◽

Adolescents And Adults

Abstract Introduction Allogeneic hematopoïetic stem cell transplantation (HSCT) is the only established curative therapy for patients (pts) with sickle cell disease (SCD). It is mostly performed in children 1, due to higher risk of graft-versus-host disease (GVHD) and transplant related mortality in adults. Different approaches have been developped to improve tolerance of transplant in adults: use of reduced intensity conditioning (RIC) regimens 2 and intensive immunosuppression to avoid GVHD. Here, we have studied the impact of such approaches on immune reconstitution in adolescents and adults transplanted for SCD. Patients and methods We report 39 transplants in adolescents and adults, performed in Saint Louis hospital from 2008 to 2020: 25 were matched related transplants (MRT) and 14 haplo-identical related transplant (HRT). In MRT, conditioning was myeloablative (MAC) in 15 pts (busulfan, cyclophosphamide, rabbit anti-thymoglobulin (ATG) 20 mg/kg) and non myeloablative (NMA) in 10 pts (alemtuzumab 1 mg/kg, 3 Gy total body irradiation (TBI)). In MAC transplants, stem cell source was bone marrow and post-transplant immunosuppression was methotrexate and cyclosporine. In NMA transplants, stem cell source was peripheral blood cells with post-transplant immunosuppression by sirolimus. In the 14 HRT, the conditioning was reduced (cyclophosphamide, thiotepa, fludarabine, 2 Gy TBI, ATG 4.5 mg/kg), stem cell source was bone marrow and GVHD prophylaxis was ensured by post-transplant cyclophosphamide (100 mg/kg), sirolimus and mycophenolate mofetil. Results Median age at transplant was 17 years (y) old (range (r) 14-39). With a median follow-up of 3.6 y, the 2-y overall survival and survival without SCD were 97% (IC95%: 0.92-1) and 92% (IC95%: 0.83-1) respectively: no event after MRT, 1 death of GVHD and 2 graft rejections after HRT. The acute GVHD grade II-IV rate was 33%: 21% after HRT, 13% after MAC MRT and 0% after NMA MRT. Chronic GVHD occured in 3 pts (8%): severe in 1 HRT and mild in 2 MAC MRT. At 6 months, the blood chimerism evaluated in the 36 patients alive without rejection, was more often mixed (5 to 95% of donor) after NMA MRT (100%) versus MAC MRT (40%, p = 0.003) and HRT (18%, p < 0.001). Total lymphocytes (TL) counts increased rapidly in HRT and MAC MRT with a normalization from 3 months post-transplant. In contrast, NMA MRT experienced a slower recovery: at 6 months, median count was 1039/mm3 (r 463-1767) compared to 2071/mm3 (r 882-5985, p = 0.002) after MAC MRT and 2382/mm3 (r 676-3978, p = 0.005) after HRT. After NMA MRT, TL counts remained lower than normal values up to 12 months with a median of 1195/mm3 (r 870-3210) (Figure 1A). HRT displayed a rapid normalization of CD4 counts with a 3-month median count of 645/mm3 (r 350-1076) higher than reported after MRT (p < 0.001). Evolution of CD4 counts was similar after NMA and MAC MRT. They were lower than normal values during the first 12 months: median 364/mm3 and 388/mm3 respectively at 12 months (p = 0.25) (Figure 1B). From 3 months post-transplant, CD8 counts reached normal values after MAC MRT (314/mm3, r 108-2175) and were superior to normal after HRT (1335/mm3, r 66-4529), with a significant difference between HRT and MRT (p = 0.003). After NMA MRT, there was a trend for lower 3-month CD8 counts compared to MAC MRT: median of 107/mm3 (r 18-631, p = 0.08). CD8 counts remained under normal values after NMA MRT up to 12 months post-transplant (Figure 1C). From 3 to 6 months, CD4 and CD8 were mostly memory, with only 3.2% (r 0.1%-20.6%) and 6.2% (r 2.1%-11.2%) of CD45RA+ CCR7+ naïve CD8+ and CD4+ respectively. In the 3 groups NK cell counts reached normal values after 3 months. B lymphocytes counts normalized in the first months post-transplant except for patients who received rituximab for EBV reactivation. From 3 to 6 months, B lymphocytes were mostly naive: 98% of CD27- (r 92%-99%). Gammaglobuline levels were normal from 3 months in the 3 groups. Twelve (31%) pts were treated for a CMV and 6 (15%) for an EBV reactivation. No patient had CMV or adenovirus disease, or post-transplant lymphoproliferative disorder. Infections according to transplant types are detailed in figure 1D. Conclusion NMA MRT were associated with a delayed CD4 and CD8 recovery probably due to alemtuzumab. As previously reported 3, HRT displayed a rapid immune reconstitution. Despite use of serotherapy in the three modalities of transplant, the rate of viral infections remained acceptable without severe episode. Figure 1 Figure 1. Disclosures Pondarré: ADDMEDICA: Honoraria. Peffault De Latour: Jazz Pharmaceuticals: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Amgen: Consultancy, Other, Research Funding; Alexion, AstraZeneca Rare Disease: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding. Boissel: CELGENE: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; JAZZ Pharma: Honoraria, Research Funding; Incyte: Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Servier: Consultancy, Honoraria; SANOFI: Honoraria; PFIZER: Consultancy, Honoraria.

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Central Nervous System Involvement By Mantle Cell Lymphoma

Blood ◽

10.1182/blood-2021-148447 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2426-2426

Author(s):

Nicole McLaughlin ◽

Jonas Paludo ◽

Yucai Wang ◽

David J. Inwards ◽

Nora Bennani ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Data Monitoring Committee ◽

Advisory Board ◽

Control Group ◽

Cns Involvement ◽

Extranodal Involvement ◽

Advisory Committees ◽

Scientific Advisory Board ◽

Scientific Advisory

Abstract Background: While extranodal involvement by mantle cell lymphoma (MCL) is relatively common, involvement of the central nervous system (CNS) is rare (<5% of cases), with limited treatment options. We report the outcomes of 36 patients (pts) with CNS involvement compared to 72 matched control MCL pts without CNS involvement. Methods: MCL pts with CNS involvement seen at Mayo Clinic between 1/1995-9/2020 were identified using the Mayo Data Explorer tool. CNS involvement was defined by tissue biopsy confirmed CNS MCL, CSF analysis demonstrating lymphoma cells, and/or neuroimaging findings compatible with CNS involvement. A 2:1 control group of MCL pts without CNS involvement, matched by age (+/- 2 years) and year of diagnosis (+/- 1 year), was selected among all MCL cases. Medical records were reviewed for baseline characteristics, treatment modalities, and outcomes. Kaplan-Meier method was used for time to event analysis. Wilcoxon test was used to compare continuous variables and Chi square test was used for categorical variables. Results: Out of 1,753 pts with MCL, 36 (2%) had evidence of CNS involvement, including 4 pts with CNS involvement at initial MCL diagnosis. Baseline characteristics of pts with CNS involvement (CNS MCL group) and those without CNS involvement (control group) are shown in Table 1. At MCL diagnosis, non-CNS extranodal involvement was seen in 30 (83%) pts in the CNS MCL group (24 pts with 1 site and 6 pts with ≥ 2 sites), with bone marrow being the most common extranodal site of involvement (n=24, 67%). For the control group, 54 (75%) pts had extranodal involvement (44 pts with 1 site and 10 pts with ≥ 2 sites), and bone marrow was also the most common extranodal site of involvement (n=50, 69%). Notably, advanced stage disease (stage 3-4) was more commonly seen in the CNS MCL group (n=32, 97%) than in the control group (n=59, 83%) (p=0.04) at MCL diagnosis. Blastoid variant was present in a higher proportion of pts in the CNS MCL group (n=11, 31%) compared to the control group (n=8, 11%) (p=0.02). The CNS MCL group also presented with a higher median serum LDH at diagnosis (239 U/L [range 153-1901] vs. 187 U/L [range 124-588], p=0.02), and higher Ki-67 (40% [range 15-100] vs. 30% [range 10-90], p=0.04) compared to the control group. The most common frontline treatment regimen was anthracycline-based therapies (i.e. R-CHOP, Nordic regimen, R-hyperCVAD) for both groups (58% in CNS MCL group and 56% in control group). 14 (39%) pts in the CNS MCL group underwent autologous stem cell transplant in CR1 vs. 31 pts (43%) in the control group. Similar use of rituximab maintenance was seen in both groups (31% in CNS MCL group and 25% in control group). Median total lines of therapy from initial MCL diagnosis was 3 (range 1-9) in CNS MCL group and 2 (range 1-9) in the control group. The median follow-up from MCL diagnosis was 134 months (95% CI:119-163) for the entire cohort. Median OS from MCL diagnosis was 50.3 months (95% CI: 20.9-71.1) for the CNS MCL group compared to 97.1 months (95% CI: 82.6-192.7; p=<0.001) for the control group (Figure 1). Median time from MCL diagnosis to CNS involvement was 25 months (range 0-167). Median OS from CNS involvement was 4.7 months (95% CI: 2.3-6.7). At last follow up, 31 (86%) pts were deceased from the CNS MCL group, compared to 38 (52%) pts in the control group. For the CNS MCL group, the causes of death were CNS lymphoma in 10 (32%) pts, systemic lymphoma in 9 (29%) pts, treatment-related complication in 7 (23%) pts, and other/unknown in 5 (16%) pts. For the control group, the causes of death were systemic lymphoma in 15 (39%) pts, treatment-related in 2 (5%) pts, and other/unknown in 21 (55%) pts. Conclusion: In pts with MCL, CNS involvement is associated with worse outcomes as evident by a shorter median OS from initial MCL diagnosis (50 months vs. 97 months). Involvement of the CNS by lymphoma is an important contributor for the shorter OS as suggested by the median OS of only 5 months from CNS involvement. Advanced stage, blastoid variant, elevated LDH, and elevated Ki67 at MCL diagnosis were features more commonly seen in the CNS MCL cohort. Validation of risk factors at initial MCL diagnosis associated with CNS involvement and exploring the role of CNS prophylaxis are important topics for further investigation. Figure 1 Figure 1. Disclosures Paludo: Karyopharm: Research Funding. Wang: Novartis: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; MorphoSys: Research Funding; InnoCare: Research Funding; 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; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: 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. Nowakowski: Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene, NanoString Technologies, MorphoSys: 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. Habermann: Seagen: Other: Data Monitoring Committee; Tess Therapeutics: Other: Data Monitoring Committee; Incyte: Other: Scientific Advisory Board; Morphosys: Other: Scientific Advisory Board; Loxo Oncology: Other: Scientific Advisory Board; Eli Lilly & Co.,: Other: Scientific Advisor. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding.

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