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Anti-angiogenic drugs increase anti-tumor efficacy of immune checkpoint inhibitors (ICIs). However, the optimal dose of anti-angiogenic drugs remains unclear.We retrospectively analyzed efficacy and safety data from patients diagnosed with advanced or metastatic non-small cell lung cancer (NSCLC) that received PD-1 blockade with low-doses of anlotinib, a highly selective receptor tyrosine kinase inhibitor mainly targeting vascular endothelial growth factor receptors, as second or later line therapy. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), overall response rate (ORR), disease control rate (DCR), and safety profile. Univariate and multivariate analyses were used to identify prognostic factors.A total of 40 eligible patients were included. The median PFS was 11.4 months. The median OS of the entire cohort was 27.0 months. ORR was achieved in 16 patients (40.0%) and DCR was maintained in 33 patients (82.5%). The overall incidence of adverse events (AEs) was 52.5%, and the most common all grade AE was gastrointestinal reactions, which occurred in four patients (10.0%). Treatment-related grade 3/4 toxicity was observed in one patient (2.5%). Conclusions Low-dose anlotinib may be an effective and well-tolerated anti-angiogenesis partner for combination therapy with ICIs in second-line and later settings for advanced NSCLC.

Cytopenias are important but less studied adverse events following chimeric antigen receptor-engineered T cell (CAR-T) therapy. In our analysis of patients with large cell lymphoma who received axicabtagene ciloleucel (axi-cel), we sought to determine the rate and risk factors of clinically significant short term cytopenias defined as grade ≥3 neutropenia, anemia, or thrombocytopenia, or treatment with growth factors or blood product transfusions between days 20-30 after axi-cel. Fifty-three pts received axi-cel during the study period and severe cytopenias were observed in 32 (60%) pts. Significant cytopenias were more common in non-responders (stable or progressive disease) vs. responders (partial or complete response) (100% vs. 70%

Supplementary Data from Scalable Manufacturing of CAR T Cells for Cancer Immunotherapy

As of April 2021, there are five commercially available chimeric antigen receptor (CAR) T cell therapies for hematologic malignancies. With the current transition of CAR T cell manufacturing from academia to industry, there is a shift toward Good Manufacturing Practice (GMP)–compliant closed and automated systems to ensure reproducibility and to meet the increased demand for patients with cancer. In this review, we describe current CAR T cell clinical manufacturing models and discuss emerging technologic advances that embrace scaling and production optimization. We summarize measures being used to shorten CAR T cell manufacturing times and highlight regulatory challenges to scaling production for clinical use.Significance:As the demand for CAR T cell cancer therapy increases, several closed and automated production platforms are being deployed, and others are in development. This review provides a critical appraisal of these technologies, which can be leveraged to scale and optimize the production of next-generation CAR T cells.See related video:https://aacrjournals.org/content/webinar-car-t-cell-manufacturing

CD20 is an attractive immunotherapy target for B-cell non-Hodgkin lymphomas, and adoptive transfer of T cells genetically modified to express a chimeric antigen receptor (CAR) targeting CD20 is a promising strategy. A theoretical limitation is that residual serum rituximab might block CAR binding to CD20 and thereby impede T cell–mediated anti-lymphoma responses. The activity of CD20 CAR-modified T cells in the presence of various concentrations of rituximab was tested in vitro and in vivo. CAR-binding sites on CD20+ tumor cells were blocked by rituximab in a dose-dependent fashion, although at 37°C blockade was incomplete at concentrations up to 200 μg/mL. T cells with CD20 CARs also exhibited modest dose-dependent reductions in cytokine secretion and cytotoxicity, but not proliferation, against lymphoma cell lines. At rituximab concentrations of 100 μg/mL, CAR T cells retained ≥50% of baseline activity against targets with high CD20 expression, but were more strongly inhibited when target cells expressed low CD20. In a murine xenograft model using a rituximab-refractory lymphoma cell line, rituximab did not impair CAR T-cell activity, and tumors were eradicated in >85% of mice. Clinical residual rituximab serum concentrations were measured in 103 lymphoma patients after rituximab therapy, with the median level found to be only 38 μg/mL (interquartile range, 19–72 μg/mL). Thus, despite modest functional impairment in vitro, the in vivo activity of CD20-targeted CAR T cells remains intact at clinically relevant levels of rituximab, making use of these T cells clinically feasible. Cancer Immunol Res; 4(6); 509–19. ©2016 AACR.See related Spotlight by Sadelain, p. 473.

Pretargeted radioimmunotherapy (PRIT) has been investigated as a multi-step approach to decrease relapse and toxicity for high-risk acute myeloid leukemia (AML). Relevant factors including endogenous biotin and immunogenicity, however, have limited the use of PRIT with an anti-CD45 antibody streptavidin conjugate and radiolabeled DOTA-biotin. To overcome these limitations we designed anti-murine and anti-human CD45 bispecific antibody constructs using 30F11 and BC8 antibodies, respectively, combined with an anti-yttrium (Y)-DOTA single-chain variable fragment (C825) to capture a radiolabeled ligand. The bispecific construct targeting human CD45 (BC8-Fc-C825) had high uptake in leukemia HEL xenografts [7.8 ± 0.02% percent injected dose/gram of tissue (% ID/g)]. Therapy studies showed that 70% of mice with HEL human xenografts treated with BC8-Fc-C825 followed by 44.4 MBq (1,200 μCi) of 90Y-DOTA-biotin survived at least 170 days after therapy, while all nontreated controls required euthanasia because of tumor progression by day 32. High uptake at sites of leukemia (spleen and bone marrow) was also seen with 30F11-IgG1-C825 in a syngeneic disseminated SJL murine leukemia model (spleen, 9.0 ± 1.5% ID/g and bone marrow, 8.1 ± 1.2% ID/g), with minimal uptake in all other normal organs (90Y-DOTA injections. SJL leukemia mice treated with the bispecific 30F11-IgG1-C825 and 29.6 MBq (800 μCi) of 90Y-DOTA-biotin had a survival advantage compared with untreated leukemic mice (median, 43 vs. 30 days, respectively; P < 0.0001). These data suggest bispecific antibody–mediated PRIT may be highly effective for leukemia therapy and translation to human studies.

Supplementary Materials, Methods and relevant AA sequences

Table S1 presents mouse survival data for in vivo experiments

Figures including: Supplemental Figure 1- Dose finding pharmacokinetics. Supplemental Figure 2- Dose finding tissue biodistribution. Supplemental Figure 3- body weight over time in a therapy study. Supplemental Figure 4- blood counts over time in a therapy study. Supplemental Figure 5- fusion protein binding to Ramos and Granta cell lines

Streptavidin (SA)-biotin pretargeted radioimmunotherapy (PRIT) that targets CD20 in non-Hodgkin lymphoma (NHL) exhibits remarkable efficacy in model systems, but SA immunogenicity and interference by endogenous biotin may complicate clinical translation of this approach. In this study, we engineered a bispecific fusion protein (FP) that evades the limitations imposed by this system. Briefly, one arm of the FP was an anti-human CD20 antibody (2H7), with the other arm of the FP an anti-chelated radiometal trap for a radiolabeled ligand (yttrium[Y]-DOTA) captured by a very high-affinity anti-Y-DOTA scFv antibody (C825). Head-to-head biodistribution experiments comparing SA-biotin and bispecific FP (2H7-Fc-C825) PRIT in murine subjects bearing human lymphoma xenografts demonstrated nearly identical tumor targeting by each modality at 24 hours. However, residual radioactivity in the blood and normal organs was consistently higher following administration of 1F5-SA compared with 2H7-Fc-C825. Consequently, tumor-to-normal tissue ratios of distribution were superior for 2H7-Fc-C825 (P < 0.0001). Therapy studies in subjects bearing either Ramos or Granta subcutaneous lymphomas demonstrated that 2H7-Fc-C825 PRIT is highly effective and significantly less myelosuppressive than 1F5-SA (P < 0.0001). All animals receiving optimal doses of 2H7-Fc-C825 followed by 90Y-DOTA were cured by 150 days, whereas the growth of tumors in control animals progressed rapidly with complete morbidity by 25 days. In addition to demonstrating reduced risk of immunogenicity and an absence of endogenous biotin interference, our findings offer a preclinical proof of concept for the preferred use of bispecific PRIT in future clinical trials, due to a slightly superior biodistribution profile, less myelosuppression, and superior efficacy. Cancer Res; 76(22); 6669–79. ©2016 AACR.

Constitutive B-cell receptor signaling leads to overexpression of the antiapoptotic BCL-2 protein and is implicated in the pathogenesis of many types of B-cell non-Hodgkin lymphoma (B-NHL). The BCL-2 small-molecule inhibitor venetoclax shows promising clinical response rates in several lymphomas, but is not curative as monotherapy. Radiotherapy is a rational candidate for combining with BCL-2 inhibition, as DNA damage caused by radiotherapy increases the activity of pro-apoptotic BCL-2 pathway proteins, and lymphomas are exquisitely sensitive to radiation. We tested B-NHL responses to venetoclax combined with either external beam radiotherapy or radioimmunotherapy (RIT), which joins the selectivity of antibody targeting with the effectiveness of irradiation. We first tested cytotoxicity of cesium-137 irradiation plus venetoclax in 14 B-NHL cell lines representing five lymphoma subtypes. Combination treatment synergistically increased cell death in 10 of 14 lines. Lack of synergy was predicted by resistance to single-agent venetoclax and high BCL-XL expression. We then assessed the efficacy of external beam radiotherapy plus venetoclax in murine xenograft models of mantle cell (MCL), germinal-center diffuse large B-cell (GCB-DLBCL), and activated B-cell (ABC-DLBCL) lymphomas. In each model, external beam radiotherapy plus venetoclax synergistically increased mouse survival time, curing up to 10%. We finally combined venetoclax treatment of MCL and ABC-DLBCL xenografts with a pretargeted RIT (PRIT) system directed against the CD20 antigen. Optimal dosing of PRIT plus venetoclax cured 100% of mice with no detectable toxicity. Venetoclax combined with radiotherapy may be a promising treatment for a wide range of lymphomas Cancer Res; 77(14); 3885–93. ©2017 AACR.

Concurrent administration pembrolizumab with chemotherapy in untreated classical Hodgkin lymphoma (CHL) has not previously been studied. To investigate this combination, we conducted a single arm study of concurrent pembrolizumab with AVD (APVD) for untreated CHL. We enrolled 30 patients (6 early favorable, 6 early unfavorable, and 18 advanced stage, median age 33 years (range 18-69 years)) and met the primary safety endpoint with no observed significant treatment delays in the first two cycles. Twelve patients experienced grade 3-4 non-hematologic adverse events (AEs) most commonly febrile neutropenia (5, 17%) and infection/sepsis (3, 10%). Grade 3-4 immune-related AEs were seen in 3 patients, including ALT elevation (3, 10%) and AST elevation (1, 3%). One patient experienced an episode of grade 2 colitis and arthritis. Six (20%) patients missed at least one dose of pembrolizumab due to adverse events, primarily grade 2 or higher transaminitis (5, 17%). Among 29 response-evaluable patients, the best overall response rate was 100% and CR rate of 90%. With median follow up of 2.1 years, 2-year progression-free survival (PFS) and overall survival were 97% and 100%, respectively. To date, no patient who withheld or discontinued pembrolizumab due to toxicity has progressed. Clearance of ctDNA was associated with superior PFS when measured after cycle 2 (p=0.025) and at end of treatment (EOT, p=0.0016). None of the 4 patients with persistent disease by FDG-PET at EOT yet negative ctDNA have relapsed to date. Concurrent APVD shows promising safety and efficacy, but may yield spurious PET findings in some patients. Trial Registration Number: NCT03331341

Prior reports evaluating SARS-CoV-2 vaccine efficacy in chronic lymphocytic leukaemia (CLL) used semiquantitative measurements of anti-S to evaluate immunity; however, neutralization assays were used to assess functional immunity in the trials leading to vaccine approval. Here, we identified decreased rates of seroconversion in vaccinated CLL patients and lower anti-S levels compared to healthy controls. Notably, we demonstrated similar results with the Roche anti-S assay and neutralization activity. Durable responses were seen at six months; augmentation with boosters was possible in responding patients. Absence of normal B cells, frequently seen in patients receiving Bruton tyrosine kinase and B-cell lymphoma 2 inhibitors, was a strong predictor of lack of seroconversion.

Summary Background Relapsed or refractory classical Hodgkin lymphoma could be treated with multiagent salvage chemotherapy followed by autologous haematopoietic stem-cell transplantation. The aim of this study is to establish the safety and activity of dose-dense brentuximab vedotin combined with ifosfamide, carboplatin, and etoposide (BV-ICE) chemotherapy in second-line treatment of classical Hodgkin lymphoma. Methods We conducted a single-arm, open-label, phase 1/2 study of dose-dense BV-ICE at the Seattle Cancer Care Alliance, University of Washington (Seattle, WA, USA). Eligibility criteria were age 18 years or older; diagnosis of first relapse, primary refractory classical Hodgkin lymphoma after one previous line of therapy; measurable disease of at least 1 cm in the longest axis, CT of chest, abdomen, and pelvis with PET within the past 28 days; Eastern Cooperative Oncology Group performance status of 0–1; and adequate organ function. A 3 + 3 dose escalation study was done for the phase 1 part of the trial to establish the maximum tolerated dose to be used for the phase 2 study. Brentuximab vedotin was delivered on days 1 and 8 at either 1·2 mg/kg (dose level 1) or 1·5 mg/kg (dose level 2) intravenously (capped at 150 mg) with standard dosing of ICE on days 1–3 (ifosfamide 5 g/m2 plus mesna 5 g/m2 intravenously over 24 h on day 2, carboplatin area under the curve 5 on day 2 in one intravenous injection, and etoposide 100 mg/m2 on days 1–3 in one intravenous injection per day) for two 21-day cycles. The primary endpoint was to establish the recommended phase 2 dose (phase 1 part) and complete response rate after two cycles, with a prespecified target of 78% (phase 2 part). Safety analysis was done in all enrolled participants and the primary activity analysis was done in all patients with evaluable response data. This study is registered with ClinicalTrials.gov (NCT02227199); enrolment and study treatment are complete. Findings Between Oct 16, 2014, and Feb 10, 2020, we enrolled 45 patients with a median age of 31 years (IQR 28–45). The recommended phase 2 dose of brentuximab vedotin was established to be 1·5 mg/kg. After a median follow-up of 3·1 years (IQR 1·7–4·1), 32 (74%; 95% CI 58·8–86·5) of 43 evaluable patients had complete responses after two cycles of treatment. Grade 3–4 haematological toxic effects were common, including neutropenia (33 [73%]), anaemia (six [13%]), and thrombocytopenia (36 [80%]). The most common grade 3–4 non-haematological toxic effects were febrile neutropenia (four [9%]), sepsis (six [13%]), increased alanine aminotransferase (five [11%]), hyperglycaemia (three [7%]), pulmonary embolism (two [4%]), and increased aspartate aminotransferase (two [4%]). There was one (2%) on-treatment death due to multisystem organ failure that was considered treatment related. Serious adverse events occurred in 13 (29%) patients. Interpretation Our data suggest that dose-dense BV-ICE is a rapidly administered and active salvage regimen for patients with relapsed or refractory classical Hodgkin lymphoma despite a complete response in this trial lower than the prespecified phase 2 target. Although cross-trial comparisons should be made with caution, activity results seem to be similar to previously presented brentuximab vedotin chemotherapy salvage combinations delivered over much longer durations and can be considered in young ( Funding Seagen, Lymphoma Research Foundation, National Institutes of Health/National Cancer Institute, and generous philanthropic donations to the University of Washington from numerous individuals and families in support of lymphoma research.

Chimeric antigen receptor T-cell (CAR T) therapy has shown promising efficacy in relapsed and refractory diffuse large B cell lymphoma (DLBCL). While most patients undergo CAR T infusion with active disease, the impact of some clinical variables, such as responsiveness to the pre-CAR T chemotherapy on the response to CAR T, is unknown. In this single-institution study, we studied the impact of several pre-CAR T variables on the post-CAR outcomes. Sixty patients underwent apheresis for axicabtagene-ciloleucel (axi-cel) and 42 of them (70.0%) had primary refractory disease. Bridging therapy between apheresis and lymphodepletion was given in 34 patients (56.7%). After axi-cel, the overall response rate was 63.3%. Responsiveness to the immediate pre-CAR T therapy did not show a significant association with response to axi-cel, progression-free (PFS) or overall (OS) survival. Multivariable analysis determined that bulky disease before lymphodepletion was independently associated with inferior outcomes, and patients that presented with high-burden disease unresponsive to immediate pre-CAR T therapy had a dismal outcome. This data supports proceeding with treatment in CAR T candidates regardless of their response to immediate pre-CAR T therapy. Interim therapeutic interventions should be considered in patients who have known risk factors for poor outcomes (bulky disease, high LDH).

This was an open-label, phase 1b study assessing the safety, tolerability, preliminary efficacy and pharmacokinetics of the combination of atezolizumab and obinutuzumab in patients with relapsed/refractory follicular lymphoma (FL) or diffuse large B-cell lymphoma (DLBCL). There is a mechanistic rationale suggesting that this combination may enhance recruitment of both innate and adaptive immunity and be effective against CD20+ B-cell malignancies.The study consisted of a safety evaluation stage and an expansion stage. Patients received obinutuzumab 1000 mg intravenously (IV) in cycle (C) 1, obinutuzumab plus atezolizumab 1200 mg IV for C2-8, and atezolizumab only from C9. Primary endpoints were to identify a recommended phase 2 dose (RP2D) for atezolizumab, and safety and tolerability in the safety and expansion stages.A total of 49 patients were enrolled (FL, n = 26; DLBCL, n = 23), with a median of 2 prior lines of treatment. The RP2D for atezolizumab was 1200 mg IV every 3 weeks. Adverse events reported in ≥ 20% of patients were fatigue (15 patients [31%]), nausea (13 patients [27%]), cough, and diarrhea (10 patients [20%] each). Objective response rate was 54% in the FL cohort (complete response [CR] rate: 23%) and 17% in the DLBCL cohort (CR: 4%). Median progression-free survival was 9 months for FL and 3 months for DLBCL. Median overall survival was not estimable for FL and 9 months for DLBCL.The combination of obinutuzumab and atezolizumab was determined to be safe and tolerable, with no new toxicities observed.

Recently, combination regimens based on programmed cell death-1 (PD-1) blockade have become increasingly common in clinical practice for the treatment of cancer. Such combinations significantly improve efficacy, but treatment-related adverse events have also become more complex and severe. Here, we report an acute toxic epidermal necrolysis (TEN)-like reaction in a patient with gallbladder cancer who received camrelizumab (an anti-PD-1 antibody) in combination with apatinib. Interestingly, distinct clinical and pathological characteristics were observed that differed from those of the reported cases of severe cutaneous reactions induced by anti-PD-1 antibodies alone; thus, we speculate that it was induced by the combination of camrelizumab and apatinib. It is worth noting that the TEN-like reaction showed resistance to methylprednisolone initially, which was gradually resolved after the addition of intravenous immunoglobulin (IVIg). Immunohistochemical staining revealed that the skin lesion was infiltrated by moderate numbers of CD4+ T cells and large numbers of CD8+ T cells during the progression of the TEN-like reaction, and mass cytometry by time-of-flight showed a significant reduction in the CD4+ and CD8+ T cell proportions in the peripheral blood after the rash improved. All these findings highlight the essential role of CD4+ T cells and CD8+ T cells in the TEN-like reaction induced by camrelizumab plus apatinib treatment, and we speculate that T cells, especially CD8+ T cells, attack keratinocytes. In conclusion, the TEN-like reaction induced by camrelizumab and apatinib deserves clinical attention, and further work is needed to elucidate the exact pathophysiologic mechanism as well as the optimal management strategy.

As of April 2021, there are five commercially available chimeric antigen receptor (CAR) T cell therapies for hematologic malignancies. With the current transition of CAR T cell manufacturing from academia to industry, there is a shift toward Good Manufacturing Practice (GMP)–compliant closed and automated systems to ensure reproducibility and to meet the increased demand for patients with cancer. In this review, we describe current CAR T cell clinical manufacturing models and discuss emerging technologic advances that embrace scaling and production optimization. We summarize measures being used to shorten CAR T cell manufacturing times and highlight regulatory challenges to scaling production for clinical use. Significance: As the demand for CAR T cell cancer therapy increases, several closed and automated production platforms are being deployed, and others are in development. This review provides a critical appraisal of these technologies, which can be leveraged to scale and optimize the production of next-generation CAR T cells. See related video: https://aacrjournals.org/content/webinar-car-t-cell-manufacturing

High hepatitis B virus (HBV) DNA level is an independent risk factor for postoperative HBV-associated liver cancer recurrence. We sought to examine whether HBV DNA level and antiviral therapy are associated with survival outcomes in patients with advanced hepatocellular carcinoma (HCC) treated with anti-programmed cell death protein 1 (PD-1)based immunotherapy.This single-institution retrospective analysis included 217 patients with advanced HBV-related HCC treated from 1 June 2018, through 30 December 2020. Baseline information was compared between patients with low and high HBV DNA levels. Overall survival (OS) and progression-free survival (PFS) were compared, and univariate and multivariate analyses were applied to identify potential risk factors for oncologic outcomes.The 217 patients included in the analysis had a median survival time of 20.6 months. Of these HBV-associated HCC patients, 165 had known baseline HBV DNA levels. Baseline HBV DNA level was not significantly associated with OS (P = 0.59) or PFS (P = 0.098). Compared to patients who did not receive antiviral therapy, patients who received antiviral therapy had significantly better OS (20.6 vs 11.1 months, P = 0.020), regardless of HBV DNA levels. Moreover, antiviral status (adjusted HR = 0.24, 95% CI 0.094-0.63, P = 0.004) was an independent protective factor for OS in a multivariate analysis of patients with HBV-related HCC.HBV viral load does not compromise the clinical outcome of patients with HBV-related HCC treated with anti-PD-1-based immunotherapy. The use of antiviral therapy significantly improves survival time of HBV-related HCC patients.

Background: Classical Hodgkin lymphoma (CHL) patients (pts) requiring second line therapy may still be cured with multiagent salvage chemotherapy followed by autologous stem cell transplant (ASCT). The likelihood of long-term remission following ASCT for relapsed/refractory (R/R) CHL is predicted by response to pre-ASCT salvage therapy (Moskowitz et al. Blood 2012). The anti-CD30 antibody-drug conjugate brentuximab vedotin (BV) is effective as a single agent in R/R CHL. We hypothesized that concurrent therapy with dose-dense BV and 2 cycles of ICE would be safe, efficient, and produce high CR rates necessary for superior outcomes after ASCT. (#NCT02227199) Methods: Patients (pts) ≥ 18 years old with first relapse or primary refractory CD30+ cHL were eligible for this IRB-approved prospective clinical trial. Treatment included BV on Days 1 and 8 at either 1.2 or 1.5 mg/kg (based on 3+3 dose-escalation schema; capped at 150 mg), ifosfamide and mesna 5 g/m2 each on Day 2, carboplatin AUC 5 (capped at 800 mg) on Day 2, and etoposide 100 mg/m2 daily on Days 1-3. Two 21-day cycles were given with G-CSF support. BV 1.5 mg/kg was selected as the phase II dose based on reported dose escalation data (ASH 2016, #1834). PET was performed after Cycle 2, with response assigned per Cheson 2007. Stem cells were collected after Cycle 2 at discretion of treating investigator. Peripheral blood (PB) pre- and post-treatment, stem cell (PBSC) product, and (when available) archived formalin-fixed paraffin-embedded tissue (FFPET) from presentation and relapse were collected for correlative studies. Pre-treatment PB cytokine levels were measured by Luminex. Immunohistochemistry (IHC) on FFPET identified components of inflammatory microenvironment. The primary endpoint was to determine the MTD and CR rate after 2 cycles. Secondary endpoints included PFS, OS, stem cell collection, and molecular correlates. Results: All 45 pts have enrolled and completed study treatment, including 42 pts who were assigned treatment at the MTD of 1.5 mg/kg on day 1 and 8 of each cycle. Median age was 31 (range, 21-61). 16/45 (36%) were male, 28/45 (62%) had primary refractory disease, and 11/45 (24%) had extranodal involvement at relapse. 41 pts completed both cycles of therapy. One pt experienced grade 5 multi-system organ-failure during cycle 1, one pt was removed from protocol due to non-compliance, and two pts omitted cycle 2 due to toxicity (grade 4 sepsis, grade 3 Sweet syndrome attributable to G-CSF). 2 pts received all ICE dosing, but omitted at least one dose of BV due to toxicity. In addition, 13/41 (32%) pts delayed initiation of cycle 2 by a median of 7 days (range 6-17) due to toxicity, primarily elevated transaminases (10/13, 77%). 16/45 (36%) pts experienced neuropathy, but grade ≥2 neuropathy was rare (3/45, 7%). Other grade 3-4 non-hematologic toxicity included febrile neutropenia/sepsis (11%), elevated ALT (11%), hyperglycemia (7%), pulmonary embolism (4%), and elevated AST (4%). 36 pts underwent PBSC collection at our institution and had all data available for analysis. 30/36 pts were able to collect at least 5x106 CD34+ cells/kg. 5/6 of the remaining pts were still able to proceed with ASCT with the amount collected, and the other pt was not deemed an ASCT candidate due to social reasons. 37/43 pts (86%) who were evaluable for response proceeded to ASCT (2 subjects declined ASCT, 2 were ineligible due to social issues, one was lost to follow up, one remained chemorefractory despite additional salvage chemotherapy). Only 4/37 pts who received an ASCT subsequently relapsed. 43 pts were evaluable for efficacy. Overall response rate (ORR) and CR for all enrolled patients were 91% and 74%, respectively. Among primary refractory pts, ORR and CR were 86% and 68%, respectively. With a median follow-up of 26.5 months (range 0.7-62) months, 2-year PFS and OS were 82% and 98%. Updated results will be presented at the meeting. Conclusions: BV-ICE is a rapid, active and tolerable salvage regimen for R/R CHL patients, including those with primary refractory disease. Efficacy results are comparable to previously presented BV-chemo salvage combinations often delivered over longer durations. BV-ICE should be considered in R/R CHL prior to ASCT. Figure Disclosures Lynch: Juno Therpeutics: Research Funding; TG Therapeutics: Research Funding; Takeda: Research Funding; Incyte: Research Funding; Rhizen Pharmaceuticals: Research Funding; Bayer: Research Funding; Cyteir: Research Funding; MorphoSys: Consultancy; Genentech: Research Funding. Cassaday:Merck: Research Funding; Amgen: Consultancy, Research Funding; Pfizer: Honoraria, Research Funding; Vanda Pharmaceuticals: Research Funding; Seattle Genetics: Current Employment, Current equity holder in publicly-traded company; Kite/Gilead: Consultancy, Research Funding. Smith:AstraZeneca: Research Funding; Acerta Pharma BV: Research Funding; Beigene: Consultancy; Millenium/Takeda: Consultancy; AstraZeneca: Consultancy; Seattle Genetics: Research Funding; Portola: Research Funding; Pharmacyclics: Research Funding; Merck: Research Funding; Incyte: Research Funding; Ignyta: Research Funding; Genentech: Research Funding; De Novo Biopharma: Research Funding; Bristol Meyers Squibb: Research Funding; Bayer: Research Funding; Ayala: Research Funding; Karyopharm: Consultancy. Fromm:Merck: Research Funding. Cowan:Abbvie: Research Funding; Bristol Myers Squibb: Research Funding; Cellectar: Consultancy; Sanofi: Consultancy; Janssen: Consultancy, Research Funding. Shadman:Mustang Bio, Celgene, Pharmacyclics, Gilead, Genentech, Abbvie, TG therapeutics, Beigene, Astra Zeneca, Sunesis, Beigene: Research Funding; Abbvie, Genentech, Astra Zeneca, Sound Biologics , Pharmacyclics, Verastem, ADC therapeutics, Beigene, Cellectar, BMS, Morphosys and Atara Biotherapeutics: Consultancy. Shustov:Seattle Genetics: Research Funding. Till:Mustang: Patents & Royalties, Research Funding. Ujjani:MorphoSys: Consultancy; Genentech: Consultancy, Honoraria; Atara: Consultancy, Honoraria; Gilead/Kite: Consultancy, Research Funding; Verastem Oncology: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding. Gopal:IgM bio, BMS, merck: Research Funding; imab bio, takeda,astrazeneca,gilead: Research Funding; Seattle Genetics; Janssen; Takeda; IgM Bio; IMab Bio; BMS; Astra Zeneca; Merck; Gilead: Research Funding; Seattle Genetics; Janssen; IMab Bio; TG Therapeutics; Astra Zeneca; Merck; Gilead; ADC Therapeutics; Nurix; TG therapeutics, Cellectar; Actinium: Consultancy.

Minimal residual disease (MRD) has become an increasingly prevalent and important entity in multiple myeloma (MM). Despite deepening responses to frontline therapy, roughly 75% of MM patients never become MRD-negative to ≤10(−5), which is concerning because MRD-negative status predicts significantly longer survival. MM is highly heterogeneous, and MRD persistence may reflect survival of isolated single cells and small clusters of treatment-resistant subclones. Virtually all MM clones are exquisitely sensitive to radiation, and the α-emitter astatine-211 ((211)At) deposits prodigious energy within 3 cell diameters, which is ideal for eliminating MRD if effectively targeted. CD38 is a proven MM target, and we conjugated (211)At to an anti-CD38 monoclonal antibody to create an (211)At-CD38 therapy. When examined in a bulky xenograft model of MM, single-dose (211)At-CD38 at 15 to 45 µCi at least doubled median survival of mice relative to untreated controls (P < .003), but no mice achieved complete remission and all died within 75 days. In contrast, in a disseminated disease model designed to reflect low-burden MRD, 3 studies demonstrated that single-dose (211)At-CD38 at 24 to 45 µCi produced sustained remission and long-term survival (>150 days) for 50% to 80% of mice, where all untreated mice died in 20 to 55 days (P < .0001). Treatment toxicities were transient and minimal. These data suggest that (211)At-CD38 offers the potential to eliminate residual MM cell clones in low-disease-burden settings, including MRD. We are optimistic that, in a planned clinical trial, addition of (211)At-CD38 to an autologous stem cell transplant (ASCT) conditioning regimen may improve ASCT outcomes for MM patients.

Background Patients with chronic lymphocytic leukemia (CLL) treated with chemoimmunotherapy are at increased risk of developing therapy-related (t-) myelodysplastic syndrome (MDS). It is unclear whether antecedent CLL adds prognostic value to the revised International Prognostic Scoring System (IPSS-R) for MDS. We performed a retrospective analysis to evaluate the significance of a previous CLL diagnosis as an independent adverse prognostic factor. Patients and Methods We identified 18 consecutive patients with t-MDS, previously treated for CLL (CLL-MDS) from 2002 to 2016. For each CLL-MDS patient, we identified 2 control patients with de novo MDS matched for age (≤ 65 or > 65 years), IPSS-R (≤ 3 or > 3), and year of MDS diagnosis (before or after 2008). Multivariable models were developed to test for independent predictors of progression to acute myeloid leukemia (AML) and overall survival (OS). Results Median time from CLL to MDS diagnosis was 58.8 months (range, 12-280 months) and median number of treatment lines for CLL was 1 (range, 1-5), including alkylating agents in 15 patients (83%) and fludarabine, cyclophosphamide, rituximab in 12 patients (67%). Hypomethylating agents were administered in 13 (72%) of CLL-MDS patients and 33 (91%) of de novo MDS patients. After a median follow-up of 19.2 months, OS was not different between CLL-MDS and matched de novo MDS patients. CLL-MDS patients with IPSS-R score ≤ 3 had better OS compared with those with IPSS-R score > 3. In multivariate analysis, there was no significant independent association between history of CLL OS or progression to AML. Conclusion History of CLL did not independently affect OS in t-MDS patients beyond IPSS-R score.

Autologous T cells engineered to express a CD19-specific chimeric antigen receptor (CAR) have produced impressive minimal residual disease–negative (MRD-negative) complete remission (CR) rates in patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). However, the factors associated with durable remissions after CAR T-cell therapy have not been fully elucidated. We studied patients with relapsed/refractory B-ALL enrolled in a phase 1/2 clinical trial evaluating lymphodepletion chemotherapy followed by CD19 CAR T-cell therapy at our institution. Forty-five (85%) of 53 patients who received CD19 CAR T-cell therapy and were evaluable for response achieved MRD-negative CR by high-resolution flow cytometry. With a median follow-up of 30.9 months, event-free survival (EFS) and overall survival (OS) were significantly better in the patients who achieved MRD-negative CR compared with those who did not (median EFS, 7.6 vs 0.8 months; P < .0001; median OS, 20.0 vs 5.0 months; P = .014). In patients who achieved MRD-negative CR by flow cytometry, absence of the index malignant clone by IGH deep sequencing was associated with better EFS (P = .034). Stepwise multivariable modeling in patients achieving MRD-negative CR showed that lower prelymphodepletion lactate dehydrogenase concentration (hazard ratio [HR], 1.38 per 100 U/L increment increase), higher prelymphodepletion platelet count (HR, 0.74 per 50 000/μL increment increase), incorporation of fludarabine into the lymphodepletion regimen (HR, 0.25), and allogeneic hematopoietic cell transplantation (HCT) after CAR T-cell therapy (HR, 0.39) were associated with better EFS. These data allow identification of patients at higher risk of relapse after CAR T-cell immunotherapy who might benefit from consolidation strategies such as allogeneic HCT. This trial was registered at www.clinicaltrials.gov as #NCT01865617.

PURPOSE/OBJECTIVE(S) Patients with relapsed/refractory (r/r) diffuse large B-cell lymphoma (DLBCL) often require palliative radiotherapy (pRT) for symptomatic relief, bridging therapy, or salvage treatment (i.e., irradiation of only site of disease). Prognostication remains a challenge, especially with the advent of novel therapies such as chimeric antigen receptor (CAR)-T cells. We aimed to construct a predictive model for survival in r/r DLBCL treated with pRT. MATERIALS/METHODS Patients with r/r DLBCL who received their first course of pRT between 2009 and 2020 were included. OS was defined as time from pRT consult to death. A multivariable prognostic model was developed using Cox proportional hazard regression with LASSO (Least Absolute Shrinkage and Selection Operator)-regularization, which optimizes variable inclusion based on the model's overall prediction accuracy. Model discrimination performance was summarized using the concordance index after optimism-adjustment with the bootstrap (internal validation). RESULTS 82 patients met the inclusion criteria. Mean age at pRT was 62 years, with the majority of patients being male (59%) and Caucasian (80%). Most patients had an ECOG 0-1 (78%), despite being heavily pretreated (50% ≥3 systemic therapies, 22% transplant, 20% CAR-T cell therapy). pRT was most commonly delivered for symptoms (54%), followed by salvage (34%) and bridging (12%) to another systemic therapy. With a median follow-up of 6.3 months (range, 0.1- 91.2), 57 deaths (70%) were observed with median survival (MS) of 7.8 months. Treatment intent was associated with differences in MS: 4.1 mo (symptomatic), 10.4 mo (bridging), and 11.9 mo (salvage; P = 0.026). The LASSO method selected 5 co-variates for the multivariable OS model (Table 1), which was associated with an optimism-adjusted concordance index of 0.70 (95% CI, 0.61-0.80). Conversely, age, tachycardia, double/triple hit lymphoma, prior transplant or CAR-T cell therapy, and time from diagnosis were not selected by the LASSO for the model. CONCLUSION Our pilot prognostic model for survival of patients with r/r DLBCL treated with pRT has good predictive performance (concordance index 0.7), with performance status, treatment intent, and number of prior lines of therapy having the most impact on predictions. Interestingly, types of prior therapies (e.g., CAR-T cell) and pathologic features at diagnosis were not selected for the model. Future work will focus on validating these findings in other cohorts, where larger numbers may permit development and validation of a stronger prognostic model.

Identification of reliable biomarkers to predict efficacy of immune checkpoint inhibitors and to monitor relapse in cancer patients receiving this therapy remains one of the main objectives of cancer immunotherapy research. We found that the pretreatment B cell number in the peripheral blood differed significantly between responders and non-responders to anti-PD-1-based immunotherapy. Patients with various cancer types achieving a clinical response had a significantly lower number of B cells compared with those with progressive disease. Patients who progressed from partial response to progressive disease exhibited a gradually increased number of circulating B cells. Our findings suggest that B cells represent a promising biomarker for anti-PD-1-based immunotherapy responses and inhibit the effect of PD-1 blockade immunotherapy. Thus, preemptive strategies targeting B cells may increase the efficacy of PD-1 blockade immunotherapy in patients with solid tumors.

Autologous hematopoietic cell transplantation (AHCT) is a standard of care for several subtypes of high-risk lymphoma, but durable remissions are not achieved in the majority of patients. Intensified conditioning using CD45-targeted antibody-radionuclide conjugate (ARC) preceding AHCT may improve outcomes in lymphoma by permitting the delivery of curative doses of radiation to disease sites while minimizing toxicity. We performed sequential phase I trials of escalating doses of yttrium-90 (90Y)-labeled anti-CD45 antibody with or without BEAM (carmustine, etoposide, cytarabine, melphalan) chemotherapy followed by AHCT in adults with relapsed/refractory or high-risk B cell non-Hodgkin lymphoma (NHL), T cell NHL (T-NHL), or Hodgkin lymphoma (HL). Twenty-one patients were enrolled (16 NHL, 4 HL, 1 T-NHL). Nineteen patients received BEAM concurrently. No dose-limiting toxicities were observed; therefore, the maximum tolerated dose is estimated to be ≥34 Gy to the liver. Nonhematologic toxicities and engraftment kinetics were similar to standard myeloablative AHCT. Late myeloid malignancies and 100-day nonrelapse deaths were not observed. At a median follow-up of 5 years, the estimates of progression-free and overall survival of 19 patients were 37% and 68%, respectively. Two patients did not receive BEAM; one had stable disease and the other progressive disease post-transplant. The combination of 90Y-anti-CD45 with BEAM and AHCT was feasible and tolerable in patients with relapsed and refractory lymphoma. The use of anti-CD45 ARC as an adjunct to hematopoietic cell transplantation regimens or in combination with novel therapies/immunotherapies should be further explored based on these and other data.

To improve disease control without increasing the toxicity of a reduced-intensity allogeneic hematopoietic cell transplantation (HCT) in multiple myeloma (MM), a phase I trial was performed using an antibody-radionuclide conjugate targeting CD45 (90Y-DOTA-BC8) as conditioning. 90Y-DOTA-BC8 was combined with fludarabine and low-dose TBI followed by allogeneic HCT in patients with MM and ≥1 adverse risk characteristic at diagnosis, relapse after autologous transplant, or plasma cell leukemia (PCL). The primary objective was to estimate the maximum tolerated radiation absorbed dose. Fourteen patients were treated (one with PCL, nine failed prior autologous HCT, and nine with ≥1 adverse cytogenetics). Absorbed doses up to 32 Gy to liver were delivered. No dose-limiting toxicities occurred. Non-hematologic toxicities were manageable and included primarily gastrointestinal (43%) and metabolic/electrolyte disturbances (36%). Treatment-related mortality at 100 days was 0%. At a median follow-up of 5 years, the overall survival was 71% (median not reached) and the progression-free survival was 41% (median 40.9 months). The incorporation of CD45-targeted radioimmunotherapy (RIT) into a reduced-intensity allogeneic HCT is well-tolerated and may induce long-term remissions among patients with poor-risk MM, supporting further development of RIT-augmented conditioning regimens for HCT.

CD19-targeted chimeric antigen receptor-engineered (CD19 CAR) T-cell therapy has shown significant efficacy for relapsed or refractory (R/R) B-cell malignancies. Yet, CD19 CAR T cells fail to induce durable responses in most patients. Second infusions of CD19 CAR T cells (CART2) have been considered as a possible approach to improve outcomes. We analyzed data from 44 patients with R/R B-cell malignancies (acute lymphoblastic leukemia [ALL], n = 14; chronic lymphocytic leukemia [CLL], n = 9; non-Hodgkin lymphoma [NHL], n = 21) who received CART2 on a phase 1/2 trial (NCT01865617) at our institution. Despite a CART2 dose increase in 82% of patients, we observed a low incidence of severe toxicity after CART2 (grade ≥3 cytokine release syndrome, 9%; grade ≥3 neurotoxicity, 11%). After CART2, complete response (CR) was achieved in 22% of CLL, 19% of NHL, and 21% of ALL patients. The median durations of response after CART2 in CLL, NHL, and ALL patients were 33, 6, and 4 months, respectively. Addition of fludarabine to cyclophosphamide-based lymphodepletion before the first CAR T-cell infusion (CART1) and an increase in the CART2 dose compared with CART1 were independently associated with higher overall response rates and longer progression-free survival after CART2. We observed durable CAR T-cell persistence after CART2 in patients who received cyclophosphamide and fludarabine (Cy-Flu) lymphodepletion before CART1 and a higher CART2 compared with CART1 cell dose. The identification of 2 modifiable pretreatment factors independently associated with better outcomes after CART2 suggests strategies to improve in vivo CAR T-cell kinetics and responses after repeat CAR T-cell infusions, and has implications for the design of trials of novel CAR T-cell products after failure of prior CAR T-cell immunotherapies.

Pretargeted radioimmunotherapy (PRIT) has been investigated as a multi-step approach to decrease relapse and toxicity for high-risk acute myeloid leukemia (AML). Relevant factors including endogenous biotin and immunogenicity, however, have limited the use of PRIT with an anti-CD45 antibody (Ab)-streptavidin (SA) conjugate and radiolabeled DOTA-biotin. To overcome these limitations we designed anti-murine and anti-human CD45 bispecific antibody (Ab) constructs using 30F11 and BC8 Ab, respectively, combined with an anti-yttrium (Y)-DOTA single-chain variable fragment (C825) to capture a radiolabeled ligand. The bispecific construct targeting human CD45 (BC8-Fc-C825) had high uptake in leukemia HEL xenografts [7.8 ± 0.02% percent injected dose/gram of tissue (%ID/g)]. Therapy studies showed that 70% of mice with HEL human xenografts treated with BC8-Fc-C825 followed by 44.4 MBq (1200 [Formula: see text] Ci) of (90)Y-DOTA-biotin survived at least 170 days after therapy, while all non-treated controls required euthanasia due to tumor progression by day 32. High uptake at sites of leukemia (spleen and bone marrow) was also seen with 30F11-IgG1-C825 in a syngeneic disseminated SJL murine leukemia model (spleen: 9.0 ± 1.5% ID/g, and bone marrow: 8.1 ± 1.2% ID/g), with minimal uptake in all other normal organs (

Pretargeted radioimmunotherapy (PRIT) has been investigated as a multi-step approach to decrease relapse and toxicity for high-risk acute myeloid leukemia (AML). Relevant factors including endogenous biotin and immunogenicity, however, have limited the use of PRIT with an anti-CD45 antibody streptavidin conjugate and radiolabeled DOTA-biotin. To overcome these limitations we designed anti-murine and anti-human CD45 bispecific antibody constructs using 30F11 and BC8 antibodies, respectively, combined with an anti-yttrium (Y)-DOTA single-chain variable fragment (C825) to capture a radiolabeled ligand. The bispecific construct targeting human CD45 (BC8-Fc-C825) had high uptake in leukemia HEL xenografts [7.8 ± 0.02% percent injected dose/gram of tissue (% ID/g)]. Therapy studies showed that 70% of mice with HEL human xenografts treated with BC8-Fc-C825 followed by 44.4 MBq (1,200 μCi) of 90Y-DOTA-biotin survived at least 170 days after therapy, while all nontreated controls required euthanasia because of tumor progression by day 32. High uptake at sites of leukemia (spleen and bone marrow) was also seen with 30F11-IgG1-C825 in a syngeneic disseminated SJL murine leukemia model (spleen, 9.0 ± 1.5% ID/g and bone marrow, 8.1 ± 1.2% ID/g), with minimal uptake in all other normal organs (

The adoptive transfer of genetically engineered T cells modified to express a chimeric antigen receptor (CAR) has shown remarkable activity and induces long-term remissions in patients with advanced hematologic malignancies. To date, little is known about predictive indicators of therapeutic efficacy or serious toxicity after CAR T-cell therapy in clinical practice. Biomarkers are not only potentially able to inform physicians and researchers of immunotherapy targets in particular but could also be used to monitor the effectiveness of treatments and to predict incidence of side effects in some circumstances. Identification of new biomarkers can therefore not only contribute to the development of new therapeutic and prognostic strategies for CAR T-cell therapy for cancer but also help to generate improved clinical practices for early recognition and minimization of adverse effects while preserving the antitumor activity of the CAR T cells. Herein, we will consider a variety of predictive and therapeutic biomarkers in CAR T-cell therapy and the state of current understanding of their clinical utility. The incorporation of biomarker studies in CAR T-cell clinical trials and practice will help to realize the potential clinical benefit of biomarker-guided therapy.

Background Bendamustine is a chemotherapeutic agent that has shown broad activity in patients with lymphoid malignancies. It contains both alkylating and nucleoside analog moieties, and thus, is not commonly used for stem cell mobilization due to concerns that it may adversely affect stem cell collection. Here we describe the lymphoma subset of a prospective, non-randomized phase II study of bendamustine, etoposide, and dexamethasone (BED) as a mobilization agent for lymphoid malignancies. Methods This subset analysis includes diffuse large B-cell lymphoma (N=3), follicular lymphoma (N=1), primary mediastinal B-cell lymphoma (N=1), and NK/T-cell lymphoma (N=1). Patients received bendamustine (120 mg/m2 IV d 1, 2), etoposide (200 mg/m2 IV d 1-3), and dexamethasone (40 mg PO d 1-4) followed by filgrastim (10 mcg/kg/d sc. through collection). Results We successfully collected stem cells from all patients, with a median of 7.9×106/kg of body weight (range, 4.4 to 17.3×106/kg) over a median of 1.5 days (range, 1 to 3) of apheresis. All patients who received transplants were engrafted using kinetics that were comparable to those of other mobilization regimens. Three non-hematologic significant adverse events were observed in one patient, and included bacterial sepsis (grade 3), tumor lysis syndrome (grade 3), and disease progression (grade 5). Conclusion For non-Hodgkin lymphoma, mobilization with bendamustine is safe and effective.

Pretargeted radioimmunotherapy (PRIT) has demonstrated remarkable efficacy targeting tumor antigens, but immunogenicity and endogenous biotin blocking may limit clinical translation. We describe a new PRIT approach for the treatment of multiple myeloma (MM) and other B-cell malignancies, for which we developed an anti-CD38-bispecific fusion protein that eliminates endogenous biotin interference and immunogenic elements. In murine xenograft models of MM and non-Hodgkin lymphoma (NHL), the CD38-bispecific construct demonstrated excellent blood clearance and tumor targeting. Dosimetry calculations showed a tumor-absorbed dose of 43.8 Gy per millicurie injected dose of 90Y, with tumor-to-normal organ dose ratios of 7:1 for liver and 15:1 for lung and kidney. In therapy studies, CD38-bispecific PRIT resulted in 100% complete remissions by day 12 in MM and NHL xenograft models, ultimately curing 80% of mice at optimal doses. In direct comparisons, efficacy of the CD38 bispecific proved equal or superior to streptavidin (SA)-biotin-based CD38-SA PRIT. Each approach cured at least 75% of mice at the highest radiation dose tested (1200 µCi), whereas at 600- and 1000-µCi doses, the bispecific outperformed the SA approach, curing 35% more mice overall (P < .004). The high efficacy of bispecific PRIT, combined with its reduced risk of immunogenicity and endogenous biotin interference, make the CD38 bispecific an attractive candidate for clinical translation. Critically, CD38 PRIT may benefit patients with unresponsive, high-risk disease because refractory disease typically retains radiation sensitivity. We posit that PRIT might not only prolong survival, but possibly cure MM and treatment-refractory NHL patients.

Autologous stem cell transplant (ASCT) consolidation has become a standard approach for patients with mantle cell lymphoma (MCL), yet there is little consensus on the role of total body irradiation (TBI) as part of high-dose transplantation conditioning. We analyzed 75 consecutive patients with MCL who underwent ASCT at our institution between 2001 and 2011 with either TBI-based (n = 43) or carmustine, etoposide, cytarabine, melphalan (BEAM; n = 32) high-dose conditioning. Most patients (97%) had chemosensitive disease and underwent transplantation in first remission (89%). On univariate analysis, TBI conditioning was associated with a trend toward improved PFS (hazard ratio [HR], .53; 95% confidence interval [CI], .28-1.00; P = .052) and similar OS (HR, .59; 95% CI, .26-1.35; P = .21), with a median follow-up of 6.3 years in the TBI group and 6.6 years in the BEAM group. The 5-year PFS was 66% in the TBI group versus 52% in the BEAM group; OS was 82% versus 68%, respectively. However, on multivariate analysis, TBI-based conditioning was not significantly associated with PFS (HR, .57; 95% CI .24-1.34; P = .20), after controlling for age, disease status at ASCT, and receipt of post-transplantation rituximab maintenance. Likewise, early toxicity, nonrelapse mortality, and secondary malignancies were similar in the 2 groups. Our data suggest that both TBI and BEAM-based conditioning regimens remain viable conditioning options for patients with MCL undergoing ASCT.

Chimeric antigen receptor (CAR) based adoptive T cell therapy is a highly promising treatment for lymphoid malignancies, and CD20 is an ideal target antigen. We previously developed a lentiviral construct encoding a 3rd generation CD20-targeted CAR but identified several features that required additional optimization prior to clinical translation. We describe here several improvements, including replacement of the immunogenic murine antigen-binding moiety with a fully human domain, streamlining the transgene insert to enhance lentiviral titers, modifications to the extracellular IgG spacer that abrogate nonspecific activation resulting from binding to Fc receptors, and evaluation of CD28, 4-1BB, or CD28 and 4-1BB costimulatory domains. We also found that re-stimulation of CAR T cells with an irradiated CD20+ cell line boosted cell growth, increased the fraction CAR-expressing cells, and preserved in vivo function despite leading to a reduced capacity for cytokine secretion in vitro. We also found that cryopreservation of CAR T cells did not impact immunophenotype or in vivo anti-tumor activity compared with fresh cells. These optimization steps resulted in significant improvement in anti-tumor activity in mouse models, resulting in eradication of established systemic lymphoma tumors in 75% of mice with a single infusion of CAR T cells, and prolonged in vivo persistence of modified cells. These results provide the basis for clinical testing of a lentiviral construct encoding a fully human CD20-targeted CAR with CD28 and 4-1BB costimulatory domains and truncated CD19 (tCD19) transduction marker.

Introduction Infusional da-EPOCH-R (dose-adjusted etoposide, doxorubicin, and cyclophosphamide with vincristine, prednisone, and rituximab) is a dose-intensified regimen with a potential role in treating high-risk subtypes of aggressive B-cell non-Hodgkin lymphoma (B-NHL). Studies of da-EPOCH-R use daily injections of granulocyte colony-stimulating factor (GCSF) to tailor chemotherapy dosing, and whether 1-time administration of pegylated GCSF (peg-GCSF) is as efficacious has not been addressed. Patients and Methods We reviewed aggressive B-NHL patients treated at our center with first-line da-EPOCH-R for clinician choice of growth factor, and analyzed dose level achieved, rate of unplanned hospitalizations, and patient outcomes. Results Among 73 patients, 44 received peg-GCSF. Overall, 11 patients (15%) patients achieved dose level 4. Baseline characteristics between peg-GCSF and GCSF groups were similar. The proportion of patients who achieved dose level 4 was comparable in the peg-GCSF group (5 of 44 [11%]) and daily GCSF (6 of 29 [21%]; P = .24). The rate of unplanned hospitalizations, and event-free and overall survival, were also similar between groups. Conclusion We suggest routine use of peg-GCSF is an acceptable alternative to daily GCSF, for patients in whom da-EPOCH-R is selected as first-line treatment for aggressive B-NHL.

Introduction ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) represents standard frontline therapy for classical Hodgkin lymphoma (CHL) in North America. Substituting brentuximab vedotin for bleomycin in this regimen demonstrated improved efficacy in advanced stage patients (pts) but also increased toxicity (Connors et al NEJM 2017). PD-1 inhibitors are highly active in relapsed/refractory CHL, and the first-line setting may represent the ideal time for incorporating PD1 inhibition given the relatively intact host immunity and juxtaposition of malignant cells with T cells in the tumor microenvironment. Methods This was a single arm pilot study combining pembrolizumab with AVD in untreated CHL of any stage. Eligibility requiredECOG 0-1, adequate organ function, and measurable disease. The trial intended to enroll 30 pts. AVD was given at standard doses on days 1 and 15 of a 28-day cycle. Pembrolizumab (200 mg IV) was given starting cycle 1 day 1 and every 21 days thereafter (cycle 1 day 22, cycle 2 day 15 etc.). The primary objective was to estimate the safety of delivering 2 cycles of APVD. The secondary objective was to estimate the FDG-PET2 negative (Deauville score 1-3) rate after 2 cycles of APVD. Exploratory objectives included overall and progression free survival, predictive capacity of PET2 after APVD, analysis of ctDNA as well as assessments of metabolic tumor volume. After PET2 response assessment, subjects could continue APVD for up to 6 total cycles as deemed appropriate for their stage/risk factors (including alternate systemic therapy or radiotherapy). Results All 30 subjects have enrolled and received at least 2 cycles of therapy. Median age was 32 years (range 18-69). Most pts had advanced stage (stage I n =1 (3%), stage II n=11 (37%), stage III n=7 (23%), stage IV n=11, (37%)). Thirteen (43%) pts had B symptoms at diagnosis and 5 (17%) had bulky disease. Among the 30 pts enrolled, 28 are evaluable for response (one pt declined interim-PET and further treatment and final patient will have PET2 shortly after abstract deadline.Nineteen (68%) pts were PET2 neg (5PS 1-3). No PET2+ pts have progressed to date. End of therapy (EOT) PET negativity (after 2-6 cycles) was 78% (18/23). Among the 5 pts with residual FDG uptake at EOT, only 1 (20%) has developed recurrent lymphoma. With median follow-up of 10.3 months, 1-year PFS and OS were 96% and 100%, respectively. Six (20%) pts required interruption of pembrolizumab due to toxicity, primarily grade ≥ 2 transaminitis (83%). Those with grade 2 transaminitis (2/6) completed chemotherapy prior to resolving to grade 1 and did not receive additional pembrolizumab. Those with grade ≥ 3 transaminitis (3/6) were required to permanently discontinue pembrolizumab. All transaminitis was transient and resolved with steroids and/or withholding pembrolizumab. No pneumonitis and no other grade ≥ 3 immune-related AEs were observed. Toxicities were otherwise similar to those expected with ABVD chemotherapy. No pt had a treatment delay of > 21 days during the first 2 cycles, and no pt who interrupted pembrolizumab due to toxicity has relapsed. Updated efficacy and more detailed safety data will be presented at the meeting. Conclusion Pembrolizumab + AVD without a PD-1 lead-in is safe and effective therapy for frontline HL. In this study, PET2+ following APVD does not appear to be associated with high risk of disease relapse. Additional analyses of MTV and ctDNA are ongoing to better understand these results. Concurrent APVD, without an anti-PD-1 run-in, represents a well-tolerated, and efficacious backbone that can be further evaluated in all stages of CHL. Figure 1 Figure 1. Disclosures Lynch: Incyte: Research Funding; TG Therapeutics: Research Funding; Cyteir: Research Funding; Genentech: Research Funding; SeaGen: Research Funding; Bayer: Research Funding; Juno Therapetics: Research Funding; Morphosys: Consultancy. Ujjani: ACDT: Honoraria; Kite, a Gilead Company: Honoraria; Gilead: Honoraria; TG Therapeutics: Honoraria; Janssen: Consultancy; Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Atara Bio: Consultancy; Loxo: Research Funding; Adaptive Biotechnologies: Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding. Poh: Acrotech: Honoraria; Incyte: Research Funding; Morphosys: Consultancy. Smith: Incyte Corporation: Research Funding; Merck Sharp & Dohme Corp: Research Funding; Ignyta (spouse): Research Funding; Acerta Pharma BV: Research Funding; Portola Pharmaceuticals: Research Funding; ADC Therapeutics: Consultancy; Karyopharm: Consultancy; Ayala (spouse): Research Funding; De Novo Biopharma: Research Funding; KITE pharm: Consultancy; Genentech: Research Funding; AstraZeneca: Consultancy, Research Funding; Bristol Myers Squibb (spouse): Research Funding; Incyte: Consultancy; Bayer: Research Funding; Beigene: Consultancy, Research Funding; Millenium/Takeda: Consultancy. Shadman: Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, Abbvie, TG Therapeutics, Beigene, AstraZeneca, Sunesis, Atara Biotherapeutics, GenMab: Research Funding; Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, Adaptimmune , Mustang Bio and Atara Biotherapeutics: Consultancy. Shustov: Seagen Inc.: Research Funding. Till: Mustang Bio: Consultancy, Patents & Royalties, Research Funding. Alizadeh: Gilead: Consultancy; Janssen Oncology: Honoraria; Roche: Consultancy, Honoraria; Celgene: Consultancy, Research Funding; Foresight Diagnostics: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Bristol Myers Squibb: Research Funding; Forty Seven: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; CAPP Medical: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Cibermed: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Gopal: Epizyme: Consultancy, Honoraria; MorphoSys: Honoraria; Gilead: Consultancy, Honoraria, Research Funding; I-Mab bio: Consultancy, Honoraria, Research Funding; Genetech: Consultancy, Honoraria, Research Funding; Teva: Research Funding; Beigene: Consultancy, Honoraria; SeaGen: Consultancy, Honoraria, Research Funding; Incyte: Honoraria; Acrotech: Consultancy, Honoraria; Cellectar: Consultancy, Honoraria; Nurix Inc: Consultancy, Honoraria; ADC Therapeutics: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Merck: Consultancy, Honoraria, Research Funding; Takeda: Research Funding; Astra-Zeneca: Research Funding; Agios: Research Funding; Bristol Meyers Squibb: Research Funding; Karyopharm: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; IGM Biosciences: Research Funding; Kite: Consultancy, Honoraria.

Background: Autologous CD19-targeting chimeric antigen receptor T cell (CAR-T) products are approved as standard treatment options for patients (pts) with relapsed diffuse large cell lymphoma (DLBCL), mantle cell lymphoma (MCL), and follicular lymphoma (FL). Their long-term efficacy for DLBCL is ~40% and is unknown for other histologies. Additionally, associated toxicities including cytokine-release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) remain a challenge. CD20 is a proven target for treatment of B-NHLs/CLL with demonstrated high clinical efficacy of unmodified, radiolabeled, and bispecific antibodies. Therefore, CD20-targeted CAR-T represents a promising adoptive immunotherapy option that could be utilized to treat relapsed/refractory (R/R) B-NHLs and CLL. MB-106 is a fully human 3rd-generation CD20-targeted CAR-T product with both 4-1BB and CD28 costimulatory domains. We present results of our ongoing phase I/II clinical trial investigating safety and efficacy of CD20 CAR-T for high-risk B-NHLs and CLL (NCT03277729). Methods: Pts with R/R CD20+ B-cell malignancies are eligible, including but not limited to DLBCL, FL, MCL, and CLL. Prior treatment with CD19 CAR-T is permitted. Lymphodepletion (LD) consists of cyclophosphamide (Cy) ± fludarabine (Flu). CAR-T cells are administered at one of 4 dose levels (DL): DL1: 3.3x10 5, DL2: 1x10 6, DL3: 3.3x10 6, DL4: 1x10 7 CAR T cells/kg. A continual reassessment method dose escalation design was used to find the maximally tolerated dose. CAR-T is infused in the outpatient setting except for the first pt of each dose cohort (overnight observation). Treatment response is assessed on day 28. CRS and ICANS are graded per ASTCT consensus grading. The study underwent a major cell manufacturing modification after treating 7 pts with no objective responses as previously reported (Shadman, ASH 2020, #1443). This abstract includes pts who were treated under the modified process. Results: Between Dec 2019 and July 2021, 16 pts (12 FL, 2 MCL, 1 CLL, 1 DLBCL) were treated after LD with Cy-Flu and had day 28 assessment. All DLs were reached (see table), with no dose-limiting toxicities to date. CRS occurred in 7 pts (44%): 4 pts with grade (Gr) 1 and 3 with Gr 2. ICANS was observed in 1 pt (6.2%) at Gr 2. There were no Gr 3 or Gr 4 CRS or ICANS. Median time to CRS was 6.5 days (range, 0-12); the 1 ICANS event occurred on day 12. One pt (CLL) developed Gr 3 temporary neuropathic pain which, in the absence of other explanation, was attributed to the CAR-T. No pts had tumor lysis syndrome or Gr 3-4 infections. Thrombocytopenia (Gr 3-4: 19%) and neutropenia (Gr 3-4: 94%) were common but there were no bleeding complications, and the rate of febrile neutropenia was 19%. Overall response (ORR) was 94% (15/16) with complete response (CR) rate of 62% (10/16). In FL pts (n =12), ORR was 92% (11/12) and CR rate was 75% (9/12). Among FL pts who received DL 3 or 4, the CR rate was 86%. The CLL pt had a PET-negative CR and undetectable measurable residual disease in peripheral blood and bone marrow by flow cytometry (10 -4) (uMRD4) on day 28. The pt with DLBCL achieved a partial response (PR) on day 28 and a repeat PET on day ~ 90 showed continued improvement but still indicating a PR. Among pts who achieved a CR, only one pt (FL) relapsed after 9 months. All other CRs are ongoing (range: 3-18 months). CAR-T persistence was lost at day 95 in 1 pt who had progression and proceeded to other anti-lymphoma treatment; 2 other patients lost CAR-T engraftment by day 181 and 201 with B cell recovery. All other patients continue to have detectable CAR-T cells as of last follow-up (max 13 months post-infusion). Conclusion: Treatment with MB-106 shows a favorable safety profile with no Gr 3 or Gr 4 CRS or ICANS. In addition, we observed a high rate of ORR and CR with ongoing CRs and high rate of CAR-T persistence. Enrollment is currently ongoing; data will be updated at the time of presentation. Figure 1 Figure 1. Disclosures Shadman: Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, Abbvie, TG Therapeutics, Beigene, AstraZeneca, Sunesis, Atara Biotherapeutics, GenMab: Research Funding; Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, Adaptimmune , Mustang Bio and Atara Biotherapeutics: Consultancy. Yeung: Merck,Celgene: Consultancy. Ujjani: ACDT: Honoraria; Gilead: Honoraria; TG Therapeutics: Honoraria; Janssen: Consultancy; Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Atara Bio: Consultancy; Loxo: Research Funding; Adaptive Biotechnologies: Research Funding; Kite, a Gilead Company: Honoraria; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding. Dezube: Mustang Bio: Current Employment, Current holder of individual stocks in a privately-held company. Poh: Acrotech: Honoraria; Incyte: Research Funding; Morphosys: Consultancy. Chapuis: Karkinos Therapeutics: Other: Ownership; Lonza: Other: Intellectual Property; Cullian: Other: Intellectual Property; TScan Therapeutics, Inc.: Consultancy, Other: Ownership; SignalOne Bio: Consultancy, Other: Ownership; Bluebird bio: Other: Intellectual Property; Juno therapeutics: Other: Intellectual Property; Adapyive Biotechnologies Corporation: Other: Ownership/Intellectual Property; Pfizer: Other: Intellectual Property; Affini-T: Other: Ownership; Ridgeline: Consultancy; BioNTech: Consultancy. Green: Seagen Inc.: Research Funding; bristol myers squibb: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Cellectar Biosciences: Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees; Janssen Biotech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Therapeutics: Patents & Royalties, Research Funding; Legend Biotech: Consultancy; Neoleukin Therapeutics: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; SpringWorks Therapeutics: Research Funding. Cowan: Abbvie: Consultancy, Research Funding; Harpoon: Research Funding; Janssen: Consultancy, Research Funding; Sanofi Aventis: Consultancy, Research Funding; Bristol Myers Squibb: Research Funding; Nektar: Research Funding; GSK: Consultancy; Secura Bio: Consultancy; Cellectar: Consultancy. Cassaday: Amgen: Consultancy, Research Funding; Servier: Research Funding; Vanda Pharmaceuticals: Research Funding; Pfizer: Consultancy, Research Funding; Kite/Gilead: Consultancy, Honoraria, Research Funding; Pepromene Bio: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding. Kiem: Homology Medicines: Consultancy; VOR Biopharma: Consultancy; Ensoma Inc.: Consultancy, Current holder of individual stocks in a privately-held company. Gauthier: Janssen: Membership on an entity's Board of Directors or advisory committees; Multerra Bio: Consultancy; Legend Biotech: Membership on an entity's Board of Directors or advisory committees; Larvol: Consultancy; JMP: Consultancy; Eusapharma: Consultancy. Turtle: T-CURX: Other: Scientific Advisory Board; Century Therapeutics: Consultancy, Other: Scientific Advisory Board; Arsenal Bio: Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; Eureka Therapeutics: Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; Nektar Therapeutics: Consultancy, Research Funding; Precision Biosciences: Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; Caribou Biosciences: Consultancy, Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; Juno Therapeutics/BMS: Patents & Royalties: Right to receive royalties from Fred Hutch for patents licensed to Juno Therapeutics, Research Funding; AstraZeneca: Consultancy, Research Funding; Myeloid Therapeutics: Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; Asher Bio: Consultancy; Amgen: Consultancy; PACT Pharma: Consultancy; TCR2 Therapeutics: Research Funding; Allogene: Consultancy. Lynch: TG Therapeutics: Research Funding; Bayer: Research Funding; Incyte: Research Funding; Juno Therapetics: Research Funding; Morphosys: Consultancy; Genentech: Research Funding; SeaGen: Research Funding; Cyteir: Research Funding. Smith: Portola Pharmaceuticals: Research Funding; Acerta Pharma BV: Research Funding; ADC Therapeutics: Consultancy; Incyte Corporation: Research Funding; AstraZeneca: Consultancy, Research Funding; Incyte: Consultancy; Ayala (spouse): Research Funding; Merck Sharp & Dohme Corp: Research Funding; Bristol Myers Squibb (spouse): Research Funding; De Novo Biopharma: Research Funding; Ignyta (spouse): Research Funding; KITE pharm: Consultancy; Millenium/Takeda: Consultancy; Bayer: Research Funding; Karyopharm: Consultancy; Beigene: Consultancy, Research Funding; Genentech: Research Funding. Gopal: Gilead: Consultancy, Honoraria, Research Funding; Genetech: Consultancy, Honoraria, Research Funding; SeaGen: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Research Funding; Bristol Meyers Squibb: Research Funding; Agios: Research Funding; MorphoSys: Honoraria; IGM Biosciences: Research Funding; ADC Therapeutics: Consultancy, Honoraria; Acrotech: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Merck: Consultancy, Honoraria, Research Funding; Kite: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Nurix Inc: Consultancy, Honoraria; Takeda: Research Funding; Teva: Research Funding; I-Mab bio: Consultancy, Honoraria, Research Funding; Epizyme: Consultancy, Honoraria; Incyte: Honoraria; Beigene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Cellectar: Consultancy, Honoraria. Maloney: BioLineRx, Juno, Celgene, Kite, a Gilead Company, Gilead, Novartis, and Pharmacyclics: Honoraria; A2 Biotherapeutics: Consultancy; Kite, a Gilead Company, Juno, and Celgene: Research Funding; Juno: Patents & Royalties; A2 Biotherapeutics: Divested equity in a private or publicly-traded company in the past 24 months. Till: Mustang Bio: Consultancy, Patents & Royalties, Research Funding.