Refractory non-Hodgkin Lymphoma Research Articles

Immunotherapy of Hematological Malignancies of Human B-Cell Origin with CD19 CAR T Lymphocytes.

Acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL) are hematological malignancies with high incidence rates that respond relatively well to conventional therapies. However, a major issue is the clinical emergence of patients with relapsed or refractory (r/r) NHL or ALL. In such circumstances, opportunities for complete remission significantly decline and mortality rates increase. The recent FDA approval of multiple cell-based therapies, Kymriah (tisagenlecleucel), Yescarta (axicabtagene ciloleucel), Tecartus (Brexucabtagene autoleucel KTE-X19), and Breyanzi (Lisocabtagene Maraleucel), has provided hope for those with r/r NHL and ALL. These new cell-based immunotherapies use genetically engineered chimeric antigen receptor (CAR) T-cells, whose success can be attributed to CAR's high specificity in recognizing B-cell-specific CD19 surface markers present on various B-cell malignancies and the subsequent initiation of anti-tumor activity. The efficacy of these treatments has led to promising results in many clinical trials, but relapses and adverse reactions such as cytokine release syndrome (CRS) and neurotoxicity (NT) remain pervasive, leaving areas for improvement in current and subsequent trials. In this review, we highlight the current information on traditional treatments of NHL and ALL, the design and manufacturing of various generations of CAR T-cells, the FDA approval of Kymriah, Yescarta Tecartus, and Breyanzi, and a summary of prominent clinical trials and the notable disadvantages of treatments. We further discuss approaches to potentially enhance CAR T-cell therapy for these malignancies, such as the inclusion of a suicide gene and use of FDA-approved drugs.

457 A Phase I Trial of Tazemetostat and Venetoclax in Relapsed and Refractory non-Hodgkin Lymphoma

OBJECTIVES/GOALS: Primary Objective: To evaluate the safety of venetoclax plus tazemetostat in patients with relapsed and refractory (R/R) Follicular lymphoma (FL) or Diffuse large B-cell lymphoma (DLBCL) Secondary Objectives: 1. To evaluate the tolerability of the combination of T+V using patient reported outcomes (PROs) 2. To evaluate the efficacy of T+V METHODS/STUDY POPULATION: Study design: A phase I trial in two parts: Part 1: a single-arm, open-label sequential dose escalation (3+3) of venetoclax in combination with tazemetostat, given at its recommended phase II dose (RP2D) of 800mg BID, to determine the maximum tolerated dose (MTD) of venetoclax. Part 2: two expansion cohorts (R/R DLBCL and R/R FL) to further characterize the safety and tolerability of the combination, and to estimate the preliminary efficacy. We will perform additional exploratory studies to determine if there are biologic features that correlate with responses. Eligibility: up to 38 patients aged >/=18 years old with histologically confirmed diagnosis of FL or DLBCL who have received at least 2 prior lines of therapy for lymphoma with evidence of disease progression and meet inclusion criteria RESULTS/ANTICIPATED RESULTS: Primary Endpoints: 1. Incidence and severity of adverse events as per CTCAEv5 2. Dose-limiting toxicity (DLT) of T+V, and to establish the maximum tolerated dose (MTD) of V plus fixed dose T Secondary Endpoints: 1. Incidence and Severity of toxicity and quality of life as per PRO-CTCAE and FACT-Lym 2. Overall response rate (ORR), complete response (CR) rate, partial response (PR) rate, as per Lugano criteria 3. Duration of response (DOR), progression-free survival (PFS), overall survival (OS)Exploratory Endpoints: 1. Characterization of tumor cells pre-treatment (including EZH2 mutations and BCL2 translocations) 2. Phenotypic analysis (including BCL2 expression) and quantification of the tumor microenvironment in pre-treatment samples (using image mass cytometry)Explorato DISCUSSION/SIGNIFICANCE: There is a need for novel therapeutic approaches to improve the prognosis for patients with R/R NHL. Preclinical data suggests synergism between the pair.5 Importantly, this represents a chemotherapy-free, oral regimen. If well tolerated, this could present an alternative therapeutic option for patients ineligible for more intensive therapies.

Primary vs. pre-emptive anti-seizure medication prophylaxis in anti-CD19 CAR T-cell therapy.

Seizures may occur in up to 30% of non-Hodgkin lymphoma patients who received anti-CD19 CAR T-cell therapy, yet the optimal anti-seizure medication (ASM) prevention strategy has not been thoroughly investigated. Consecutive patients affected by refractory non-Hodgkin lymphoma who received anti-CD19 CAR T-cells were included. Patients were selected and assessed using similar internal protocols. ASM was started either as a primary prophylaxis (PP-group) before CAR T-cells infusion or as a pre-emptive therapy (PET-group) only upon the onset of neurotoxicity development. One hundred fifty-six patients were included (PP-group = 88, PET-group = 66). Overall, neurotoxicity and severe neurotoxicity occurred in 45 (29%) and 20 (13%) patients, respectively, equally distributed between the two groups. Five patients experienced epileptic events (PET-group = 3 [4%]; PP-group = 2 [2%]). For all the PET-group patients, seizure/status epilepticus occurred in the absence of overt CAR-T-related neurotoxicity, whereas patients in the PP-group experienced brief seizures only in the context of critical neurotoxicity with progressive severe encephalopathy. ASMs were well-tolerated by all patients, even without titration. No patients developed epilepsy or required long-term ASMs. Our data suggest that both primary and pre-emptive anti-seizure prophylaxis are safe and effective in anti-CD19 CAR T-cell recipients. Clinical rationale suggests a possible more favourable profile of primary prophylaxis, yet no definitive conclusion of superiority between the two ASM strategies can be drawn from our study.

Role of FDG PET/CT in Patients With Lymphoma Treated With Chimeric Antigen Receptor T-Cell Therapy: Current Concepts.

Chimeric antigen receptor (CAR) T-cell therapy is a cellular therapy in which the patient's T cells are enhanced to recognize and bind to specific tumor antigens. CAR T-cell therapy was initially developed for the treatment of leukemia, but its current main indication is the treatment of relapsed or refractory non-Hodgkin lymphoma. FDG PET/CT plays a fundamental role in the diagnosis, staging, therapy response assessment, and recurrence evaluation of patients with metabolically active lymphoma. Consistent with the examination's role in lymphoma management, FDG PET/CT is also the imaging modality of choice to evaluate patients before and after CAR T-cell therapy, and evidence supporting its utility in this setting continues to accumulate. In this article, we review current concepts in CAR T-cell therapy in patients with lymphoma, emphasizing the critical role of FDG PET/CT before and after therapy. A framework is presented that entails performing FDG PET/CT at four time points over the course of CAR T-cell therapy: pretherapy at baseline at the time of decision to administer CAR T-cell therapy and after any bridging therapies and posttherapy 1 and 3 months after infusion. PET parameters assessed at these time points predict various patient outcomes.

Evaluation of the cardiac safety of parsaclisib, a selective PI3Kδ inhibitor, in patients with previously treated B-cell malignancies: Results from the CITADEL-101 study.

Parsaclisib, a potent and selective phosphatidylinositol 3 kinase δ inhibitor, has been investigated for the treatment of B-cell malignancies and studied in patients with autoimmune diseases and myelofibrosis. The CITADEL-101 study (NCT02018861) assessed safety, tolerability, and preliminary efficacy of parsaclisib in patients with relapsed or refractory non-Hodgkin lymphoma. This study evaluated the cardiac safety of parsaclisib as monotherapy based on data from 72 patients enrolled in the CITADEL-101 study. Time-matched pharmacokinetic and ECG measurements were collected at specified times for 69 patients receiving monotherapy in doses of 5, 10, 15, 20, 30, and 45 mg once daily. Based on the categorical outlier analysis, no dose-dependent effect was observed on the incidence of outliers in QT interval corrected for heart rate (HR) by Fridericia's method (QTcF), HR, or cardiac conduction. Based on central tendency analysis, the least square means (LSMs) (90% confidence interval [CI]) of ΔQTcF from the central tendency analysis ranged from -6.83 (-18.8 to 5.19) to 4.75 ms (0.410-9.09) across dose groups (below 20 ms, the threshold of large QT effects) and was not considered dose dependent. Moreover, the LSMs of ΔHR, ΔPR interval, and ΔQRS interval were minor. From the concentration-ΔQTcF analyses, the predicted ΔQTcF (90% CI) for all dose levels was between 0.365 (-1.75 to 2.48) and 7.87 ms (0.921-14.8), with the highest upper limit of CIs well below 20 ms, and therefore, a large QT/QTc effect was ruled out up to the highest dose level (45 mg) investigated. Overall, parsaclisib at the dose ranges studied did not reveal concentration-dependent effects on change in QTcF and did not have a significant effect on HR or cardiac conduction.

Peripheral blood stem cells mobilization in patients with relapsed or refractory lymphomas: A single-center experience

ABSTRACT Context: High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (AHSCT) is an established treatment for chemosensitive patients with relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL). Aims: We present the results of using different salvage chemotherapy plus granulocyte colony stimulating factor (G-CSF) for mobilization of peripheral blood stem cells in R/R lymphoma patients. Subjects and Methods: For salvage chemotherapy, 93 patients received platinum-containing regimens, 4 patients received cytarabine-containing regimens, and 5 patients received other regimens. Patient distributions were HL (n = 35) and NHL (n = 67). Results: In 87.2% of patients, first mobilization trial was successful (>2 × 106 CD34+ cells/kg). In 58.8% of patients, first apheresis season >5 × 106 CD34+ cells/kg collections was achieved. All 12.7% of patients were poorly mobilized at the first mobilization. There was no statistical difference between the previous chemotherapy numbers and failed mobilization (P > 0.05). Five patients who were poorly mobilized and 4 patients who were successfully mobilized underwent a previous radiotherapy (P < 0.05). Thirteen patients who were poorly mobilized in the first mobilization underwent a platinum-containing salvage regimen. At the time of the first mobilization, the average peripheral CD 34 counts in the successfully mobilized group were statistically higher than that in the poorly mobilized group (P < 0.01). Conclusions: We demonstrated that peripheral CD 34 cell count in the peripheral blood on the first apheresis day was a significant factor for more stem cell mobilization, fewer apheresis sessions, less volume, and earlier neutrophil engraftment for patients with R/R lymphoma and eligible for AHSCT. The history of the previous radiotherapy was a significant factor for poor mobilization.

Loss of CD20 expression as a mechanism of resistance to mosunetuzumab in relapsed/refractory B-cell lymphomas

AbstractCD20 is an established therapeutic target in B-cell malignancies. The CD20 × CD3 bispecific antibody mosunetuzumab has significant efficacy in B-cell non-Hodgkin lymphomas (NHLs). Because target antigen loss is a recognized mechanism of resistance, we evaluated CD20 expression relative to clinical response in patients with relapsed and/or refractory NHL in the phase 1/2 GO29781 trial investigating mosunetuzumab monotherapy. CD20 was studied using immunohistochemistry (IHC), RNA sequencing, and whole-exome sequencing performed centrally in biopsy specimens collected before treatment at predose, during treatment, or upon progression. Before treatment, most patients exhibited a high proportion of tumor cells expressing CD20; however, in 16 of 293 patients (5.5%) the proportion was <10%. Analyses of paired biopsy specimens from patients on treatment revealed that CD20 levels were maintained in 29 of 30 patients (97%) vs at progression, where CD20 loss was observed in 11 of 32 patients (34%). Reduced transcription or acquisition of truncating mutations explained most but not all cases of CD20 loss. In vitro modeling confirmed the effects of CD20 variants identified in clinical samples on reduction of CD20 expression and missense mutations in the extracellular domain that could block mosunetuzumab binding. This study expands the knowledge about the occurrence of target antigen loss after anti-CD20 therapeutics to include CD20-targeting bispecific antibodies and elucidates mechanisms of reduced CD20 expression at disease progression that may be generalizable to other anti-CD20 targeting agents. These results also confirm the utility of readily available IHC staining for CD20 as a tool to inform clinical decisions. This trial was registered at www.ClinicalTrials.gov as #NCT02500407.

Real-World Efficacy and Safety of Rituximab, Lenalidomide and İbrutinib Combination in Patients with Relapsed and/or Refractory Non-Hodgkin Lymphoma

Background: Relapsed or refractory (R/R) Non-Hodgkin Lymphoma (NHL) is associated with poor outcomes and the therapic options are limited. Recently, the combination of rituximab, lenalidomide, and ibrutinib (RLI) suggest promising efficacy in some clinical studies. Consequently, we report outcome of patients with R/R HL treated with RLI in this retrospective study aiming at evaluating efficacy and safety of RLI in a real-life setting. Methods: This retrospective, single-center study analyzed the outcomes of RLI as an off label salvage theraphy in patients with R/R NHL between June 2020 and April 2022. All patients received Lenalidomide 10-25 mg po daily on days 1-21 every 28 days and Ibrutinib 560 mg po daily on days 1-28. Patients with diffuse large B-cell lymphoma (DLBCL), primary central nervous system lymphoma (PCNSL), marginal zone lymphoma (MZL) received Rituximab at a dose of 375 mg/m2 iv on day 1 of cycles 1-6 every 28 days, patients with mantle cell lymphoma (MCL) received the same dose of Rituximab once a week for 4 weeks during cycle 1, then on day 1 of cycles 2-12 every 8 weeks. Ibrutinib and/or lenalidomide was administered until progression or unacceptable toxicity. The response was assessed with according to the Lugano criteria. The primary end point was overall response rate (ORR). Secondary endpoints were complete response (CR), partial response (PR), time to response (TTR), duration of response (DoR), overall survival (OS), progression free survival (PFS) and safety. Results: We analyzed 21 patients including DLBCL (n = 16), PCNSL (n = 2), MCL (n = 2), MZL (n = 1). The median age was 60 years (range, 24-84). The majority of patients had advanced disease stage (53%) and were refractory to their last therapy (57%). The non-GCB type was more common (67%) in patients with DLBCL and PCNSL. Nine patients (56%) with DLBCL had MYC and BCL2 and/or BCL6 rearrangements. Median number of prior therapies was 3 (range, 2-6). Eleven patients had prior auto and/or allo stem cell transplantation. Median follow-up time was 6.6 months (range, 0.4-22.3). Eleven patients (52%), 6 patients (29%) and 2 patients (10%) received RLI for ≥ 3, 6 and 12 months respectively. Patients had received a median of 3 (range, 1-19) cycles of RLI. Progressive disease (PD) was the most common reason for treatment discontinuation (53%). All of the patients were evaluable for response. The median TTR was 2 months (range, 1.7-3.8). The ORR was 38% (95% CI 15%-61%) with 29% CR and 9% PR. At the time of the analysis, the median DoR was 12.8 monts (range, 4.4-19.5+). Deaths were reported for 13 (62%) patients [n = 10 PD, n = 3 adverse events (AEs)]. The median OS was 7.9 months (95% CI 2.2-13.5) and median PFS was 3.5 months (95% CI 0.0- 8.3). The most common non-hematologic AEs were fatigue (48%), infection (38%), diarrhea (29%). AEs were frequently reported at the 25 mg lenalidomise dose, but the majority (77%) of patients experienced a grade 1-2 AE. The hematologic AEs were neutropenia (48%) [grade 3-4 (100%)], thrombocytopenia (19%) and anaemia (19%). AEs led to discontinuation in 5% (n = 1) of patients (sepsis). Conclusions: Our results suggest that RLI is a viable therapeutic option with promising activity and favorable toxicity profile in patients with R/R NHL patients.

The Outcome of Tisagenlecleucel (Tisa-Cel) Vs Axicabtagene Ciloleucel (Axi-Cel) CD-19 CAR-T Cell Therapy in Relapsed/Refractory NHL, Real World Data, Single Institution Experience

ABSTRACT Background: In the Kingdom of Saudi Arabia, non-Hodgkin lymphoma (NHL) reported as 6.1%. The estimated age adjusted incidence is 6/100,000. The more advanced disease stage at presentation reaches up to 40% stage IV. The cure rate with first line of therapy (R-CHOP) reaches up to 70%. The CD 19 chimeric antigen receptor (CAR) T-cell therapy targets CD19-expressing B cells and shows efficacy against B-cell lymphomas. Objective: The registration of CAR-T therapy products at KSA was in 2020 for Tisa-Cel and 2022 for Axi-Cel. The objective is to describe the outcome of the more available CAR-T therapy products in relapsed or refractory NHL. Methods: Retrospective analysis of CAR-T therapy outcome in NHL and compare the outcome of the two products for the same patient's population, using patients' chart electronic file assessment in the tertiary institution treating over 500 new lymphoma per year. Patients: Between November 2020 and May 2023, 44 patients with relapsed or refractory NHL to ≥2 lines of therapy, Follicular lymphoma (FL) relapsed after three lines of therapy counted for four patients treated with Axi-Cel. All patients received an infusion were included in the analysis. Of the 44 patients, 54.5% were male (n=24), the median age was 51 (20-75), and ECOG was 0-3. NHL subtype includes germinal center B-cell (GCB) 52% (n=23) and activated B-cell (ABC) 38.6% (n=17); the disease stage by PET/CT scan was III (47.7%, n=21) and IV (47.7%, n=21). In Axi-Cel group, 9.1% (n=4) received CAR-T as second line for relapse refractory disease or relapse within 12 months of complete remission (CR) after 1 st line therapy. Other patients received at least two lines of therapy prior to CAR-T infusion; 65.9% received ≥ 3 lines of therapy. Seven patients (16%) relapsed after autologous stem cell transplantation (ASCT) have received CAR-T therapy Tica-Cel product (n=6). Four patients (9.1%) have controlled CNS involvement at the infusion time. All patients received lymphodepletion (LD) therapy with fludarabine and cyclophosphamide (Flu/Cy). 25% (n=11) needed bridging chemotherapy therapy before LD, radiation therapy (XRT) bridging was counted for 13 patients (29.5%). The patients' characteristics and disease in Table-1. Results: Overall response rate (ORR), complete responses (CR), partial responses (PR). The respective toxicities include cytokine release syndrome (CRS) and neurologic events namely ICANS. The best ORR was 68.2%; 43.2% of the patients had CR and 25% had PR. The disease progression (DP) was 29.5%. In Axi-Cel group, ORR, CR, PR, and DP was 84.2%, 52.6%, 31.6% and 10.5, respectively. In Tica-Cel group; ORR, CR, PR, and DP was 56%, 36%, 20% and 44%, respectively. The estimated 2 years overall survival was 75% in all patients; 89.5% and 64% in Axi-Cel and Tica-Cel, respectively (p=0.47), Figure1. The estimated overall progressive free survival (PFS) was 61.4% with 73.7% in Axi-Cel group and 52% in Tica-Cel group (p=0.2), Figure2, the best PFS was seen in GCB subtype 65.2% vs 47.1% in ABC, (p= 0.05), Figure4. In FL, PFS was 100%, the patient number is small. PFS was 62.5% in-patient with CRS compared with 50% on non-CRS patient, not statistically significant (p= 0.7), Figure3. The main toxicities post CAR-T cell infusion including cytokines release syndrome (CRS) was 90.9% with 9% grade ≥ 3. In Tica-Cel, grade CRS-IV was 9% while 0% in Axi-Cel. Neurotoxicity (NT)-ICANS was 27% with grade ≥ 3 of 13.6% in both groups (20% in Tica-Cel and 5.6% in Axi-Cel). Tocilizumab was used in 72.7% in all cohorts with higher number of patients in Axi-Cel 17/19 (98.5%). Dexamethasone (Dexa) was used in CRS in 36.4%, in Axi-Cel; 42% of patients received Dexa while 32% in Tica-Cel group. In addition, for treatment of ICANS; Dexa was needed in 31.6% of Axi-Cel patients and 20% in Tica-Cel group. Upon the latest patient's follow-up, two patients (10.5%) in Axi-Cel group and 36% (n=9) in Tica-Cel group died from DP. The outcome of both products is summarized in Table-2. Conclusions: In this single-center retrospective analysis of CAR T-cell therapy in relapsed or refractory NHL or FL in adults, the rates of durable responses were like the real-world data. The best response rate was higher in Axi-Cel group; however, the follow-up duration of disease response is shorter in Axi-Cel group. The toxicity profile is similar in both groups with a bit higher of Grade-III-IV ICANS in Tica-Cel group. Keywords NHL, FL, CAR-T, CRS, ICANS

ATA3431: Allogeneic CD19/CD20 Bispecific CAR EBV T Cells for the Treatment of B-Cell Malignancies

BACKGROUND: Chimeric antigen receptor (CAR) therapy targeted against CD19 has yielded remarkable clinical responses in the treatment of relapsed/refractory B-cell malignancies, but about a third of patients ultimately relapse due to the loss or downregulation of CD19. Furthermore, technical and logistical challenges associated with autologous CAR T therapy limits access for a majority of eligible patients. To help address these challenges, we have developed an allogeneic bispecific tandem CAR directed against both CD19 and CD20 (ATA3431) built on our Epstein-Barr virus (EBV) T-cell platform. EBV T cells maintain expression of endogenous T-cell receptors that have inherently low alloreactivity due to their recognition of defined viral antigens. CAR EBV T cells have demonstrated a favorable safety profile with no associated evidence for graft-versus-host disease or high-grade cytokine release syndrome (Curran KJ, 2020). The bispecific tandem CAR design allows either CD19 or CD20 target antigen recognition to activate the CAR EBV T cell, with the goal of extending durability of response and limiting antigen escape. In clinical trials, autologous bispecific CAR T cells were shown to be efficacious and safe (Larson 2023, Shah 2020). Additionally, a 1XX mutated CD3ζ signaling domain and our optimized CAR EBV T-cell platform preserve a central memory phenotype, robust expansion, functional persistence, and potent antitumor activity of ATA3431. METHODS: We generated CD20/CD19 bispecific CAR EBV T cells containing a modified CD3ζ signaling domain 1XX using our EBV T-cell platform. As a benchmark comparator, we generated autologous CD20/CD19 bispecific CAR T cells using a 12-day process derived from OKT3/CD28-activated T cells. The final products were characterized via immunophenotyping and evaluated for in vitro and in vivo response to antigen expressing targets. RESULTS: CD20/CD19 bispecific CAR EBV T cells generated from multiple healthy donors demonstrated stable CAR expression, a high proportion of T-cell memory populations, and consistent HLA-independent killing of CD19 + and/or CD20 + tumor cells over repeated in vitrochallenges. ATA3431 mediated highly potent antitumor activity in an established disseminated tumor model of Burkitt's lymphoma and correlated with long-term in vivo persistence of CAR T cells without additional cytokine support. Moreover, ATA3431-treated animals showed superior tumor growth inhibition compared to animals treated with autologous CD20/CD19 bispecific benchmark CAR T cells. No treatment-related toxicities were observed in animals treated with ATA3431. CONCLUSIONS: Preclinical evaluations of ATA3431 show B-cell tumor growth inhibition without any treatment-related toxicities and thereby support advancing ATA3431 for clinical evaluation. Curran KJ, Sauter CS, Kernan CS, et al. Durable remission following “off-the-shelf” chimeric antigen receptor (CAR) T-cells in patients with relapse/refractory (R/R) B-cell malignancies. 2020 Transplantation &amp; Cellular Therapy Meetings. Orlando. Larson SM, Walthers CM, Ji B, Ghafouri SN, et al. CD19/CD20 bispecific chimeric antigen receptor (CAR) in naive/memory T cells for the treatment of relapsed or refractory non-Hodgkin lymphoma. Cancer Discov. 2023 Mar 1;13(3):580-597. doi: 10.1158/2159-8290.CD-22-0964. PMID: 36416874; PMCID: PMC9992104. Shah NN, Johnson BD, Schneider D, et al. Bispecific anti-CD20, anti-CD19 CAR T cells for relapsed B cell malignancies: a phase 1 dose escalation and expansion trial. Nat Med. 2020 Oct;26(10):1569-1575. doi: 10.1038/s41591-020-1081-3. Epub 2020 Oct 5. PMID: 33020647.

Updated Follow-up of a Phase 1 Trial of Bispecific CART19/20 Cells for Relapsed or Refractory Non-Hodgkin Lymphoma

CART19/20 was developed by engineering autologous naïve/memory T (T N/MEM) cells with a bispecific anti-CD19/CD20 chimeric antigen receptor (CAR) with the goal of mitigating antigen escape and lack of CAR T-cell persistence. We report an update of an ongoing first-in-human phase 1 clinical trial of CART19/20 for patients with relapsed/refractory non-Hodgkin lymphoma (R/R NHL) (NCT04007029). Eligible patients were ≥18 years old with R/R diffuse large B-cell lymphoma (DLBCL) or primary mediastinal B-cell lymphoma (PMBCL) after ≥2 prior lines of therapy, or with mantle-cell lymphoma (MCL), follicular lymphoma (FL), or CLL/SLL after ≥3 prior lines of therapy. Autologous leukocytes were obtained by leukapheresis and sorted for CD14-/CD25-/CD62L+ T N/MEM cells, followed by lentiviral transduction of the bispecific CD19/CD20 CAR. Lymphodepletion chemotherapy with fludarabine 30 mg/m 2/day and cyclophosphamide 500 mg/m 2/day was administered on Days −5 to −3 prior to CAR T-cell infusion. The primary endpoint was assessment of safety. Secondary endpoints were overall response rate (ORR), progression free survival (PFS), overall survival (OS), and CART19/20 transgene persistence. As of data cutoff on July 21, 2023, 11 patients had received CART19/20 cells (6 DLBCL, including 4 transformed FL; 3 primary FL; 1 PMBCL; 1 MCL). Patients were treated at two dose levels, either 50 x 10 6 ± 30% CAR+ cells (8 patients) or 200 x 10 6 ± 30% CAR+ cells (3 patients). The median age was 58 (range: 34 to 70). Patients had received a median of 3 prior lines of therapy (range: 2 - 4). None of the treated patients had received prior CAR-T cell therapy; one patient had received a prior CD19-directed therapy. All patients had stage IV disease and 9 of 11 patients received bridging therapy. The engineered CART19/20 cells were enriched with central-memory T cells (T CM: CD45RA-/CD45RO+/CD62L+) which composed a median of 30.8% (range: 5.3 - 80.1%) of the CAR+ T-cells in the infused products. There were no occurrences of CRS grade ≥ 2 or neurotoxicity of any grade. Six patients had grade 1 cytokine release syndrome (CRS) with a median onset of 8 days from infusion (range: 5 - 11 days). One patient met criteria for dose-limiting toxicity with persistent thrombocytopenia after Day+120. Ten of the 11 patients achieved an objective response (91% ORR), with 8 patients (73%) achieving complete response (CR). One patient with FL, who progressed 18 months after receiving CART19/20, received a second infusion of CART19/20 cells and achieved a second CR for 14.9 months. With a median follow-up of 32.3 months (range: 5.1 - 44.0 months), the median PFS (95% CI 2.6 months - not estimable) and median OS (95% CI 5.7 months - not estimable) have not been reached. Overall, CART19/20 demonstrated a favorable safety profile with no severe CRS or neurotoxicity of any grade. Moreover, CART19/20 showed robust activity in patients with R/R NHL with durable responses seen. By utilizing a bispecific CAR and enriching for T N/MEM cells, this phase 1 trial of CART19/20 demonstrates the possibility of improving outcomes through targeting common mechanisms of CAR-T cell resistance.

Long-Term Efficacy and Immune Reconstitution with Bendamustine As a Lymphodepleting Agent for Axicabtagene Ciloleucel (Axi-Cel) in Patients with Refractory or Relapsed Large B-Cell Lymphoma (LBCL)

Introduction: Lymphodepletion (LD) is crucial for the expansion and persistence of CAR T cells. Fludarabine in combination with cyclophosphamide (FC) is the LD standard regimen. A national fludarabine shortage in 2022 necessitated the exploration of alternative LD regimens. Bendamustine (benda) is a purine analog and an alkylating chemotherapy that has been used as an LD agent for tisagenlecleucel (Ghilardi et al.,2022). However, there is no data for benda LD in other commonly used CART products for relapsed or refractory non-hodgkin lymphoma (rel/ref NHL). Early safety, efficacy, and expansion kinetics data were presented previously (Bharadwaj, ASH 2022). We are now reporting long-term efficacy and immune reconstitution data. Methods: 84 consecutive patients with relapsed/refractory LBCL treated with axi-cel were included in this single-institution study. 27 patients who received Bendamustine lymphodepletion (90mg/m2 on days -4 and -3) were compared to a preceding 57-patient FC cohort. Response, survival, and cytopenia data were collected closest to the 12-month time point for all patients who had not progressed. Response was assessed using the Lugano 2014 criteria, while toxicities were evaluated using the CTCAE version 5.0 and the ASTCT grading. To reduce the influence of confounding variables in this study, a covariate balance propensity score weighting approach (IPTW) was implemented. Covariates included age, sex, presence of bridging therapy, IPI score at apheresis, number of prior therapy lines, absolute lymphocyte count at leukapheresis, prior auto SCT, and pre-lymphodepletion LDH, ALC, ANC, and platelet count. Continuous outcomes were compared using the Mann-Whitney U test, categorical outcomes using chi-square tests, and time-to-event outcomes using a log-rank test weighted in the IPTW sample. Statistical significance was considered when p &amp;lt; 0.05. All analyses were conducted in R 4.3.0. Results: There was no significant difference in the best complete response (CR) rate and best overall response rate (ORR) between the two groups, with a CR rate of 71.9% for FC and 74% for bendamustine (p = 0.182), and an ORR of 89.4% for FC and 85.1% for bendamustine (p = 0.502). For the FC group, 9-month progression-free survival (PFS) and overall survival (OS) were 63.16% (95% CI: 49.29% to 74.19%) and 78.95% (95% CI: 65.92% to 87.45%), respectively with a median follow-up of 15.5 months (IQR: 13.6, 16.8). 9-month PFS and OS point-estimates for the bendamustine group were 70.37% (95% CI: 49.4% to 83.94%) and 77.41% (95% CI: 56.41% to 89.18%), respectively, with a median follow-up of 9.5 months (IQR: 8.6, 9.8). No significant difference was found between groups in either 9 months PFS ( P=0.055) or 9 months OS ( P=0.6290). Median PFS and OS have not been achieved for either group [Figure 1]. Bendamustine was effective in achieving severe lymphodepletion, with a median absolute lymphocyte count (ALC) nadir of 0.11 K/ul (IQR: 0.04, 0.17) occurring within one day after axi-cel infusion. In comparison, the FC group had a lower median ALC nadir of 0.03 K/ul (IQR: 0.01, 0.06) occurring on the day of axi-cel infusion ( P=0.01). Both cohorts showed a similar pattern of lymphocyte recovery over 1, 3, and 6 months. Median ALC counts at 9-12 months post-infusion indicated better lymphocyte recovery in the bendamustine group with a median ALC of 1.55 K/ul (IQR: 1.04, 1.94) compared to 0.96 K/ul (IQR: 0.58, 1.23) in the FC group ( P=0.043) [Figure 2]. There was no significant difference in the recovery of absolute neutrophil count, hemoglobin, and platelets. Updated efficacy analysis and immune reconstitution data including T-cell, B-cell, and NK cell recovery will be reported at the time meeting, as all patients will have completed at least one year of follow-up by September 2023. Discussion: Bendamustine lymphodepletion prior to axi-cel therapy showed comparable efficacy and safety outcomes to the standard FC regimen in relapsed/refractory LBCL patients. Bendamustine demonstrated effective lymphodepletion and better lymphocyte recovery at 9-12 months post-infusion compared to FC cohort. These findings suggest that bendamustine may be an acceptable alternative lymphodepleting regimen. Prospective studies, ideally randomized control trial, are warranted.

Long Term Follow-up Results of Brl-201 Phase I Study, a Crispr-Based Non-Viral PD-1 Locus Specific Integrated Anti-CD19 CAR-T Cells in Treating Relapsed or Refractory Non-Hodgkin's Lymphoma

BACKGROUND ： CAR-T cell products are manufactured traditionally by using virus, which leads to the potential tumorigenesis risk and makes CAR-T cell therapy expensive and time-consuming. We developed a novel approach to generate non-viral, genome-specific integrated CAR-T cells through CRISPR/Cas9, thereby breaking through both virus usage and random integration simultaneously. Here, we update long term follow up data of trial of non-viral PD1 locus specifically integrated anti-CD19 CAR-T cells (BRL-201) in patients with relapsed/refractory (r/r) Non-Hodgkin's lymphoma (#NCT04213469). Recently, a phase I/II of BRL-201 (#NCT05741359) is ongoing with a large-scale and multi-center design to further evaluate of BRL-201 antitumor activity in lower dose level. METHODS : This phase I investigator initiated trial evaluates BRL-201 in adult patients with r/r B-NHL. Adult patients with r/r B-NHL underwent leukapheresis and a lymphodepletion chemotherapy with cyclophosphamide (500mg/m 2, D -3 to -2) and fludarabine (30mg/m 2, D -4 to -2) before BRL-201 infusion. Dose escalation are based on 3+3 escalation rule, including three cohorts: 2×10 6/kg, 4×10 6/kg, 6×10 6/kg. Besides, 3 subjects received non-standard infusion doses at 0.56~0.8 × 10 6/kg. The primary endpoint was the incidence of dose-limiting toxicities (DLT). The secondary endpoint was the proportion of patients achieving an objective response at 3 months as per investigator's assessment. In the phase I/II sponsor initiated clinical trial, we employed 3+3 rule in the escalation phase. RESULTS: Between May 3, 2020 and August 10, 2021, 25 patients with r/r B-NHL were enrolled and 21 received BRL-201 with a median age of 56 years (34-70) and a median of 4 (1-9) prior lines of therapy. Among all the treated patients, 17 patients (93.8%) were diagnosed with disease stage III or IV, and 13 patients (81.3%) were assessed with high-intermediate to high risk according to IPI or aaIPI score assessment. Two patients had undergone autologous hematopoietic stem cell transplantation (HSCT) and one patient had a history of primary refractory disease. Of 17 patients with pretreatment tumor samples PD-L1 expression detection, 4 (23.5%) had &amp;gt; 50% PD-L1 expression, 13 (76.5%) had ≤50% PD-L1 expression. As of May 17, 2023, the median follow- up of investigaor initiated phase I study was 29.0 months (21.5-36.2 m). All of 21 (100%) patients had an objective response to BRL-201 and 18 (85.7%) patients had a complete response (CR) as best response (Fig. 1). 7 patients achieved and maintained CR at data cut-off date, among these, 3 patients had PD-L1 expression &amp;gt; 50%, 1 patient was negative and 3 unknown. The median duration of response(DOR) for all 21 patients was 18.6 months (95%CI：5.1, NA ) (Fig. 2a). The median progression free survival (PFS) was 20.8 (95%CI：8.2, NA) months (Fig. 2b), while the estimated median overall survival (OS) was not reached, 12-month OS rate was 76.2% (95% CI: 60%, 96.8%) (Fig. 2c). No grade 3-4 CRS and ICANS were observed. 14 patients (66.7%) experienced grade 1-2 cytokine release syndrome (CRS) and only one patient received tocilizumab. 4 patients (19.0%) experienced grade 1-2 immune effector cell-associated neurotoxicity syndrome (ICANS). No new AEs/SAEs were observed during the last follow up. In the ongoing phase I study, 1 patient with DLBCL was treated with BRL-201 and no DLT observed during 28 days after infusion at dose of 2×10 5/kg. CONCLUSIONS : Over a median follow up of 29 months, BRL-201 was demonstrated durable response with a high median PFS of 20.8 months and 12-month OS rate of 76.2%. The median OS was not reached yet for responding patients, and the safety profile was manageable. More data will be collected to prove the value of clinical usage of BRL-201.

Evaluation of the Impact of Tocilizumab Use in Recipients of CAR T Cells for Non-Hodgkin Lymphoma

Introduction: CAR T has revolutionized the treatment of patients with relapsed or refractory (R/R) Non-Hodgkin lymphoma (NHL). Treatment of the major toxicity of cytokine release syndrome (CRS) is tocilizumab (toci) and corticosteroids based on the ASTCT grade. Real-world experiences in the United States and Europe have reported a higher rate of tocilizumab use than in pivotal trials; however, the impact of single or multiple administrations on clinical outcomes is not clear. Methods: Patients diagnosed with diffuse (DLBCL), high grade (HGBCL) and primary mediastinal B cell lymphoma (PMBL) treated at our institution with commercial CAR T were retrospectively identified. The association between the number of doses received with best overall response by day 100, PFS, and OS was investigated through a Cox regression model using a 14-day landmark analysis. Late neutropenia was defined as an ANC &amp;lt;1000/mmc for two consecutive counts beyond day 30 post CAR-T infusion and a 30-day landmark analysis was performed in this case. Results: 230 patients with R/R DLBCL (80%), HGBCL (17%) and PMBL (3%) were included in the analysis. Axicabtagene ciloleucel (Axi-cel), tisagenlecleucel (Tisa-cel), and lisocabtagene maraleucel (Liso-cel) were administered in 62%, 29% and 9% of cases, respectively. Median age at time of CAR-T infusion was 65 years (range 20-86), with a male predominance (63%). The median number of prior treatment lines was 3 (range 1-12), and 21% underwent a prior autologous hematopoietic cell transplant. Disease burden prior to CAR-T infusion can be inferred by the following: bridging therapy was deemed necessary in 77% of patients, pre-lymphodepletion LDH was elevated in 40%, and bulky disease with largest mass diameter was &amp;gt; 10 cm in 10%. CRS and ICANS were grade 2 in 107 patients (46%) and 46 patients (20%), respectively. Median time to first administration of toci was 4 days (range 1-16) with patients receiving 0 (51%), 1 (27%), 2 (14%), or 3-4 (8%) doses. Best response by day 100 for the whole cohort was CR in 138 (60%) and PR in 36 (16%) patients. In univariable analysis, factors associated with a lower likelihood of response were the administration of Tisa-cel (p=0.014), bulky disease (p&amp;lt;0.001), administration of bridging therapy (p=0.009), and being refractory to the last treatment line (p=0.006). Number of doses of tocilizumab did not impact the likelihood of response (p=0.72). In a Cox regression model for survival, number of doses of tocilizumab was not associated with worse PFS (p=0.38, Figure 1) or OS (p=0.64), while other known negative predictors of response had impact on survival, such as bulky and refractory disease. By univariable analysis, tocilizumab administration was significantly associated with prolonged neutropenia (p&amp;lt;0.001). The likelihood to observe an ANC&amp;lt;1000/mmc beyond day 30 increased accordingly to the number of doses received (Figure 2). Other factors associated with late neutropenia were bulky disease (P=0.013), need of bridging therapy (p=0.004), and corticosteroids administration (p&amp;lt;0.001). Conclusion: The number of tocilizumab infusions did not impact CAR T efficacy in terms of overall response and long-term survival, a finding that is concordant with other real-world experiences. The cumulative incidence of late neutropenia events was impacted by the number of doses received. We speculate that a severe CRS driven systemic inflammatory response, requiring several tocilizumab and corticosteroids administrations, may hinder the bone marrow function and recovery.

Preliminary Results of Nathali-01: A First-in-Human Phase I/IIa Study of UCART20x22, a Dual Allogeneic CAR-T Cell Product Targeting CD20 and CD22, in Relapsed or Refractory (R/R) Non-Hodgkin Lymphoma (NHL)

Background: UCART20x22 is a dual targeted allogeneic CAR T-cell product candidate generated from healthy donor T-cells. Donor-derived T-cells are transduced with a bicistronic lentiviral vector to express CARs targeting CD20 and CD22. TALEN ® gene editing technology is used to inactivate the TRAC and CD52 genes to minimize graft-versus-host disease (GvHD) and allow for the use of alemtuzumab (CLLS52, an anti-CD52 monoclonal antibody) in the lymphodepletion (LD) regimen, respectively. UCART20x22 previously demonstrated robust and sustained activity in vitro and in vivo (Aranda-Orgilles B, et al. Cancer Immunol Res 2023). Here we present the initial preliminary results from the NatHaLi-01 trial (NCT05607420), the first-in-human Phase 1/2a dose-finding and expansion study evaluating UCART20x22 in R/R B-cell NHL. Methods: The primary endpoints are safety, tolerability, and determining the recommended phase 2 dose of UCART20x22. Additional endpoints include anti-lymphoma activity and cellular kinetics of UCART20x22. Key eligibility criteria are age 18-80y, lymphoma expression of CD20 and/or CD22 by local assessment, and ≥ 2 prior treatment regimens including autologous CD19 CAR T-cell therapy (CAR19), if eligible. After LD with FCA (fludarabine 30 mg/m 2 × 3d, cyclophosphamide 0.5g/m 2 × 3d, CLLS52 12 mg on D1, 24 mg on D2, D3), a single infusion of UCART20x22 is administered at a flat dose level ([DL1] 50 x 10 6 cells; [DL2] 150 x 10 6 cells; and [DL3] 450 x 10 6 cells). Results: As of 01 July 2023, 3 pts were enrolled and treated at DL1. Pt 1 is a 76yo female with double-expressor diffuse large B-cell lymphoma (DLBCL) relapsed after R-CHOP, radiation therapy, and polatuzumab vedotin with bendamustine/rituximab (BR) and was considered ineligible for CAR19 due to recent high dose bendamustine. Pt 2 is a 65yo female with R/R triple-hit lymphoma transformed from follicular lymphoma who was previously treated with radiation therapy, BR, dose-adjusted R-EPOCH, and two separate CAR19 treatments. Pt 3 is an 18yo female with R/R DLBCL transformed from marginal zone lymphoma who previously received chemoimmunotherapy, venetoclax, ibrutinib, BR, CAR19, obinutuzumab, glofitamab, tafasitamab, lenalidomide, and an experimental epigenetic modifier. Cytokine release syndrome (CRS) occurred in all patients. Pt 1 had G1 CRS and received tocilizumab (toci) x3 and dexamethasone (dex) x1. Pt 2 had G2 CRS and received toci and dex x1. Pt 3 had G1 CRS and received toci x1. All pts' CRS resolved with treatment. No immune effector cell associated neurotoxicity (ICANS) or GvHD was observed. There were no UCART20x22 dose limiting toxicities (DLTs), and there was 1 CLLS52 SAE and 1 DLT. The SAE was G3 CMV reactivation and was managed with IV antivirals. The DLT was in Pt 2, who entered the study with G1/2 cytopenias and a hypocellular bone marrow and had prolonged bone marrow aplasia after treatment thought to be due to cumulative chemotherapy exposure. This pt proceeded to allogeneic hematopoietic stem cell transplant (HSCT) from a matched donor while in complete remission from UCART20x22 treatment. Responses were assessed per Lugano criteria beginning on D28. At D28, all 3 pts responded with 2 CRs and 1 PR. Host lymphocytes remained suppressed through D28 for all pts. UCART20x22 expansion was observed by flow cytometry in 3/3 pts and was initially detected on D7 followed by peaks between D9-14. Peak expansion ranged from 16-682 cells/μL and was predominantly CD8 T-cells. Ferritin levels and increases in serum cytokines, including IFNγ, TNFα, IL-2, and IL-6, correlated closely with UCART20x22 expansion. Summary: Treatment with UCART20x22 at DL1 has been safe and well-tolerated, with no UCART20x22 DLTs or ICANS, and CRS was &amp;lt;G3 in all pts. There was 1 DLT of prolonged bone marrow aplasia in a pt with impaired hematopoietic reserve at study entry. UCART20x22 was active at DL1, with all 3 pts responding, including 2 CRs in pts who had previously received CAR19. UCART20x22 expansion was observed in all pts. These initial data support the continued study of UCART20x22 in R/R NHL, and updated results will be presented.

Multiple Doses of Cnty-101, an iPSC-Derived Allogeneic CD19 Targeting CAR-NK Product, Are Safe and Result in Tumor Microenvironment Changes Associated with Response: A Case Study

Introduction Despite recent approvals of autologous cell therapy products for relapsed, refractory (R/R) non-Hodgkin lymphoma, there remains a clear unmet need for safe, efficacious, and affordable off-the-shelf products that can deliver durable responses. CNTY-101 is an allogeneic iPSC-derived chimeric antigen receptor NK (CAR-NK) cell product with a CD19-targeting CAR, secreted IL-15 to enhance persistence, EGFR safety switch, and a suite of Alloevasion TM edits (B2M and CIITA knock outs, and HLA-E knock in) intended to reduce allo-rejection in the recipient, thereby allowing for repeated dosing. Here we describe a case-study of the first subject dosed in ELiPSE-1, a first-in-human phase 1, multicenter, open-label study of CNTY-101 in subjects with R/R CD19-Positive B-cell malignancies, which is currently enrolling patients (NCT05336409). Methods A 63-year-old subject with R/R POD 24 (progression of disease within 2 years) follicular lymphoma, treated with 4 prior lines of therapy was enrolled at dose level 1 (DL1), 100 million cells CNTY-101. To date, the patient has received four 28-day cycles of a single infusion of CNTY-101 at DL1 with day 1 of each cycle being approximately 6 weeks apart (Table 1). Cycles 1 and 2 included three days of standard Fludarabine and Cyclophosphamide lymphodepletion (LDC), cycles 3 and 4 were given with no LDC. In cycles 2-4, low dose (3 million units) subcutaneous interleukin-2 (IL-2) was administered on days 1-8 of each cycle. Each cycle of CNTY-101 beyond cycle 1 required FDA approval. The described schedule facilitated evaluation of feasibility, safety, biomarker and efficacy evaluations after each infusion, +/- IL-2, and +/- LDC. Biomarker assessments were performed on blood and serum collected pre- and post- each infusion, and on tumor biopsies collected pre- and post-1 st infusion only. Pharmacokinetic (PK) assessments were performed using ddPCR, serum cytokines were measured using Meso Scale Discovery technology, serum anti-drug-antibodies (ADA) were measured using flow-based assays to detect direct IgG and IgM binding to the cell product or assays specifically measuring ADA targeting the CAR construct. Functional ADA were evaluated using an assay to detect complement-dependent cytotoxicity (CDC) function of bound ADA. Tumor biopsies at baseline and day 8 were interrogated for changes in the immune microenvironment using custom Vectra multiplexed immunofluorescence panels and RNA-ISH methodology. Results All doses of CNTY 101 with and without IL-2 or LDC demonstrated acceptable safety and clinical benefit (i.e. stable disease or better per Lugano 2014 criteria). No concerted changes in inflammatory cytokines and mediators associated with cytokine release syndrome or neurotoxicity were detected. The IL-2 dosing regimen resulted in continuous measurable bioavailability of IL-2 during the period of dosing, including trough periods. PK measurements showed that CNTY-101 cells were detected after each infusion with comparable kinetics, with a limited duration in circulation. Serum assessments after the 1 st three cycles showed that, despite administration of two cycles with and one cycle without LDC, no evidence of functional (CDC-inducing) pre-existing or induced ADA were observed. Importantly, tumor microenvironment analyses demonstrated a dramatic increase in T cells within 8 days of the 1 st CNTY-101 cell infusion. Specific increases in proliferating cytotoxic T cells, intratumoral production of TNFα and IFNγ, and key checkpoint molecules were observed, suggestive of induction of adaptive immune responses within the tumor. These responses were associated with tumor shrinkage and ongoing CR of a duration of 5 months since the first CNTY-101 infusion. Conclusions The presented case study demonstrates the potential and feasibility of safely delivering up to 4 cycles of CNTY-101 +/- IL-2 and +/- LDC, at the 100 million dose level. No measurable induction of CDC-inducing functional ADA was detected after the 1 st 3 cycles. Additionally, tumor studies have provided early insight into the mechanism of action. The treatment was associated with changes in tumor microenvironment within 8 days post-infusion, augmentation of adaptive T cell responses, and tumor shrinkage. Updated data will be presented at the conference.

Population Pharmacokinetics and CD20 Binding Dynamics for Mosunetuzumab in Relapsed/Refractory B-Cell Non-Hodgkin Lymphoma (R/R NHL)

Introduction: Mosunetuzumab (Mosun) is a CD20xCD3 T-cell engaging bispecific antibody that redirects T cells to eliminate malignant B cells. Clinical data from GO29781 (NCT02500407), a Phase I/II, open-label, multicenter dose-escalation and expansion study of Mosun in pts with relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL), was used to develop a population pharmacokinetic (popPK) model describing Mosun concentration-time data. Prior to initiation of Mosun, many patients had circulating levels of other anti-CD20 drugs (e.g. rituximab (R) or obinutuzumab (G)) from prior treatment. In order to elucidate exposure-response (ER) relationships in the presence of these competitors, CD20 binding and R/G pharmacokinetics were incorporated into the popPK model to calculate the Mosun CD20 receptor occupancy percentage (RO%) over time. Methods: Mosun PK data were available in 439 pts with indolent or aggressive R/R NHL who received either Mosun fixed dosing (n= 32; 0.05-2.8mg every 3 weeks (q3w)) or Cycle 1 step-up dosing (n=407, 0.4/1.0/2.8 - 1/2/60/30mg). The popPK model was developed using NONMEM® software (v7.4.3), with a clinical cut-off date of December 4, 2020. Clinically relevant covariates were investigated for their potential to explain Mosun PK variability. The Mosun CD20 RO% time course for each pt was derived by integrating the Mosun, R, and G model predicted concentration-time courses and their respective CD20 affinities (Kds) into the popPK model. R and G concentration-time courses were predicted by the model using their baseline values and published half-lives, and binding kinetics were assumed to be at equilibrium. PopPK model simulations (n=1000) were done with the final model to establish Mosun concentration ranges for the approved 1/2/60/30 mg dose regimen, given that this regimen was designed to mitigate cytokine release syndrome (CRS) through its step-up Cycle 1 design. Additional popPK model simulations, incorporating Mosun dose delays, were conducted and compared to the 1/2/60/30 mg nominal dose regimen to inform treatment resumption protocols necessary to mitigate CRS. Results : A two-compartment PK model with time-dependent clearance (CL) best described Mosun PK. Mosun CL decreased from an initial value of 1.08 L/day transitioning to a steady state clearance of 0.584 L/day by Cycle 4 (Figure 1A). Mosun terminal phase half-life at steady state was 16.1 days. Concentrations of R/G were present in 50% of patients prior to Mosun therapy (Figure 1A), and the median predose R/G concentration for these patients was 10.0 µg/mL. Statistically relevant covariates on PK parameters included body weight, albumin, sex, tumor burden, and baseline concentrations of R/G; however, no covariate was deemed to have a clinically relevant impact on PK at the recommended dose of 1/2/60/30mg. Mosun CD20 RO% was more variable than Mosun PK (Figure 1B), attributed to the large variability in baseline R/G concentrations. The 60mg loading doses increased Mosun CD20 RO% to steady-state ranges by Cycle 1 (Figure 1B), thereby providing Mosun efficacious exposure in the presence of competing residual, transient R/G concentrations from prior treatment therapies (Figure 1A). From the popPK model simulations, patients with dose delays greater than or equal to 6 weeks had Mosun concentrations that fell below levels after the Day 1 (1mg) and Day 8 (2mg) doses; as such, these pts are instructed to repeat these doses prior to treatment continuation. For Mosun dose delays less than 6 weeks, popPK simulations supported pts either to repeat the last Mosun dose administered, or to continue along with the planned regimen [Lunsumio ® USPI]. Conclusions: Mosun PK was characterized using a two-compartment model with time dependent CL. R/G PK and CD20 binding kinetics were incorporated into the Mosun popPK model to calculate Mosun CD20 RO% over time. The use of two 60mg loading doses enables early achievement of Mosun steady-state target CD20 RO% range, especially benefitting those pts with high levels of precirculating R or G. Simulations with the popPK model supported labeling recommendations for restarting Mosun treatment after dose delays. Acknowledgments: This study was sponsored by F. Hoffmann-La Roche Ltd / Genentech, Inc

A Phase 1 Cohort Dose Escalation and Expansion Trial to Determine the Safety, Tolerance, Maximum Tolerated Dose, and Preliminary Antineoplastic Activity of IKS03 in Patients with Advanced B-Cell Non-Hodgkin Lymphomas (NHL)

Background: IKS03 is an antibody-drug conjugate (ADC) comprising an anti-CD19 antibody conjugated with novel ConjuALL technology to a highly potent proprietary DNA-crosslinking pyrrolobenzodiazepine (PBD) prodrug payload for the treatment of CD19-positive hematologic malignancies. Both the payload and the linker of IKS03 incorporate an innovative tumor-selective chemistry that takes advantage of the overexpression of beta glucuronidase in cancer cells compared to most normal tissues. Payload release and activation require cleavage of glucuronide moieties that are incorporated into the linker payload structure providing improvements in both efficacy and safety compared to traditional ADC formats. This “glucuronide trigger” is stable while in circulation with minimal to no systemic payload release from the ADC. Following binding and internalization of IKS03 into a CD19-positive cancer cell, beta glucuronidase can release the active PBD payload leading to cell death. Normal tissues without CD19 expression and/or with low levels of the beta glucuronidase enzyme have limited ADC uptake, are less able to process IKS03 and are differentially spared. In preclinical studies, IKS03 demonstrated significant in vivo efficacy with complete tumor regressions in CD19-positive diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and mantle cell lymphoma (MCL) xenograft models at single doses of 0.1 to 1 mg/kg. IKS03 demonstrated greater activity than the clinical benchmark ADC loncastuximab tesirine. IKS03 is also highly effective in patient-derived xenograft models that contain some of the genetic alterations commonly found in relapsed/refractory NHL patients. Results from toxicology studies in cynomologus monkey suggest a manageable safety profile at single doses, well above those required for in vivo activity. Pharmacokinetics are favorable with a mean total ADC half-life of 8 days and undetectable levels of the active PBD payload in circulation confirming targeted delivery of the payload. Study Design and Methods: This Phase 1 multicenter, open label, non-randomized study of IKS03 will consist of two parts: dose-escalation (Part I) and dose-expansion (Part II) together enrolling approximately 140 adult patients with relapsed or refractory B-cell NHL after at least two prior lines of systemic therapy. Patients will receive repeat doses of study drug by IV infusion on Day 1 of each 21-day cycle, until disease progression, unacceptable toxicity, or another withdrawal criterion is met. Key exclusion criteria include: active central nervous system involvement with NHL; clinically significant cardiovascular, pulmonary or hepatic disease; or receipt of other CD19-directed therapy within 3 months. Part I dose escalation will enroll patients with confirmed CD19-positive, measurable or non-measurable advanced B-cell NHL. Eligible subtypes include DLBCL, MCL, FL, high-grade B-cell, and marginal zone lymphoma as per WHO 2016 classification. Patients with Burkitt's lymphoma, Waldenström macroglobulinemia, and chronic lymphocytic leukemia are excluded. In Part 1, the primary objective is establishment of the recommended Phase 2 dose (RP2D) by evaluation of safety, tolerability and the maximum tolerated dose (MTD) of IKS03. Dose escalation will follow a 3+3 design. A two cycle Dose-Limiting Toxicity (DLT) assessment period will be observed, and dose-escalation decisions will be guided by a study safety committee. Dose escalation increments will be adjusted based on occurrence of protocol-specified DLTs as well as overall tolerability. Secondary objectives include characterization of immunogenicity and pharmacokinetic (PK) profile of IKS03. Exploratory objectives include preliminary antineoplastic activity per Lugano criteria (Cheson et al, JCO 2014) and evaluation of pharmacodynamic markers. Part II will further evaluate the antineoplastic activity of IKS03 at the RP2D in expansion cohorts of patients with selected NHL subtypes and with measurable disease. Sample size will be determined for each subtype using a Simon Two-Stage design. Secondary objectives include further evaluation of safety, tolerability, immunogenicity and PK profile of IKS03 as well as confirmation of the RP2D. Clinical trial information: NCT05365659.

A First-in-Human Phase 1 Study of ABBV-525, a Small-Molecule MALT1 Inhibitor, in Patients with Relapsed or Refractory B-Cell Non-Hodgkin Lymphoma

Background and Significance Many B-cell malignancies are characterized by chronic activation of the B-cell receptor (BCR) and nuclear factor kappa B (NF-κB) signaling pathways. In many non-Hodgkin lymphoma (NHL) subtypes, constitutive NF-κB activation results from genetic mutations and/or auto-antigen stimulation of the BCR pathway. While agents targeting the BCR pathway are effective treatments for many B-cell malignancies, patients (pts) often have progressive disease due to acquired resistance to BCR-targeted agents. Thus, there is an unmet medical need for novel therapeutic targets and treatment approaches. The mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) is an enzymatic and scaffolding node in the BCR pathway and a key mediator of the BCR/NF-κB signal transduction pathway. Its action is downstream, or in some instances parallel to, resistance mechanisms to existing NHL therapies, including BTK C481S and PLCG2 mutations, which are known acquired mechanisms of resistance to covalent Bruton's tyrosine kinase (BTK) inhibitors in pts with chronic lymphocytic leukemia (CLL). MALT1 inhibition represents a novel therapeutic approach for malignancies with chronic activation of NF-κB, including those pts with acquired resistance to upstream targets. ABBV-MALT1 is a small-molecule, tool compound, MALT1 inhibitor. Preclinical studies of ABBV-MALT1 have demonstrated potent activity against MALT1-relevant biomarkers, including inhibition of BCR pathway signal transduction and reduced NF-κB gene activation in non-germinal center B-cell diffuse large B-cell lymphoma (non-GCB DLBCL) cell lines. ABBV-MALT1 has also shown activity in a range of preclinical lymphoma models as both monotherapy and in combination with venetoclax, including robust antitumor activity in malignant B-cell models that are resistant to BTK inhibitors. This phase 1 study evaluates the clinical candidate MALT1 inhibitor ABBV-525 as monotherapy in pts with relapsed or refractory (R/R) B-cell NHL. Study Design and Methods This is a first-in-human, phase 1, open-label, multicenter study of single-agent ABBV-525 in pts with R/R B-cell NHL (NCT05618028). Eligibility criteria are listed in Table 1. The primary objectives are to evaluate safety, tolerability, and pharmacokinetics (PK) of ABBV-525 and to determine the recommended phase 2 dose (RP2D). The secondary objective is to assess the preliminary efficacy of ABBV-525 in subsets of pts with R/R B-cell NHL. Exploratory objectives include evaluating biomarkers predictive of response and pharmacodynamic biomarkers, including the effects of ABBV-525 on BCR pathway signal transduction and NF-κB gene activation. This is a 3-part study (Figure 1): dose escalation (part 1), dose optimization (part 2), and dose expansion (part 3). Part 1 aims to establish the maximum administered dose/maximum tolerated dose of ABBV-525 and is primarily guided by a Bayesian optimal interval design. Part 2 aims to identify the RP2D of ABBV-525. Part 3 will further characterize the safety profile of ABBV-525 at the RP2D. Approximately 150 pts are planned for enrollment, including those with various R/R mature B-cell lymphomas in part 1, pts with documented diagnosis of R/R CLL in part 2, and pts with documented diagnosis of non-GCB DLBCL in part 3. ABBV-525 is orally administered until disease progression, intolerable toxicity, or other study discontinuation criteria are met. Safety assessments include dose-limiting toxicities, adverse events (per National Cancer Institute Common Terminology Criteria for Adverse Events v5.0), clinical laboratory parameters, vital signs, and electrocardiogram variables. PK parameters, including maximum observed plasma concentration (C max), time to C max, and area under the concentration-time curve will be analyzed using noncompartmental methods. Efficacy will be assessed through response per disease-specific criteria (including International Workshop on Chronic Lymphocytic Leukemia, International Workshop on Waldenstrom's Macroglobulinemia, and Lugano classification). Duration of response will be evaluated by Kaplan-Meier estimates. Biomarker data will be analyzed as change from baseline and summarized for each scheduled postbaseline visit. Pts are being enrolled in 25 sites across the USA, Australia, Belgium, France, Germany, Israel, Spain, and UK. As of August 1, 2023, 2 pts had been treated.

Infectious Complications in Patients with Relapsed or Refractory (R/R) Non-Hodgkin's Lymphoma (NHL) Treated with the Anti-CD20xCD3 Bispecific Antibody (BsAb) Mosunetuzumab

Introduction:NHL treatment with anti-CD20 antibodies is associated with an increased risk of infections. Mosunetuzumab (mosun) is a novel anti-CD20xCD3 BsAb that has been examined in clinical trials for different NHL subtypes and was recently approved for treating R/R follicular lymphoma. While the open-label clinical trial of mosun reported that 17% of the patients experienced infectious complications, a detailed analysis of the incidence and types of infections in patients receiving this treatment has not been reported. Methods: This is a single-center, IRB-approved, retrospective analysis of patients with R/R NHL receiving mosun, either on a study protocol (NCT02500407) at the recommended phase 2 dose or as commercial use. Patients who completed at least 1 treatment cycle and had at least 30 days of follow-up were included in this analysis. Patient demographics, information on the lymphoma, and infection variables were collected by chart review. All infection-specific variables were collected from the start of mosun therapy until the initiation of the next line of therapy or the last follow-up, whichever came first. The data cut-off was on 7/22/23. Infectious events were graded according to common terminology criteria for adverse events (CTCAE) version 5.0. Baseline characteristics were analyzed for infection risk by performing a Cox regression analysis. Results: Between October 2016 and July 2023, 48 patients were treated with mosun at our center, and 44 met the study inclusion criteria. Four patients had only received one dose or did not have sufficient follow at the time of the analysis. Baseline characteristics are summarized in Table 1. After a median follow-up of 6.8 months (range 0.7-59.7), we recorded 37 infection episodes in 16/44 patients (36.4%). Amongst these, the frequencies of viral, bacterial, and fungal infections were 54.1% (20/37), 43.2% (16/37), and 2.7% (1/37), respectively. The most common infection types were upper respiratory tract infections 42.1% (20/37), skin and soft tissue infections16.2% (6/37), including 3 shingles episodes), genitourinary infections 10.8% (4/37), and lower respiratory tract infections 10.8% (4/37). Of all the infections, 9/37 (24.3%) were Grade 3 or higher; of these, 2/37 (5.4%) were Grade 5 (1 biliary sepsis, 1 COVID pneumonia). The cumulative incidence of infection was 25% over the follow-up period (figure 1). The median time to the first infection was 144 days (range 29-1821). Among the patients who experienced infections, the infection rate was 1.54 every 100 days at risk within the first three months. The infection rate was 1.69 every 100 days at risk between three and six months and 0.37 every 100 days at risk beyond six months for patients with infection. We evaluated the type of lymphoma (i.e., aggressive vs. indolent), patients' age, number of prior therapies before BsAb administration, prior CAR-T therapy, prior autologous SCT, baseline hypogammaglobulinemia, and baseline cytopenia's as risk factors of infection with a univariate Cox regression analysis. We found that none of these characteristics were associated with the risk of infection with statistical significance. However, in a multivariate Cox regression analysis, patients who received CAR-T therapy before starting a BsAb were at a slightly higher risk of developing an infection (OR = 6.13; 95% CI: 0.90, 41.74, p = 0.063). Conclusion: Infection risk in patients with R/R NHL treated with mosun either on protocol or for commercial use appears to be higher than in the clinical trial experience reported in the literature. Viral infections were especially common, including respiratory infections and shingles episodes. Our findings highlight the need for careful monitoring and implementation of preventive strategies to decrease the infection burden in these vulnerable patients.