Clinical Tumor Lysis Syndrome Research Articles

A retrospective review of rasburicase utilization in pediatric and adult patients across a large health system.

This study aimed to characterize rasburicase dosing and duration. Secondary objectives included characterizing the indication of rasburicase and identifying the utilization of prophylactic therapy for tumor lysis syndrome (TLS). This retrospective review included patients 0 to 89 years old admitted between 1 January 2021 and 31 December 2021, and received at least one dose of rasburicase. Patients were excluded if they were >89 years old, pregnant, lactating, or received rasburicase outpatient. A total of 192 patients, 176 adults and 16 pediatric patients were included in the retrospective review. Of the total population, 184 received a fixed dose of rasburicase and 8 patients received a weight-based dose (0.15 mg/kg/dose) of rasburicase. The average dose administered was 3.4 mg for fixed and 2.99 mg for weight-based dosing. Nearly half (49.5%) the patients received rasburicase for an elevated uric acid but did not meet Cairo-Bishop criteria for TLS. Only 42.2% received at least one dose of allopurinol within 5 days prior to rasburicase and 18.8% received aggressive hydration within 72 h prior to rasburicase. The majority of rasburicase administered was ordered as fixed dose for a uric acid level ≥7.5 mg/dL. Most patients did not meet criteria for laboratory or clinical TLS and less than half the patients received prophylactic allopurinol and/or aggressive hydration. These study results are supported by recent literature for fixed dose rasburicase as a safe and economical dosing strategy compared to weight-based dosing.

Tumor lysis syndrome in induction therapy for acute myeloid leukemia before the rasburicase era.

Guidelines recommend rasburicase for high-risk patients to prevent tumor lysis syndrome (TLS). However, little information is available on the incidence and outcome of TLS in AML patients. We analyzed 145 patients with AML who underwent induction therapy before the approval of rasburicase to evaluate the incidence of TLS and the necessity of rasburicase as prophylaxis. Three patients had already developed clinical TLS (CTLS) at diagnosis of AML, and another three developed CTLS after the initiation of chemotherapy. In patients without TLS at diagnosis of AML, the risk for developing TLS was classified as high in 44 patients, intermediate in 41 and low in 57, according to the current guidelines. Allopurinol alone was administered to prevent hyperuricemia in all patients. All three patients who developed CTLS after diagnosis of AML were at high risk of TLS, and had elevated serum creatinine levels and a WBC count greater than 200,000 per microliter at diagnosis of AML. Allopurinol may be insufficient to prevent TLS in high-risk patients with renal dysfunction at diagnosis of AML, especially those with a high tumor burden and a WBC count of 200,000 or more, which indicates that prophylactic administration of rasburicase should be considered.

Low incidence of tumor lysis syndrome in elderly patients with chronic lymphocytic leukemia treated with venetoclax under real-world conditions: results from the prospective observational VeRVe study.

Venetoclax is active in both frontline and relapsed/refractory settings for the treatment of chronic lymphocytic leukemia (CLL). Although the prevalence and severity of tumor lysis syndrome (TLS) are well characterized in clinical trials, laboratory and clinical TLS remain relatively unexplored in real-world clinical practice.In this prospective, real-world observational study, we aimed to determine the incidence and outcomes of TLS in patients with CLL receiving venetoclax outside a clinical trial. The study (VeRVe) was conducted in centers in Austria, Germany, and Switzerland.Two hundred and thirty-nine patients were treated according to local label with at least one dose of venetoclax. Patient demographics, baseline characteristics, and blood chemistry at baseline were documented, and descriptive statistical analyses were conducted.Seventy eight patients (33%) were treated with venetoclax monotherapy, 101 (42%) with venetoclax in combination with rituximab and 60 (25%) with venetoclax in combination with obinutuzumab. In all cases, the TLS risk mitigation strategy adhered to the ramp-up protocol. Median age was 73 years and 66% of patients were male. The majority of patients (75%) had relapsed/refractory CLL, 63/192 (32.8%) patients tested had a del(17p) and 93/134 (69.4%) patients tested had unmutated immunoglobulin heavy chain variable region gene (IGHV). Clinical TLS occurred in 5 patients (2.1%) and laboratory TLS occurred in 15 patients (6.3%). Ten patients received specific treatment, of which 6 were hospitalized. There were no deaths due to a TLS event and venetoclax was well-tolerated. Of the 5 clinical TLS events reported, none were fatal or resulted in renal failure (NCT03342144, registered on Nov 10, 2017).

Venetoclax Initiation in Chronic Lymphocytic Leukemia: International Insights and Innovative Approaches for Optimal Patient Care.

Venetoclax, a highly selective, oral B-cell lymphoma 2 inhibitor, provides a robust targeted-therapy option for the treatment of chronic lymphocytic leukemia (CLL), including patients with high-risk del(17p)/mutated-TP53 and immunoglobulin heavy variable region unmutated CLL and those refractory to chemoimmunotherapy across all age groups. Due to the potent pro-apoptotic effect of venetoclax, treatment initiation carries a risk of tumor lysis syndrome (TLS). Prompt and appropriate management is needed to limit clinical TLS, which may entail serious adverse events and death. Venetoclax ramp-up involves gradual, stepwise increases in daily venetoclax dosing from 20 mg to 400 mg (target dose) over 5 weeks; adherence to on-label scheduling provides a tumor debulking phase, reducing the risk of TLS. The key components of safe venetoclax therapy involve assessment (radiographic evaluation and baseline blood chemistry), preparation (adequate hydration), and initiation (blood chemistry monitoring). In addition to summarizing the evidence for venetoclax's efficacy and safety, this review uses hypothetical patient scenarios based on risk level for TLS (high, medium, low) to share the authors' clinical experience with venetoclax initiation and present global approaches utilized in various treatment settings. These hypothetical scenarios highlight the importance of a multidisciplinary approach and shared decision-making, outlining best practices for venetoclax initiation and overall optimal treatment strategies in patients with CLL.

Laboratory and clinical features of tumor lysis syndrome in children with non-Hodgkin lymphoma and evaluation of long-term renal functions in survivors

ObjectiveThe purpose of our study is to investigate the laboratory and clinical features of tumor lysis syndrome (TLS) and acute kidney injury (AKI) in childhood non-Hodgkin lymphomas (NHL) and to reveal their impact on long term kidney function in survivors.MethodsOur single-center retrospective study included 107 patients (0-18 years old) with NHL who were admitted and treated at our hospital between 1998 and 2020. The relationship between TLS and age, gender, histopathological subgroup, tumor stage, lactate dehydrogenase (LDH) level at presentation, bone marrow and kidney involvement were assessed. The long-term renal functions of the patients were investigated.Results80.3% of the patients were male with a median age of 9.8 years. The most common detected histopathological subgroup was Burkitt lymphoma. Hyperhydration with or without alkalinisation, and allopurinol were used in first-line treatment and prophylaxis of TLS. Laboratory TLS and clinical TLS was observed in 30.8% and 12.1% of patients, respectively. A significant correlation was found between young age, advanced stage, high LDH level at presentation, and TLS. AKI was observed in 12.1% of the patients. When the glomerular filtration rate values of the patients at the first and last admissions were compared after an average of 6.9 years, a mean decrease of 10 mL/min/1.73 m2 was found. It was not, however, found to be statistically significant.ConclusionLower age, advanced stage, and high LDH level at presentation were found to be risk factors for TLS in our study. Long-term renal function loss was not observed in the survivors who received early and careful prophylaxis/treatment for TLS. The survivors are still being followed up.

Real-world evidence of obinutuzumab and venetoclax in previously treated patients with chronic lymphocytic leukemia or small lymphocytic lymphoma

Venetoclax-obinutuzumab (Ven-O) is frequently administered off-label in relapsed/refractory (r/r) CLL/SLL where venetoclax-rituximab is the approved regimen. We conducted this retrospective, real-world study to evaluate Ven-O in r/r CLL/SLL. Between 7/2019 and 6/2022, 40 patients with r/r CLL/SLL on Ven-O were included. The median age was 72, 28.2% had TP53 mutation and/or 17p deletion, median number of prior therapies was 1 (range, 1–6), and 55% had prior BTK inhibitor exposure. The overall response rate was 90% (complete response [CR] or CR with incomplete marrow recovery in 27.5% and partial response in 62.5%) of patients, and the 2-year progression-free survival was 81.2% (95% CI, 69.5–94.8). Therapy was well tolerated. No laboratory or clinical TLS occurred with venetoclax (Howard criteria). One (3%) patient experienced laboratory TLS with obinutuzumab initiation. In summary, this retrospective cohort study demonstrated that Ven-O achieves frequent, durable responses and can be safely administered in r/r CLL/SLL.

Tumor Lysis Syndrome in Patients with AML Initiated on Venetoclax-Based Treatment without a Dose Ramp-up

Introduction Treatment with the combination of a hypomethylating agent (HMA) and venetoclax (VEN) is the standard of care for older patients (pts) with acute myeloid leukemia (AML). Venetoclax, an oral BCL-2 inhibitor, was initially approved for the treatment of chronic lymphocytic leukemia (CLL). In the early, pivotal studies assessing VEN safety, tumor lysis syndrome (TLS) was found to be a dose-limiting, potentially fatal toxicity. Dosing modifications were made to allow for safer initiation of the drug and, ultimately, a dose ramp-up was included in the dosing recommendation for CLL. Given the risk for TLS with VEN initiation for CLL, it was hypothesized that the risk would be the same, or potentially greater, when treating pts with AML. Therefore, studies of VEN in AML have included a dose ramp-up. Although reported rates of tumor lysis syndrome in these studies have been much lower than expected, a dose ramp-up for pts with AML is included in the package insert for VEN and continues to be utilized in clinical trials. Methods We conducted a retrospective analysis of pts ≥18 years of age with newly diagnosed or relapsed/refractory AML treated with a standard dose hypomethylating agent (HMA), either azacitidine or decitabine, and VEN without a dose ramp-up (initiated at 400mg daily or 100mg daily if on concomitant voriconazole or posaconazole) at Thomas Jefferson University Hospital from January 1, 2018- August 1, 2021. The primary objective of this study was to determine the rate of laboratory and clinical TLS within 72 hours after chemotherapy initiation, as defined by the Cairo-Bishop criteria (Table 1). The secondary objectives were (1) to identify clinical and laboratory risk factors for the development of TLS in pts with AML who were treated with HMA-VEN without a VEN dose ramp-up and (2) to compare rates of TLS in pts with AML who were treated with HMA-VEN without a VEN dose ramp-up to historical rates of TLS in pts who underwent a VEN dose ramp-up. In the Phase 3 study of azacitidine and venetoclax the rate of TLS during the VEN dose ramp-up period (days 1-3 of treatment) was 1% (DiNardo CD, Jonas BA, Pullarkat V, et al. Azacitidine and venetoclax in previously untreated acute myeloid leukemia. N Engl J Med. 2020;383(7):617-629.). Results Ninety pts were included in the analysis. Seventy-one pts had newly diagnosed AML and 19 had relapsed/refractory disease. The majority of pts (58/90, 64%) had adverse risk disease by 2017 European LeukemiaNet Criteria. Median baseline white blood cell count at the time of therapy initiation was 3.25 (range 0.5-161.4). Sixty-one pts (68%) were receiving allopurinol prophylaxis at the time of HMA-VEN administration. Eighteen pts (20%) had a history of underlying renal disease. Fifteen pts (17%) were on medications, such as thiazide diuretics, aspirin, or levodopa, that can increase the risk of TLS at the time of treatment. Zero pts met the defined criteria for laboratory or clinical TLS. One pt developed acute kidney injury and one pt developed a cardiac arrhythmia (atrial fibrillation) but neither had concomitant evidence of laboratory TLS. Discussion In this retrospective study of 90 pts with newly diagnosed or relapsed/refractory AML who were treated with HMA-VEN without a VEN dose ramp-up no pts developed clinical or laboratory tumor lysis syndrome. This is comparable to the rate of TLS (1%) seen in the registration trial of HMA-VEN where pts were treated with VEN 100 mg on day 1, 200 mg on day 2, and 400 mg on day 3 and thereafter. Starting pts with AML on full dose VEN on day 1, regardless of white blood cell count, renal function, or concomitant medications, appears safe and could be implemented in clinical practice and clinical trials moving forward. This would simplify dosing for pts, pharmacists, and providers and allow for easier initiation of therapy.

A Phase 2 Study of Minimal Residual Disease (MRD)-Adapted Front Line Venetoclax and Obinutuzumab in Fit Patients with Chronic Lymphocytic Leukemia (CLL): Effect of Obinutuzumab on Tumor Lysis Syndrome (TLS) Risk and Safety of Outpatient Venetoclax Dose Escalation

Introduction: Venetoclax (V) / Obinutuzumab (O) is an effective one-year fixed duration therapy for patients (pts) requiring first-line CLL treatment (tx). In CLL14, tumor lysis syndrome (TLS) risk assessment (including lymph node measurements by imaging and ALC) was required once prior to tx initiation, and O's impact on TLS risk prior to introduction of V was not a pre-planned study endpoint. Therefore, TLS prophylaxis (ppx) and tx setting for V dose escalation did not account for the possibility that O may decrease TLS risk prior to V escalation. Based on this approach, 22% of pts in the CLL14 study were high risk for TLS, thus requiring hospitalization for intensive laboratory monitoring during V dose escalation. (Fischer, NEJM 2019) We hypothesized that cycle (C) 1 of O would significantly decrease TLS risk prior to V escalation and that all pts, regardless of TLS risk category, could safely undergo a standard 5-week V dose escalation in the outpatient setting. Methods: We are conducting a Phase 2 study (NCT04447768) designed to examine the efficacy of a minimal residual disease (MRD)-adapted approach to V/O combination for fit pts in the front-line setting (study schema, Figure 1). A planned secondary study endpoint is to evaluate the effect of O monotherapy in C1 on TLS risk. Here we present interim results of TLS risk modification for the first 80 patients. Per protocol, TLS risk assessment including CT imaging and ALC measurement was performed at two defined timepoints: (1) prior to C1 day (D) 1 and (2) immediately prior to V initiation on C1D22. Key eligibility criteria: adult pts with CLL requiring first line tx per iwCLL guidelines, CIRS score ≤ 6, adequate heme function (Hgb ≥8 g/dL, ANC ≥1 x 10 9/L, Plt ≥30 x 10 9/L), creatinine clearance >50 mL/min. O was administered on C1 D1/2, 8 and 15. Per protocol, pts underwent V dose escalation in the outpatient setting, regardless of TLS risk. For pts with low and medium (med) tumor burden, TLS ppx was per FDA label. For pts who remained high TLS risk at the time of V initiation, TLS ppx throughout dose escalation included allopurinol to start at least 3 days prior to V initiation, sevelamer to start 12 hours prior to V initiation, and oral intake of ≥2 L water daily. On days of dose escalation, ppx additionally included kayexalate, rasburicase, and IV normal saline on D1 and D2 of each dose escalation. TLS labs were monitored according to FDA label guidance. Statistical analysis of TLS risk and adverse events was descriptive. Results: As of 5/2023, 80 pts have enrolled in this study. Seventy-eight pts completed the 5-week V ramp-up. Two pts were removed after receiving at least one dose of O but before repeat assessment of TLS risk and initiation of V (1 death unrelated to tx/disease, 1 patient with recurrent grade 3 (G3) O infusion-related reaction (IRR) leading to consent withdrawal). Median pt age was 57.5 years, 68% male, 95% white. Prior to tx initiation, TLS risk categories were low: 16%, med: 58%, and high: 26% (n=80). Change in TLS risk from baseline to C1D22 is detailed in Figure 2. Of the 20 pts who had sequential assessments with high baseline TLS risk, TLS risk after C1 O (C1D22) was low: 55%, med: 35%, high: 10%. For pts with med TLS risk at baseline with sequential assessments (n=45), TLS risk at C1D22 was low: 82%, med: 18%. One patient developed laboratory TLS on C1D3 following administration of O; no clinical TLS was observed. All pts accomplished V dose escalation in the outpatient setting with no observed laboratory or clinical TLS as defined by Howard Criteria. Grade 3 / 4 tx emergent AEs that occurred in >5% between C1D1 and C3D1 included neutropenia (35% G3, 11% G4), IRR (11% G3, 0% G4), and thrombocytopenia (9% G3, 3% G4). Conclusions: A single cycle of O effectively reduced TLS risk prior to introduction of V escalation with most pts achieving low or med TLS risk by C1D22. Notably, 90% of pts with high pre-tx TLS risk converted to low or med risk following C1 of O allowing for outpatient V escalation per FDA label. Further, we demonstrate that V dose escalation can be safely accomplished in the outpatient setting with close monitoring regardless of TLS risk. With this strategy, we observed no laboratory or clinical TLS during V dose escalation. Eliminating the need for hospitalization during V dose escalation may enhance patient and provider convenience and decrease the economic burden of this regimen. This study is ongoing; efficacy results of this MRD-guided approach to V/O are forthcoming.

A Phase I Study of Copanlisib and Venetoclax in Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma

Introduction: Diffuse large B-cell lymphoma (DLBCL) is a genomically heterogenous disease, which can be classified into distinct subgroups or clusters (Chapuy et al., Nat. Medicine, 2018, Wright et al., Cancer Cell, 2020). Leveraging knowledge of genetic alterations to design novel personalized treatment strategies may improve outcomes. Preclinical data suggest that the pan-phosphoinositide 3-kinase (PI3K) inhibitor, copanlisib, plus the BCL-2 inhibitor, venetoclax, are synergistic in genetically defined, high-risk, subtypes of DLBCL (Bojarczuk et al., Blood, 2019). We therefore hypothesized that copanlisib plus venetoclax would be an active treatment for patients with relapsed/refractory DLBCL, particularly in those with perturbed B-cell receptor (BCR)/PI3K signaling, which were predicted to be enriched in the relapsed setting. Here, we report the results of a phase I study of copanlisib plus venetoclax for patients (pts) with R/R DLBCL. Methods: This is an investigator-initiated, phase I, multicenter trial (NCT04572763) with the primary objective of determining the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of copanlisib and venetoclax in pts with R/R DLBCL. A standard 3+3 dose escalation design was employed, in which pts were treated with 60 mg IV copanlisib on days 1, 8, and 15 in addition to escalating doses of daily venetoclax for each 28-day cycle. During cycle 1, a venetoclax dose ramp-up was performed in the outpatient setting to a target dose of 200 mg (dose level (DL) +1), 400 mg (DL +2) and 800 mg (DL +3). The DLT observation period was the first cycle. Patients with progressive disease prior to the end of the DLT window were replaced. Key eligibility criteria included a confirmed diagnosis of DLBCL or high-grade B-cell lymphoma (HGBCL), relapse after or not a candidate for autologous stem cell transplant or chimeric antigen receptor (CAR) T-cell therapy, and adequate hematologic and organ function. Key exclusion criteria were poorly controlled hypertension or diabetes. CTCAE v5 and Lugano criteria were used to evaluate toxicity and efficacy, respectively. Results: As of July 21, 2023, 12 pts were evaluable. Patients were treated in DL +1 (n=5), DL +2 (n=3), and DL +3 (n=4). The median age was 62 years (range 24-87). Eighty three percent were male. Median number of prior treatments was 6 (range 1-11) and 10 pts had received prior CAR T-cell therapy. No DLTs were observed, though 2 pts in DL +3 were not able to escalate to 800 mg due to recurrent neutropenia and noncompliance, respectively. The most common toxicities were neutropenia (50%, all gr3/4), thrombocytopenia (42%, 8% ≥ gr3), nausea (33%, 8% ≥ gr3), fatigue (25%, 8% ≥ gr3), and headache (25%, 8% ≥ gr3) (Figure). Hyperglycemia occurred in 2 pts (both gr1). Serious adverse events occurred in 50% of pts and included fracture (n=1), hypoxia (n=2), and death (n=3), which were not related to study treatment. The deaths were related to progressive disease. Fifty percent of pts required drug holds (n=5 for venetoclax, n=5 for copanlisib). Sixty percent required growth factor support. There were no cases of laboratory or clinical tumor lysis syndrome. Sponsor support was withdrawn prior to completion of enrollment to DL+3, but DL+2 (copanlisib plus 400 mg venetoclax) was safe and well tolerated. The overall response rate (ORR) and complete metabolic response (CMR) rate was 8% (90% CI: 0 - 34%), as 1 pt in DL +1, who had received >5 lines of prior therapy, achieved a CMR, with response lasting 3 months. The median follow-up was 9.1 months. The median overall survival (OS) and progression-free survival (PFS) were 3.5 and 1.8 months, respectively. Conclusions: Copanlisib plus venetoclax is feasible and safe in pts with R/R DLBCL, with no DLTs observed. While it is possible that copanlisib plus venetoclax is active in select genomic subgroups of DLBCL, there was limited activity in this unselected, heavily pre-treated patient population.

Epcoritamab SC + GemOx Leads to High Complete Metabolic Response Rates in Patients with Relapsed/Refractory Diffuse Large B-Cell Lymphoma Ineligible for Autologous Stem Cell Transplant: Updated Results from Epcore NHL-2

Background: Patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) who fail or are ineligible for autologous stem cell transplant (ASCT) have poor outcomes with standard chemotherapy, and novel, effective therapeutic options are needed. A retrospective analysis showed that treatment with rituximab and gemcitabine + oxaliplatin (GemOx) in a transplant-ineligible population resulted in a complete response rate of 33% in the overall population; among patients refractory to previous therapy, 10% achieved complete response (Cazelles et al, Leuk Lymphoma 2021). Epcoritamab, a subcutaneously administered (SC) CD3xCD20 bispecific antibody, has demonstrated deep, durable responses with a manageable safety profile as a single agent in patients with R/R DLBCL. Based on these data, epcoritamab SC was approved by the US FDA for the treatment of adults with R/R DLBCL, not otherwise specified, including DLBCL arising from indolent lymphoma, and high-grade B-cell lymphoma, after ≥2 lines of systemic therapy. In the EPCORE ™ NHL-2 phase 1/2 trial (NCT04663347), epcoritamab + GemOx treatment showed encouraging preliminary efficacy with overall expected and manageable safety in patients with R/R DLBCL who failed or were ineligible for ASCT. Here, we present updated results with longer follow-up. Methods: Adults with R/R CD20 + DLBCL who had failed or were ineligible for ASCT were enrolled. Patients received epcoritamab SC in 28-d cycles (Cs) as follows: weekly, C1-3; every 2 weeks, C4-9; every 4 weeks, C≥10 until progressive disease or unacceptable toxicity. Patients received GemOx every 2 weeks in C1-4. Step-up epcoritamab dosing (step-up doses 1 and 2 followed by 48-mg full doses) and corticosteroid prophylaxis were required in C1 to mitigate CRS. The primary endpoint was overall response rate (ORR) as assessed by PET-CT per Lugano criteria. Results: A total of 34 patients (median age, 71 y; range, 47-87) with a median follow-up of 20.3 mo (range, 1.0+ to 26.8) received epcoritamab SC 48 mg + GemOx on or prior to August 24, 2022. At the data cutoff date (April 24, 2023), treatment was ongoing in 35% of patients. A majority of patients (68%) had stage III or IV disease, 53% had primary refractory disease, 38% were refractory to ≥2 consecutive lines of prior therapy, and 79% were refractory to the last line of therapy. The median number of prior lines of treatment was 2 (range, 1-6); 11 patients (32%) had 3 or more prior lines of treatment. A total of 7 patients (21%) had prior CAR T, and 5 patients (15%) had previously received ASCT. The most common treatment-emergent AEs (TEAEs) of any grade (G) were thrombocytopenia/decreased platelet count (68%), diarrhea (59%), anemia (56%), CRS (56%), and neutropenia/decreased neutrophil count (56%). This trial was conducted amid the COVID-19 pandemic and 32% of patients experienced COVID-19. Most CRS events were low grade (53% G1-2; 3% G3) and primarily occurred following the first full dose (C1D15); no incidence of CRS resulted in epcoritamab discontinuation, and all events resolved. ICANS (G1) was reported in 1 patient; this event resolved in 2 d. No clinical tumor lysis syndrome was reported. There were 10 G5 TEAEs; in 2 cases, the contribution of epcoritamab could not be ruled out by the investigator (small intestinal perforation and multiple organ dysfunction syndrome; both patients had multiple confounding factors). The ORR was 91% (31/34), with 59% (20/34) of patients achieving complete metabolic response (CMR). Median times to response and CMR were 1.5 mo and 2.6 mo, respectively. The ORR and CMR rates were 94% and 39% among patients with primary refractory disease, 89% and 78% among patients ≥75 y of age, and 90% and 50% among patients with IPI ≥3 ( Table). Response rates were comparable for patients with and without prior CAR T treatment: ORR of 86% and CMR rate of 57% among patients with prior CAR T; ORR of 93% and CMR rate of 59% among CAR T-naive patients. Conclusions: Epcoritamab SC + GemOx led to high CMR rates in this difficult-to-treat R/R DLBCL population ineligible for transplant with high unmet medical need. No new safety signals were identified, and the safety profile was consistent with those of the individual drugs. These data are encouraging and underline the versatility of epcoritamab SC for the treatment of R/R DLBCL. Additional data and subgroup analyses will be presented.

Identification of Optimal Dosing Regimen for Subcutaneous Epcoritamab in Relapsed or Refractory B-Cell Non-Hodgkin Lymphoma

Background: Epcoritamab SC, a CD3xCD20 bispecific antibody developed using the DuoBody ® platform, engages T cells to target CD20-expressing B cells. Epcoritamab was granted approval by the US FDA in May 2023 for the treatment of adults with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL), not otherwise specified, including DLBCL arising from indolent lymphoma, and high-grade B-cell lymphoma after ≥2 lines of systemic therapy. The recommended dosing regimen for epcoritamab is presented in the Table. Methods: A wide range of epcoritamab doses was explored in patients with R/R B-cell non-Hodgkin lymphoma, including priming doses (0.004-0.16 mg), intermediate doses (0.25-1.6 mg), and full doses (0.0128-60 mg). To identify the optimal dosing regimen for epcoritamab, comprehensive analyses of clinical safety, efficacy, pharmacokinetic (PK), and pharmacodynamic (PD) data (including PK/PD modeling and exposure-efficacy and exposure-safety analyses) were conducted using data from patients with R/R large B-cell lymphoma (LBCL) in the phase 1/2 EPCORE™ NHL-1 (NCT03625037) and EPCORE NHL-3 (NCT04542824) trials with a clinical data cutoff of Jan 31, 2022. Logistic regression analyses were performed to investigate the relationship between epcoritamab exposure and efficacy and safety across the entire range of studied doses. Results: Treatment with the approved dosing regimen led to a high overall response rate (ORR; 63%) and complete response (CR) rate (39%) and durable responses in this highly refractory patient population (median duration of response, 12.0 mo [95% CI, 6.6-not reached]; Thieblemont et al, JCO 2023). Overall, the safety profile of epcoritamab with the recommended dosing regimen is manageable. Higher exposure was associated with higher ORR ( P<0.0005 for the EPCORE NHL-1 LBCL population; n=192, 116 [60%] with response) and CR rate ( P<0.0005 for the EPCORE NHL-1 LBCL population; n=192, 74 [39%] with CR). Additionally, higher exposure improved progression-free survival ( P<0.0005 for the EPCORE NHL-1 LBCL population; lower 50%, n=97; upper 50%, n=98) and overall survival ( P=0.003 for the EPCORE NHL-1 LBCL population; lower 50%, n=97; upper 50%, n=98). The duration of response data exhibited a similar numerical trend ( P=0.278 for the EPCORE NHL-1 LBCL population; lower 50%, n=58; upper 50%, n=58). The pooled analysis of EPCORE NHL-1 and EPCORE NHL-3 LBCL populations showed similar trends. Importantly, a potential plateau of efficacy was observed at 48 mg or above. Furthermore, the majority of initial responses (94%) were achieved within the first 3 cycles (QW dosing interval), with a median time to response of 1.4 mo and a median time to CR of 2.7 mo in the expansion portion of EPCORE NHL-1 (Thieblemont et al, JCO 2023). Most responders maintained or improved their responses during the subsequent Q2W and Q4W dosing schedules, independent of exposure (C trough) during these periods. The step-up doses (0.16/0.8 mg) were clinically active and helped mitigate the risk of CRS at the subsequent therapeutic full (48-mg) doses. Complete B-cell depletion was observed as early as following the first priming dose. Very few first CRS events occurred after the second full dose or subsequent doses in patients who had not previously experienced CRS. The exposure-safety analysis did not identify any safety concerns with the approved dosing regimen. The rate of AEs, including grade ≥3 treatment-emergent AEs (TEAEs), serious TEAEs, grade ≥3 neutropenia, grade ≥3 infections, TEAEs leading to dose delay, TEAEs leading to treatment discontinuation, any-grade CRS, grade ≥2 CRS, CRS requiring tocilizumab, ICANS, and clinical tumor lysis syndrome, did not increase with increasing epcoritamab exposure. Conclusions: Our analyses informed the optimal dosing regimen for epcoritamab. Clinically active step-up doses (0.16/0.8 mg) demonstrated antitumor activity and mitigated the risk of CRS at subsequent therapeutic full doses. The recommended full dose (48 mg) provided deep and durable responses and a manageable safety profile in patients with LBCL. Lower full doses resulted in compromised efficacy without improvement of the benefit-risk profile, whereas increasing the full dose is not expected to lead to significantly higher efficacy. The recommended dosing intervals for epcoritamab treatment not only induced rapid responses but also maintained or improved responses during treatment.

Mitigating the Risk of Cytokine Release Syndrome (CRS): Preliminary Results from a DLBCL Cohort of Epcore NHL-1

Background: Epcoritamab SC, a CD3xCD20 T-cell-engaging bispecific antibody, has recently been approved by the US FDA for the treatment of adults with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), not otherwise specified, including DLBCL arising from indolent lymphoma, and high-grade B-cell lymphoma after ≥2 lines of systemic therapy. As a single agent, epcoritamab SC has demonstrated deep, durable responses with a manageable safety profile in patients with R/R large B-cell lymphoma in the expansion portion of the phase 1/2 EPCORE ™ NHL-1 trial (NCT03625037). Cytokine release syndrome (CRS) events in the dose expansion part of the trial were primarily low grade (49.7% overall; 31.8% grade [G] 1, 15.3% G2, 2.5% G3); timing was predictable, and the majority of events occurred following the first full dose at cycle 1 day 15 (C1D15). To mitigate CRS in dose expansion, subcutaneous administration, step-up dosing, and premedication, including prednisolone, were used. Here, we present preliminary results from a DLBCL optimization cohort of the EPCORE NHL-1 trial that further investigates mitigating the risk of CRS in patients treated with epcoritamab SC monotherapy. Methods: Adult patients with R/R CD20 + DLBCL (previously treated with ≥2 lines of systemic therapy) were enrolled to receive epcoritamab SC in 28-d cycles as follows: weekly, C1-3; every 2 weeks, C4-9; every 4 weeks, C≥10 until progressive disease or unacceptable toxicity. Patients received 2 step-up doses (step-up dose 1, 0.16 mg, and step-up dose 2, 0.8 mg) followed by 48-mg full doses. To further mitigate CRS, C1 of the optimization cohort included mandatory administration of dexamethasone 15 mg as premedication on D1, D8, D15, and D22 and as prophylaxis on D2-4, D9-11, D16-18, and D23-25, and diphenhydramine and acetaminophen as premedication on D1, D8, D15, and D22 with each dose. In C1, it was strongly recommended that patients be well hydrated and that antihypertensive medications be held for 24 h prior to epcoritamab SC administration. Patients were also encouraged to monitor their temperatures following the first 4 doses. Hospitalization and inpatient observation were optional. The primary endpoint was rate of G2 or higher CRS and all CRS events. Secondary pharmacokinetic/pharmacodynamic (PK/PD) analyses were performed. Results: As of April 21, 2023, 24 patients (median age, 65 y) had been treated in this DLBCL optimization cohort. The median number of prior lines of treatment was 3 (range, 2-10), 75% of patients were primary refractory, 71% had stage IV disease, and 58% had prior CAR T. With a median follow-up of 1.3 mo, 18 patients (75%) remained on treatment. The most common treatment-emergent AEs (TEAEs) of any grade were infections (38%; COVID-19, 8%), fatigue (21%), CRS (17%), headache (17%), anemia (13%), constipation (13%), decreased platelet count (13%), dyspnea (13%), hyponatremia (13%), insomnia (13%), and neutropenia (13%; febrile neutropenia, 4%). All CRS events were G1; 1 patient was treated with anticytokine therapy (tocilizumab); there were no treatment discontinuations due to CRS. The most commonly observed CRS symptom was fever (100%). Most CRS events (3/5 events) occurred following the first full dose on C1D15. The median time to CRS resolution was 3.5 d (range, 1-25) and all events resolved. Compared with the DLBCL expansion cohort, circulating interleukin 6 (IL-6) levels were decreased 24 h after the first full dose (C1D15) of epcoritamab SC ( Figure). The median circulating IL-6 level at C1D16 was lower in the dose optimization cohort at 6.92 pg/mL (2.97 pg/mL at C1D1 predose), compared with 21.24 pg/mL (2.45 pg/mL at C1D1 predose) in the DLBCL expansion cohort. The addition of dexamethasone and fluids in optimization did not appear to interfere with T-cell margination or T-cell activation, given that the fold-change values of T-cell absolute counts and percentage of activated T cells were similar between DLBCL optimization and expansion cohorts at C1D16. No patients experienced ICANS, clinical tumor lysis syndrome, or fatal TEAEs. Conclusions: Encouraging preliminary data from this DLBCL CRS optimization cohort, which incorporates prophylactic dexamethasone and hydration of patients during cycle 1, indicate that this approach is effective in decreasing rates and severity of CRS. Data with additional patients and follow-up will be presented.

Subcutaneous Epcoritamab Plus Lenalidomide in Patients with Relapsed/Refractory Diffuse Large B-Cell Lymphoma from EPCORE NHL-5

Background: The prognosis for patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) is poor, even if treated with salvage chemotherapy and autologous stem cell transplantation. CAR T cell therapy provides long-term remission in only 40% of patients. Epcoritamab, a subcutaneous CD3xCD20 bispecific antibody developed using the DuoBody ® platform, received accelerated FDA approval for adults with R/R DLBCL not otherwise specified, including DLBCL arising from indolent lymphoma, and high-grade B-cell lymphoma after ≥2 lines of systemic therapy. Single-agent epcoritamab has demonstrated deep and durable responses (overall response rate, 63%; complete responses, 40%) and a manageable safety profile in patients with R/R large B-cell lymphoma in the EPCORE NHL-1 trial (Karimi et al, ASCO 2023, abstract 7525). Combining epcoritamab with antineoplastic agents that have different mechanisms of action may offer enhanced clinical benefit to patients. Therefore, EPCORE NHL-5 (NCT05283720) evaluated the safety, tolerability, and preliminary efficacy of epcoritamab, as well as defining its recommended dose when coadministered with other antineoplastic agents in patients with non-Hodgkin lymphoma. Here, we present results from arm 1 that evaluated epcoritamab combined with lenalidomide in patients with R/R DLBCL. Methods: EPCORE NHL-5 is a phase 1b/2, nonrandomized, open-label, multicenter study. In arm 1, adults with CD20 + R/R DLBCL (ECOG 0-2) received subcutaneous epcoritamab (weekly during cycle 1-3, every 4 weeks during cycle 4-12) and oral lenalidomide (once daily on days 1-21) for 12 cycles of 28 days. Patients had received at least 1 prior combined systemic therapy that contained an anti-CD20 monoclonal antibody. The primary endpoint was the identification of dose-limiting toxicities (DLTs). Key secondary endpoints included investigator-assessed best overall response by Lugano 2014 criteria and time to response. Safety endpoints included severity and incidence of adverse events (AEs) including AEs of special interest to epcoritamab (cytokine release syndrome [CRS], immune cell-associated neurotoxicity syndrome [ICANS], and clinical tumor lysis syndrome). Results: As of May 22, 2023, 26 patients (median age, 71 years; DLBCL, n=24 [92%]; follicular lymphoma grade [G] 3b, n=2 [8%]) had received epcoritamab plus lenalidomide. Median duration of epcoritamab exposure was 3.8 months (range, 0-7.5) and median duration of lenalidomide exposure was 4.0 months (range, 0.1-8.2); 15 patients (58%) remain on epcoritamab and lenalidomide. Median number of prior lines of therapy was 1 (range, 1-4), with 15 (58%) receiving 1 prior line of anticancer therapy. Six patients (23%) had received prior CAR T and 2 patients had undergone hematopoietic stem cell transplantation. One DLT (neutropenia) was observed. The most common G3-4 treatment-emergent AEs (TEAEs) were neutropenia (n=15; 58%), anemia (n=4; 15%), thrombocytopenia (n=4; 15%), and febrile neutropenia (n=3; 12%). Primary granulocyte colony-stimulating factor prophylaxis was not mandatory. TEAEs led to epcoritamab discontinuation in 1 patient (3.8%; thrombocytopenia). No patients experienced a TEAE leading to death that was considered related to epcoritamab. CRS was predominantly low grade (73% [19/26] any grade; 65% G1-2; 8% G3) and occurred mostly after the first full dose (C1D15). Preliminary biomarker analysis showed pharmacodynamic profiles consistent with the mechanism of action of epcoritamab. These include predictable cytokine peaks immediately after the first full dose (IFN-gamma, IL-2, and IL-6) with a rapid and sustained depletion of peripheral B cells. One patient experienced ICANS (G3), which resolved after 2 days. Among response-evaluable patients (n=24), the overall response rate was 75% (95% CI, 53.3, 90.2). Complete metabolic responses were seen in 14 patients (58%) and partial responses in 4 patients (17%), of which 3 were ongoing at time of data cutoff ( Table). Median time to first response was 1.8 months (range, 1.0-2.8). Follow-up is ongoing. Conclusions: Epcoritamab combined with lenalidomide showed promising antitumor activity with a tolerable safety profile in patients with R/R DLBCL.

Phase I Safety and Preliminary Efficacy of Acalabrutinib, Venetoclax, and Obinutuzumab (AVO) in Patients with Relapsed/Refractory Mantle Cell Lymphoma

Introduction: Patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL), even when treated with novel targeted agents, generally have only limited benefit (Rule et al., Leukemia 2018). The triple combination of the first-generation Bruton tyrosine kinase inhibitor (BTKi), ibrutinib, the BCL-2 inhibitor, venetoclax, and anti-CD20 monoclonal antibody, obinutuzumab has demonstrated preliminary safety and efficacy in R/R and treatment naïve (TN) MCL (Le Gouill et al., Blood 2021). We therefore hypothesized that given the favorable toxicity profile of the second-generation BTKi, acalabrutinib, when given in combination with venetoclax and obinutuzumab (AVO), would be effective and well tolerated in both R/R and TN MCL. Here, we report the results of the phase I dose-finding cohort of AVO in patients with R/R MCL. Methods: This is an investigator-initiated, multicenter, multi-cohort phase I/II trial (NCT04855695). The primary endpoints of the phase I portion are the recommended phase II dose (RP2D) and the safety and tolerability of AVO in R/R MCL. The study was designed to evaluate up to 2 dose levels of acalabrutinib, starting with the FDA-approved dose (100 mg po bid, dose level 0 [DL0]) followed by a lower dose (100 mg po daily, DL-1) if dose limiting toxicities (DLTs) occurred in > 1/6 patients in DL0 during the first 4 cycles. Patients were treated in 28-day cycles with acalabrutinib starting with cycle 1, followed by obinutuzumab in cycle 2 (100 mg IV on day 1, 900 mg IV on day 2, 1000 mg IV on days 8 and 15, and on day 1 of cycles 3-7), and venetoclax (weekly dose ramp-up starting in cycle 3 to a target dose of 400 mg daily). Acalabrutinib and venetoclax were continued indefinitely and obinutuzumab maintenance was given every 2 cycles starting with cycle 9 for 12 doses. Patients with progressive disease (PD) or who were unable to receive > 80% of the doses of acalabrutinib and venetoclax during the first 4 cycles were replaced. Key eligibility criteria included R/R MCL after at least one anti-CD20 mAb-based therapy, ECOG PS ≤ 2, and adequate hematologic and organ function. Key exclusion criteria were progression or relapse following prior BTKi or BCL-2 inhibitor and CNS involvement. CTCAE v5 and Lugano criteria were used to evaluate toxicity and efficacy, respectively. Results: As of July 26, 2023, 9 patients in DL0 were evaluable for response as 3 patients were replaced prior to reaching the DLT window. The median age was 67 (range 63-79). 78% were male. Median number of prior treatments was 1 (range 1-2). 33% relapsed after autologous stem cell transplant and 22% had primary refractory disease. All patients had advanced stage MCL, with stage IV disease in 89%. MIPI score was 22% high, 56% intermediate, and 22% low risk. Ki67 index ≥ 30% in 44% and ≥ 50% in 33%. 33% patients had complex karyotype, 22% TP53 mutation, 33% p53 IHC expression > 50%, and 33% blastoid variant. No DLTs were observed and DL0 was determined to be the RP2D. All 9 patients were evaluable for toxicity (Figure 1A). Hematologic toxicity included neutropenia (67%; 33% Gr 3), thrombocytopenia (56%; 22% Gr 3/4), and anemia (22%; all Gr 3). The most common toxicities were headache (77%; all Gr 1/2), bruising (67%; all Gr 1), diarrhea (44%; all Gr 1/2), and upper respiratory infection (22%; 11% Gr 3). There were no serious adverse events. There was no occurrence of febrile neutropenia, atrial fibrillation, bleeding, or laboratory or clinical tumor lysis syndrome. Median follow-up was 6 months (range 1-21). ORR was 78% (7/9) and CR rate was 67% (6/9) after 3 cycles of AVO. Both patients with TP53 mutation and 2/3 patients with blastoid variant achieved CR. Of the 3 patients replaced prior to the DLT window, 2 patients had PD and 1 patient was unable to receive > 80% of the acalabrutinib and venetoclax doses due to grade 4 thrombocytopenia, although achieved CR. 5 patients (56%) remain on treatment and in CR. 1 patient achieved PR after cycle 3 but progressed after cycle 7. Median overall and progression-free survival were not reached. Conclusions: AVO is safe and feasible in patients with R/R MCL with no DLTs observed. RP2D was determined at the full FDA approved dosage of all three drugs. Preliminary efficacy is encouraging in this high-risk R/R MCL population. The phase II TN transplant ineligible or TP53 mutated MCL cohort is now enrolling with minimal residual disease (MRD)-guided time-limited therapy (Figure 1B). The phase I R/R expansion cohort will also open to enrollment.

Monotherapy with Second-Generation BCL2 Inhibitor Sonrotoclax (BGB-11417) Is Well Tolerated with High Response Rates in Patients with Relapsed/Refractory Marginal Zone Lymphoma: Data from an Ongoing Phase 1 Study

Background: Marginal zone lymphoma (MZL) is an uncommon type of non-Hodgkin lymphoma (NHL) that is generally considered incurable, with most patients experiencing a relapse after remission. Development of novel MZL therapies that are effective and tolerable is needed. Sonrotoclax (BGB-11417) is a next-generation BH3 mimetic which binds and inhibits BCL2 with a potency >10x that of venetoclax in biochemical assays. BGB-11417-101 (NCT04277637) is an ongoing, first-in-human, phase 1/1b dose-escalation and dose-expansion study looking at a wide array of B-cell malignancies. Previous interim analyses indicate sonrotoclax is well tolerated as monotherapy at all doses tested, up to 640 mg once daily (QD). This analysis investigated the safety, tolerability, and efficacy of sonrotoclax in patients with relapsed/refractory (R/R) MZL. Methods:Patients with R/R MZL received sonrotoclax (dose escalation: 40, 80, 160, 320, or 640 mg QD) with a 3-day ramp-up to the intended dose, followed by expansions at 640 mg and 320 mg. Dose-limiting toxicity (DLT), predefined in the protocol for each dose cohort, was evaluated during dose ramp-up through day 21 at the intended dose. The primary objective was to determine the safety and tolerability of sonrotoclax; a secondary objective for the expansion phase was to evaluate the activity of BGB-11417 as measured by the overall response rate (ORR, defined as partial response [PR] or better). Responses were assessed per Lugano criteria 2014. Adverse events (AEs) were reported per CTCAE v5.0 and tumor lysis syndrome (TLS) was assessed per Howard (2011) criteria. Results: As of April 24, 2023, 13 patients with MZL had received sonrotoclax across dose-escalation and -expansion cohorts (n=1, 40 mg; n=2, 160 mg; n=10, 640 mg). Overall, median age was 73 years (range: 54-85) and the median number of prior treatments was 1 (range: 1-3). Four patients progressed on Bruton tyrosine kinase inhibitors (BTKi), of which three had BTKi as last prior therapy. Dose escalation occurred per protocol at all defined doses. The maximum tolerated dose was not achieved with a maximum assessed dose of 640 mg; one DLT of febrile neutropenia was observed in the 160 mg cohort. Dose expansion was completed with the recommended phase 2 dose of 640 mg. Median follow-up was 7.8 months (range, 2.6-36.6 months). Treatment-emergent AEs (TEAEs) occurring in ≥20% of patients were nausea (39%) and pyrexia, diarrhea, and constipation (31% each). The most common grade ≥3 TEAEs were neutropenia, febrile neutropenia/neutropenic sepsis, and TLS (n=2 [15%] each). Five patients discontinued treatment (n=3, progressive disease; n=1, AE [infection]; n=1, withdrawal). No TEAEs leading to death occurred. Two patients in the 640-mg cohort experienced laboratory TLS following the initial ramp-up dose. The first patient (baseline: nodes, 60 mm; spleen, 21 cm; white blood cells [WBC], 46.9 × 10 9/L) had laboratory TLS (elevated potassium, phosphate, and urate) after a 160 mg dose, which resolved within 24 hours with intravenous hydration and supportive care without sequela or dose modification. Following a protocol amendment, patients with circulating tumor cells received an additional 3-day ramp-up starting at 40 mg. A second patient (baseline: nodes, 28 mm; spleen, 20 cm; WBC, 352 × 10 9/L) had laboratory TLS (elevated phosphate and urate) after initial 40- and 80-mg doses. Both episodes resolved within 24 hours without sequela or change in dosing. Overall, 12 patients were assessable for response; ORR was 67% (n=8), including four patients (33%) with complete response (CR). Nine of the 10 patients treated at 640 mg were assessable for response, where the ORR was 78% (n=7), including four patients (44%) who achieved a CR (Figure). Responses of PR or better were observed in all four patients with previous progression on BTKi (n=3, CR; n=1, PR). Conclusions: These data confirm sonrotoclax monotherapy had a tolerable safety profile across all doses tested and encouraging antitumor activity in patients with MZL. Two patients had laboratory TLS following the initial doses that resolved. No clinical TLS were observed, indicating that TLS can be mitigated with current measures, including revised ramp-up. An exploratory 320-mg cohort is currently enrolling.

Primary Analysis and Results of Bendamustine, Rituximab, and Venetoclax (BR-VEN) for Initial Treatment of Mantle Cell Lymphoma in Subjects over 60 Years of Age (PrE0405)

Background Mantle cell lymphoma (MCL) is an incurable form of aggressive non-Hodgkin lymphoma. Treatment choice at diagnosis is based on tolerability of cytarabine and high-dose chemotherapy. With a median age of 60-70 years, many patients are ineligible for aggressive treatment. Bendamustine and rituximab (BR) is a reasonable treatment option (E1411, Smith MR et al. ASH 2022) for this patient population and venetoclax (VEN) has shown pre-clinical evidence of synergy with chemoimmunotherapy. PrECOG 0405 was designed to evaluate the addition of VEN to BR in previously untreated patients with MCL aged over 60 years. Methods Eligible patients included those that were previously untreated and diagnosed with MCL as defined as the presence of t(11;14) by FISH or cyclin D1 expression by IHC. Patients must have been at least 60 years of age or older on D1C1 of therapy with a good performance status (ECOG 0-2). Adequate marrow and organ function was required, specifically a creatinine clearance of ≥ 40 mL/min. Treatment administration is summarized in Figure 1. Dose of bendamustine was either 90mg/m 2 D1&2; or, for subjects over the age of 75 years, 70mg/m 2 was allowed per investigator discretion. VEN was dose escalated during Cycle 1 to 200mg. At the time of C2, BR was repeated and VEN was also escalated to 400mg. With C2-6, VEN 400mg PO daily was given D1-10 only. Primary endpoint was PET-negative complete response (CR) rate at end of treatment (EOT) by Lugano Criteria. A negative bone marrow biopsy was required to confirm CR if involved at screening. Minimal residual disease (MRD) by next-generation sequencing was performed at the EOT. Maintenance rituximab was encouraged per investigator discretion. This was a single arm study with an original accrual goal of 53 subjects to detect a 15% improvement in CR rate compared to historical data. However, due to slow study accrual during COVID pandemic and preliminary efficacy data from E1411 study, the statistical parameters were updated after 25 subjects had been accrued. The revised accrual goal was 33 patients to obtain 32 eligible and treated patients, which provided 81.8% statistical power to detect a 17% difference in CR rate (from 60% [E1411 data] to 77%) using an exact binomial test with a 1-sided alpha of 11.6%. This combination regimen will be considered promising if 23 or more (out of 32) patients attain CR. Results From January 2020 to March 2022, 33 subjects enrolled and were treated on study. Subject characteristics are listed in Table 1. Seven (21%) unique subjects were treated with 70mg/m 2 of bendamustine during induction cycles. Laboratory tumor lysis syndrome (TLS) was seen in 2/33 during C1 only; clinical TLS was not seen. Treatment was generally well tolerated with treatment-related adverse events (TRAE) of Grade ≥3 and occurring in >10% of subjects being neutropenia (n=5, 15%), thrombocytopenia (n=5, 15%) and lymphopenia (n=9, 27%). Other common non-hematologic TRAE of all grades were nausea/vomiting (n=26, 79%), diarrhea (n=10, 30%), and fatigue (n=17, 52%). There were 4 (12%) instances of COVID-19/COVID-19 pneumonia considered treatment related. Dose adjustments and delays for any drug occurred in 36% and 67% of subjects respectively. 22/33 (66.7%) subjects completed 6 cycles of BR-VEN. Maintenance rituximab was administered in 19/33 (57.6%) of subjects. Overall response rate was 97% (32/33) and PET-negative bone marrow biopsy confirmed CR Rate at EOT was 85% (28/33), achieving the primary endpoint (≥23 CRs). MRD at EOT is under analysis. With a median survival follow up of 21.5 months (mo), Median PFS and OS were not reached; estimated 2-year PFS and OS was 69.7% and 81.1% respectively. During follow up, there have been 6 deaths, 4 from COVID-19 (all in remission), one from influenza A (in remission), and one from disease progression (non-responding pt). There have been 2 other progression events who are alive. Conclusions BR-VEN was generally well-tolerated in this older patient population though GI toxicities were common. With a PET-negative CR rate of 85%, the combination is promising but longer follow-up is needed. There was a competing risk of death related to upper respiratory viruses identified, mostly COVID-19, as has been seen in other BR-based protocols during the COVID-19 pandemic. MRD analysis and survival data will be updated.

Outcomes of Patients with Relapsed/Refractory Lymphoplasmacytic Lymphoma Treated with Venetoclax: A Multicenter Retrospective Analysis

Outcomes of Patients with Relapsed/Refractory Lymphoplasmacytic Lymphoma Treated with Venetoclax: A Multicenter Retrospective Analysis

Real-World Venetoclax-Obinutuzumab in 232 Treatment Naive CLL Patients: Feasibility and Tolerability

Fixed duration venetoclax-obinutuzumab (VO) is approved in treatment naïve (TN) chronic lymphocytic leukemia (CLL), based on CLL14 study addressed to patients (pts) with coexisting conditions. The combinations showed also to be effective and well tolerated in the younger population enrolled in the randomized CLL13 trial. The aim of this retrospective, multicenter Italian study is to evaluate the feasibility and tolerability of this combination in TN CLL in common clinical practice as well as reasons for choosing fixed-duration VO instead of continuous BTKi. Consecutive pts receiving first-line therapy after VO approval/reimbursement in Italy (May 2022) were considered. Reasons for choosing the fixed duration treatment were recorded. The impact of clinical, biological, and demographic characteristics on VO feasibility (definitive treatment discontinuation and/or schedule modifications due to toxicity) and tolerability were analyzed. Debulking (Deb) phase (D1-D56) was separately evaluated to better understand its influence on treatment management. From May 2022 to June 2023, 790 treatment naïve continuous pts were treated with targeted agents in 49 centers. Treatment choice consisted of: continuous BTKi in 558 pts and fixed-duration VO in 232 (the latter representing the population of our analysis). The main reasons given by physicians for choosing VO instead of BTKi were: disease biology 46% (mutated IgHV status), fixed duration 33%, comorbidities 15%, patient choice 6%. Pts' characteristics are shown in Table 1. When considering Deb-phase (232 pts), VO was regularly administered according to the investigator brochure in 150 (64.7%). In 22 cases (9.5%) the schedule was a priori modified by clinicians: 12 pts started with V led-in and postponed O infusion at C2D1; in 10 planned O D8 and D15 infusions were omitted. Overall, 12 pts (5.2%) permanently discontinued VO due to toxicity. 3 of them dying due to: COVID pneumonia, invasive aspergillosis, VO-unrelated cachexia. In the remaining 48 (20.7%) schedule was adjusted due to AEs. Treatment modifications, overlapping in some cases were: 42 extended the Deb-phase (median days to completion 63, range 59-130); 14, never reached the full V dose; 31 did not perform the planned 5 O infusions (median 3 infusions, range 1-4). No age, neither coexisting conditions influenced treatment feasibility. The only parameters having an impact on Deb-phase discontinuation or schedule modifications due to toxicity were: baseline ANC<1500/mmc (OR 3.1, p=.035), hypogammaglobulinemia (OR 2.2, p=.018), concomitant use of anticoagulants (3.13, p=.029). Overall 23 pts (9.9%), including 7 categorized as high risk TLS, were hospitalized for treatment initiation. During Deb-phase grade 3-4 AEs occurred in 69 pts (30%): neutropenia (18%); thrombocytopenia (14%); infections (5%); IRR (5%). Development of any severe AE was influenced by: upper GI disorder, baseline neutropenia or thrombocytopenia. TLS was recorded in 13 pts (6%): 11 O-related and 4 V-related. All 4 clinical TLS were considered as secondary to O. Only high CLL-CI risk was associated with TLS. None of the baseline factors nor type of steroids premedication predicted IRR. At the present follow-up of the 232 pts considered: 142 completed the 6 cycles of combinations treatment, 75 are still ongoing, 15 definitively discontinued treatment for AEs. Overall, 42 pts received VO with an adjusted schedule for toxicities: 22 are receiving V at reduced dose, 39 pts did not complete the planned O infusions (treatment modifications overlapping in some cases). G 3-4 toxicity developed in 78 pts being neutropenia and infections the most common reported. At univariate analysis factors affecting treatment feasibility were: presence of endocrine comorbidity; intermediate/high CLL-CI and hypogammaglobulinemia. To our knowledge this is the first real-world study on clinical factors that may influence VO feasibility. Despite this setting of unselected population, most clinicians were adherent to VO schedule. A low rate of pts permanently discontinued therapy during Deb-phase with no impact of age or comorbidities on feasibility. Furthermore, TLS and IRR were in line with clinical trials. Longer follow-up data will be reported at the meeting allowing by multivariate analysis to better clarify the role of comorbidities on treatment management and the reproducibility of VO tolerability in common clinical practice.

Combination Treatment with Sonrotoclax (BGB-11417), a Second-Generation BCL2 Inhibitor, and Zanubrutinib, a Bruton Tyrosine Kinase (BTK) Inhibitor, Is Well Tolerated and Achieves Deep Responses in Patients with Treatment-Naïve Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (TN-CLL/SLL): Data from an Ongoing Phase 1/2 Study

Background: The combination of BCL2 and BTK inhibitors has shown synergistic activity. The combination of venetoclax, a BCL2 inhibitor, and ibrutinib, a BTK inhibitor, is an effective treatment for CLL/SLL. Sonrotoclax (BGB-11417) is a BH3 mimetic that binds and inhibits BCL2 with potency >10x that of venetoclax in biochemical assays. Zanubrutinib, a next-generation BTK inhibitor, has shown improved PFS with fewer cardiac adverse events (AEs) vs ibrutinib in a randomized study of patients with CLL/SLL (Brown et al. N Engl J Med. 2023). BGB-11417-101 (NCT04277637) is an ongoing, first-in-human, phase 1/1b dose-escalation/expansion study of patients with various B-cell malignancies. In a preliminary report, sonrotoclax, alone or in combination with zanubrutinib, was well tolerated at all doses tested up to 640 mg. This abstract describes the safety and efficacy data from patients with treatment-naïve (TN) CLL/SLL who received the combination of sonrotoclax and zanubrutinib. Methods:Patients received zanubrutinib (320 mg QD or 160 mg BID) 8-12 weeks before starting sonrotoclax using a ramp-up schedule starting from 1 mg to the intended target dosage of 160 mg or 320 mg QD (doubling weekly [W] or 30% increase every day 5 d/week [D]) to mitigate risk of tumor lysis syndrome (TLS). Patients were treated until progression, unacceptable toxicity, or could elect to stop. TLS was assessed per Howard (2011) criteria; mitigation included mandatory oral hydration and antihyperuricemics. Primary endpoint was safety (reported per CTCAEs v5.0); a secondary endpoint was ORR (per iwCLL 2008 criteria) and minimal residual disease assessed in blood by ERIC flow every 24 weeks (uMRD4; <1 CLL cell per 10,000 leukocytes, or <0.01%) was an exploratory endpoint. Results: As of May 21, 2023, 94 patients with TN-CLL/SLL were enrolled (sonrotoclax 160 mg QD, n=41 [26 W, 15 D] and 320 mg QD, n=53 [25 W, 28 D]); 15 patients were still receiving zanubrutinib monotherapy and 79 started sonrotoclax (160 mg, n=32 [25 W, 7 D] and 320 mg, n=47 [24 W, 23 D]). Median follow-up was 8.5 mo (range: 0.6-18.2) for all patients; 160 mg, 12.1 mo (range: 0.6-18.2); 320 mg, 7.0 mo (range: 1.1-14.6). No deaths have occurred, and all patients remain on study. Treatment-emergent AEs (TEAEs) occurring in ≥20% patients who received sonrotoclax plus zanubrutinib (n=79) are listed in theTable; TEAE frequencies were similar between the two sonrotoclax cohorts. Contusion, neutropenia, and low-grade gastrointestinal toxicity were the most common TEAEs; neutropenia was the most common grade ≥3 TEAE (n=13 [17%]). No cases of clinical or laboratory TLS occurred in either ramp-up schedule; no patient experienced atrial fibrillation. One TEAE (cryptococcal meningitis at 11 weeks treated with azoles) led to treatment discontinuation. Sonrotoclax dose holds occurred in 17 patients (22%) for a median duration of 11 days (range: 3-37) and three patients (4%) had dose reduction. The most common TEAEs resulting in dose holds were COVID-19 (n=9 [11%]) and diarrhea (n=3 [4%]). A total of 56 patients had a response assessment. The ORR was 100% (CR: 160 mg, n=9 [36%]; 320 mg, n=6 [19%]). Across all doses, rate of CR increased with time; overall median time to CR was 10.1 mo (range: 5.4, 17.1). No progression was reported in either cohort (Figure). Week 24 blood uMRD4 rates were 50% (n=12/24) in 160 mg and 65% (n=13/20) in 320 mg patients. Week 48 blood uMRD4 rates were 73% in 160 mg (n=11/15) and 100% (n=1/1) in 320 mg; no patient has lost uMRD4. Conclusion: Sonrotoclax (160 mg and 320 mg) in combination with zanubrutinib was well tolerated in patients with TN CLL/SLL. Only one patient discontinued treatment and three patients had dosage reductions. No TLS was seen with either ramp-up schedule. Acknowledging the short follow up, efficacy is encouraging with 100% ORR in assessed patients and no PFS events. High rates of blood uMRD4 occurred early. Based on these data, a phase 3 study assessing this combination is planned.

Fixed-Duration Pirtobrutinib Combined with Venetoclax ± Rituximab in Relapsed/Refractory Chronic Lymphocytic Leukemia: Updated Results, Including MRD Data, from the BRUIN Phase 1b Study

Background: Covalent (c) Bruton tyrosine kinase inhibitors (BTKi) have transformed the management of chronic lymphocytic leukemia (CLL). Recent clinical studies have evaluated the safety and efficacy of fixed-duration regimens with venetoclax and cBTKi. While these combinations are effective, their use may be limited by toxicity. Pirtobrutinib, a highly selective, non-covalent (reversible) BTKi, has shown promising safety and efficacy in heavily pretreated relapsed or refractory (R/R) CLL patients (pts). Here, we report the safety and efficacy of fixed-duration pirtobrutinib combined with venetoclax ± rituximab in pts with R/R CLL. Methods: Pts with R/R CLL were eligible for pirtobrutinib combined with venetoclax ± rituximab in the phase 1b portion of the multicenter phase 1/2 BRUIN study (NCT03740529). Prior cBTKi therapy was allowed, but not prior venetoclax. Pts were enrolled into sequential cohorts, first in the pirtobrutinib + venetoclax (PV) cohort and then the PV + rituximab (PVR) cohort. Pirtobrutinib 200 mg QD was started on cycle 1 day 1, and venetoclax was started on cycle 2 day 1 with the standard 5-week dose ramp to 400 mg QD target dose. PV was given for up to 24 cycles; each cycle was 28 days. For the PVR cohort, rituximab was given at 375 mg/m 2 on cycle 1 day 1 and then 500 mg/m 2 on day 1 of cycles 2-6. The primary endpoint was safety as assessed by treatment-emergent adverse events (TEAEs) graded according to CTCAE v5.0. Other key endpoints included overall response rate (ORR), progression-free survival (PFS), and minimal residual disease (MRD). Undetectable MRD (uMRD) was defined as less than 1 CLL cell/10,000 nucleated cells (<1x10 -4) in peripheral blood by ClonoSEQ® assay (Adaptive Biotechnologies, Seattle, WA). A data cut of May 5, 2023, was utilized. Results: Fifteen pts received PV, and 10 received PVR. Median age was 66 years (range, 49-77) for those who received PV and 69 (range, 39-78) for those who received PVR. Median prior lines of therapy was 1 (range, 1-2) for the PV cohort and 2 (range 1-4) for the PVR cohort. Most pts had received prior chemotherapy (PV=53%; PVR=60%), CD20 monoclonal antibody (73%; 70%), and cBTKi (73%; 60%). The majority of pts had IGHV unmutated CLL (PV=73%; PVR=89%). ORR was 93.3% (95% CI, 68.1-99.8) for the 15 pts receiving PV and 100% (95% CI, 69.2-100.0) for the 10 pts receiving PVR, with 10 complete responses (PV=7; PVR=3). Median duration of follow-up for PFS was 22.1 months (IQR, 20.1-25.7) for PV and 22.1 months (IQR, 20.7-22.1) for PVR; PFS at 18 months was 92.9% (95% CI, 59.1-99.0) for the 15 pts receiving PV and 80.0% (95% CI, 40.9-94.6) for the 10 pts receiving PVR. The overall uMRD rate at cycle 13 was 70.8% (PV=10; PVR=7) for the 24 evaluable pts, with 87.5% (PV=12; PVR=9) of pts achieving uMRD at some time during the trial and all but one pt sustaining uMRD during subsequent MRD assessments ( Figure). Twenty-two pts discontinued treatment (PV=14; PVR=8); of these, 14 completed all 24 cycles of therapy (PV=9; PVR=5) and 8 discontinued early because of progressive disease (PV=2), adverse events (PVR=2), protocol noncompliance (PV=1), death unrelated to treatment (PVR=1), or other reasons (PV=2). Three pts (PV=1; PVR=2) continue to receive treatment. The median relative dose intensity was similar in both cohorts (PV=97.9%; PVR=98.6%). The most common TEAE of any grade included nausea (PV=60.0%; PVR=40.0%), fatigue (53.3%; 50.0%), and diarrhea (46.7%; 60.0%). The most common grade ≥3 TEAE was neutropenia/neutrophil count decreased (PV=46.7%; PVR=60.0%). Grade ≥3 clinical tumor lysis syndrome occurred during venetoclax dose escalation (PV=2), including a grade 3 case that resolved spontaneously after 24 hours and a grade 4 case that resolved after short-term intravenous fluids. Treatment-related adverse events led to dose reductions in three pts (PV=1; PVR=2) and treatment discontinuation in two pts (PVR=2). Conclusions: Fixed-duration pirtobrutinib combined with venetoclax ± rituximab was well tolerated and demonstrated sufficiently promising efficacy to warrant further investigation in pts with R/R CLL. The BRUIN CLL-322 phase 3 trial comparing PVR vs VR in previously treated CLL is currently enrolling pts (NCT04965493).