Leslie, Lori A.

Abstract Introduction: The first-generation BCL2 inhibitor,venetoclax, is an effective treatment for CLL/SLL, but its usage may be limited by toxicity. Sonrotoclax, a next-generation BCL2 inhibitor, is a more selective and pharmacologically potent inhibitor of BCL2 than venetoclax, with a shorter half-life and no drug accumulation. BGB-11417-101 (NCT04277637) is an ongoing, phase 1/1b, dose-escalation/expansion study in patients with B-cell malignancies. Presented here are preliminary data for sonrotoclax + obinutuzumab in patients with treatment-naive (TN) CLL/SLL in BGB-11417-101. Methods: Obinutuzumab is administered intravenously at 100 mg on day (D) 1, 900 mg on D2, 1,000 mg on D8 and D15 of cycle (C) 1, and then 1,000 mg on D1 of C2-6 of each 28-day cycle. Beginning on C2D1, sonrotoclax is administered orally once daily with ramp-up to the target doses, 160 or 320 mg. Patients can continue treatment until progressive disease (PD), unacceptable toxicity, or undetectable minimal residual disease (uMRD4; <1 CLL cell per 10,000 leukocytes [<0.01%]) in peripheral blood (PB) by next-generation sequencing (NGS; ClonoSEQ) after 15 treatment cycles. Study endpoints include safety per NCI-CTCAE v5.0, overall response rate (ORR) per iwCLL guidelines, and MRD status in PB per modified ERIC flow cytometry (FC) assay or NGS, depending on the timepoint. Tumor lysis syndrome (TLS) is assessed per Howard (2011) criteria. Results: As of May 16, 2025, 55 patients with TN CLL/SLL were enrolled (160 mg, n=20; 320 mg, n=35), and 21 patients (all 320 mg) have discontinued sonrotoclax + obinutuzumab (due to uMRD4 per NGS as protocol-mandated [n=17], PI decision uMRD4 per FC [n=2], and PD [n=2]). Four patients discontinued obinutuzumab only per PI decision (160 mg, n=1), thrombocytopenia (320 mg, n=2), and prostate cancer prior to starting sonrotoclax (160 mg, n=1). For all patients, the median age was 62 y, 65% were male, and 89% were White. At baseline, 14% of patients (8/55) had high tumor burden and 58% (31/53) had unmutated IGHV. Median study follow-up was 8.9 months (range, 0.4-25.4 months) for all patients; 6.4 months (range, 0.4-9.0 months) for 160 mg; and 16.0 months (range, 2.9-25.4 months) for 320 mg. Maximum tolerated dose was not reached. The most common any-grade treatment-emergent AEs (TEAEs) were thrombocytopenia (56%), infusion-related reaction (56%), and neutropenia (49%). Neutropenia was the most common grade ≥3 TEAE (38%). No deaths due to TEAEs occurred, and no TEAEs led to sonrotoclax discontinuation. Two cases of laboratory TLS occurred after C1D1 of obinutuzumab prior to starting sonrotoclax; no clinical or laboratory TLS occurred during sonrotoclax ramp up. No meaningful safety differences were observed among sonrotoclax dose cohorts. In 37 efficacy-evaluable patients (160 mg, n=7; 320 mg, n=30), the ORR was 89%; for the 320-mg cohort, ORR was 93% (28/30). Complete response (CR) rates (CR + CR with incomplete marrow recovery [CRi]) were 46% (all patients) and 43% (320 mg). For 23 patients in the 320 mg cohort who reached the C15 MRD assessment, the best C15 uMRD4 rate per FC was 87% (20/23; 2 not evaluable; 1 missing); per NGS, the uMRD4 rate at C15 was 78% (18/23; 5 missing). All patients with an available C15 MRD assessment achieved uMRD4 and remain in remission as of the data cutoff date. The median time from reaching sonrotoclax target dose to uMRD4 was 2.3 months (range, 1.4-5.6 months) in the 320-mg cohort. Three patients experienced PFS events: 1 died from an indeterminate cause (160 mg, discontinued treatment after C1D9 of obinutuzumab) and 2 had PD (320 mg; both Richter's transformation at C6 and C2). Conclusions: Sonrotoclax + obinutuzumab was generally well tolerated in patients with TN CLL/SLL, with no sonrotoclax discontinuations or deaths due to TEAEs. No laboratory or clinical TLS events occurred during sonrotoclax ramp-up. Encouraging antitumor activity was observed with sonrotoclax 320 mg. High rates of blood uMRD4 occurred early and deepened over time. All patients with an available C15 MRD assessment by NGS or FC achieved uMRD4 and remain in remission. A registrational phase 3 study (CELESTIAL-RRCLL, BGB-11417-303) assessing this combination with sonrotoclax 320 mg is currently recruiting.

Abstract Background: Venetoclax (VEN)+obinutuzumab (VO) is an effective therapy for CLL/SLL requiring regular monitoring for tumor lysis syndrome (TLS) during VEN ramp-up. The CLL14 trial of VO reported no TLS during VEN ramp-up; however, there are limited real-world data on monitoring practices and TLS outcomes for different dose levels and monitoring timepoints. This study assessed VEN initiation prophylaxis and monitoring outcomes for patients (pts) with CLL/SLL starting VO in first line (1L) in an outpatient, real-world setting. Methods This interim analysis relied onretrospective observational data from 4 US sites of the CLL Collaborative Study of Real-World Evidence (CORE). Adult pts with CLL/SLL were eligible if they: (1) started VO per-label outside of a clinical trial in 1L, or immediately after exposure in 1L to agents with different mechanisms of action (i.e., BTKi, anti-CD20 only) of <30 days; (2) prior to VEN start, had either (i) low physician-determined tumor burden (TB) (i.e., all lymph nodes [LN] <5 cm and ALC <25 x 109/L), or (ii) medium physician-determined TB (i.e., any LN ≥5-<10 cm or ALC ≥25 x 109/L) with creatinine clearance ≥80 mL/min; (3) had no strong CYP3A inhibitors or prophylactic rasburicase from 3 days prior to VEN start until end of VEN ramp-up; and (4) had VEN ramp-up in an outpatient setting. TB-related labs/imaging was assessed from 2 months prior to obinutuzumab initiation (i.e., index date) until VEN start. VEN characteristics (i.e., dosing, duration), prophylaxis measures (i.e., antihyperuricemics and IV hydration), and TLS-related monitoring and management (i.e., lab results and interventions received) were collected per ramp-up week and TLS monitoring timepoint. Results Of 128 pts in CORE who initiated VO in any line, 72 pts met inclusion criteria (low TB: 57 [79.2%]; medium TB: 15 [20.8%]). Median (IQR) age was 62 (56.0, 68.5) years, 58.3% were male, and 81.9% had ECOG grade ≤1. Among pts tested, 7/68 (10.3%) had del(17p)/TP53 mutation and 43/66 (65.2%) had unmutated IGHV. Median (IQR) time from index to VEN start was 23.0 (22.0, 30.0) days. Most pts completed ramp-up (98.6% [71/72]) and followed a per-label regular dosing schedule (93.1% [67/72]). Prior to VEN ramp-up, all pts received prophylactic antihyperuricemics (allopurinol: 71 [98.6%]; febuxostat: 2 [2.8%]) and prophylactic hydration. In the 2 days prior to a dose escalation for at least 1 week of ramp-up, prophylactic IV hydration was reported for 27 (37.5%) pts based on physician determination. One pt stopped VEN after week 2 due to neutropenia (grade 3+). During ramp-up (median [IQR] of 9 [8, 12] blood tests per pt), no lab or clinical TLS was reported. Of 21 (29.2%) pts who received an intervention following a lab assessment, most had low TB at VEN start (16 [76.2%]). All interventions were either prophylactic or non-TLS-related. Following a lab assessment for at least 1 week of ramp-up, prophylactic IV or escalated oral hydration intervention was reported in 17/21 pts (81.0%) based on physician determination (e.g., to manage impaired baseline renal function in those with low TB, patient request, or institutional practice) (IV hydration: 15 pts; escalated oral hydration: 2 pts). By per-label monitoring timepoints, hydration intervention was given prophylactically following pre-dose lab tests for 7 pts (across weeks 1-5), 6-8 hours post-dose for 5 pts (weeks 1-2), and 24 hours post-dose for 10 pts (weeks 1-2). By per-label monitoring timepoints, other non-TLS-related interventions (i.e., blood transfusion for anemia, insulin for hyperglycemia, and potassium for non-TLS-related hypokalemia) were given following pre-dose lab tests for 2 pts (weeks 1-5) and 24 hours post-dose for 4 pts (weeks 1-2). Conclusion Consistent with the CLL14 trial, no TLS was reported in this real-world, interim analysis of pts with mostly low TB and good renal function at 1L VO initation. All interventions during VEN ramp-up were prophylactic or non-TLS-related, with prophylactic hydration commonly given based on physician preference. These results suggest that VO initiation is manageable in an outpatient setting. Consideration should be given for simplified monitoring requirements including potential removal of 6-8 hour post-dose lab in this population and be further explored in prospective studies. Data collection for this study is ongoing to further contextualize real-world VEN initiation prophylaxis and monitoring outcomes in a larger cohort.

Abstract Background: Despite the promising efficacy of CAR-T for patients with relapsed or refractory (R/R) large B-cell lymphomas (LBCL), more than 60% of patients will relapse, the majority of which occur in the first 6 months. Approximately 30% of patients with LBCL treated with CAR-T achieve a partial response (PR) on day 30 (D30) PET-CT assessment. Of patients in a D30 PR, 70% will eventually progress, yet the standard of care remains close observation. Early consolidative treatment strategies utilizing therapies with a different mechanism of action may improve outcomes, but there are currently no reliable biomarkers. Epcoritamab (Epco), a bispecific antibody directed against CD20 and CD3, has been approved by the FDA for LBCL patients who relapse after at least 2 lines of therapy. By treating prior to overt relapse, Epco has the potential to salvage inadequate responses post CAR-T. This study is a trial-in-progress that will evaluate the efficacy of epco compared to observation for patients with LBCLs achieving a PR on D30 post CAR-T PET-CT assessment. Methods This is an investigator-initiated, randomized, phase II, multicenter, open-label study (NCT06238648) evaluating epco monotherapy for a fixed duration of 12 cycles compared to observation for LBCL patients with D30 PR after standard of care CAR-T. A maximum of 120 patients will be randomized 1:1 to epco or observation across 10 academic centers. Stratification factors include line of CAR-T (second vs third line) and costimulatory domain (CD28 vs 4-1BB). Key inclusion criteria include PET evidence of a D30 PR. non-bulky disease ( <7.5cm), ANC of >1000, hemoglobin >7 g/dL if asymptomatic or >8 if symptomatic, platelet count >50,000. G-CSF, pRBCs and platelet transfusions are allowed. Key exclusion criteria include ongoing or uncontrolled CRS or ICANS, and active or symptomatic CNS disease. This study is available to all eligible patients, regardless of race, gender, or ethnic origin. To adapt to current practices, prior bispecific antibody exposure is allowed if used as holding or bridging therapy without disease progression. Epco is administered subcutaneously at a dose of 0.16mg on day 1, 0.8mg on day 8, prior to full dose of 48mg on day 15. Epco is administered weekly in 28 day cycles (C) for C1-3, on day 1 and 15 of C4-9 and on day 1 of C10-12. PET-CT response is assessed by the 2014 Lugano criteria after 2 cycles, and then every 3 months during active treatment. The primary objective is efficacy, measured as conversion from D30 PR to CR. The secondary endpoints include frequency and severity of treatment emergent adverse events, ORR, duration of response, duration of complete response, progression free survival, event free survival, and overall survival. Peripheral blood samples will be collected pre-treatment and during treatment to assess for biomarkers of response and resistance and CAR-T persistence. The study was activated in January 2024 and recruitment is ongoing.

TPS7100 Background: Despite the promising efficacy of CAR-T for patients with relapsed or refractory (R/R) large B-cell lymphomas (LBCL), more than 60% of patients will relapse, the majority of which occur in the first 6 months. Approximately 30% of patients with LBCL treated with CAR-T achieve a partial response (PR) on day 30 (D30) PET-CT assessment. Of patients in a D30 PR, 70% will eventually progress, yet the standard of care remains close observation. Early consolidative treatment strategies utilizing therapies with a different mechanism of action may improve outcomes, but there are currently no reliable biomarkers. Epcoritamab (Epco), a bispecific antibody directed against CD20 and CD3, has been approved by the FDA for LBCL patients who relapse after at least 2 lines of therapy. In the phase 2 study, Epco was associated with an overall response rate (ORR) of 63% and a complete response (CR) rate of 39%, including similar responses in a subset of patients who were relapsed 100 days post CAR-T. This study is a trial-in-progress that will evaluate the efficacy of epco compared to observation for patients with LBCLs achieving a PR on D30 post CAR-T PET-CT assessment. Methods: This is an investigator-initiated, randomized, phase II, multicenter, open-label study (NCT06238648) evaluating epco monotherapy for a fixed duration of 12 cycles compared to observation for LBCL patients with D30 PR after standard of care CAR-T. A maximum of 120 patients will be randomized 1:1 to epco or observation across 10 academic centers. Stratification factors include line of CAR-T (second vs third line) and costimulatory domain (CD28 vs 4-1BB). Key inclusion criteria include PET evidence of a D30 PR. non-bulky disease ( <7.5cm), ANC of >1000, hemoglobin >7 g/dL if asymptomatic or >8 if symptomatic, platelet count >50,000. G-CSF, pRBCs and platelet transfusions are allowed. Key exclusion criteria include prior anti CD20xCD3 bispecific antibody therapy, ongoing or uncontrolled CRS or ICANS, and active or symptomatic CNS disease. Epco is administered subcutaneously at a dose of 0.16mg on day 1, 0.8mg on day 8, prior to full dose of 48mg on day 15. Epco is administered weekly in 28 day cycles (C) for C1-3, on day 1 and 15 of C4-9 and on day 1 of C10-12. PET-CT response is assessed by the 2014 Lugano criteria after 2 cycles, and then every 3 months during active treatment. The primary objective is efficacy, measured as conversion from D30 PR to CR. The secondary endpoints include frequency and severity of treatment emergent adverse events, ORR, duration of response, duration of complete response, progression free survival, event free survival, and overall survival. Peripheral blood samples will be collected pre-treatment and during treatment to assess for biomarkers of response and resistance. The study was activated in January 2024 and recruitment is ongoing. Clinical trial information: NCT06238648 .

Background: Primary central nervous system lymphoma (PCNSL) is a rare and aggressive form of NHL isolated to the central nervous system or vitreoretinal space. Despite high initial rates of responses to available therapies, most PCNLS relapse in two years, presenting a very poor prognosis. Combination with novel therapies may overcome resistance (Guidetti 2023a). Upregulation of the B-cell receptor (BCR/NF-κB) and toll-like receptor (TLR)/NF-κB) signaling axis have been identified as key pathways in the pathogenesis of PCNSL. MYD88 L265P, a widely expressed somatic mutation in more than 70% of PCNSL patients, activates NF-κB signaling through stimulation of BTK and IRAK4. Emavusertib (CA-4948) is a novel, potent oral inhibitor of interleukin 1 receptor-associated kinase 4 (IRAK4), with additional inhibitory activity against FMS-like tyrosine kinase 3 (FLT3) and CDC-like kinases (CLK1/2/4). Targeted inhibition of IRAK4 with emavusertib in PCNSL xenografts indicated sufficient blood brain barrier penetration of emavusertib, target inhibition, and antitumor activity (von Roemeling 2022). Further preclinical studies have demonstrated that emavusertib synergizes with ibrutinib and can re-sensitize and overcome resistance to BTK inhibitors (Guidetti 2023a and 2023b). Initial clinical data have reported responses in BTK-resistant PCNSL and good tolerance of the combination (Iqbal 2022; Grommes 2023). Study Design: This is an ongoing multi-center, open-label trial (NCT03328078) in adult patients with hematologic malignancies to evaluate the safety, PK, and anti-cancer activity of oral administration of emavusertib alone or in combination with ibrutinib. Part Bis an open trial expansion cohort with BTKi relapsed or refractory PCNSL. About 20 evaluable PCNSL patients will be enrolled globally. Patients will receive oral CA-4948 at 100 or 200 mg BID in combination with ibrutinib at 560 mg QD in 28-day cycles until disease progression or intolerable toxicity. The primary endpoint is expanded safety/tolerability; secondary endpoints include ORR, DOR, PFS, OS, and pharmacokinetics. Key inclusion criteria for this expansion cohort: pathologically confirmed diagnosis of PCNSL with evidence of disease progression, measurable disease, relapsed or refractory with no more than 3 lines of prior anti-PCNSL therapy (including BTKi), and absence of residual Grade ≥2 toxicity from prior therapy. Key exclusion criteria: intraocular PCNSL without brain lesion or CSF involvement or significant co-morbidity. Key clinical assessments include brain imaging, CSF- and ocular examinations.

Introduction: Historically, older patients (pts) with relapsed/refractory large B-cell lymphoma (R/R LBCL) were often deemed ineligible for curative-intent autologous stem cell transplant (ASCT) due to age and concern for increased toxicity related to comorbidities. We previously demonstrated in the pivotal ZUMA-7 study that older pts with R/R LBCL can safely receive axicabtagene ciloleucel (axi-cel) as second-line (2L) therapy with improved event-free survival (EFS), response rate, and quality of life compared with standard of care (SOC) based on results from the primary EFS analysis (Westin, et al. Clin Cancer Res. 2023). At a median follow-up of 47.2 months (mo), results from the ZUMA-7 primary overall survival (OS) analysis demonstrated superior OS in the intention-to-treat (ITT) analysis (hazard ratio [HR], 0.73; 95% CI, 0.54-0.98; stratified two-sided log-rank P=0.03; Westin, et al. N Engl J Med. 2023; NCT03391466). We now report updated efficacy and safety results from the primary OS analysis among ZUMA-7 pts aged ≥65 years (y) and ≥70 y. Methods: Eligible pts were randomized 1:1 to axi-cel or SOC (2-3 cycles of platinum-based chemoimmunotherapy; responding pts proceeded to high-dose chemotherapy with ASCT). The primary OS analysis occurred 5 y after the first pt was randomized (01/25/2018) per protocol. Other endpoints included progression-free survival (PFS) per investigator assessment and safety. A planned subgroup analysis of pts aged ≥65 y was conducted in addition to an analysis for those ≥70 y. Multivariate analyses were performed to examine treatment efficacy with axi-cel compared with SOC after adjusting for multiple covariates, including sex, disease type, molecular subgroup, lactate dehydrogenase (LDH), tumor burden, and age; strata for these analyses included second-line age-adjusted International Prognostic Index (aaIPI), and relapsed vs refractory disease. Exploratory analyses were conducted to determine the association between OS and axi-cel product characteristics for pts aged ≥65 y. Results: A total of 109 pts were included in the analysis (axi-cel: 51 were ≥65 y, 26 of whom were ≥70 y, maximum age was 80 y; SOC: 58 were ≥65 y, 27 of whom were ≥70 y, maximum age was 81 y). Compared with SOC pts at baseline, more axi-cel pts had high-risk features, including aaIPI 2-3, elevated LDH, and high-grade B-cell lymphoma. At a median follow-up of 46.6 mo, OS was prolonged in the axicel vs SOC arm in pts aged ≥65 y (HR, 0.691; 95% CI, 0.401-1.190) and for those ≥70 y (HR, 0.330; 95% CI, 0.135-0.809). Similar results were observed using the piecewise Cox regression model. The median OS for axi-cel and SOC pts was 43.5 mo (95% CI, 20.9-not estimable [NE]) and 19.6 mo (95% CI, 12.3-NE), respectively, among those aged ≥65 y, and 24.7 mo (95% CI, 12.8-NE) and 11.2 mo (95% CI, 6.1-NE), respectively, among those aged ≥70 y. In the SOC arm, 57% and 52% of pts received subsequent cellular immunotherapy off protocol in pts aged ≥65 y and ≥70 y, respectively. Multivariate analyses demonstrated an even greater OS benefit with axi-cel over SOC when adjusting for differences in baseline characteristics in pts aged ≥65 y (HR, 0.526; 95% CI, 0.266-1.041) and in pts aged ≥70 y (HR, 0.184; 95% CI, 0.045-0.755). PFS assessed by investigator confirmed benefit of axi-cel over SOC in pts aged ≥65 y (HR, 0.406; 95% CI, 0.230-0.715) and in pts aged ≥70 y (HR, 0.206; 95% CI, 0.078-0.547). The median PFS for axi-cel and SOC pts was 28.7 mo (95% CI, 5.1-NE) and 5.0 mo (95% CI, 2.8-7.2), respectively, for those aged ≥65 y, and 11.4 mo (95% CI, 4.1-NE) and 2.7 mo (95% CI, 1.7-5.0), respectively, for those aged ≥70 y. No new treatment-related deaths occurred since the primary EFS analysis. There were no manufacturing failures for any pt who underwent leukapheresis. Similar associations between product characteristics and outcomes were observed among the elderly and overall populations, including improved OS associated with a greater (&gt;median) proportion of juvenile or stem memory T-cell phenotype cells (CCR7+CD45RA+ T cells) in the axi-cel product among pts aged ≥65 y (HR, 0.369; 95% CI, 0.138-0.984). Conclusion: Axi-cel as 2L therapy prolonged survival over SOC in pts aged ≥65 y, including in pts aged ≥70 y. These findings confirm that age alone should not be a barrier for consideration of CAR T-cell therapy, supporting the use of axi-cel as a curative-intent 2L therapeutic option for older pts with R/R LBCL.

Background: Emavusertib (CA-4948) is a novel oral inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4), which is essential for toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling in B cell proliferation. Additional inhibitory activity against FMS-like tyrosine kinase 3 (FLT3) and CDC-like kinases (CLK1/2/4) is also present in emavusertib. IRAK4 forms a Myddosome complex with MYD88 adaptor protein and drives overactivation ofnuclear factor-kappa B (NF-κB), causing inflammation and tumor growth. Emavusertib has been reported to be well tolerated and active as monotherapy in heavily pretreated patients with relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL) (Nowakowski 2020). Preclinical studies demonstrated that tumor resistance and survival via IRAK4 activation could be delayed or reversed. Emavusertib crossed the blood-brain barrier in a murine PDX model of PCNS lymphoma, blocked the activated IRAK4 pathway, and induced tumor response and prolonged survival (von Roemeling 2022). In combination with Bruton tyrosine kinase (BTK) inhibitors, emavusertib showed in vitro synergy and re-sensitization of resistant cell lines, overcoming BTK resistance (Guidetti 2023a and 2023b). In vivo synergy in B-cell NHL was also demonstrated. Adaptive chemotherapy treatment resistance through IRAK4 upregulation and activation was also described in other disease models (Melgar 2019, Li 2019). This abstract presents preliminary efficacy and safety data of emavusertib + ibrutinib in R/R NHL patients. Aim:Assessment of safety and clinical activity of emavusertib in combination with ibrutinib. Methods: This is an ongoing open-label trial (NCT03328078) of emavusertib as monotherapy and in combination with ibrutinib. Part A1 - completed; dose escalation of emavusertib as monotherapy; the recommended phase 2 dose (RP2D) is 300 mg BID with continuous oral dosing (Nowakowski 2020). Part A2 - completed; dose escalation of emavusertib in combination with ibrutinib at 420 and 560 mg QD (Joffe 2022). Part B - ongoing; an expansion cohort of PCNSL patients with resistance to prior BTK inhibitors for additional safety and efficacy related to exposure: emavusertib at 100 or 200 mg BID + ibrutinib at 560 mg QD in 28-Day cycles. Results:As of 19 July 2023, 18 heavily pretreated NHL (including five PCNSL) patients received emavusertib at 100, 200, or 300 mg BID in combination with full ibrutinib doses per label. Median age was 63.5 years (range 50-92). Median number of prior lines of anti-cancer therapies was 3 (range 1-10). Eleven of 18 patients failed prior BTK inhibitors. Median treatment duration was 95.5 days (21-587 days), suggesting acceptable safety and tolerability. No DLTs were observed at the 200 mg BID dose level, and two reversible DLTs (stomatitis and syncope) were observed at the 300 mg BID dose level. The preliminary efficacy data of 16 evaluable patients in combination with ibrutinib showed 5 CRs (2 MCL, 3 PCNSL) and 1 PR (1 CLL). All 3 PCNSL patients with CR were previously treated with BTK inhibitors. Conclusion: The combination ofemavusertib plus ibrutinib (ema+ibr) is well tolerated with an acceptable long-term safety profile and promising efficacy, showing several objective responses in heavily pretreated and/or BTK inhibitor resistant patients. Emavusertib may have the potential to overcome BTK inhibitor resistance and the combination of ema+ibr has the potential to show increased anti-cancer activity compared to ibrutinib monotherapy.

Multiple CD19-directed therapies are available for the treatment of relapsed and refractory (R/R) DLBCL, including CAR T cells, tafasitamab/lenalidomide (TL), and loncastuximab tesirine (lonca-T) (Sermer D., Blood Rev 2023). However, there are few data available on the efficacy of sequential CD19-directed therapies. We performed a retrospective study evaluating all patients with R/R LBCL treated consecutively with TL at 11 institutions from 8/2020 to 8/2022, identifying 178 patients. In this study, we specifically evaluate outcomes in patients who received anti-CD19 therapy prior to or after TL. The primary outcome of interest was progression-free survival (PFS) in TL recipients who previously received CD19-directed CAR T therapy, with overall response rate (ORR), complete response rate (CRR), and overall survival (OS) also evaluated. Outcomes of lonca-T and CAR T after TL therapy were evaluated. Data on CD19 expression was assessed on biopsies after TL; this was determined locally using flow cytometry or immunohistochemistry per institutional protocols. In subgroup analyses, ORR and CRR were compared using Fisher's exact test. PFS and OS were estimated using the Kaplan-Meier method, with differences tested using the log-rank test. Of 178 patients who received TL, 52 had received prior anti-CD19 CAR T therapy, at a median of 7.4 months before TL (Table 1). Median PFS was lower in prior CAR T recipients (1.6 mo, 95% CI 1.1-2.5) vs no prior CAR T (2.1 mo, 95% CI 1.8-3.2), with hazard ratio 1.46 (p = 0.04; Figure 1). Best ORR was lower in patients with prior CAR T exposure (15% vs 33%, p = 0.02) though CRR was not significantly different (15% vs 18%, p = 1.0). We specifically evaluated TL outcomes based on prior response to CAR T, given the previously identified association of refractory disease with poor TL outcomes (Qualls D et al., presented at ASH 2022). Of 19 patients who had progressive disease more than 6 months after CAR T, ORR and CRR to TL therapy were 31.6% (all responses were CRs); in 33 patients with refractory disease (less than CR or relapse within 6 months) after CAR T, ORR and CRR to TL were significantly lower, at 6.1% (p = 0.04). Median PFS after TL was shorter in CAR-refractory than CAR-relapsed disease, at 1.4 vs 3.5 months (HR 2.2, p = 0.02). Of 88 patients who received therapy after TL, 20 (23%) received lonca-T and 14 (16%) received CAR T. Data on survival and initiation of new treatment after CAR T or lonca-T was available, but response and progression data after CAR T or lonca-T therapy is pending. These data allowed an estimate of OS and event-free survival (EFS), defined as survival without initiation of a new treatment after CAR T or lonca-T. With a median 3.9 months' follow-up, median EFS after CAR T administration was 3.7 months (95% CI, 0.9 - 6.5), and median OS was 8.1 months (95% CI, 0.6 - 15.7). In patients who received lonca-T, with median 2.7 months' follow-up from initiation, median EFS was 2.8 months (95% CI, 0.9 - 4.7), and median OS was 3.5 months (95% CI, 1.2 - 5.7). When comparing CAR T and lonca-T to polatuzumab vedotin- or chemotherapy-based therapies after TL, there were no significant differences in OS or EFS. In patients who discontinued TL, 24 had a biopsy a median of 18 days after the last dose of tafasitamab. Of these, 13 (54%) were CD19-positive and 11 (46%) were CD19-negative. All samples obtained more than 21 days after tafasitamab (6/6) were CD19-positive, while 46% obtained within 21 days were CD19-positive. These time-dependent findings may reflect “epitope masking” by tafasitamab rather than CD19 loss, reflecting other recent reports (Fitzgerald K., Leuk Lym 2022; Duell J., Leuk Lym 2022). In patients receiving TL after CAR T, responses and PFS were lower than in patients without prior CAR T therapy; however, with disease that was not refractory to prior CAR T, results were similar to patients who had not had prior CAR T. This may reflect that refractory disease, regardless of prior therapy, is associated with shorter PFS, though the possibility of CD19-mediated mechanisms of resistance remains. Modest EFS and OS were seen in patients receiving CAR T therapy or lonca-T after already receiving TL, though this may also reflect the high-risk disease characteristics of this cohort. Overall, in a high-risk, real-world cohort of TL-treated patients, these data suggest that some patients may benefit from subsequent CD19-directed therapies, but better therapeutic options are needed.

Abstract In this real-world evaluation of tafasitamab-lenalidomide (TL) in relapsed or refractory LBCL, patients receiving TL had higher rates of comorbidities and high-risk disease characteristics, and substantially lower progression-free survival and overall survival, compared with the L-MIND registration clinical trial for TL.