Ayed, Ayed O.

7029 Background: Mosun, a CD20xCD3 T-cell engaging bispecific antibody, is approved for relapsed/refractory follicular lymphoma after ≥2 prior lines of therapy. We report an interim analysis and PROs with Mosun SC in elderly/unfit patients with previously untreated DLBCL. Methods: MorningSun (NCT05207670) is a Phase 2, basket study of Mosun SC in patients with B-cell non-Hodgkin lymphoma. In the DLBCL cohort, eligible patients (aged ≥80 years, or 65–79 years and ineligible for chemoimmunotherapy) received outpatient Mosun SC: Day (D) 1 (5 mg), D8 (45 mg) and D15 (45 mg) of Cycle (C) 1, then 45 mg on D1 for up to 17 21-day cycles. Primary endpoint was progression-free survival (PFS) rate at 24 months. Other endpoints included overall survival (OS), objective response rate (ORR), complete response (CR) rate, change from baseline (CfB) in lymphoma symptoms as assessed by the Functional Assessment of Cancer Therapy-Lymphoma subscale (FACT-Lym LYMS; higher scores indicate improvement, a ≥3-point increase is considered clinically meaningful) and safety. Results: Forty-nine patients were enrolled, primarily from community sites (n=34). Median age was 83 years (range: 71–101). International Prognostic Index was 3–5 in 53.1% patients and 18.4% of patients had bulky disease. As of February 10, 2025, the median duration of follow-up was 12.5 months (range: 1.4–30.8). PFS and OS rates at 12 months were 71.3% (95% confidence interval [CI]: 54.8–82.7) and 74.7% (95% CI: 58.5–85.4), respectively. ORR was 73.5% and CR rate was 59.2%. Completion rates for FACT-Lym LYMS were ≥95% at baseline and remained ≥87% at each subsequent timepoint. Patients reported improvement in health-related quality of life (HRQoL) over time, demonstrated by increased mean CfB (standard deviation [SD]) in FACT-Lym LYMS scores: C4D1, 5.1 (9.8); C9D1, 5.6 (11.8); C17D1, 9.8 (11.4). Clinically meaningful improvements in lymphoma symptoms were observed in 53.1% (95% CI: 38.3–67.5) of patients. The most common any-grade adverse event (AE) was injection site reaction (53.1%; all Grade [Gr] 1/2). Gr 3/4 AEs were reported in 65.3% of patients and 8.2% experienced a Gr 5 AE (no Gr 5 AEs were Mosun related, per investigator assessment). Serious AEs occurred in 42.9% of patients. Infection AEs occurred in 49.0% of patients (Gr 1: 4.1%; Gr 2: 28.6%; Gr 3: 16.3%) and resolved in 91.7%. Cytokine release syndrome occurred in 12.2% of patients (Gr 1: 10.2%; Gr 2: 2.0%; all resolved). Updated data with around one additional year of follow-up will be presented. Conclusions: Mosun SC showed promising efficacy with manageable safety in elderly/unfit patients with previously untreated DLBCL in an outpatient setting. Clinically meaningful improvements in lymphoma symptoms suggest that Mosun SC improves aspects of HRQoL in this population. Clinical trial information: NCT05207670 .

Abstract Background: Mosunetuzumab (Mosun) is an off-the-shelf, CD20xCD3 T-cell engaging bispecific antibody that redirects T cells to eliminate B cells, including those that cause malignant disease. Mosun is FDA- and EMA-approved for relapsed/refractory follicular lymphoma (FL) after ≥2 prior lines of therapy as a fixed-duration intravenous treatment, and can be given in an outpatient setting without mandatory hospitalization. Initial Phase I/II data with Mosun monotherapy have shown notable efficacy and manageable safety in patients with previously untreated diffuse large B-cell lymphoma (DLBCL; NCT03677154; Olszewski et al. ASH 2022). The Phase II MorningSun study is the first to assess the efficacy and safety of subcutaneous (SC) Mosun monotherapy in elderly/unfit patients with previously untreated DLBCL; we report an interim analysis for this study. Methods: MorningSun (NCT05207670) is an open-label, multicenter, Phase II, basket study evaluating the safety, efficacy, and pharmacokinetics of Mosun SC monotherapy in patients with B-cell non-Hodgkin lymphoma. In the DLBCL cohort, eligible patients aged ≥80 years or aged 65–79 and considered ineligible for chemoimmunotherapy (CIT) were enrolled, primarily in US community sites. Hospitalization was not mandatory. Step-up doses of Mosun SC were administered on Day (D) 1 (5mg), D8 (45mg) and D15 (45mg) of Cycle 1, followed by 45mg on D1 of 21-day cycles, for up to 17 cycles or until unacceptable toxicity. The primary endpoint in this cohort was progression-free survival (PFS) rate at 24 months after first study treatment. Secondary endpoints included objective response rate (ORR), complete response (CR) rate, time to response (TTR), duration of response (DOR), duration of complete response (DOCR), overall survival (OS), and safety. An exploratory circulating tumor DNA analysis was performed using an AOA-NHL assay. Results: Overall,49 patients were enrolled, the majority at community sites (community, n=34; academic, n=15). Thirty-six patients had DLBCL, 6 had high-grade [Gr] B-cell lymphoma, 2 had T-cell/histiocyte-rich large B-cell lymphoma, and 1 had Gr 3B FL (histology missing/other lymphoma, n=4). Median age was 82.5 years (range: 71–101); 63.3% and 20.4% of patients had an ECOG performance status of 1 and 2, respectively; 40.8% had Ann Arbor stage IV disease; 51.0% had extranodal involvement; 18.4% had bulky disease; and 53.1% had an IPI score of 3–5. At the clinical cut-off date of February 10, 2025, 23 (46.9%) patients had discontinued treatment, mainly due to progressive disease (n=12, 24.5%) or an adverse event (AE; n=5, 10.2%); the median duration of follow-up was 12.5 months (range: 1.4–30.8) and the median number of cycles received was 14 (range: 1–17). The PFS rate at 12 months was 68.8% (95% confidence interval [CI]: 52.1–80.6) and OS rate at 12 months was 77.2% (95% CI: 61.1–87.3). The ORR and CR rates were 73.5% and 59.2%, respectively. Median TTR was 2.7 (range: 2.5–6.1) months. DOR and DOCR rates at 12 months were 84.6% (95% CI: 66.8–93.3) and 95.0% (95% CI: 69.5–99.3), respectively. The most common AE (any grade) was injection site reaction (n=25, 51.0%), which was mostly Gr 1 (n=24, 49.0%). Gr 3/4 AEs occurred in 65.3% (n=32) of patients, most commonly infections (16.3% [n=8]) and decreased neutrophil count (10.2% [n=5]); serious AEs occurred in 42.9% (n=21) of patients. Four patients experienced Gr 5 AEs (congestive cardiac failure, volvulus, unexplained death and intracranial hemorrhage, n=1 each); none were related to Mosun per investigator assessment. Infections occurred in 46.9% (n=23) of patients (Gr 1/2, 30.6% [n=15]; Gr 3, 16.3% [n=8]); no Gr 4/5 infections were observed. No immune effector cell-associated neurotoxicity syndrome events occurred. Cytokine release syndrome was reported in 12.2% (n=6) of patients, with 10.2% (n=5) Gr 1 and 2.0% (n=1) Gr 2 events, all of which resolved. In evaluable patients with a CR (n=16), 68.8% (n=11) of patients were minimal residual disease negative (p-value cut-off 0.005).Conclusions: There remains an unmet need for effective chemotherapy-free options in previously untreated elderly and CIT-ineligible patients with DLBCL. Interim data from MorningSun demonstrate that fixed-duration Mosun SC monotherapy is active in these patients, with promising efficacy and a manageable safety profile, with predominantly mild-to-moderate AEs, allowing for outpatient administration in the community practice setting.

Abstract Background Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is a devastating event occurring in approximately 5% of patients treated with standard R-CHOP (Thanarajasingam et al, ASH 2015, abs 1456). Isolated CNS relapse is associated with significant morbidity and mortality. New treatment regimens with agents that cross the blood-brain barrier (BBB) are needed. The combination of lenalidomide with R-CHOP (R2CHOP) has shown promising results in activated B-cell (ABC) type DLBCL in phase 2 studies and is currently being evaluated in randomized trials. Lenalidomide crosses the BBB and has been demonstrated to have single-agent activity in relapsed CNS lymphoma. Accordingly, the addition of lenalidomide to R-CHOP may decrease the risk of CNS relapse. Here we characterize the combined incidence of isolated CNS relapse in a population of DLBCL patients who received R2CHOP for induction therapy in two independent phase 2 studies. Methods We analyzed the incidence of isolated CNS relapse in patients with histologically-confirmed DLBCL enrolled in two R2CHOP phase 2 trials - one conducted by Mayo Clinic (MC) and the other by Italian Lymphoma Foundation (FIL) - in the context of clinical variables that included age, gender, disease stage, cell of origin, and administration of CNS prophylaxis. We assessed CNS-International Prognostic Index (CNS-IPI) factors (age, stage, lactate dehydrogenase level, ECOG performance status, extranodal sites, adrenal/kidney involvement) and classified patients into groups of low, intermediate, and high risk of CNS relapse. The risk of CNS relapse in R2CHOP-treated patients was then estimated and compared against published rates in RCHOP-treated patients based on CNS-IPI score. Results One hundred thirty-six patients with DLBCL from both cohorts (87 MC patients, 49 FIL patients) were included in this analysis. Mean age was 65 and median follow-up in 104 patients still alive was 48.2 months (range: 2.1-88.5). 61.8% of patients were male; 86.0% had stage III disease or higher; 44.1% had ECOG performance status of 0; cell of origin phenotype by immunohistochemistry according to Hans algorithm was germinal center B-cell (GCB), non-GCB (ABC), and not available in 43.4%, 36.8%, and 19.8%, respectively; 14.7% received intrathecal (IT) methotrexate for CNS prophylaxis per local practice. No patients received intravenous methotrexate. 10.3%, 71.3%, and 18.4% of patients were classified into low, intermediate, and high-risk CNS-IPI groups, respectively. Only one of 136 patients developed isolated CNS relapse, corresponding to an estimated incidence of CNS relapse of 0.007 (0.7%). Conclusions Despite a large proportion of patients with intermediate and high risk of CNS relapse treated in both phase 2 studies, induction therapy with R2CHOP in patients with DLBCL is associated with a lower-than-expected rate of isolated CNS relapse. The latter is unlikely to be explained by use of IT chemotherapy, which is considered to be marginally effective in this setting and was implemented only in a small proportion of patients. This suggests that addition of CNS-penetrating small molecules, such as lenalidomide, to R-CHOP may decrease the risk of CNS relapse. Disclosures Chiappella: Celgene: Speakers Bureau; Teva: Speakers Bureau; Roche: Speakers Bureau; Pfizer: Speakers Bureau; Janssen-Cilag: Speakers Bureau; Amgen: Speakers Bureau. Nowakowski:Morphosys: Research Funding; Celgene: Research Funding; Bayer: Consultancy, Research Funding. Cavallo:Janssen-Cilag: Honoraria; Onyx: Honoraria; Celgene: Honoraria. Gaidano:Roche: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Morphosys: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau. Spina:Mundipharma: Membership on an entity's Board of Directors or advisory committees, Other: Speaker Fee; Teva Pharmaceuticals Industries: Membership on an entity's Board of Directors or advisory committees, Other: Speaker Fee. Vitolo:Takeda: Other: Honoraria for lectures; Gilead: Other: Honoraria for lectures; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Honoraria for lectures; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Honoraria for lectures.

Abstract Background Follicular lymphoma (FL) is an indolent non-Hodgkin lymphoma (NHL) with heterogeneous outcomes and remains largely incurable. Immunochemotherapy (IC) continues to be the standard therapy backbone in the frontline and relapsed settings, though novel agents are increasingly used and investigated. Lenalidomide is an immunomodulatory molecule with known single-agent activity in relapsed lymphoma. It is also active in the frontline setting and has been reported to be effective and tolerated in upfront combination regimens in FL (Fowler et al, Lancet Oncol. 2014, 15(12):1311-8). Here we report our experience with frontline use of R2CHOP (lenalidomide in combination with R-CHOP) in patients with FL. Methods A phase 1/2 study of R2CHOP was conducted in NHL patients with primarily diffuse large B-cell lymphoma (DLBCL). While the phase 2 study was focused on DLBCL patients, treatment-naive patients with stage II-IV, histologically-confirmed FL (grades 1, 2, and 3a) meeting criteria for therapy were eligible for the phase 1 part of the study. Additionally, FL patients were identified in the phase 2 portion of the study after central pathology review. These patients were allowed to complete therapy and were followed accordingly. Treatment consisted of 6 cycles of R2CHOP with lenalidomide given on days 1-10 and R-CHOP given in 21-day cycles. All patients received pegfilgrastim and aspirin (if not on anticoagulation) along with other supportive measures per provider discretion. Primary objectives were safety assessment and efficacy. Results Ten patients with FL (3 had grade 1, 3 had grade 2, and 4 had grade 3a) were enrolled in the R2CHOP phase 1/2 study at Mayo Clinic. One patient was in the phase 1 arm at dose level 2 (lenalidomide 20 mg/d) and 9 patients were in the phase 2 arm (lenalidomide 25 mg/d). The mean age was 60.8 years (range: 41-82). Eight out of ten patients were male; 5/10 had ECOG performance status of 0; 5/10 had an IPI score of intermediate or higher. All patients completed 6 cycles of planned treatment. One patient required lenalidomide dose adjustment due to toxicity. There were no lenalidomide dose interruptions. The overall response rate (ORR) was 100% and the complete response (CR) rate defined by PET imaging was 90%. Eight out of ten remain progression-free and 9/10 are alive at a median follow-up of 4.6 years (range: 2.1-5.3). Estimated progression-free survival (PFS) at 5 years was 79% (95% CI: 56-100%). The main toxicity was reversible myelosuppression with 80% treatment-related hematologic grade 3 or higher adverse events (AEs) (leukopenia 80%, neutropenia 80%, thrombocytopenia 40%, anemia 20%, transaminitis 20%). Rate of nonhematologic grade 3 or higher AEs was 20% (fatigue 10%, pneumonia 10%). Conclusions Frontline therapy with R2CHOP in patients with untreated FL appears to be effective and associated with acceptable toxicity. The observed PET-based CR rate and PFS were promising in this cohort. Whether R2CHOP is superior to lenalidomide/rituximab alone or standard bendamustine/rituximab will require randomized studies. Figure Estimated PFS in FL patients treated with upfront R2CHOP. Figure. Estimated PFS in FL patients treated with upfront R2CHOP. Disclosures Reeder: Celgene: Research Funding; Novartis: Research Funding; BMS: Research Funding; Millennium: Research Funding. Foran:novartis: Honoraria; Millennium Pharmaceuticals, Inc.: Research Funding; pfizer: Honoraria; karyopharm: Honoraria; medscape: Honoraria; boehringer ingelheim: Research Funding; agios: Research Funding; Cellerant: Research Funding. Nowakowski:Bayer: Consultancy, Research Funding; Morphosys: Research Funding; Celgene: Research Funding.

The Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib, which antagonizes B cell receptor (BCR) signals, demonstrates remarkable clinical activity in chronic lymphocytic leukemia (CLL). The lymphocytosis experienced by most patients under ibrutinib has previously been attributed to inhibition of BTK-dependent integrin and chemokine cues operating to retain the tumor cells in nodal compartments. Here, we show that the VLA-4 integrin, as expressed by CD49d-positive CLL, can be inside-out activated upon BCR triggering, thus reinforcing the adhesive capacities of CLL cells. In vitro and in vivo ibrutinib treatment, although reducing the constitutive VLA-4 activation and cell adhesion, can be overcome by exogenous BCR triggering in a BTK-independent manner involving PI3K. Clinically, in three independent ibrutinib-treated CLL cohorts, CD49d expression identifies cases with reduced lymphocytosis and inferior nodal response and behaves as independent predictor of shorter progression-free survival, suggesting the retention of CD49d-expressing CLL cells in tissue sites via activated VLA-4. Evaluation of CD49d expression should be incorporated in the characterization of CLL undergoing therapy with BCR inhibitors.

AbstractBackgroundCentral nervous system (CNS) relapse in non‐Hodgkin lymphoma (NHL) is a rare but serious complication that carries a poor prognosis. The use of infusional etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (EPOCH‐R) for frontline treatment of diffuse large B cell lymphoma (DLBCL) is increasing, though little is known about incidence of and risk factors for CNS relapse with this regimenPatients and methodsWe completed a chart review of patients with NHL who received EPOCH‐R as front line therapy. Data obtained included baseline and treatment characteristics including if patients received CNS directed therapy. We measured overall survival (OS), progression free survival (PFS), and progression to CNS involvement.ResultsWe identified 223 patients who met the inclusion criteria, 72% had DLBCL. Of all the patients, 5.8% experienced CNS relapse, and 38.6% were treated with CNS prophylaxis. There was no difference in rate of CNS relapse, OS, or PFS between patients who had and had not received CNS prophylaxis. Patients whose serum lactate dehydrogenase was greater than twice the upper limit of normal at diagnosis and those with extranodal disease were significantly more likely to have CNS relapse (P = .0247 and 0.022, respectively) than their counterparts.ConclusionsThe rate of CNS relapse in this patient population approaches 6%, not significantly different from reports on those receiving R‐CHOP. The results of this study suggest that CNS prophylaxis might be more selectively used among patients treated with EPOCH‐R with certain high‐risk features.