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Abstract Background Standardizing beam modeling in the treatment planning system is challenging due to machine‐specific configuration variations. Because of the proton therapy system (PTS) complexity and continuous development, there is no vendor's representative (“golden”) beam data like in LINACs at this stage. Purpose The primary goal of this study is to create a PTS‐specific repository of source model parameters and beam commissioning data for scanning proton therapy treatment planning systems and establish a set of reference values with associated bands of variations for this data. Methods We conducted a survey of 31 PTSs at 27 proton therapy centers to gather beam commissioning source model parameters used in their treatment planning system, ensuring a diverse selection of PTSs from major vendors: Hitachi, IBA, Varian, and Mevion. For each proton therapy center, we collected (i) beam meterset calibration in protons per MU, (ii) in‐air spot size at isocenter in terms of standard deviation in x‐ (crossline, σ x ) and y‐ (inline, σ y ) directions, (iii) in‐air angular spread at isocenter in x‐direction (θ x ) and y‐direction (θ y ) and (iv) distal falloff. For each PTS, we plotted each parameter as a function of nominal energy and performed polynomial regression analysis with optimal model selection based on Akaike Information Criterion. We calculated intraclass correlation coefficients (ICC) to quantify inter‐PTS variability and generated uncertainty bands representing standard deviations across PTSs for each parameter. Additionally, we computed percentage deviations of each individual PTS from the overall multi‐vendor mean to identify systematic vendor‐specific patterns and outliers across the 31 total PTSs analyzed. Results Multi‐vendor beam parameter analysis across 31 PTSs revealed systematic vendor‐specific patterns in inter‐PTS consistency and energy dependencies. Beam meterset calibration demonstrated excellent inter‐PTS consistency across most vendors (ICC: Varian ProBeam ≈ 0, IBA Proteus ONE = 0.006, Mevion S250i with HYPERSCAN = 0.015), with IBA Proteus PLUS systems showing moderate variation (ICC = 0.156 for the dedicated nozzle, ICC = 0.248, for the universal nozzle). Spot size and angular spread variability were highly vendor‐dependent, ranging from excellent consistency in IBA Proteus ONE to substantial variation in IBA Proteus PLUS with the universal nozzle (angular spread ICC = 0.566). Distal falloff maintained excellent consistency across all vendors (ICC < 0.023), indicating reliable energy spread characteristics. Uncertainty band analysis revealed characteristic energy‐dependent patterns, with most systems showing larger uncertainties at lower energies for spot size and angular spread, while IBA Proteus PLUS with the universal nozzle exhibited the largest uncertainty bands overall. Percentage deviation analysis demonstrated vendor‐specific clustering patterns, with some systems showing systematic positive or negative deviations from the multi‐vendor mean. Conclusions The reference data provided in this work will help to cross‐check the beam model during treatment planning system commissioning. Furthermore, this information is useful for Monte Carlo applications and research, where beam characteristics are required to set up phase space parameters, thereby avoiding the need to model the entire PTS. Finally, the results of this study will have indispensable educational value by providing valuable insights into the characteristics and capabilities of different PTSs.

Abstract Pyroptosis is a form of programmed cell death characterized by the cleavage of the gasdermin (GSDM) family proteins that form pores in the plasma membrane, cell rupture, and the release of proinflammatory cytokines. In this study, we performed immunohistochemistry for cleaved gasdermin D (GSDMD), gasdermin E (GSDME) N-terminus, and gasdermin C (GSDMC) in 2 different cohorts of diffuse large B-cell lymphoma (DLBCL) and analyzed the impact of GSDM expression on prognosis and immunity. The results showed frequent cleaved GSDMD (N-terminal) expression. Only cytoplasmic GSDMD N-terminal expression correlated with significantly better patient survival in the 2 cohorts. In contrast, GSDME was mainly expressed in the vascular endothelium, and correlated with significantly adverse prognostic effect. Correlating with the multiplex fluorescent immunohistochemistry results, we found that cytoplasmic GSDMD N-terminal expression was associated with increased CD38+ (activated) M1 macrophages in both cohorts, cognate interactions between live DLBCL cells and activated M1 macrophages (and T cells), and lower PD-1/PD-L1 expression in the analyzed cases. In contrast, T-cell pyroptosis, lymphoma cell-resistance to cell death, and phagocytosis by M2 macrophages were observed in tissues with predominantly nuclear GSDMD N-terminal expression. Bulk gene expression profiling and deconvolution analysis revealed associations of cytoplasmic GSDMD N-terminal expression with downregulation of “Don’t eat me”–signaling genes, upregulation of many RNA genes, decreased frequency of “inflammatory” lymphoma microenvironment subtype, increased frequencies of prognostically favorable cell states and ecotypes, and decreased frequency of T-cell exhaustion state. In summary, this study showed distinct cellular and subcellular patterns of 3 GSDM proteins and their associated immune response phenotypes and prognostic effects, with implications for novel therapeutic strategies for B-cell lymphoma.

Abstract Background: Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL), accounting for approximately 30% of all NHL cases. DLBCL diagnosis relies on histologic examination, immunophenotyping, molecular and fluorescence in situ hybridization (FISH) analysis to differentiate it from similar NHL subtypes with overlapping morphological features, including more high-grade lymphomas like double-hit lymphoma. Because FISH is performed in a panel of single- or dual-target test format and analyzed through microscopy and manual image analysis, assessment of multiple target biomarkers can be cumbersome and expensive. As additional biomarkers for diagnosis, subtyping, prognosis, and therapeutic decision-making become available, target panels will become larger, posing additional challenges to clinical laboratories. Patients and Methods In this study, Hi-C sequencing of FFPE samples was performed to identify all genomic rearrangements by a single sequencing analysis for an unselected DLBCL case series of 159 patients, and the results were compared to FISH for the detection of clinically important variants. Results Hi-C sequencing showed superior performance compared to FISH: standard FISH for DLBCL includes testing for MYC, BCL2, and BCL6. Between FISH and Hi-C, these biomarkers were detected 105 times, of which, FISH detected 80/105 (76%) and Hi-C detected 102/105 (97%). The cohort included 4 double-hit lymphomas by FISH but Hi-C sequencing detected five. Besides DLBCL diagnostic biomarkers (MYC, BCL2, BCL6), many additional biomarkers were detected by Hi-C sequencing including variants not tested by FISH because the clinical suspicion was ambiguous and the relevant FISH probes were not used, and those not tested because the biomarkers were not thought to be common and, hence, left out of the FISH panel. In total, Hi-C sequencing detected additional biomarkers in 42 (26%) cases, including (1) variants targeted by FISH (i.e. MYC, BCL2, BCL6) but negative, (2) classification biomarkers for other lymphomas (CCND1, MALT, IRF4), and (3) those not tested because the biomarkers are not common and not included in the FISH panel. These additional biomarkers were supportive of suspected diagnosis of DLBCL versus double-hit lymphoma (24 cases), prompted reconsideration of a different diagnosis that may have led to different treatments (6 cases, e.g. mantle cell lymphoma), or biomarkers such as PDL1, ALK, and ATM which have implications for targeted therapies and/or inclusion in clinical trials (5 cases). Conclusion The Hi-C FFPE sequencing technology has the potential to improve the workflow of pathology labs for detection of a wide range of structural variants informing precision diagnosis and treatment for lymphomas.

Abstract Background and Significance Diffuse large B-cell lymphoma (DLBCL) and other LBCLs account for 35–40% of non-Hodgkin lymphoma cases in North America, Europe, and East Asia. Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is the standard first-line treatment for DLBCL, achieving cure rates in approximately 60–70% of patients. However, 30–40% of patients will relapse or become refractory (R/R) to treatment, facing poor prognosis. Patients with high International Prognostic Index (IPI) scores (3–5) and those with IPI 1–2 who have bulky disease and/or very high lactate dehydrogenase (LDH) are recognized as high-risk (HR) subsets with suboptimal outcomes (Maurer et al, ASH 2023, #4512). Novel combination strategies are an area of focus for improving efficacy in this population. GOLCA is a potential, first-in-class, oral CELMoD agent designed for the treatment of lymphoma, with preferential distribution to lymphoid organs and enhanced activity in lymphoma cell lines. GOLCA drives the closed, active conformation of cereblon to induce rapid and deep degradation of Ikaros and Aiolos, leading to direct cell killing (agnostic of cell of origin [COO]) and immunomodulatory activity. In the Phase 1b study CC-220-DLBCL-001, GOLCA in combination with R-CHOP demonstrated a predictable and manageable safety profile with high rates of durable responses, irrespective of COO, in previously untreated aggressive B-cell lymphomas (BCL), including promising activity in HR patients (Amzallag et al, ASH 2024, #579). The median relative dose intensity for GOLCA and CHO components was high (97–99%), indicating uncompromised delivery of curative standard-of-care treatment and combinability. GOLCA ± rituximab has also shown encouraging efficacy and safety in patients with R/R DLBCL (Bachy et al, ICML, #148). These findings support the further study of GOLCA + R-CHOP combination in the Phase 3 setting. Study Design and Methods GOLSEEK-1 (NCT06356129) is a randomized, double-blind, placebo-controlled, Phase 3 study evaluating GOLCA + R-CHOP versus placebo + R-CHOP in patients with previously untreated HR LBCL. Approximately 850 patients with previously untreated LBCL will be randomized 1:1 to either GOLCA + R-CHOP or placebo + R-CHOP. Eligible patients include those with histologically confirmed LBCL per WHO 2022 criteria—including DLBCL (not otherwise specified [NOS], ABC/GCB), high-grade BCL with MYC and BCL2 rearrangements or NOS, T-cell/histiocyte–rich LBCL, or Epstein Barr Virus-positive DLBCL. HR status is defined by IPI ≥3, or IPI 1–2 with HR features: LDH &gt;1.3× upper limit of normal and/or bulky disease (≥7 cm lesion). All patients must have measurable disease as defined by Lugano criteria. Key exclusion criteria are other lymphoma subtypes such as primary mediastinal LBCL; primary cutaneous DLBCL-leg type, grade 3b follicular lymphoma (FL); transformed indolent lymphoma; anaplastic lymphoma kinase (ALK) positive LBCL; primary effusion lymphoma; and Burkitt lymphoma and known or suspected central nervous system involvement. Randomization will be stratified by IPI score (HR 1–2 and 3 vs 4–5) and bulky disease status (≥7 cm vs &lt;7 cm). After a screening period of ≤4 weeks, patients will receive either GOLCA (0.4 mg) or placebo orally once daily for 7 consecutive days in each of 6 cycles, combined with R-CHOP every 21 days. The primary endpoint is progression-free survival (PFS) by investigator assessment per Lugano Response Criteria. Key secondary endpoints include PFS in non–high-grade BCL, event-free survival, independently assessed complete metabolic response, undetectable minimal residual disease by PhasED-Seq (defined as undetectable circulating tumor DNA levels at end of treatment), and overall survival. Patients will be followed up for up to approximately 67 months after beginning treatment. This study is currently recruiting at 309 sites in 36 countries , across the United States, Europe, Latin America, and East Asia. Acknowledgement BMS Artificial Intelligence was used to revise existing text with human author oversight.

Abstract Background: Mosunetuzumab, a CD20xCD3 bispecific antibody, can be administered in the outpatient setting for a fixed duration. Mosunetuzumab by intravenous (IV) administration is FDA- and EMA-approved in relapsed/refractory (R/R) FL after ≥2 prior lines of therapy. Interim results from the Phase II MorningSun study (NCT05207670) demonstrated promising efficacy and manageable safety of mosunetuzumab SC in pts with previously untreated HTB FL (Flinn et al. ASCO 2025). We report 12-month follow-up efficacy and safety data of mosunetuzumab SC in pts with previously untreated HTB FL in the MorningSun study, including pts who received optional maintenance therapy. Methods: Pts with previously untreated HTB FL, per Groupe D'Etude des Lymphomes Folliculaires criteria, and Eastern Cooperative Oncology Group performance status of 0–2 were enrolled, primarily from United States (US) community sites. Mosunetuzumab SC was administered as step-up dosing in Cycle (C)1 (Day [D]1, 5mg; D8, 45mg; D15, 45mg) followed by 45mg on D1 of each 21-day cycle, for up to 17 cycles (1 year). Pts with a partial or complete metabolic response (CMR) after C17 could receive optional mosunetuzumab maintenance treatment (45mg every 8 weeks for up to 1 year). The primary endpoint was progression-free survival (PFS) rate at 1 year. Key secondary endpoints included objective response rate (ORR), duration of response (DOR), duration of complete response (DOCR) and safety. Exploratory analysis of ctDNA levels was performed using the AOA-NHL assay. Results: As of February 10, 2025, 103 pts were enrolled (n=82 pts from community sites, n=21 pts from academic sites). Overall, the median age was 65 years (range: 24–86), 51.5% of pts were female and most pts had Ann Arbor stage III/IV disease (91.3%) and a FLIPI score ≥2 (78.6%). In total, 69 pts completed initial treatment (17 cycles), 33 discontinued (primarily due to progressive disease [PD; n=18] and adverse events [AEs; n=5]), and 1 pt was continuing treatment. After 17 cycles, 68 pts were eligible for maintenance treatment, of whom 46 received maintenance, and 15 were continuing maintenance treatment at the time of data cut-off. Median duration of follow-up was 22.3 months (95% confidence interval [CI]: 20.9–24.1). The 12-month PFS rate was 85.5% (95% CI: 76.2–91.3). The ORR was 87.4% (95% CI: 79.4–93.1); 64.1% of pts had a CMR. The 12-month OS rate was 91.9% (95% CI: 84.5–95.9); the 12-month DOR and DOCR rates were 89.6% (95% CI: 80.2–94.7) and 91.1% (95% CI: 79.4–96.2), respectively. Of the 46 pts who received maintenance, no pts experienced PD, and 1 pt died (reason unknown). Of the 22 pts who were eligible but did not receive maintenance, 1 pt had PD. The most common AEs (≥30%) were injection-site reaction (67.0%), fatigue (44.7%), cytokine release syndrome ([CRS] 34.0%), headache (32.0%), and nausea (32.0%). Grade (Gr) ≥3 AEs and serious AEs were reported in 47.6% and 35.9% of pts, respectively. Five pts experienced Gr 5 AEs: COVID-19 pneumonia (n=2) and cardiogenic shock, unexplained death, pneumonia (n=1 each). Infections occurred in 77.7% of pts and were predominantly Gr 1/2 (Gr 1: 10.7%; Gr 2: 47.6%; Gr 3: 12.6%; Gr 4: 3.9%), with the most common infection being COVID-19 (24.3%). Of 3 (2.9%) Gr 5 infections reported, 1 occurred during initial treatment (COVID-19), 1 during maintenance (pneumonia), and 1 occurred 2.8 months after completion of treatment (COVID-19). AEs were reported in 80.4% of pts in the maintenance phase, mostly Gr 1/2 events. No CRS events occurred during maintenance treatment. Infections were reported in 45.7% of pts during maintenance, with the majority being Gr 1/2 events (37.0%), and were similar types of infection as during initial therapy. ctDNA levels were assessed in a subset of pts who achieved a CMR; 86.4% (19/22) of pts were minimal residual disease (MRD) negative (p-value cut-off 0.005).Conclusions: Longer follow-up of mosunetuzumab SC with optional maintenance treatment continues to demonstrate promising PFS and OS rates, and a manageable safety profile in pts with previously untreated HTB FL. Exploratory analysis of ctDNA in a subset of CMR pts showed MRD negativity in 86.4%, thus supporting fixed treatment duration of mosunetuzumab SC. Overall, these data support the outpatient administration of mosunetuzumab SC in US community practices and further evaluation of mosunetuzumab-based treatment in first-line HTB FL.

Abstract Background: Pyroptosis is a form of programmed cell death characterized by cleavage of gasdermin (GSDM) family proteins that form pores in the plasma membrane, cell rupture, and release of pro-inflammatory cytokines. Its pro-inflammatory potential has garnered significant research attention in recent years but has not been studied in lymphoma. Patients and Methods: We performed immunohistochemistry for cleaved GSDMD (n-terminal) in two large cohorts of diffuse large B-cell lymphoma (DLBCL) with multiplex fluorescent IHC (mfIHC) data, and analyzed for prognostic and immune impact. Results: Cleaved GSDMD was frequently expressed in DLBCL, and only the cytoplasmic (versus nuclear) form of expression correlated with significantly better patient survival in two DLBCL cohorts. To understand the expression at the single-cell level, we examined mfIHC results, which revealed that GSDMD+cells were tumor or immune cells, and varied in Ki-67, BCL2, and MYC expression. Cases with cytoplasmic cleaved GSDMD expression had higher mean and median levels of CD38+ (activated) M1 macrophages in two cohorts and lower PD-1/PD-L1 expression, as well as phenotypes of cognate interactions between live activated M1 macrophages, DLBCL cells, and T cells in spatially resolved immune landscape by mfIHC. In contrast, phagocytosis of pyroptotic lymphoma cells by M2 macrophages and cell death of T cells were observed in cases with predominantly nuclear form of cleaved GSDMD expression. Bulk gene expression profiling analysis identified a large proportion of RNA genes upregulated in DLBCLs with cytoplasmic cleaved GSDMD expression, and deconvolution analysis found decreased frequency of the “Inflammatory” lymphoma microenvironment (LME) subtype, increased frequency of cell states and ecotypes with favorable prognostic associations, and decreased frequency of T cell exhaustion states. Summary: Analysis of pyroptosis-inducing cleaved GSDMD (n-terminal) expression in a large number of DLBCL patients revealed dinstinctive cytoplasmic and nuclear expression patterns in live and pyroptotic cells associated with different prognostic and immune effects. Cytoplasmic cleaved GSDMD expression is a marker of cognate interactions between live cells (e.g., activated M1 macrophages) associated with adaptive responses and favorable prognostic effects, whereas nuclear cleaved GSDMD expression is associated with immunosuppressive mechanisms, including T cell death and phagocytosis by M2 macrophages.

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: There remains an opportunity for new therapies to improve long-term outcomes for patients with low-tumor burden follicular lymphoma (FL). Mosunetuzumab is an off-the-shelf CD20xCD3 bispecific antibody, approved as an intravenous therapy for patients with relapsed/refractory FL after ≥2 lines of systemic therapy. Mosunetuzumab can be administered in the outpatient setting as a fixed-duration regimen. In an open-label, multicenter, Phase II study conducted mainly across US community sites (MorningSun; NCT05207670), mosunetuzumab administered subcutaneously (SC) induced high response rates with a manageable safety profile in patients with previously untreated low-tumor burden FL (Burke et al. ASH 2024). Here we present updated efficacy and safety data for mosunetuzumab SC in patients with previously untreated, low-tumor burden FL. Methods: Patients had untreated Grade 1 or 2 low-tumor burden FL per Groupe d'Etude des Lymphomes Folliculaires criteria, Ann Arbor stage III/IV disease, and Eastern Cooperative Oncology Group performance status (ECOG PS) of 0–2. Mosunetuzumab SC was administered with step-up dosing in Cycle 1 (Day [D]1, 5mg; D8, 45mg; D15, 45mg), then 45mg on D1 of each 21-day cycle. Hospitalization was not mandatory. Patients with a complete metabolic response after 8 cycles could complete therapy and patients with a partial metabolic response or stable disease continued treatment for up to 17 cycles. The primary endpoint was progression-free survival (PFS) at 24 months. Key secondary endpoints included objective response rate (ORR), time to response (TTR), overall survival (OS), duration of response (DOR), duration of complete response (DOCR), and safety. Exploratory analyses assessed pharmacodynamic changes in B-cell subsets. Here, we report interim data. Results: As of February 10, 2025 (clinical cut-off date), 101 patients were enrolled from US community (n=56) and academic (n=45) centers; 52 patients had completed treatment, 21 had discontinued (mainly due to adverse events [AEs; n=6] and progressive disease [n=5]), and 28 were ongoing on treatment. Median age was 65 years (range: 34–82). Most patients had an ECOG PS of 0 (81.2%) or 1 (18.8%) and 43 patients (42.6%) had extranodal involvement. Median duration of follow-up was 13.8 months (95% confidence interval [CI]: 11.5–16.9) and median number of cycles received was 10 (range: 3–17). The ORR was 98.0% (95% CI: 93.0–99.8) and the complete response rate was 89.1% (95% CI: 81.3–94.4). Median TTR was 2.8 months (range: 1.4–8.3). Landmark DOR and DOCR rates at 12 months were 91.8% (95% CI: 81.5–96.5) and 95.7% (95% CI: 82.6–99.0), respectively. The 12-month PFS and OS rates were 92.0% (95% CI: 83.8‒96.1) and 99.0% (95% CI: 93.2‒99.9), respectively. The most common AE was injection-site reaction (ISR, 81.2%; Grade 1, 74.3%; Grade 2, 5.9%; Grade 3, 1.0%). Grade 3/4 AEs were reported in 51.5% of patients; the most common (≥10%) events were cytopenias (36.6%) and infections (11.9%). Cytokine release syndrome (CRS) was reported in 48.5% of patients (Grade 1, 40.6%; Grade 2, 7.9%). Overall,infections occurred in 63.4% of patients (Grade 1, 7.9%; Grade 2, 42.6%; Grade 3, 11.9%; Grade 5, 1.0%) with the most common (≥10%) being upper respiratory tract infection (21.8%), COVID-19 (17.8%), sinusitis (13.9%), and pneumonia (11.9%). At the time of data cut-off, ISR, CRS, and infection AEs were resolved at rates of 98.2%, 100%, and 89.0%, respectively. Two patients had a Grade 5 AE (sepsis, n=1; unknown cause, n=1).No immune effector cell-associated neurotoxicity syndrome events were reported. B-cell depletion was observed following the first dose of mosunetuzumab, with subsequent B-cell recovery observed within six months of treatment completion. Conclusions: Fixed-duration mosunetuzumab SC demonstrates high efficacy rates with deep and sustained responses in patients with previously untreated, low-tumor burden FL. The manageable safety profile supports ease of outpatient administration without mandatory hospitalization, including in community oncology practices. Additionally, exploratory analyses demonstrating B-cell recovery after treatment completion also substantiate the use of mosunetuzumab SC as a fixed-duration regimen. These data support further evaluation of mosunetuzumab SC in patients with previously untreated, low-tumor burden FL.

Key Points Inositol polyphosphate-5-phosphatase E (INPP5E) and type Ig phosphatidylinositol-4-phosphate 5-kinase (PIPKIγ) coordinated the homeostasis of phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5-bisphosphate in primary cilia. Modulating INPP5E or PIPKIγ activity changed the level of polycystin-1 and polycystin-2 in primary cilia. INPP5E inhibition increased the hypomorphic PKD1 variants (PC1-R3277C) in cilia and reduced cystogenesis in the kidney in vitro . Background Autosomal dominant polycystic kidney disease is mainly caused by mutations in PKD1 and PKD2 , which encode polycystin-1 (PC1) and polycystin-2 (PC2), respectively. PC1 and PC2 assemble a cation channel complex enriched in primary cilium, a sensory organelle associated with various developmental diseases, including polycystic kidney disease (PKD). Accumulating evidence supports the necessity of functional polycystin (PC) complex in cilia to prevent cystogenesis in the kidney, indicating that improving their ciliary levels may ameliorate defects underlying PKD pathogenesis. Yet, molecular mechanisms underlying the ciliary targeting and homeostasis of the PC complex are not fully understood. Methods Indirect immunofluorescence microscopy was used to monitor ciliary levels of PC1 and PC2 in renal epithelial cells. Electrophysiology analysis in oocytes was used to determine the channel activity of the PC complex. Cystogenesis in the kidney was measured using in vitro 3D-Matrigel cell models and ex vivo mouse embryonic kidney models. Results Suppressing inositol polyphosphate-5-phosphatase E (INPP5E) or activating type Ig phosphatidylinositol-4-phosphate 5-kinase raised ciliary levels of the PC complex in both normal renal epithelial cells and cells carrying autosomal dominant polycystic kidney disease mutations that interrupt the trafficking of PCs into cilia, including GANAB inactivation and the trafficking PKD1 mutation p.Arg3277Cys (RC). PC1 RC formed a complex with PC2 and exhibited normal channel activity in vitro . An INPP5E that increases PC1 and PC2 in cilia, suppressed in vitro forskolin-induced cystogenesis of inner medullary collecting duct epithelial cell line 3 cells in 3D Matrigel and ex vivo cyst formation in embryonic Pkd1 RC/RC mouse kidneys. Conclusions Our results demonstrated that increasing the ciliary level of PCs, by manipulating a ciliary phosphoinositide signaling axis, enhanced the functionality of PCs and suppressed cystogenesis of renal epithelial cells in vitro .

ABSTRACT Background Optimal management in patients presenting with persistent atrial fibrillation, cardiomyopathy, and atrial as well as ventricular dyssynchrony with left bundle branch block is unclear. Results and Methods A 67‐year‐old female patient presented with persistent atrial fibrillation, cardiomyopathy with a newly reduced ejection fraction (EF), increased P wave duration on electrocardiogram (ECG) and left bundle branch block. After shared decision making, the patient elected to proceed with Bachman bundle/left bundle branch area pacing plus atrioventricular (AV) node ablation. At 6‐month follow‐up post procedure, a repeat echocardiogram showed normalized atrial size and EF (65%). Device interrogation demonstrated no recurrent atrial fibrillation with the patient off antiarrhythmic and heart failure medical therapy. Conclusions Integrated atrial and ventricular synchronization through Bachmann bundle and left bundle branch area pacing may help break the cycle of dyssynchrony, remodeling, and arrhythmia. In combination with AV node ablation, it may be considered as an alternative treatment option in certain cases after shared decision making.