Citations

ObjectiveVagus nerve stimulation (VNS) paired with rehabilitation therapy improved motor status compared to rehabilitation alone in the phase III VNS‐REHAB stroke trial, but treatment response was variable and not associated with any clinical measures acquired at baseline, such as age or side of paresis. We hypothesized that neuroimaging measures would be associated with treatment‐related gains, examining performance of regional injury measures versus global brain health measures in parallel with clinical measures.MethodsBaseline magnetic resonance imaging (MRI) scans in the VNS‐REHAB trial were used to derive regional injury measures (extent of injury to corticospinal tract, the primary regional measure; plus extent of injury to precentral gyrus and postcentral gyrus; lesion volume; and lesion topography) and global brain health measures (degree of white matter hyperintensities, the primary global brain measure; plus volumes of cerebrospinal fluid, cortical gray matter, white matter, each thalamus, and total brain). Eight clinical measures assessed at baseline were also evaluated (treatment group, age, race, gender, paretic side, pre‐stroke dominant hand, time since stroke, and baseline Fugl‐Meyer upper extremity score). Bivariate analyses compared each measure with the primary trial end point (change in Fugl‐Meyer upper extremity score from baseline to end of 6 weeks of treatment) across all subjects, with secondary analyses examining trial groups separately.ResultsMRIs were available from 80 patients (age = 59.8 ± 9.5 years, 29 women). Across all patients, less white matter hyperintensities (r = −0.25, p = 0.028) at baseline was associated with larger Fugl‐Meyer score change. In the VNS group, less white matter hyperintensities (r = −0.37, p = 0.018) and larger ipsilesional thalamus volume (r = 0.33, p = 0.046) were each associated with larger Fugl‐Meyer score change. Analysis of covariance (ANCOVA) analyses tested the interaction that each baseline measure had with treatment group and found that the model examining white matter hyperintensities had a significant interaction term, indicating 2.3 less change in Fugl‐Meyer Upper Extremity (FM‐UE) points in the VNS group relative to the control group for each point increase in modified Fazekas scale.InterpretationNeuroimaging measures are associated with extent of gains on the primary endpoint of a phase III stroke recovery trial. Among the neuroimaging measures examined, a measure of global brain health (extent of white matter hyperintensities) was better at explaining the change in arm impairment as compared with measures of regional injury; this was true when examining all study subjects as well as only those in the VNS group and is consistent with the global mechanism of action that VNS has throughout the cerebrum. Future studies can evaluate additional measures that further predict response to VNS therapy. The current findings suggest that individual patient neuroimaging results may be useful for a personalized medicine approach to stroke recovery therapeutics. ANN NEUROL 2025;97:709–719

Abstract Background Etrasimod is an oral, once daily (QD), selective sphingosine 1-phosphate1,4,5 receptor modulator for the treatment of moderately to severely active ulcerative colitis (UC). We assessed the benefit of etrasimod monotherapy and the impact of concomitant corticosteroids (CS) and/or 5-aminosalicylates (5-ASA) therapy. Methods In ELEVATE UC 52 and ELEVATE UC 12, patients with moderately to severely active UC were randomized 2:1 to etrasimod 2 mg QD or placebo for 52 and 12 weeks, respectively. Oral CS or 5-ASA were allowed at baseline. Patients in the monotherapy subgroup received etrasimod or placebo without concomitant CS and/or 5-ASA at baseline. Predefined primary (clinical remission) and key secondary efficacy endpoints aligned with those from both trials and were assessed at Week 12 and Week 52. Safety was assessed up to Week 52. Results Clinical remission rates at Weeks 12 and 52 were significantly higher for etrasimod compared with placebo in patients receiving monotherapy (Week 12: 26.2% vs 4.8%; Week 52: 35.7% vs 4.0%). Differences vs placebo were statistically significant for all predefined endpoints at both time points in patients receiving monotherapy or etrasimod with concomitant 5-ASA only (all P < .05); numerical differences, due to small sample sizes, vs placebo were observed for all endpoints in the CS only and CS + 5-ASA subgroups. Safety was consistent with the overall population. Conclusions Etrasimod monotherapy showed consistent efficacy and safety vs placebo; no apparent benefit was observed with concomitant CS and/or 5-ASA in patients receiving etrasimod. Clinical trial registration NCT03945188; NCT03996369.

Objective Evaluate the effectiveness of a digital home monitoring program for infants with cleft palate with or without cleft lip (CP ± L), compared to monitoring through in-person clinic visits. Design Retrospective cohort study. Setting One metropolitan pediatric hospital. Patients Eight-eight infants with CP ± L: 41 infants received digital home monitoring and 47 infants were monitored solely through in-person visits. Interventions Beginning in September 2022, all infants with CP ± L were enrolled in a digital home monitoring program, in which caregivers weighed their child weekly at home and submitted those weights, along with subjective evaluations of their child's feeding, using a secure website. Submissions were monitored by the cleft team nurse coordinator. Main Outcome Measures The primary outcome was the incidence of malnutrition at 4 months of age. The secondary outcome was the average number of in-person clinic visits during the first 4 months of life. Results There was not a significant difference ( P = .764) in the incidence of malnutrition between infants monitored in-person compared to infants in the home monitoring program (13% vs 17%). Infants in the home monitoring program had fewer in-person visits with speech–language pathology (5.4 vs 3.9; P < .001). Across groups, malnutrition was associated with Child Protective Services involvement ( P = .001) and presence of a syndrome ( P = .014). Conclusions The digital home monitoring program did not decrease the incidence of malnutrition, but it did reduce the number of speech–language pathology in-person visits. The program appears to distinguish infants who are gaining weight appropriately from those with feeding challenges, but it does not fully address the multifactorial contributors to malnutrition.

Abstract Objectives Patients with hypermobile Ehlers–Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD) experience a wide array of symptoms and system disorders. This study aimed to identify whether differences occurred in 115 self-reported symptoms and comorbidities in patients diagnosed with hEDS or HSD. Methods In this study we analysed self-reported data from an EDS Clinic intake questionnaire in patients diagnosed with hEDS, HSD or no hypermobile conditions. Results From 1 November 2019 to 7 March 2024, the EDS Clinic saw 2088 patients. Using the 2017 diagnostic criteria, 66.5% were diagnosed with HSD (n = 1389), 20.3% with hEDS (n = 423), 10.6% with historic HSD (H-HSD) or localized HSD (L-HSD) (n = 256) (hypermobile controls) and 2.6% were not diagnosed with hEDS, HSD, H-HSD or L-HSD (n = 55) (controls). Symptoms/comorbidities that occurred with high prevalence in both hEDS and HSD included joint pain (hEDS 82.0%, HSD 88.9%), allergy (hEDS 77.0%, HSD 77.0%), subluxations (hEDS 71.2%, HSD 72.6%), brain fog (hEDS 70.0%, HSD 74.7%), headache (hEDS 68.1%, HSD 69.1%), anxiety (hEDS 60.3%, HSD 69.3%), depression (hEDS 52.2%, HSD 58.0%), migraine (hEDS 53.7%, HSD 52.5%), nausea (hEDS 54.6%, HSD 59.5%) and constipation (hEDS 53.0%, HSD 57.2%). In contrast, 9/115 (8%) symptoms/comorbidities were self-reported significantly more often in hEDS but 42/115 (37%) in HSD. hEDS patients reported more symptoms that suggest a defect in collagen, such as dislocation, hernias and rectal prolapse, while HSD patients reported more joint, muscle, allergy, neurological, gastrointestinal, sleep and psychological symptoms/comorbidities. Conclusion Although we found an overlap in some symptoms and comorbidities self-reported by hEDS/HSD patients, such as allergy/atopy, headache/migraine and gastrointestinal symptoms, our findings suggest key differences exist between the two diagnoses, suggesting that hEDS and HSD may be distinct conditions.

Background Migraine is associated with obesity. These analyses evaluated weight change with atogepant used as a preventive migraine treatment. Methods Five atogepant clinical trials in adults with migraine (one phase 2b/3; four phase 3) were included: Three 12-week, randomized, placebo-controlled trials (episodic migraine: two; chronic migraine: one); one 40-week, open-label extension trial and one 52-week, standard care, randomized, long-term safety trial in episodic migraine. Change from baseline in body weight was measured. Results Mean baseline body mass indexes were 30.0–30.7 kg/m 2 (pooled episodic migraine [United States only]) and 25.0–25.5 kg/m 2 (chronic migraine [East Asia, Europe, and North America]). More participants treated with atogepant 60 mg once-daily compared to placebo experienced ≥7% weight loss at any time in the pooled episodic migraine placebo-controlled trials (4.9% vs. 2.8%), chronic migraine placebo-controlled trial (5.8% vs. 2.0%), and pooled open-label extension and long-term safety trials (24.0% vs.14.7% in standard care [long-term safety only]). In the placebo-controlled trials, weight loss with atogepant 60 mg once-daily was observed at week 2 (pooled episodic migraine: −0.32%; chronic migraine: −0.39%), increasing at week 12 (pooled episodic migraine: −1.02%; chronic migraine: −1.50%); compared to weight gain with placebo at week 12 (pooled episodic migraine: +0.49%; chronic migraine: +0.10%). In the long-term episodic migraine studies, weight loss with atogepant 60 mg once-daily was observed at week 4 (long-term safety: −0.42%; open-label extension: −0.76%), increasing at week 40 (long-term safety: −2.38%; open-label extension: −2.09%). Conclusion Atogepant was associated with modest dose- and duration-dependent weight loss. Trial registration ClinicalTrials.gov identifiers: NCT02848326 (CGP-MD-01); NCT03777059 (3101-301-002); NCT03700320 (long-term safety trial); NCT03939312 (open-label extension trial); NCT03855137 (3101-303-002).

Objective To assess the quality of nasopharyngoscopy video recordings used for velopharyngeal insufficiency (VPI) surgical planning and identify factors that limit evaluation of velopharyngeal closure. Design Prospective observational study. Setting Metropolitan-based hospitals with craniofacial clinics in the United States and Canada. Participants One-hundred and forty-two (142) patients with VPI across 10 hospitals. Assessment(s) Nasopharyngoscopy video recordings used for VPI surgical planning . Main Outcome Measure(s) Ratability of nasopharyngoscopy video recordings, with “ratable” defined as the video (1) visualized the velum, lateral pharyngeal wall, and posterior pharyngeal walls at some point during speech production and (2) contained an oral speech sample at the phrase level or above. Results One-hundred and forty-two (142) nasopharyngoscopy video recordings were obtained from patients undergoing VPI evaluation, of which 59.9% (n=85) were ratable. A multilevel logistic regression model was used to identify factors that influenced the quality of nasopharyngoscopy video recordings. Factors associated with unratable nasopharyngoscopy videos were age ( P =.030), sex ( P =.005*), type of scope camera used ( P =.039), presence of compensatory misarticulations ( P =.008), and a limited speech sample ( P =.040). Conclusions A substantial proportion of nasopharyngoscopy video recordings obtained during VPI evaluation are not sufficient for rating velopharyngeal closure. Lack of ratability could impact the surgery selected to treat VPI. Younger patients, those with limited speech samples, or patients with extensive compensatory articulations may be more successful in completing other VPI imaging techniques, such as videofluoroscopy or magnetic resonance imaging.

Introduction: Brexucabtagene autoleucel (brexu cel) is a CD19-targeted chimeric antigen receptor (CAR) T cell therapy approved for the treatment of adults with relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL). Some patients (pts) proceed with a consolidative allogeneic hematopoietic cell transplant (HCT) after breux cel. We do not know which pts can safely avoid a consolidative HCT and its associated morbidity. Methods: We conducted a retrospective cohort study utilizing the Real-World Outcomes Collaborative of CAR-T in Adult ALL (ROCCA) dataset. ROCCA is a registry of brexu cel pts in 32 centers in North America. We defined complete remission (CR) as &lt; 5% blasts in the bone marrow and no central nervous system (CNS) or extramedullary (EM) disease on or around D28 after brexu cel. We defined measurable residual disease negative (MRD-) CR as CR and no abnormal blasts in the bone marrow by multiparameter flow cytometry, quantitative polymerase chain reaction, ClonoSeq next generation sequencing (NGS), or other sequencing modalities with lower sensitivity. ClonoSeq NGS has a sensitivity of 10-6, while the other modalities have a sensitivity of at least 10-4. We defined progression free survival (PFS) as the time from CAR-T infusion to relapse or death, censored at the date of last follow-up. Statistical analyses were performed in R. Univariable Cox proportional hazards regression analyses were performed to determine the association of pre-specified variables with PFS. Variables known to be associated with CAR T outcomes in ALL were entered into a multivariable model. HCT was incorporated as a time-varying covariate. Results: During the study period, 281 pts were infused with brexu cel. We focused our analysis on 172 (61%) pts with confirmed MRD- CR on D28, as that is the group with clinical equipoise regarding maintenance strategy. 38 (22%) of those pts received a consolidative HCT, 30 (17%) received another form of maintenance therapy (primarily tyrosine kinase inhibitors for Philadelphia (Ph)-chromosome positive ALL), and 104 (60%) pts received no maintenance therapy. Pts who underwent consolidative HCT were younger (median age 35 years) than those who received no maintenance (42y) (p = 0.023) and were less likely to have a history of prior HCT (13% vs. 47%, p &lt; 0.001). No differences were observed with respect to sex, TP53 mutation status, prior inotuzumab (ino) or blinatumomab (blina) exposure, disease burden prior to CAR, or development of any cytokine release syndrome (CRS) or any neurotoxicity with brexu cel. We performed univariable Cox proportional hazard regression analyses among pts in MRD- CR on D28, excluding those who received other maintenance therapy besides HCT; the median follow up was 8.1 months. In univariable analyses, D28 MRD negativity by ClonoSeq NGS (versus MRD negativity by other, less sensitive methods), development of CRS, and pre-CAR BM blasts &lt; 5% were associated with improved PFS; prior ino exposure was negatively associated with PFS (p &lt; 0.05). Age, sex, Ph status, TP53 status, and neurotoxicity development were not associated with PFS. In a multivariable model incorporating ALL type, prior HCT, prior ino/blina, and pre-CAR blast burden, as well as consolidative HCT as a time-varying covariate, only MRD negativity by ClonoSeq NGS with at least 10-6 sensitivity retained statistical significance (PFS hazard ratio 0.34, 95% confidence interval (CI) 0.15-0.77, p = 0.005). Pts who were MRD- by ClonoSeq NGS on D28 and received no maintenance had favorable 6m PFS of 76% (95% CI: 59-98%) and OS of 100% with a median follow up of 6.3 months in this subgroup. Among those in MRD- CR by NGS, HCT as a time-varying covariate was not associated with improved PFS (HR 0.6, p = 0.6). Conclusions: In a large real-world cohort of adults with R/R B-ALL infused with brexu cel, we identified practice variation regarding the use of consolidative HCT. Among brexu cel recipients who entered an MRD- CR, we identified ClonoSeq NGS MRD negativity as a novel predictive factor of favorable oncologic outcomes, even without a consolidative HCT. Similar results have been obtained in pediatric ALL patietns ftreated with 41BB-based tisagenleucleucel (Pulsipher et al., Blood Cancer Discovery 2022). Longer follow-up is needed to validate the safety of omitting consolidative HCT in such pts, but these results encourage the potential for definitive therapy with brexu cel when D28 ClonoSeq NGS MRD is negative.

Introduction The International Prognostic Scoring System (IPSS) and its revised version (IPSS-R) were developed using datasets from patients (pts) with untreated MDS. The cytogenetic risk groups used in IPSS-R were expanded to 5 groups from the 3 used in IPSS. Among the new groups introduced in IPSS-R is the “very complex” karyotype (VCK) where ≥4 karyotypic abnormalities are seen compared to “complex karyotype (CK)” with only 3 abnormalities. However, the prognostic impact of VCK vs CK, as well as individual cytogenetic abnormalities and TP53 mutation (TP53mut) status within the CK and VCK subgroups in pts with MDS treated with hypomethylating agents (HMAs) has not been well studied. Hence, we analyzed these questions in a large cohort of HMA-treated MDS pts in the icMDS VALIDATE database. Methods The icMDS VALIDATE database contains MDS pts treated with frontline HMA monotherapy or HMA-based combinations from 22 specialized international centers. Pts with unknown HMA type, date of HMA initiation, missing age, missing sex, missing cytogenetic data, bone marrow or peripheral blood blasts ≥20%, or missing survival status were excluded. We performed time-to-event analyses using the Kaplan-Meier method and compared groups by the log-rank test. We measured overall survival (OS) from time of HMA initiation. VALIDATE protocol was exempted, acknowledged, or approved by all centers' IRBs. VALIDATE is supported by an independent grant from Abbvie. Results A total of 1940 pts were included. Median age was 70 (range: 18-99) years and 66% were men. According to IPSS-R cytogenetic risk groups, 1.9% (37) were very good, 43.4% (841) good, 15.5% (301) intermediate, 11.6% (226) poor, and 27.6% (535) very poor. By HMA type, 71% of pts were treated with azacitidine, 14% with decitabine, 6% with HMA and venetoclax, and 9% with another HMA combination. Approximately 28% of pts underwent allogeneic hematopoietic stem cell transplant (alloHSCT). The IPSS-R cytogenetic risk groups had different OS (p&lt;0.001)with median OS (mOS; months [mo], 95% CI) as follows: very good (43.4, 34.7-72.5), good (41.7, 36.4-46.8), intermediate (24.5, 23.1-32.4), poor (24.2, 19.2-28.5), and very poor (13.6, 12.5-14.5). The difference remained significant (p=0.001) after censoring at time of alloHSCT with mOS as follows: very good (40.4, 23.2-64.3), good (24.3, 22.2-26.3), intermediate (19.3, 15.1-22.2), poor (12.2, 10.3-14.8), and very poor (9.1, 8.2-19.7). Interestingly, the difference between mOS for intermediate and poor risk cytogenetics became more apparent after censoring at time of alloHSCT. Next, we compared the outcomes of pts with CK and VCK to non-complex karyotype (NCK) MDS. The mOS for pts with VCK MDS (13.6 mo, 12.5-14.5) was worse compared to pts with CK (19.9 mo, 19.9-16.8; p=0.004) and NCK (36.1 mo, 32.7-37.8; p&lt;0.001) MDS. Among the 1458 pts with available molecular data, more pts with VCK (75%, 330) MDS had a concurrent TP53mut compared to pts with CK (40%, 21; p&lt;0.001) and NCK (7%, 64 p&lt;0.001) MDS. Considering only patients with TP53mut MDS, mOS for pts with VCK (12.2, 11.1-13.9) was worse compared with NCK (24.2, 16-1-53.1; p&lt;0.001) but not with CK (19.9, 9.5-NR; p=0.9); the difference between CK and NCK was not significant (p=0.16). Among pts with TP53 wildtype (TP53WT) MDS, VCK (15.0, 13.2-18.2) had a similar mOS to TP53WT CK (18.8, 12.6-41.1; p=0.19) while both groups had worse mOS compared to TP53WT NCK (33.4, 30.1-37.0) (p=0.01). In a survival analysis of 616 pts with MDS with ≥3 cytogenetic abnormalities, -17/del(17p) (12.8 mo; p=0.009), inv(3)/t(3q)/del(3q) (10.9 mo; p=0.006), and del(7q) (12.1mo; p=0.024), though not -7 (12.6mo; p=0.23), were associated with lower mOS compared to the pts with MDS without these abnormalities (14.3mo). Conclusions Using one of the largest databases of HMA-treated MDS pts, we show that IPSS-R cytogenetic risk categories associate with significantly different survivals among HMA-treated MDS pts, even after censoring at time of alloHSCT. Importantly, VCK MDS was associated with worse mOS compared to CK and NCK MDS but not in pts with a concurrent TP53mut. Among pts with MDS with ≥3 chromosomal abnormalities, having -17/del(17p), inv(3)/t(3q)/del(3q), or del(7q) was associated with worse survival.

Introduction: There are discrepant definitions of both iron deficiency and anemia in pregnancy. It is recognized that iron requirements increase during pregnancy, particularly in the third trimester, and that deficiencies should be corrected to avoid adverse maternal-fetal outcomes. While low dose iron supplementation is recommended for all pregnant persons (ACOG Bulletin 233), dosing through prenatal vitamins varies widely. Additionally, despite the epidemic of iron deficiency in reproductive-age females globally and availability of high-value biomarkers (e.g., ferritin), current guidelines only recommend screening for iron deficiency during pregnancy in the presence of anemia. As anemia is the terminal manifestation of iron deficiency and reference ranges vary by organization, these guidelines and practices warrant further investigation and discussion. Methods: Retrospective review and analysis of the electronic health record at Mayo Clinic (Rochester, MN) was performed for obstetric deliveries between June 2022 and May 2023. Iron deficiency was defined as a ferritin &lt;50 mcg/L and anemia was defined as a hemoglobin &lt;11 g/dL. Results: A total of 2,141 unique deliveries were identified. The median age at delivery was 31 years old (range: 15 - 45) with 82% identifying as white. Anemia was documented in 42% (n=904) of pregnancies at least once throughout gestation, with an increasing frequency of 2% (n=43) in the first trimester, 11% (n=230) in the second trimester, 17% (n=361) in the third trimester, and 38% (n=803) from admission for delivery through the peri-partum period. There were five documented pRBC transfusions prior to admission for delivery; however, from admission for delivery through the peri-partum period, there were a total of 102 documented pRBC transfusions. In total, 15% (n=318) of pregnancies were screened for iron deficiency through ferritin testing. Ferritin levels were measured 415 times with 23% (n=96) occurring between the last menstrual period and 12 weeks gestational age (WGA), 24% (n=100) occurring between 13-27 WGA, 40% (n=164) occurring between 28-40 WGA, and 13% (n=55) occurring post-partum. Iron deficiency was found in 70% (n=67), 79% (n=79), 80% (n=164), and 78% (n=43) of measured ferritin levels, respectively. Despite the paucity of screening, prescriptions for oral iron increased throughout gestation with supplementation in pregnancy for 8% (n=170) prior to 12 WGA, 14% (n=290) for those 13-27 WGA, and 23% (n=489) for those 28-40 WGA. Similarly, intravenous iron infusions increased throughout gestation with supplementation in pregnancy for 0.3% (n=7) prior to 12 WGA, 0.7% (n=16) for those 13-27 WGA, and 4% (n=95) for those 28-40 WGA. Prenatal vitamins were documented in over 90% of pregnancies throughout gestation, although the majority were non-prescription and contained variable amounts of elemental iron. Conclusions: Iron deficiency in pregnancy is underrecognized and undertreated. It follows that the accuracy of current reference ranges for anemia in pregnancy are suspect without rigorous verification of replete iron stores in the reference population. Given potential implications for blood product utilization and prenatal care, additional studies are warranted to better characterize iron deficiency in pregnancy as well as clinical sequelae for both mothers and infants. Simultaneously, discussions are needed around current guidelines and recommendations for both screening and treating iron deficiency in pregnancy. Providers, institutions, and professional societies should pursue pragmatic quality improvement initiatives and equitable healthcare delivery efforts to optimize care for this vulnerable patient population at high risk of iron deficiency.

Background: Mosunetuzumab (Mosun), a CD20xCD3 bispecific antibody, received accelerated approval for the intravenous treatment of patients (pts) with relapsed/refractory (R/R) follicular lymphoma (FL) who have received ≥2 prior lines of systemic therapy. Mosun can be administered in the outpatient setting with a fixed treatment duration. In an ongoing Phase I/II study, Mosun administered subcutaneously (SC) induced durable responses with a manageable safety profile in pts with previously untreated low-tumor burden FL (LTB; Flinn et al. ASH 2023). Efficacy, safety and pharmacodynamic profiles of Mosun SC are being evaluated in an open-label, multicenter, Phase II study (MorningSun; NCT05207670) in pts with B-cell non-Hodgkin lymphomas, including previously untreated FL. Here we present &gt;8-month follow-up efficacy, safety and biomarker data for Mosun SC in first-line, LTB FL. Methods: Pts had untreated Grade (Gr) 1 or 2 FL, LTB by 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. Mosun SC injection was administered with step-up dosing in Cycle (C) 1 (Day [D] 1, 5mg; D8, 45mg; D15, 45mg), then 45mg on D1 of each 21-day cycle. Hospitalization was not mandatory. Pts with a complete metabolic response (CMR) after C8 could complete therapy. Pts with a partial metabolic response (PMR) or stable disease continued treatment for up to 17 cycles. Dexamethasone premedication was mandatory in C1 and C2 and optional thereafter. The primary endpoint was progression-free survival at 24 months. Exploratory analyses assessed cytokine levels in pts with versus without cytokine release syndrome (CRS) and pharmacodynamic changes in T and B cells in a subgroup of pts. Results: As of February 7, 2024, 65 pts were enrolled in US community (n=41) and academic (n=24) centers. At baseline, median age was 63 years (range: 34-82). Most pts had an ECOG PS of 0 (83.1%) or 1 (15.4%); 29 pts (44.6%) had extranodal involvement and 3 pts (4.6%) had B symptoms. Median duration of follow-up was 8.6 months (95% confidence interval [CI]: 5.7-10.9). Median number of cycles was 8 (range: 1-17). Among 60 pts with ≥1 post-baseline tumor assessment, the objective response rate was 95.0% (95% CI: 86.1-99.0; n=57) and CMR was 83.3% (95% CI: 71.5-91.7; n=50). Median time to response was 2.8 months (range: 2.3-8.3). At data cut-off, responses were ongoing in 48 pts with a CMR and in 5 pts with a PMR. In 64 safety-evaluable pts, the most common adverse event (AE) was injection-site reaction (70.3%; Gr 1, 65.6%; Gr 2, 4.7%). CRS by ASTCT occurred in 30 pts (46.9%; Gr 1, 39.1%; Gr 2, 7.8%); CRS events presented early in C1 (53.1%; Gr1, 45.3%; Gr2, 7.8%) and C2 (Gr1, 1.6%). Nineteen pts received CRS treatment (tocilizumab, 7.8%; steroids, 7.8%; tocilizumab + steroids, 4.7%; fluids, 3.1%; low-flow oxygen, 1.6%); 8 pts had a serious AE and were hospitalized. All CRS events resolved. Other common AEs included headache (45.3%; Gr 1, 29.7%; Gr 2, 15.6%), fatigue (45.3%; Gr 1, 35.9%; Gr 2, 9.4%), maculo-papular rash (31.3%; Gr 1, 14.1%; Gr 2, 15.6%; Gr 3, 1.6%), and increased alanine aminotransferase (28.1%; Gr 1, 21.9%; Gr 2, 4.7%; Gr 3, 1.6%). Gr 3/4 AEs in ≥5% of pts were neutropenia without fever (12.5%; Gr 3, 4.7%; Gr 4, 7.8%) and lymphopenia (7.8%; Gr 3, 1.6%; Gr 4, 6.3%). Suspected immune effector cell-associated neurotoxicity syndrome occurred in 2 pts (confusional state, Gr 1, n=1; Gr 2, n=1); all events resolved. Infections occurred in 30 pts (46.9%; Gr 1, 7.8%; Gr 2, 31.3%; Gr 3, 7.8%) with the most common (≥10%) being COVID-19 (17.2%; Gr 1, 7.8%; Gr 2, 7.8%; Gr 3, 1.6%) and upper respiratory tract infections (12.5%; Gr 1, 3.1%; Gr 2, 9.4%). One pt had a Gr 5 (fatal) AE 13.7 months after treatment was completed (reported as unrelated to Mosun; cause unknown). After the first Mosun dose, cytokine levels significantly increased on C1D2 (interleukin-6, n=44, p≤0.001; interferon-γ and tumor necrosis factor-α, n=41, p≤0.001). This spike in cytokine levels did not differ in pts with (n=19) versus without (n=25) CRS events in C1. Conclusions: Mosun SC monotherapy shows encouraging high efficacy as a fixed-duration treatment in first-line LTB FL. A manageable safety profile was reported, supporting ease of access for patients with drug administration in outpatient settings. Longer follow-up is needed to confirm long-term durability of response and safety.