Citations

Abstract Patients with atypical variants of Alzheimer's disease (AD) often present at a younger age with predominantly non‐amnestic impairments and a more aggressive disease course. Historically, individuals with atypical presentations have not been included in large‐scale clinical trials, which typically focus on late‐onset, sporadic amnestic‐predominant AD. Consequently, treatment options and research efforts specific to atypical AD remain limited. The emergence of amyloid‐targeting therapies that slow disease progression underscores these challenges, as evidence supporting their efficacy in early‐onset amnestic and non‐amnestic AD variants is scarce. This perspective article argues that atypical AD represents an excellent disease model for clinical trials and proposes strategies to address critical gaps in clinical trial design for this population. Key considerations include optimizing participant selection approaches, establishing syndrome‐specific or surrogate biological and clinical endpoints, and fostering advocacy to enhance early and accurate diagnosis, equitable representation, and outcomes for these populations.

Abstract Background and Aims Primary sclerosing cholangitis (PSC) increases the risk of developing cholangiocarcinoma (CCA), which is the leading cause of premature death in these patients. Current diagnostic methods for early detection of either condition remain largely suboptimal. This study investigates serum metabolites as potential non-invasive diagnostic biomarkers. Methods This multicenter international study analyzed 459 serum samples from 13 international centers, including patients with PSC (n = 216), PSC who developed CCA during follow-up (PSC to CCA; n = 24), PSC with concomitant CCA (PSC-CCA; n = 88), ulcerative colitis (UC; n = 14), and healthy individuals (n = 79). Serum metabolomics was evaluated by ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) and the accuracy of the single candidate metabolite biomarkers was further assessed. Machine learning was used to generate the best diagnostic and predictive algorithms. Results Fifty-two serum metabolites were identified as markers of PSC, independent of age, biological sex, cirrhosis, UC, or ursodeoxycholic acid (UDCA) treatment. A diagnostic model based on only six lipids distinguished PSC patients from healthy controls with high accuracy (AUC 0.952 discovery, 0.918 validation), independently of the levels of transaminases or cholestasis markers (i.e., GGT, AP, bilirubin) in blood. Subgroup analyses were performed in PSC patients with and without inflammatory bowel disease (IBD), confirming the model’s consistent performance across both subgroups when compared with their respective control groups – UC and healthy controls (AUC 0.959 and 0.939, respectively). The PSC model also confirmed its diagnostic performance in patients with established PSC-CCA or progression to CCA within 2 years, when compared to UC and healthy controls, showing AUC values ranging from 0.911 to 0.976. Additionally, 20 metabolites were significantly altered in PSC patients with CCA (PSC-CCA), regardless of demographics, cirrhosis, UDCA treatment, IBD status, or CCA subtype, and independently of serum transaminases and cholestatic markers levels. A model incorporating six lipids accurately identified PSC-CCA cases compared to PSC patients (AUC = 0.912 discovery; 0.896 validation), showing excellent performance in early-stage tumor detection (AUC 0.921) and outperforming CA19-9 (AUC 0.708). Importantly, the model retained high accuracy even in CCA patients with low CA19-9 levels (AUC 0.905) and in PSC patients who developed CCA within a year of clinical diagnosis (AUC 0.792). Conclusion The PSC and PSC-CCA blood tests provide a non-invasive approach for diagnosing PSC and PSC-CCA, addressing an important need in this population. Their integration into clinical practice could enhance risk stratification, early detection, personalized surveillance, and treatment decision-making in PSC patients.

ABSTRACT Colony stimulating factor‐1 receptor–related disorder (CSF1R‐RD) is a rare, autosomal dominant neurodegenerative disease caused by loss‐of‐function variants in the CSF1R gene, leading to microglial dysfunction and progressive white matter degeneration. Therapeutic strategies targeting microglial pathways, including activation of triggering receptor expressed on myeloid cells 2 (TREM2), have been proposed to compensate for impaired CSF1R signaling. Iluzanebart (VGL101), a monoclonal antibody TREM2 agonist, has shown promise in preclinical models. We report a longitudinal clinical course, neuroimaging findings, genetic analysis, and postmortem neuropathological examination of a 52‐year‐old patient with genetically confirmed CSF1R‐RD (c.2507G>A, p.Ser836Asn). The patient received iluzanebart as part of a Phase 2 clinical trial. Clinical progression, MRI changes, and histopathological features at autopsy were systematically analyzed. Despite treatment, the patient experienced progressive cognitive decline, neuropsychiatric symptoms, motor impairment, and seizures, culminating in death. Serial neuroimaging demonstrated worsening white matter degeneration and brain atrophy without evidence of therapeutic response. Neuropathological examination revealed characteristic features of CSF1R‐RD, including severe myelin loss, axonal spheroids, infiltration of Iba1‐positive cells with macrophage‐like morphology, and cortical neuronal abnormalities. There was no histological evidence of treatment‐related benefit or harm. This case represents the first clinicopathological assessment of iluzanebart in CSF1R‐RD and demonstrates no observable clinical, radiological, or neuropathological improvement. These findings highlight the challenges of targeting microglial dysfunction in advanced disease and suggest that TREM2 activation alone may be insufficient to alter disease progression.

Importance TMEM106B is a frontotemporal lobar degeneration (FTLD) genetic susceptibility factor, and TMEM106B protein aggregates are a feature of aging and neurodegeneration. Whether TMEM106B protein levels are associated with clinical features is unknown. Objective To investigate the clinical associations of cerebrospinal fluid (CSF) TMEM106B in FTLD. Design, Setting, and Participants This cross-sectional study was conducted in 2 independent frontotemporal dementia (FTD) cohorts (recruitment from April 2009 through July 2023, with analyses from January 2025 through April 2026), with a 2-year follow up. This multicenter clinical study integrated clinical, genetic, biomarker, and neuroimaging data. Individuals were recruited through the University of California, San Francisco (n = 3733), or ALLFTD (n = 2343). Participants with available CSF were included. A discovery cohort (n = 271) included participants with sporadic neuropathology-confirmed FTLD; presymptomatic or symptomatic carriers of pathogenic variants in C9orf72 , GRN , or MAPT ; or controls. An independent validation cohort (n = 383) included participants with clinically diagnosed sporadic FTD, Alzheimer disease (AD), and controls. Exposures CSF samples for TMEM106B quantification with aptamer proteomics (SomaScan version 3.0 [discovery cohort] and SomaScan version 4.1 [validation cohort]). Main Outcomes and Measures Parametric tests compared the primary outcome, CSF TMEM106B, by disease severity, TMEM106B rs1990622 genotype, sex, clinical syndrome, pathological diagnosis, and pathogenic variant and determined associations with brain volume. Results In the discovery (n = 271; 136 women [51%]; median [IQR] age, 59 [38-80] years) and validation (n = 383; 183 women [48%]; median [IQR] age, 64 [50-78] years) cohorts, lower CSF TMEM106B was associated with more severe disease (β, −0.15; 95% CI, −0.24 to −0.04; P = .003), lower frontotemporal brain volumes (β, 0.42; 95% CI, 0.24-0.61; P < .001), and faster clinical progression (β, −2.21; 95% CI, −3.70 to −0.72; P = .001). Associations of TMEM106B with clinical disease severity were independent of those with neurofilament light chain. TMEM106B levels were influenced by TMEM106B rs1990622 genotype, where individuals with the protective G/G genotype had lower levels than the risk A/A genotype. CSF TMEM106B levels did not differentiate between FTLD subtypes or between FTLD and AD. Conclusions and Relevance Per the results of this cross-sectional study, TMEM106B is detectable in CSF and levels reflect disease severity in sporadic and genetic FTLD and AD, but levels are also influenced by the TMEM106B rs1990622 genotype. CSF TMEM106B could support further studies to understand the mechanisms of disease and develop clinical tools in FTLD and other neurodegenerative diseases.

Abstract Myelodysplastic syndromes (MDS) are clinically and biologically diverse disorders, emphasizing the need for personalized treatment approaches. The International Working Group for Prognostication of MDS (IWG_PM) recently introduced a molecular classification, referred to as the MDS taxonomy, that categorizes patients into 16 subgroups based on 21 gene mutations, 6 cytogenetic abnormalities, and loss of heterozygosity (LOH) at TP53 and TET2 loci. This study sought to validate and enhance the clinical relevance of the MDS taxonomy by analyzing a large retrospective cohort ( n = 5136) and transcriptomic data from a prospective cohort ( n = 477). The taxonomy successfully identified subgroups with distinct clinical characteristics and disease progression patterns. However, incorporating gene interactions from taxonomy subgroups did not improve the prognostic performance of the Molecular International Prognostic Scoring System (IPSS‐M). We further assessed whether the taxonomy could guide management in patients receiving disease‐modifying therapies. Except for the “ TP53 ‐complex” subgroup, taxonomy classifications were not predictive of hypomethylating agent response or transplant outcomes. Nonetheless, they correlated with overall survival, suggesting that while both IPSS‐M and the taxonomy capture disease biology, other non‐genetic factors may influence treatment response. RNA sequencing confirmed the biological distinctiveness of the taxonomy groups. Transcriptomic profiling of CD34+ bone marrow cells revealed unique, homogeneous gene expression patterns, particularly within the AML‐like, bi TET2 , SF3B1 , and TP53 ‐complex subgroups. Further integration of multi‐omics data may refine MDS classification, improving clinical decision‐making and guiding the development of targeted therapies.

Abstract Rationale Seralutinib is an investigational, first-in-class tyrosine kinase inhibitor designed for inhalation and selective for PDGFRα, PDGFRβ, CSF1R, and cKIT, targeting proliferation, inflammation, and fibrosis ─ three core drivers of pulmonary vascular remodeling in PAH. The phase 2 TORREY trial of seralutinib added to standard-of-care treatment in adults with PAH WHO FC II or III met its primary endpoint of a statistically significant reduction in pulmonary vascular resistance (PVR) vs. placebo at 24 weeks. Methods PROSERA (NCT05934526), a phase 3, randomized, double-blind, placebo-controlled, multicenter trial, evaluated the efficacy and safety of inhaled seralutinib in PAH patients treated for up to 48 weeks. Eligible patients (WHO Group 1 PH, FC II or III; REVEAL Lite 2 Risk Score ≥5 or NT-proBNP ≥300 ng/L or PVR ≥800 dyne•s/cm5) on standard background therapy were randomized 1:1 to seralutinib 90 mg or placebo delivered by dry powder inhaler twice daily. The primary endpoint was change in six-minute walk distance (6MWD) from baseline to week 24 in the seralutinib treatment group vs. placebo. Key secondary endpoints included: time to clinical worsening (TTCW), proportion of patients with clinical improvement at week 24, change in NT-proBNP from baseline to week 24, and proportion of patients with ≥1-point decrease from baseline in REVEAL Lite 2 Risk Score at week 24. Safety endpoints included incidence of treatment-emergent adverse events (TEAEs) and serious TEAEs (SAEs). Patients who completed blinded treatment could be eligible to participate in an open-label extension study. Preliminary Blinded Results 390 patients were randomized at 132 sites worldwide. At baseline, mean age was 50.0 years. PAH etiologies included 61.0% idiopathic, 9.7% heritable, and 22.3% associated with connective tissue disease. 25.6% of patients were WHO FC II and 74.4% FC III. Mean time from diagnosis was TBD years. Most patients were receiving 2 (39.2%) or ≥ 3 (54.6%) PAH medications, 29.2% were receiving parenteral prostacyclin. Baseline PVR was 798.4 dyne•s/cm5, 6MWD was 373.7 m, and NT-proBNP was 986.8 ng/L. The difference in 6MWD from baseline to week 24 between seralutinib and placebo was TBD [SD] m (p=TBD). Secondary endpoints of TTCW, clinical improvement, NT-proBNP, and REVEAL Lite 2 Risk Score will be reported. The most common AEs were TBD (x%) and TBD (y%). SAEs and discontinuations related to AE will be reported. Conclusions The PROSERA study demonstrates⋯ [to be updated following unblinding of the data]. Funding Gossamer Bio, Inc. This abstract is funded by: Gossamer Bio, Inc.

Abstract Rationale This Registry was designed to prospectively evaluate the efficacy of extracorporeal photopheresis (ECP) to arrest the rate of FEV1 decline (FEV1 decline) and prolong survival in lung allograft recipients with Bronchiolitis Obliterans refractory to standard of care therapy. Methods After IRB approval, 258 lung transplant recipients were enrolled from 20 US lung transplant centers. Subjects were assigned to ECP treatment (ECPRx) (i.e., 24 procedures over 6 months) at or a few months after enrollment based on spirometric criteria. Maintenance ECPRx (mECP) was at the discretion of managing clinicians. Rate of FEV1 decline in mL/month (FEV1 decline) was compared between 6 months prior to and 6 & 12 months after ECPRx initiation using linear mixed effects models. Time 0 for survival was set as the start of ECPRx for generation of Kaplan-Meier curves. Hazard Ratios (HR) with 95% confidence intervals (lower-upper) were generated using Cox Proportional Hazards Regression to characterize significant (p < 0.05) independent associations of mECP and/or any other covariates (i.e., demographic, operative, enrollment site, spirometric ) and survival. Results An 89% (78%-96%) decrease in the FEV1 decline was observed 12 months after ECPRx initiation in 191 participants assigned to ECPRx. FEV1 decline (-164 mL/month: 144-185) was greater (p < 0.001) in participants who expired within six months of Time 0 (n = 28) vs participants (-111 mL/month: 101-120) who died six months after Time 0 (n = 77). Of 159 participants who survived for at least six months after ECPRx initiation, 40 participants without mECP, who had up to 24 ECPRx (ECPRx: n = 19), had a lower survival HR: 2.43(1.75-3.4) (p < 0.001) relative to 119 participants who received mECP (ECPRx: n = 86)(see Figure). The response to ECPRx (% Change in FEV1 decline prior to and 6 months after 1st ECP) was similar between subcohorts (No mECP: -81 decrease vs mECP: -85%, p = 0.3). The association of mECP persisted after multivariate adjustment HR 1.8 (1.8-2.7)(p = 0.002) using significant covariates: FEV1 HR 0.37 (0.3-0.5), FEV1 decline HR 0.001 (0.001-0.04), Male Gender HR 2.4 (1.7-3.4); Reflux Disease HR 1.8 (1.2-2.8); Coronary Disease HR 1.8 (1.2-2.7). Conclusions This analysis indicates that mECP is independently associated with enhanced survival most likely due to attenuation of relapse six months after ECP initiation based on similar initial response to ECPRx. A risk-adjusted, control cohort is being pursued to facilitate submission of a scientifically rigorous petition to CMS to expand the ECP National Coverage Decision to include BOS predicated on CMS 2024 scientific guidelines. This abstract is funded by: Therakos Inc

Abstract Rationale Impaired lung health may serve as a risk factor for, and a post-acute sequela of, SARS-CoV-2 infection. Yet most prior studies of lung health sequelae of COVID-19 lacked information on pre-infection lung health, a major antecedent confounder. To identify associations of COVID-19 with changes in lung health, we leveraged paired pre- and post-pandemic data on respiratory symptoms, lung function, and lung structure in a general population-based cohort. Methods We studied participants in the Multi-Ethnic Study of Atherosclerosis Lung Study with paired pre-pandemic (2016-2018) and post-pandemic (2022-2024) assessments of respiratory symptoms, spirometry, and lung CT. SARS-CoV-2 infection (2020-2023) was ascertained using a composite of questionnaires, serology, and medical record adjudication, and classified as severe (requiring hospitalization) or non-severe (not requiring hospitalization). Lung health was assessed by questionnaire (mMRC grade ≥2 dyspnea, chronic cough, chronic phlegm, chronic bronchitis), pre-bronchodilator spirometry (FEV1, FVC, FEV1:FVC), and lung density on non-contrast lung CT (% low attenuation areas, % high attenuation areas). Each post-pandemic lung health measure was regressed on infection history and the corresponding pre-pandemic lung health measure, adjusting for age at post-pandemic exam, sex, race/ethnicity, smoking status, and vaccination status at infection. Sensitivity analyses were included- (a) restriction to participants without pre-pandemic respiratory symptoms and (b) with additional adjustment for time since infection and variant wave. Results Among 2,015 participants (mean age 77.2±7.5 years; 55% female; 40% non-Hispanic White; 25% Black; 11% Asian; 23% Hispanic/Latino), 59 (3%) experienced severe and 506 (25%) non-severe SARS-CoV-2 infection. The prevalence of respiratory symptoms was similar or slightly higher at the post- vs. pre-pandemic exam (grade ≥2 dyspnea: 14% vs. 10%; chronic cough: 10% vs. 8%; chronic phlegm: 9% vs. 8%; chronic bronchitis: 4% vs. 4%; p-values <0.0001). Compared with participants without infection, those with severe infection had higher odds of chronic cough (OR:2.9, 95%CI:1.3-6.3) and chronic bronchitis (OR:3.3, 95%CI:1.2-9.0) at the post-pandemic exam (Table). Associations were stronger among individuals infected >90 days prior to the post-pandemic assessment and during pre-Omicron waves. Results were similar when restricted to participants without pre-pandemic symptoms. No significant associations were observed for non-severe infection (vs. no infection) or for any other lung health outcomes. Conclusions Controlling for pre-pandemic lung health, severe COVID-19 was associated with increased odds of chronic cough and chronic bronchitis but not with changes in lung function or structure in a general population-based sample. Non-severe COVID-19 was not associated with lung health outcomes. This abstract is funded by: OT2HL156812, R21HL165405, R01HL077612, 75N92025D00022, 75N92025D00026, 75N92020D00002, 75N92025D00024, 75N92025D00027, 75N92025D00025, 75N92025D00028

Abstract Rationale The impacts of COVID-19 vaccination and SAR-CoV-2 infection on brain tissues and structures remain controversial. This study examines whether COVID-19-related exposures are associated with measurable changes in structural magnetic resonance imaging (MRI) using data from the US general population-based Collaborative Cohort of Cohorts for COVID-19 Research (C4R) Study. Methods The C4R study is an observational meta-cohort study of 14 NIH-funded population-based cohorts, with directly measured data on COVID-19-related exposures, including vaccination and infection. For this analysis, we included participants with C4R data and paired brain MRI scans from both before and after the onset of the COVID-19 pandemic (defined as March 1, 2020) from two cohorts: the Atherosclerosis Risk in Communities study (ARIC) and Framingham Heart Study (FHS). MRI features examined as outcomes were white matter volume (WMV), gray matter volume (GMV), total brain volume (BV), hippocampal volume (HV), and white matter hyperintensity volume (WMH), a marker of microvascular disease. Exposures included SARS-CoV-2 infections identified via questionnaires, serosurveys, and medical record reviews from 2020-2025. Infections resulting in hospitalization were classified as severe. Time-to-recovery, symptoms of long COVID, and vaccination status were self-reported by questionnaire. Analysis of covariance (ANCOVA) estimated associations between COVID-19-related exposures and pandemic MRI-measured outcomes, with adjustment for: the corresponding pre-pandemic MRI measure, the time between the two MRI scans, age, sex, systolic blood pressure, diabetes, and cardiovascular disease. Results Of 270 participants with available data, mean (SD) age was 80.6 years (10.6); 43.0% were male; and the mean (SD) interval between paired MRI scans was 4.2 (2.0) years. Most (90%) were vaccinated (of whom 6.7% vaccinated before infection) and 7.9% reported SARS-CoV-2 infection (of which 13.6% were severe infections) prior to their pandemic MRI (conducted March 2020 - June 2022). In fully adjusted models, there was no statistically significant association for change in WMV, GMV, BV, HV, or WMH with SAR-CoV2 infection status, infection severity, vaccination status, or vaccination timing (Table, P > 0.05 for all comparisons). Self-reported symptoms of long COVID and vaccine manufacturer were also not associated with MRI outcomes. Conclusions Based on repeated (pre-pandemic and pandemic era) structural MRI scans, we found no evidence that SARS-CoV-2 infection or COVID-19 vaccination were associated with changes in brain structure or brain microvascular disease. These findings are consistent with prior data supporting COVID-19 vaccine safety and suggest resilience of brain structures following SARS-CoV-2 exposures. Nonetheless, further research is warranted using more sensitive measures and assessing longer term effects. This abstract is funded by: OT2HL156812