Citations

Abstract In 2011, a workgroup of the Alzheimer's Association Research Roundtable introduced recommendations for detecting and monitoring amyloid‐related imaging abnormalities (ARIA) in Alzheimer's disease (AD) clinical trials. Since then, anti‐amyloid immunotherapies have received regulatory approval for AD treatment and are beginning to enter clinical practice, underscoring the importance of informing healthcare providers, researchers, and patients about ARIA's implications in real‐world settings. In response, the Alzheimer's Association convened a new workgroup to review current knowledge of ARIA, including underlying mechanisms, clinical presentations, associated risk factors, mitigation strategies, radiologic detection methods, patients’ perspectives in treatment decision‐making, and outstanding challenges. Here, we outline key insights from this workgroup, highlighting that effective ARIA detection and monitoring in clinical practice requires adherence to robust protocols to mitigate risks and enhance patient safety. Limited availability of clinical and pathologic data on predictors of symptomatic and severe ARIA underscores the importance of continued real‐world data collection.

BACKGROUND: Among accepted US heart organs, listing centers accept organ offers earliest for White women, followed by Black women, White men, and Black men. Understanding the relationships of center- and geographic-level decisions is necessary to understand waitlist disparities. We sought to determine whether listing center and geography are associated with the first heart organ acceptance by candidate race, since race demographics vary regionally across the United States. METHODS: Using the United Network for Organ Sharing data sets, we identified first organ offers for Black and White candidates listed for heart transplant (October 18, 2018 to September 30, 2024) and compared models with and without listing center effects adjusted for candidate-, donor-, and offer-level variables. RESULTS: Among 20 668 candidates (31.6% Black, 68.4% White, 26.5% women), the adjusted odds of first offer acceptance were lower for Black candidates compared with White candidates (odds ratio, 0.84 [95% CI, 0.76–0.94]; P =0.001) when listing center was not included in the model; but after adjusting for listing center effects, odds were similar by race (odds ratio, 0.98 [95% CI, 0.88–1.10]; P =0.78). There were no clear geographic patterns by center, but centers with lower proportions of Black candidates had higher acceptance rates. CONCLUSIONS: Variability in overall acceptance rate among listing centers explains the lower first offer acceptance for Black compared with White heart candidates. Baseline acceptance rates were linked to the center-level proportion of Black candidates but not geography. Investigation of strategies to systemically improve early acceptance of good heart organs may reduce Black and White disparities in wait time duration.

Objective This study aims to identify factors associated with patient global assessment (PtGA) and physician global assessment (PhGA) and discordance between them in systemic sclerosis (SSc). Methods Data from adults with early SSc (<5 years) from the Collaborative National Quality and Efficacy Registry were included. PtGA and PhGA (0–10 scale), clinical evaluations, and patient‐reported outcomes (PROs) were collected every six months. Multivariable mixed‐effects linear regression identified factors associated with PtGA and PhGA using (1) clinical variables and (2) clinical variables plus PROs. Relative weight analysis (RWA) determined the relative importance of each variable. Discordance (≥2 points between PtGA and PhGA) was assessed using multinomial mixed‐effects logistic regression. Results Among 956 patients (83% women, 33% limited disease), mean PtGA and PhGA at enrollment were 4.2 (SD 2.6) and 3.4 (SD 2.0), respectively ( P < 0.001). RWA of clinical variables identified modified Rodnan skin score (mRSS) and New York Heart Association (NYHA) functional class as most influential for both global assessments. After including PROs, PtGA was most influenced by measures of pain, skin symptoms, and physical function. Discordance occurred in 53% of patients (35% PtGA worse, 18% PhGA worse). Worse PtGA was associated with higher overall pain and discomfort. Worse PhGA was associated with higher mRSS, worse NYHA class, higher pain interference, and lower diffusing capacity of the lung. Conclusion Discordance between PtGA and PhGA occurs commonly, highlighting the need for comprehensive symptom management and measurement of disease burden in this complex disease. In SSc, differences in PtGA and PhGA reflect dissimilar weighting of data elements.

Abstract INTRODUCTION Repetitive head impacts (RHI) from contact sports may cause a unique pattern of white matter hyperintensities (WMH) on T2‐weighted fluid‐attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI), termed RHI‐associated WMH (RHI‐WMH). These lesions are punctate, circular, and located at the gray–white matter boundary, an area vulnerable to trauma‐related damage. METHODS We investigated the association of RHI with these lesions in two aging cohorts: (1) former American football players versus asymptomatic unexposed men and (2) individuals with RHI from various contact sports versus non‐RHI participants. RHI‐WMH were assessed using visual ratings and a novel automated quantification pipeline. RESULTS Individuals with RHI had greater RHI‐WMH by both detection methods in both cohorts. RHI‐WMH were associated with plasma neurofilament light and p‐tau231, and flortaucipir positron emission tomography (PET) uptake. DISCUSSION RHI‐WMH may represent a new supportive biomarker for the detection of RHI‐related neuropathologies later in life.

Abstract Background: Pyrimidine synthesis is a therapeutic vulnerability in cancer but inhibition results in toxicity to normal cells. Differential targeting of CTP synthase 1 (CTPS1), sparing the CTPS2 isoenzyme, is a therapeutic strategy in lymphoid cancers, supported by human genetic studies, that can potentially avoid toxicity; however, CTPS2 activity may compensate in epithelial tumours. Loss of CTPS2 protein expression characterises 25% of solid tumours and is predicted to expose a synthetic lethal vulnerability to CTPS1 inhibition. Dencatistat (STP938) is a first in class oral CTPS1 inhibitor showing &gt;1,300-fold selectivity over CTPS2. In preclinical studies, CTPS2 expression was confirmed as a key modulator of response to CTPS1 inhibition, and dencatistat induced tumour regression in an in vivo model of CTPS2 negative ovarian cancer. Study design: The study comprises a standard 3+3 phase 1a dose escalation design, in which intra-patient dose escalation is encouraged, followed by a phase 1b safety expansion. The dose escalation study is recruiting participants with high grade advanced tumours who have exhausted standard of care therapy (excluding haematological cancers, salivary gland tumours and low grade tumours of any tissue). In addition, participants with high grade serous ovarian cancer whose tumours lack expression of CTPS2 (per central laboratory testing by immunohistochemistry) are eligible for backfill into cleared cohorts during dose escalation. The recommended phase 2 dose (RP2D) will be nominated based on safety, tolerability, target engagement and early signs of clinical efficacy. The phase 1b safety expansion study will recruit participants with CTPS2 negative ovarian, lung or endometrial cancer who will receive treatment at the RP2D. Standard inclusion criteria apply; patients with ECOG performance score &gt;2 (&gt;1 for phase 1a in France) or active/symptomatic CNS metastases are not eligible. The primary objectives of the study are to evaluate the safety and tolerability of single agent dencatistat and to determine the RP2D for further development. Secondary objectives comprise evaluation of pharmacokinetic properties and preliminary clinical activity. Exploratory endpoints include evaluation of target engagement, molecular features associated with response, and determination of drug metabolites. The study opened to enrolment in the UK, France and USA in September 2024 and is currently in dose escalation (NCT06297525). The phase 1b study is expected to commence mid-2026 and will include additional centres in Spain. Citation Format: Donna M. Graham, David Sommerhalder, Douglas Orr, Rowan Miller, Neeharika Makani, David O'Malley, Ira Winer, Philip A. Beer, Karen Smith, Maureen Higgins, John R. Hawse, Xiyin Wang, Saravut J. Weroha, Christophe Massard, Patricia Roxburgh. Lack of CTPS2 expression exposes synthetic lethal vulnerability to selective CTPS1 inhibition: A phase 1 dose escalation study of dencatistat (STP938) with safety expansion in biomarker selected cohorts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr CT075.

Abstract Despite long-standing interest in combining topoisomerase I (TOP1) poisons with PARP inhibitors (PARPis), the mechanistic basis for the variable and often unpredictable response to this strategy remains unclear. Early preclinical studies suggested that PARP inhibition amplifies TOP1 poison-induced DNA damage, implying broad therapeutic potential; however, emerging translational and clinical data—particularly in ovarian cancer—indicate that synergy is context-dependent and governed by tumor-intrinsic features that have not been fully defined.Here we assessed determinants of response in five HR proficient ovarian cancer (OC) patient-derived xenografts (PDXs) previously treated with the SN-38 prodrug etirinotecan pegol (NKTR-102) in combination with the PARPi rucaparib (C. Nitschmann, Clin. Cancer Res. 22(2) Suppl. B50, 2016). Although all models were refractory to single-agent rucaparib, 50% exhibited enhancement of NKTR-102-induced tumor regression with the addition of rucaparib. Neither PARP1 abundance nor extent of rucaparib-mediated poly(ADP-ribose) suppression correlated with therapeutic benefit. Instead, sensitization was restricted to PDXs intrinsically responsive to NKTR-102 and was strongly associated with high levels of NKTR-102-induced TOP1-DNA covalent complexes. In further analysis, 2 of 3 resistant PDXs exhibited high levels of the ABC transporter ABCG2 despite lack of previous therapy, revealing a previously underappreciated mechanism of de novo resistance that limits effective TOP1 inhibitor activity independent of homologous recombination status. Notably, NKTR-102 response did not track with platinum/taxane sensitivity, highlighting the distinct molecular circuitry governing TOP1 poison susceptibility.Collectively, these findings demonstrate that rucaparib can potentiate NKTR-102-induced regression in tumors capable of forming abundant TOP1-DNA covalent complexes. This work identifies TOP1-DNA complex trapping and lack of ABCG2 expression as mechanistic predictors of benefit, providing an updated framework for selecting patients most likely to respond to TOP1 poison/PARPi combinations and challenging the long-standing assumption that PARP inhibition can universally resensitize tumors to TOP1 poisons. Citation Format: Annapoorna Venkatachalam, Caroline C. Nitschmann, Karen S. Flatten, Rachel Hurley, Xiaonan Hou, Cristina Correia, Paula A. Schenider, Krista Goergen, Matthew Maurer, Ethan P. Heinzen, Ann L. Oberg, S John Weroha, Paul Haluska, Scott H. Kaufmann, Elizabeth M. Swisher. TOP1-DNA protein complex as a predictive biomarker for NKTR-102/Rucaparib combination therapy in PARP-inhibitor resistant ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr LB364.

Abstract Background Red cell alloimmunization complicates sickle cell disease (SCD) management despite current widespread prophylactic Rh/K matching in the United States (US). Regional antibody patterns remain poorly characterized. Study Design and Methods We conducted a retrospective analysis of 2965 SCD patients from 9 US sites (2010–2022). All hospitals prophylactically match for Rh and K antigens. Each site collected demographics, antigen status, antibody histories, and antibody screen results from their laboratory information system. Results Overall antibody prevalence was 29.7% with dramatic institutional variation (17.9%–56.0%). Alloantibody prevalence was 27.5%. Most autoantibody‐positive patients (74.23%) also had alloantibodies, identifying a high‐risk population. A third of patients with positive antibody histories had negative screens. Pediatric patients showed markedly different antibody profiles than adults. Hospitals’ antibody patterns clustered by patient age rather than geography. Rh and K antibodies were the most common and also most likely to co‐occur, followed by S, Fya, and Jkb antibodies. Antibodies against Jsa (1.82%), V (1.75%), and Kpa (1.69%) were more prevalent than anti‐Jka (1.28%). Despite regional antibody variation, antigen frequencies remained overall consistent. In antigen–antibody pairwise comparisons, 3.15% were antigen‐negative and antibody‐positive reflecting alloimmunization; 0.47% were both antibody‐ and antigen‐positive, suggesting partial/variant antigens. Discussion Substantial institutional variation in antibody prevalence suggests need for site‐specific approaches to testing and prophylactic matching. High co‐occurrence of auto‐ and alloantibodies, antibody immunogenicity patterns, and antigen–antibody discordances support the need for further research and consideration of refined testing and/or matching strategies beyond the current Rh and K standard.