Jingxia Liu

Antibody-drug conjugates (ADCs) have significantly advanced cancer therapy by enabling the selective delivery of cytotoxic agents to tumour cells. However, ADC efficacy remains constrained by its dependence on a single target antigen, which limits tumour targeting and promotes resistance in heterogeneous tumours with variable and low antigen expression^1-6. Here we introduce an in vivo bioorthogonal ligation strategy that generates functional antibody-ADC click constructs following systemic administration. This platform provides a modular and translatable approach for enhanced targeted drug delivery in heterogeneous tumours. We conjugate therapeutic antibodies and ADCs with trans-cyclooctene and tetrazine moieties for sequential administration to enable in vivo ligation of an antibody with an ADC after systemic delivery. The antibody-ADC click approach demonstrated improved antitumour activity relative to standard ADC monotherapy or antibody plus ADC combinations in preclinical models of HER2 and EGFR co-expression. These included tumours with low, ultralow, negative or heterogeneous HER2 expression and resistant or ineligible for conventional HER2-directed ADCs. This modular strategy leverages receptor biology and bioorthogonal chemistry for optimal therapeutic efficacy and does not require extensive antibody re-engineering. Moreover, the antibody-ADC click approach can be extended to other receptor pairs, which makes it a flexible modular platform to address heterogeneity and resistance to targeted therapies across different tumour types.

Background: Midlife obesity is considered one of the top modifiable risk factors for dementia and Alzheimer's disease (AD). However, body mass index (BMI) on its own does not fully represent obesity-associated risks and it is crucial to disentangle the role of body adiposity and its localization. Objective: To investigate the relationship of MRI-derived body adiposity metrics with AD-related pathology at midlife. Methods: Ninety-seven cognitively normal midlife individuals underwent brain amyloid and tau PET, body MRI, and metabolic and cognitive assessments. Key measures included hepatic fat fraction, visceral (VAT) and subcutaneous adipose tissue (SAT) volumes, and thigh muscle and adiposity. The correlation between adiposity/metabolic measurements and amyloid/tau pathologies was investigated. Results: The average age of participants was 49.8 years, 65.3% were female and 53.6% had obesity. Amyloid PET burden in Centiloids correlated with VAT (rho = 0.36, p = 0.002), BMI (rho = 0.33, p = 0.002), SAT (rho = 0.33, p = 0.002), and insulin resistance (IR) (rho = 0.34, p = 0.003) in females and Whites, lower high-density lipoprotein (HDL) cholesterol (rho = −0.36, p = 0.002) irrespective of sex and race, and lower MMSE scores (rho = −0.57, p = 0.043) in only in African-Americans, after correction for age, sex, and education. There was no evidence that HDL nor IR mediated VAT-related amyloid. VAT/SAT ratio was significantly associated with mean cortical tau SUVR (β = 0.138, p = 0.030) after adjustment for age, sex, education, and amyloid. Conclusions: Among fat depots in our study, visceral fat was more strongly correlated to amyloid pathology, and this association is present even independent from BMI. Also, higher visceral compared to subcutaneous fat is related to higher tau pathology.

Although sample size calculation for open‐cohort longitudinal cluster randomized trials (LCRTs) under a fixed design framework was developed by Kasza et al., unifying the closed‐cohort and repeated cross‐sectional sampling provided in Hooper et al. when a churn rate is constant, there has been no prior efforts in developing optimal open‐cohort LCRTs that maximizes the design efficiency. This work assumes a prespecified number of periods and a constant number of replaced individuals at each period in open‐cohort LCRTs. We propose algorithms for deriving optimal sample size under a cost‐efficiency framework and arrive at the local optimal design (LOD) for fixed correlation parameters and MaxiMin optimal design for addressing uncertainty in correlation parameters. When correlation parameters are known, as the number of replaced individuals increases, for open‐cohort PA‐LCRTs, the optimal cluster‐period size generally decreases and then increases whereas the optimal number of clusters and power under LOD first increase and then decrease. In contrast, for CRXO trials and standard SW‐CRTs, the optimal cluster‐period size and churn rate under LOD increase whereas the optimal number of clusters and power under LOD decrease. When correlation parameters are unknown, but the parameter space is available, with a small number of replaced individuals, there is no difference in optimal designs between PA‐LCRTs and CRXO trials. The number of replaced individuals also has less impact on the optimal cluster‐period size than optimal number of clusters. We demonstrate our new optimal design methods using the context of two real‐world LCRTs.

Context: The COVID-19 pandemic presented an unprecedented challenge for operations of schools in the US. In addition to masking and distancing, weekly testing for SARS-CoV-2 was recommended for students and staff during high SARS-CoV-2 transmission levels to provide an additional mitigation strategy to limit transmission. Objective: To assess testing strategies (weekly screening vs. symptomatic only) on SARS-CoV-2 infection rates in public middle and high schools predominantly attended by underrepresented minorities. Design: During the 2021–2022 school year, a cluster randomized trial was conducted among 16 middle and high schools from 5 public school districts. These schools were randomized into one of 2 intervention groups: Weekly screening testing + symptomatic testing (S + S) or symptomatic testing only. Setting: Public schools in St. Louis (Missouri). Participants: Students, staff, and family members of 16 middle and high schools. Intervention: Weekly screening + symptomatic testing or symptomatic only testing. Main Outcome Measures: Any positive test across all weeks [yes/no], number of tests, number of positive tests, and positivity test rate for each participant. Results: One thousand three hundred ninety individuals participated in this study. From the S + S schools, 894 (64.3%) individuals participated: 200 (15%) students, 353 (43%) staff, and 290 (37.5%) household members. Among the 496 (35.7%) participants from the symptomatic only schools, 183 (13%) students, 203 (47%) staff, and 83 (40%) household members participated. A total of 183 participants tested positive during the study period. When comparing school-based testing strategies, the positivity rates were not different between the 2 groups ( P = .25). Conclusions: This study did not show a benefit of weekly screening testing. Underlying disease risk or effectiveness of testing is considered however, notably the finding may be attributed to the inherent differences of identifying positive cases in each testing strategies. Finally, the participation rate in the study at the schools was low, which limits this finding.

Neuroimmune signaling across the peripheral–vascular–glial axis is increasingly recognized as a driver of both age‑related brain vulnerability and the earliest stages of neurodegenerative disease, including Alzheimer disease. Evaluating this axis in vivo remains challenging due to limited neuroinflammatory imaging biomarkers. We utilized [11C]CS1P1 positron emission tomography (PET) to quantify sphingosine-1-phosphate receptor 1 (S1PR1) availability alongside plasma proteomics in 42 cognitively normal individuals (age 21-82). Through differential abundance analysis and structural equation modeling (SEM), we identified a multi-compartment neuroimmune cascade linking peripheral T-cell activation (CD40LG), vascular endothelial disruption (ICAM1/TEK), central S1PR1 upregulation, and reactive astrogliosis (GFAP). Mediation analysis estimated this S1PR1 axis accounts for 25.5% of the total effect of CD40LG on GFAP. This cascade appears coupled to the astrocytic immune response and is exacerbated by underlying amyloid-beta pathology. These findings suggest [11C]CS1P1 may serve as an in vivo tool for evaluating peripheral-to-central immune crosstalk.

Background: Lin et al. studied the statistical properties of rule-based general A+B designs using true toxicity probabilities, without and with dose de-escalation, and derived exact formulae for key statistical quantities essential for phase I clinical trials. Methods: We systematically evaluate the impact of the parameters of A, B, C, D and E on the key statistical quantities across five dose levels within the A+B=6 framework. Simulation studies are conducted with true toxicity probabilities generated using a dose-toxicity model on known prior toxicity probabilities. Results: General A+B designs with dose de-escalation are more conservative than those without dose de-escalation. For either presence or absence of dose de-escalation, 1) under an under-toxic environment, the 33222 design is the best design and 24113 design is the second one, but 33222 design requires two more patients expected to be treated than 24113 design. 2) under a moderate-toxic and over-toxic environment, 24113 and 42111 design demonstrates an absolute and evident superiority, respectively. 3) under an unknown-toxic environment, 33122 design is the optimal choice but requires a larger total number of patients expected to be treated. 4) under an over-/unknown-toxic environment, the traditional “3+3” is one of the top two smallest total number of patients expected to be treated and patients experiencing a dose-limiting toxicity. Conclusions: Some general designs have superior performance than traditional “3+3” design, having the target toxicity level closest to target toxicity rate (TTR) and higher number of patients treated at the dose levels with toxicity probabilities close to TTR.

Immune checkpoint inhibitors (ICIs) show minimal efficacy in recurrent high-grade astrocytoma (rHGA). Laser interstitial thermal therapy (LITT), a minimally invasive cytoreductive approach, may prime rHGA for ICI response. A phase 1/randomized phase 2b trial (ClinicalTrials.gov: NCT02311582 ) was designed to test pembrolizumab in combination with LITT in patients with rHGA. Nine patients were enrolled in the phase I dose-escalation lead-in study. No dose-limiting toxicities were observed and 200 mg of pembrolizumab every three weeks was determined as the recommended phase 2 dose. The phase 2b study was initially designed to randomize (up to 45) patients 1:1 to either LITT followed by pembrolizumab (LITT + PEM) or non-LITT surgery followed by pembrolizumab (NLS + PEM). Phase 2’s primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), safety, and immune signature. After 21 patients, based on an independent Data and Safety Monitoring Committee request of unscheduled interim review of accumulating efficacy data, randomization stopped as benefit from NLS + PEM appeared limited, and the subsequent 24 patients received LITT + PEM. The pre-specified study endpoints were achieved. Among 39 per-protocol patients, LITT + PEM (n = 33) improved median OS (11.8 versus 5.2 months) and 18-month survival (42% versus 0%) compared to NLS + PEM (n = 6) (hazard ratio [HR] 0.17; 95% confidence interval [CI], 0.06–0.49; P = 0.0002). Median PFS was longer in LITT + PEM (4.5 versus 1.6 months; HR 0.21; 95% CI, 0.08–0.56; P = 0.0006). In an intent-to-treat sensitivity analysis (n = 21), OS (HR 0.29; 95% CI, 0.10–0.88) and PFS (HR 0.30; 95% CI, 0.10–0.87) again favored LITT + PEM (n = 13). Treatment was well tolerated. LITT activated non-classical monocytes, and pembrolizumab unleashed CD8⁺ T cell proliferation, clonal expansion, and coordinated memory T-cell responses. Overall, LITT + PEM is safe and may overcome rHGA immunosuppression to generate antitumor immunity.

Full results of GSEA of Hallmark pathway analysis after 90Y microsphere treatment in resistant and sensitive cell lines.

QRT-PCR validation of gene expression representing relevant biological pathways after 90Y microsphere treatment in the most sensitive (PLC/PRF/5), resistant (SK-Hep1), and intermediate (SNU-398) cell lines. Select genes involved in (A) interferon stimulation and antigen presentation were mostly upregulated in both SNU-398 and SK-Hep1 after treatment, with the exception of GBP1 in SK-Hep1 and MX1 and IFI27 in SNU-398 which did not have reliable qPCR readouts. TXNIP was strongly upregulated in SK-Hep1 after treatment, consistent with increased oxidative stress signaling. (B) SNU-398 demonstrated very strong upregulation of inflammatory response genes, in particular CCL5 and TNFAIP2. C, Distinct patterns of DNA damage and cell stress genes were seen across cell lines, with SK-Hep1 showing upregulation of BRCA1 and downregulation of BNIP3. D, ECM genes CD44 and ITGA3 were strongly upregulated in SNU-398 after treatment, suggesting stress-induced EMT acquisition. Although there was slight downregulation of these genes in SK-Hep1, they remained at highest abundance in this line consistent with an EMT-associated expression profile. All experiments were performed in technical triplicate and error bars represent SEM when >1 biological replicate was performed. nd, no reliable qRT-PCR readout.

Primer sequences for genes used for RT-qPCR