Citations

ABSTRACT BACKGROUND Platelet factor 4-polyanion enzyme-linked immunosorbent assays (ELISAs) are considered highly sensitive for diagnosing heparin-induced thrombocytopenia (HIT), such that current practice guidelines recommend use of ELISA-negative results to exclude HIT. Once HIT is ruled out, alternative, non-heparin-based anticoagulant treatments are ceased, and heparin reintroduction frequently occurs. METHODS Antigen-based and PF4-dependent functional testing were used to study PF4/polyvinyl sulfonate ELISA-negative platelet-activating antibodies in HIT-suspected patients and mice immunized with PF4/heparin. RESULTS Three patients with clinical presentations consistent with HIT tested negative in an ELISA using PF4-polyvinylsulfonate (PF4/PVS), an antigenic target very commonly used for HIT antibody detection. All three patients demonstrated PF4-dependent platelet activation in functional testing that was sensitive to blockade of platelet FcγRIIa receptors and inhibited by high concentrations of heparin, consistent with pathogenic HIT antibodies. Functional testing-based screening of 500 ELISA-negative patients identified three patients whose sera activated platelets in a PF4- and FcγRIIa-dependent manner, and had clinical histories consistent with HIT. Five of the six ELISA-negative HIT patients were re-exposed to heparin, which precipitated a decrease in platelet counts in all re-exposed patients, and one patient developed a new thrombus. To advance the study of ELISA-negative HIT antibodies, mice were immunized with PF4/heparin, and functional and antigenic assays were simultaneously used to successfully identify an ELISA-negative, PF4-dependent platelet-activating murine monoclonal antibody that recapitulated the serological characteristics of ELISA-negative HIT patients. CONCLUSIONS Recognition of ELISA-negative HIT is critical to avoid harm due to the cessation of alternative anticoagulation therapy and re-exposure of these patients to heparin.

Background: Long QT syndrome (LQTS) is a potentially lethal cardiac channelopathy that stems primarily from pathogenic variants in KCNQ1 (LQT1), KCNH2 (LQT2), or SCN5A (LQT3) and is characterized by prolongation of the cardiac action potential duration (APD) at the cellular level. Despite current therapeutic options, there is a pressing need for novel, precision medicine-based, effective pharmacological therapies for LQTS, particularly for LQT2 and LQT3. Goal: To develop a high-throughput drug screening platform to identify novel therapeutics for LQTS using induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Methods: iPSC-CMs were made for patients with LQT2 (p.G604S) or LQT3 (p.P1332L). Voltage dye assays were performed using a kinetic image cytometer (KIC) in a 96 well format. The APD at 90% repolarization (APD90) was measured in treated/untreated iPSC-CMs. Cyteseer image analysis software was used for optical APD analysis. SCN5A-P1332L iPSC-CMs were treated with 10 uM mexiletine (MEX) as a positive control. 114 compounds from a commercially available library of FDA-approved drugs were tested in triplicate to assess their APD shortening efficacy. Whole-cell patch clamp was used to confirm the lead compound’s effect in KCNH2-G604S iPSC-CMs. Results: MEX significantly shortened the APD90 of SCN5A-P1332L iPSC-CMs by 13% (669 ± 5 to 586 ± 10 ms; p<0.0001; n=50). Of the 114 tested compounds, 6 shortened the APD90 of SCN5A-P1332L iPSC-CMs by greater than 20%. The lead compound shortened the APD90 of SCN5A-P1332L iPSC-CMs by 32% (571 ± 2 ms; n=314, to 387 ± 4 ms; n=80; p<0.0001). All 6 candidate compounds also shortened the APD90 of KCNH2-G604S iPSC-CMs by greater than 20% in KIC screening assays. Whole-cell patch clamp confirmed APD shortening by the lead compound in KCNH2-G604S iPSC-CMs (759 ± 35 ms; n=13, to 599 ± 89 ms; n=9; p<0.03). Conclusion: The high-throughput KIC screen confirmed mexiletine’s APD shortening effects in SCN5A-P1332L iPSC-CMs, validating the assay's potential for efficient, large-scale drug screening. In a pilot screen, we identified 6 novel LQTS drug candidates which shortened the APD90 in SCN5A-P1332L (LQT3) and KCNH2-G604S (LQT2) iPSC-CMs more than mexiletine. The lead compound’s APD shortening effects in KCNH2-G604S iPSC-CMs were confirmed with whole cell patch clamp. The KIC platform offers a robust method for identifying novel QT shortening compounds by enabling reproducible APD measurements in a high-throughput format.

Abstract Purpose: Polatuzumab vedotin (polatuzumab) was approved for up-front treatment of diffuse large B-cell lymphoma in combination with chemoimmunotherapy (Pola-R-CHP) based on the POLARIX trial. However, when stratified by cell of origin (COO), polatuzumab seems to have greater efficacy in activated B-cell than germinal center B-cell (GCB) subtype disease. Most studies of polatuzumab used RNA expression to assess COO, whereas in routine clinical practice, the immunohistochemistry-based Hans algorithm is used. Experimental Design: To assess the impact of COO by immunohistochemistry on polatuzumab efficacy, we conducted a multicenter real-world study of adults with large B-cell lymphoma (LBCL) receiving polatuzumab from 2015 to 2024, split by receipt of polatuzumab in first-line versus relapsed/refractory settings. The primary endpoint was overall response rate (ORR) to polatuzumab-based treatment in GCB versus non-GCB relapsed/refractory LBCL. Results: Of 740 patients, 305 received polatuzumab in the first-line setting and 435 in the relapsed/refractory setting. In the relapsed/refractory cohort, the ORR in non-GCB versus GCB LBCL was 59.7% versus 36.3% [OR, 2.6; 95% confidence interval (CI), 1.77–3.84; P &lt; 0.0001], with a complete response rate of 35.7% versus 17.7% (OR, 2.6; 95% CI, 1.66–4.02; P &lt; 0.0001). Progression-free survival was longer for patients with non-GCB versus GCB COO (HR, 0.64; 95% CI, 0.5–0.83; P = 0.0006). In the first-line cohort, ORR, complete response rate, and progression-free survival were similar in non-GCB versus GCB LBCL, as hypothesized based on outcomes in the Pola-R-CHP arm of POLARIX, suggesting that the addition of polatuzumab overcomes the adverse risk of non-GCB COO in patients receiving R-CHOP. Conclusions: Based on these data, COO classification by the Hans algorithm is a strong predictor of polatuzumab efficacy in LBCL, informing real-world treatment decisions.

In the phase III placebo-controlled DeFi trial (ClinicalTrials.gov identifier: NCT03785964 ) primary analysis, nirogacestat showed significant improvement versus placebo in progression-free survival (PFS), objective response rate (ORR), and patient-reported outcomes (PRO) in adult patients with progressing desmoid tumors (DT; median [range] exposure: 20.6 [0.3-33.6] months). Here, long-term nirogacestat efficacy and safety were evaluated in patients randomly assigned to nirogacestat and followed through the final data cutoff date of December 19, 2024. End points included PFS and ORR per RECIST v1.1, PRO, and safety. The median (range) duration of exposure was 33.6 (0.3-61.8) months. Median PFS was not reached. The ORR with up to 4 years of nirogacestat treatment was 45.7% (32 of 70), with three additional partial and three additional complete responses since the primary analysis. Further target tumor size reduction occurred in most patients. Benefits in PROs were sustained while on treatment. Frequently reported treatment-emergent adverse events (TEAEs) decreased in incidence and severity over time. Since the primary analysis, four patients discontinued nirogacestat because of TEAEs between years 2 and 4. In conclusion, long-term continuous nirogacestat treatment was associated with further tumor size reductions, durable objective responses, sustained PRO benefits, and a manageable safety profile consistent with the primary analysis.

Abstract This article provides an overview of deep-learning–based techniques in CT image reconstruction and processing (referred to as “DLR”), covering technical implementations, performance evaluation, radiation dose reduction, and future perspectives. DLR methods can be categorized into projection-space, projection-to-image-space, image-space, and various hybrid techniques, with applications such as noise reduction, artefact correction, and spatial resolution enhancement. Performance evaluations include phantom-based studies, patient image-based studies, and virtual imaging trials. These evaluation studies demonstrated that DLR can effectively reduce image noise while preserving an image texture like in traditional filtered-backprojection (FBP) images, although the extent of radiation dose reduction varies widely depending on the study and the specific diagnostic task. Challenges remain in low-contrast lesion detection and characterization, where dose reduction may still be less than 50% compared to traditional reconstruction methods. Additionally, the potential for DLR methods to generate false structures or “hallucinations,” especially at low radiation doses, emphasizes the need for effective monitoring and mitigation strategies from both technical and clinical perspectives. Quantitative, accurate, and efficient evaluation techniques, such as virtual image trial-based methods, can be explored to help optimize these algorithms for reducing radiation dose and enhancing diagnostic performance.

Objectives: To determine the feasibility of reduced-dose chest computed tomographic angiography (CTA) with convolutional neural network (CNN) denoising for detecting pulmonary arteriovenous malformations (pAVMs) in children with hereditary hemorrhagic telangiectasia (cwHHT). Methods: Fifteen cwHHT underwent a chest CTA (ie, a controlled “study” dose). Noise was inserted to simulate a quarter dose (QD) exam. Images were reconstructed using iterative reconstruction (IR) and our self-trained CNN denoising model. For each case, 3 sets of images were created: study dose (SD)+IR, QD+IR, and QD+CNN. Two thoracic radiologists independently scored each set to assess quality, spatial resolution, artifacts, and the presence of pAVMs using 4-level ordinal scales. Quantitative assessments of image quality were performed using contrast-to-noise ratios (CNRs) with comparisons made between the experimental conditions. Results: Thirteen of the 15 patients recruited with hereditary hemorrhagic telangiectasia (mean age: 9.3±4.5 y) were positive for pAVM by transthoracic contrast echocardiography. The sensitivities using QD+CNN were 0.85 and 1.00 for readers 1 and 2, respectively. This was compared with 0.69 and 0.84 using QD+IR versus 0.85 and 0.92 for SD+IR. Inter-reader agreement for pAVM detection utilizing QD+CNN was moderate and resulted in kappa=0.59 ( P =0.012). The subjective assessments for QD+CNN were comparable to the SD technique. Regression analysis of reader scores revealed improved quality in QD+CNN versus QD+IR ( P =0.001). Similarly, the QD+CNN condition demonstrated the highest CNRs. Conclusions: Reduced-dose chest CTA with CNN denoising provides a level of sensitivity comparable to standard dose CTA and high CNRs for the detection of pAVMs in cwHHT.

Background: Thyroid eye disease (TED) is a debilitating autoimmune disorder linked to thyroid dysfunction. There is limited knowledge of TED in Asian populations. This multicenter study characterizes the clinical features and treatment response of TED in a large Chinese cohort. Methods: A retrospective multicenter study included 4157 patients with TED from nine Chinese hospitals from February 2016 to July 2023. Disease severity and activity were evaluated according to the European Group on Graves’ Orbitopathy standards. We examined associations of variables including sex, age, smoking status, I 131 treatment, consultation department, and geographical region with clinical outcomes. Logistic regression and nomogram models were developed to examine associations with sight-threatening TED and, in a subgroup analysis ( n = 126), patients’ responsiveness to intravenous glucocorticoid (IVGC) therapy. Results: We included 4157 patients with mean age and standard deviation (SD) 45.96 ± 16.44 years. Of these, 63.6% ( n = 2644) were females. Over half (55.6%, n = 2310) of participants were in the inactive phase, with a mean clinical activity score of 2.19 ± 1.61 (SD) for all patients. TED severity was categorized as mild (9.3%, n = 385), moderate-to-severe (82.5%, n = 3428), and sight-threatening (8.2%, n = 344). The average degree of exophthalmos was 20.04 ± 5.27 mm, and 48.8% ( n = 2029) of patients had diplopia. Patients treated with I 131 had higher disease activity (47.5%, n = 468, vs. 43.5%, n = 1379, p < 0.05). Coastal region patients exhibited more severe TED (sight-threatening cases: 10.1%, n = 195, vs. 7.2%, n = 147) and higher diplopia scores (1.00 ± 1.10 vs. 0.86 ± 1.09, p < 0.001) than inland counterparts. TED severity was also greater in patients treated in Ophthalmology departments (mild cases: 6.0%, n = 213; moderate-to-severe cases: 85.6%, n = 3055) compared with Endocrinology departments (mild cases: 29.3%, n = 172; moderate-to-severe cases: 63.5%, n = 373). Nomograms had an area under the receiver operating curve of 0.742 (confidence interval [CI] 0.716–0.768) for sight-threatening TED and 0.759 (CI 0.674–0.843) for IVGC therapy responsiveness. Conclusions: We characterized the clinical features and treatment response of TED in a large Chinese cohort. These findings offer valuable insights informing TED risk stratification in Asian patients and forming a foundation for future prospective studies.