Development of an advanced separation and characterization platform for mRNA and lipid nanoparticles using multi-detector asymmetrical flow field-flow fractionation.

In recent years, the use of lipid nanoparticles (LNPs) for delivery of messenger RNA (mRNA)-based therapies has gained substantial attention in the field of drug development. In such an application, multiple LNP attributes have to be carefully characterized to ensure product safety and quality, whereas accurate and efficient characterization of these complex mRNA-LNP formulations remains a challenging endeavor. Here, we present the development and application of an online separation and characterization platform designed for the isolation and in-depth analysis of mRNAs and mRNA-loaded LNPs. Our asymmetrical flow field-flow fractionation with a multi-detector (MD-AF4) method has demonstrated exceptional resolution between mRNA-LNPs and mRNAs, delivering excellent recoveries (over 70%) for both analytes and exceptional repeatability. Notably, this platform allows for comprehensive and multi-attribute LNP characterization, including online particle sizing, morphology characterization, and determination of encapsulation efficiency, all within a single injection. Furthermore, real-time online sizing by synchronizing multi-angle light scattering (MALS) and dynamic light scattering (DLS) presented higher resolution over traditional batch-mode DLS, particularly in differentiating heterogeneous samples with a low abundance of large-sized particles. Additionally, our method proves to be a valuable tool for monitoring LNP stability under varying stress conditions. Our work introduces a robust and versatile analytical platform using MD-AF4 that not only efficiently provides multi-attribute characterizations of mRNA-LNPs but also holds promise in advancing studies related to formulation screening, quality control, and stability assessment in the evolving field of nanoparticle delivery systems for mRNAs.

Trends in the Incidence of Gestational Diabetes Mellitus Among the Medicaid Population Before and During the COVID-19 Pandemic.

Importance: Although there are many regional and national studies on the trends in the incidence of gestational diabetes mellitus (GDM), the trends in the incidence of GDM among the Medicaid population are lacking, especially before and during coronavirus disease of 2019 (COVID-19). Objective: To investigate the trends in the incidence of GDM before and during COVID-19 pandemic (2016-2021) among the Louisiana Medicaid population. Design, Setting, and Participants: This study included 111,936, Louisiana Medicaid pregnant women of age 18-50 between January 1, 2016, to December 31, 2021. Main Outcomes and Measures: Pregnancies, GDM, and pre-pregnancy diabetes cases were identified by using the Tenth Revisions of the International Classification of Disease code. The annual incidence of GDM and annual prevalence of pre-pregnancy diabetes were calculated for each age and race subgroup. Results: The age-standardized incidence of GDM increased from 10.2% in 2016 to 14.8 in 2020 and decreased to 14.0% in 2021. The age-standardized prevalence of pre-pregnancy diabetes increased from 2.8% in 2016 to 3.4% in 2018 and decreased to 2.3% in 2021. The age-standardized rate of GDM was the highest among Asian women (23.0%), then White women (15.5%), and African American women (13.9%) (p for difference <0.001). The COVID-19 pandemic saw an increase in the incidence of GDM, with a rise in prominent GDM risk factors, such as obesity and sedentary behaviors, suggesting an association. Conclusion and Relevance: The incidence of GDM significantly increased during the COVID-19 pandemic. Potential reasons might include increased sedentary behavior and increased prevalence of obesity. GDM is a major public health issue, and the prevention of GDM is particularly essential for the Louisiana Medicaid population owing to the high prevalence of GDM-related risk factors in this population.

Treatment adherence and nasogastric tube use in hospitalized youth with anorexia nervosa and premorbid overweight/obesity.

Youth with restrictive-eating disorders (EDs) often experience significant distress and difficulty with treatment adherence during nutritional rehabilitation. This study assessed whether youth with restrictive EDs and premorbid overweight/obesity admitted for inpatient nutritional rehabilitation experience greater psychological distress and difficulty with treatment adherence than youth with premorbid BMI <85th percentile. A retrospective chart review examined 150 youth hospitalized for medical complications of restrictive EDs. Rates of nasogastric tube (NGT; used when youth could not complete meals), agitation medication use, and disposition recommendation were compared across premorbid BMI groups. Patients with premorbid overweight/obesity were three times more likely to require NGT feeds. These findings suggest greater challenges with nutritional rehabilitation, specifically consuming nutrition orally, in patients with premorbid overweight/obesity, highlighting the need for early and individualized psychological support for this vulnerable patient population.

Unlocking the Next Frontier in Precision Oncology: Addressing Drug-Tolerant Residual Disease.

SUMMARY: Drug-tolerant residual disease (DTRD) after the initial maximal response to a systemic therapy can serve as a tumor reservoir for the development of acquired drug resistance and represents a major clinical challenge across various cancers and types of therapies. To unlock the next frontier in precision oncology, we propose a fundamental paradigm shift in the treatment of metastatic cancers with a sharpened focus towards defining, monitoring, and therapeutically targeting the DTRD state.

Strong isolation by distance and evidence of population microstructure reflect ongoing Plasmodium falciparum transmission in Zanzibar.

Background: The Zanzibar archipelago of Tanzania has become a low-transmission area for Plasmodium falciparum. Despite being considered an area of pre-elimination for years, achieving elimination has been difficult, likely due to a combination of imported infections from mainland Tanzania and continued local transmission. Methods: To shed light on these sources of transmission, we applied highly multiplexed genotyping utilizing molecular inversion probes to characterize the genetic relatedness of 282 P. falciparum isolates collected across Zanzibar and in Bagamoyo district on the coastal mainland from 2016 to 2018. Results: Overall, parasite populations on the coastal mainland and Zanzibar archipelago remain highly related. However, parasite isolates from Zanzibar exhibit population microstructure due to the rapid decay of parasite relatedness over very short distances. This, along with highly related pairs within shehias, suggests ongoing low-level local transmission. We also identified highly related parasites across shehias that reflect human mobility on the main island of Unguja and identified a cluster of highly related parasites, suggestive of an outbreak, in the Micheweni district on Pemba island. Parasites in asymptomatic infections demonstrated higher complexity of infection than those in symptomatic infections, but have similar core genomes. Conclusions: Our data support importation as a main source of genetic diversity and contribution to the parasite population in Zanzibar, but they also show local outbreak clusters where targeted interventions are essential to block local transmission. These results highlight the need for preventive measures against imported malaria and enhanced control measures in areas that remain receptive to malaria reemergence due to susceptible hosts and competent vectors. Funding: This research was funded by the National Institutes of Health, grants R01AI121558, R01AI137395, R01AI155730, F30AI143172, and K24AI134990. Funding was also contributed from the Swedish Research Council, Erling-Persson Family Foundation, and the Yang Fund. RV acknowledges funding from the MRC Centre for Global Infectious Disease Analysis (reference MR/R015600/1), jointly funded by the UK Medical Research Council (MRC) and the UK Foreign, Commonwealth & Development Office (FCDO), under the MRC/FCDO Concordat agreement and is also part of the EDCTP2 program supported by the European Union. RV also acknowledges funding by Community Jameel.

Accelerated protein retention expansion microscopy using microwave radiation.

Protein retention expansion microscopy (ExM) retains genetically encoded fluorescent proteins or antibody-conjugated fluorescent probes in fixed tissue and isotropically expands the tissue through a swellable polymer network to allow nanoscale (<70 nm) resolution on diffraction-limited confocal microscopes. Despite numerous advantages ExM brings to biological studies, the full protocol is time-consuming and can take multiple days to complete. Here, we adapted the ExM protocol to the vibratome-sectioned brain tissue of Xenopus laevis tadpoles and implemented a microwave-assisted protocol to reduce the workflow from days to hours. In addition to the significantly accelerated processing time, our microwave-assisted ExM (M/WExM) protocol maintains the superior resolution and signal-to-noise ratio of the original ExM protocol. Furthermore, the M/WExM protocol yields higher magnitude of expansion, suggesting that in addition to accelerating the process through increased diffusion rate of reagents, microwave radiation may also facilitate the expansion process. To demonstrate the applicability of this method to other specimens and protocols, we adapted the microwave-accelerated protocol to whole mount adult brain tissue of Drosophila melanogaster fruit flies, and successfully reduced the total processing time of a widely-used Drosophila IHC-ExM protocol from 6 days to 2 days. Our results demonstrate that with appropriate adjustment of the microwave parameters (wattage, pulse duration, interval, and number of cycles), this protocol can be readily adapted to different model organisms and tissue types to greatly increase the efficiency of ExM experiments.

Micro-heterogeneity of transmission shapes submicroscopic malaria carriage in coastal Tanzania.

BACKGROUND: Asymptomatic carriage of malaria parasites persists even as malaria transmission declines. Low density infections are often submicroscopic, not detected by rapid diagnostic tests (RDTs) or microscopy, but detectable by PCR. METHODS: To characterize submicroscopic Plasmodium falciparum carriage in an area of declining malaria transmission, asymptomatic persons >5 years of age in rural Bagamoyo District, Tanzania, were screened using RDT, microscopy, and PCR. We investigated the size of the submicroscopic reservoir of infection across villages, determined factors associated with submicroscopic carriage, and assessed the natural history of submicroscopic malaria over four weeks. RESULTS: Among 6,076 participants, P. falciparum prevalence by RDT, microscopy, and PCR was 9%, 9%, and 28%, respectively, with roughly two-thirds of PCR-positive individuals harboring submicroscopic infection. Adult status, female gender, dry season months, screened windows, and bednet use were associated with submicroscopic carriage. Among 15 villages encompassing 80% of participants, the proportion of submicroscopic carriers increased with decreasing village-level malaria prevalence. Over four weeks, 23% (61/266) of submicroscopic carriers became RDT-positive, with half exhibiting symptoms, while half (133/266) were no longer parasitemic at the end of four weeks. Progression to RDT-positive patent malaria occurred more frequently in villages with higher malaria prevalence. CONCLUSIONS: Micro-heterogeneity in transmission observed at the village level appears to impact both the size of the submicroscopic reservoir and the likelihood of submicroscopic carriers developing patent malaria in coastal Tanzania.

Synthesis and evaluation of a novel vancomycin-infused, biomimetic bone graft using a rat model of spinal implant-associated infection.

Background: Postoperative infection is a complication of spinal fusion surgery resulting in increased patient morbidity. Strategies including intraoperative application of powdered vancomycin have been proposed to reduce the incidence of infection; however, such antimicrobial effects are short-lived. Methods: Instrumentation of the L4-L5 vertebrae was performed mimicking pedicle screw and rod fixation in 30 rats. Titanium instrumentation inoculated with either PBS or 1×105 CFU bioluminescent MRSA, along with biomimetic bone grafts infused with varying concentrations of vancomycin and 125 µg of rhBMP-2 (BioMim-rhBMP-2-VCM) were implanted prior to closure. Infection was quantified during the six-week postoperative period using bioluminescent imaging. Arthrodesis was evaluated using micro-CT. Results: Infected animals receiving a bone graft infused with low-dose (0.18 mg/g) or high-dose vancomycin (0.89 mg/g) both exhibited significantly lower bioluminescent signal over the six-week postoperative period than control animals inoculated with MRSA and implanted with bone grafts lacking vancomycin (p=.019 and p=.007, respectively). Both low and high-dose vancomycin-infused grafts also resulted in a statistically significant reduction in average bioluminescence when compared to control animals (p=.027 and p=.047, respectively), independent of time. MicroCT analysis of animals from each group revealed pseudoarthrosis only in the control group, suggesting a correlation between infection and pseudoarthrosis. MRSA-inoculated control animals also had significantly less bone volume formation on micro-CT than the PBS-inoculated control cohort (p<.001), the MRSA+low-dose vancomycin-infused bone graft cohort (p<.001), and the MRSA+high-dose vancomycin-infused bone graft cohort (p<.001). Conclusion: BioMim-rhBMP-2-VCM presents a novel tissue engineering approach to simultaneously promoting arthrodesis and antimicrobial prophylaxis in spinal fusion. Despite mixed evidence of potential osteotoxicity of vancomycin reported in literature, BioMim-rhBMP-2-VCM preserved arthrodesis and osteogenesis with increasing vancomycin loading doses due to the graft's osteoinductive composition.

Practical guidelines for eating disorder risk mitigation in patients undergoing obesity treatment for the pediatric provider.

PURPOSE OF REVIEW: Pediatric obesity is a growing concern globally. Patients with a history of overweight/obesity often experience stigmatization, especially in the healthcare setting, and are at increased risk of developing psychological comorbidities including eating disorders. This review appraises the most recent studies evaluating eating disorder risk in youth undergoing treatment for obesity, identifies gaps in the literature, and offers practical guidelines to pediatric providers regarding the management of this population. RECENT FINDINGS: Recent studies suggest that structured weight management programs may decrease the risk of and/or improve symptoms of certain eating disorders such as binge eating disorder and bulimia nervosa. There is a paucity of research on some components of obesity management such as obesity pharmacotherapeutics and eating disorder risk. SUMMARY: Children and adolescents with obesity are a psychologically vulnerable population with increased risk for the development of eating disorders. Further study is needed to evaluate general risk in the setting of specialized and primary care obesity interventions and develop appropriate screening and mitigation tools. Some evidence-based strategies can aid pediatric providers in both weight management and eating disorder prevention and risk assessment.

Detection of P. malariae using a new rapid isothermal amplification lateral flow assay.

BACKGROUND: While Plasmodium falciparum and Plasmodium vivax cause the majority of malaria cases and deaths, infection by Plasmodium malariae and other Plasmodium species also causes morbidity and mortality. Current understanding of these infections is limited in part by existing point-of-care diagnostics that fail to differentiate them and have poor sensitivity for low-density infections. Accurate diagnosis currently requires molecular assays performed in well-resourced laboratories. This report describes the development of a P. malariae diagnostic assay that uses rapid, isothermal recombinase polymerase amplification (RPA) and lateral-flow-strip detection. METHODS: Multiple combinations of custom RPA primers and probes were designed using publicly available P. malariae genomic sequences, and by modifying published primer sets. Based on manufacturer RPA reaction conditions (TwistDx nfo kit), an isothermal assay was optimized targeting the multicopy P. malariae 18S rRNA gene with 39 °C incubation and 30-min run time. RPA product was visualized using lateral strips (FAM-labeled, biotinylated amplicon detected by a sandwich immunoassay, visualized using gold nanoparticles). Analytical sensitivity was evaluated using 18S rRNA plasmid DNA, and clinical sensitivity determined using qPCR-confirmed samples collected from Tanzania, Ethiopia, and the Democratic Republic of the Congo. RESULTS: Using 18S rRNA plasmid DNA, the assay demonstrates a detection limit of 10 copies/µL (~ 1.7 genome equivalents) and 100% analytical specificity. Testing in field samples showed 95% clinical sensitivity and 88% specificity compared to qPCR. Total assay time was less than 40 min. CONCLUSION: Combined with simplified DNA extraction methods, the assay has potential for future field-deployable, point-of-care use to detect P. malariae infection, which remains largely undiagnosed but a neglected cause of chronic malaria. The assay provides a rapid, simple readout on a lateral flow strip without the need for expensive laboratory equipment.

Comparison of RT-PCR and antigen test sensitivity across nasopharyngeal, nares, and oropharyngeal swab, and saliva sample types during the SARS-CoV-2 omicron variant.

Limited data highlight the need to understand differences in SARS-CoV-2 omicron (B.1.1.529) variant viral load between the gold standard nasopharyngeal (NP) swab, mid-turbinate (MT)/anterior nasal swabs, oropharyngeal (OP) swabs, and saliva. MT, OP, and saliva samples from symptomatic individuals in Atlanta, GA, in January 2022 and longitudinal samples from a small familial cohort were tested by both RT-PCR and ultrasensitive antigen assays. Higher concentrations in the nares were observed in the familial cohort, but a dominant sample type was not found among 39 cases in the cross-sectional cohort. The composite of positive MT or OP assay for both RT-PCR and antigen assay trended toward higher diagnostic yield but did not achieve significant difference. Our data did not identify a singular preferred sample type for SARS-CoV-2 testing, but higher levels of saliva nucleocapsid, a trend toward higher yield of composite OP/MT result, and association of apparent MT or OP predominance with symptoms warrant further study.

Associations between presenting weight and premorbid weight and the medical sequelae in hospitalized youth with anorexia nervosa or atypical anorexia nervosa.

PURPOSE: To identify unique treatment considerations for youth with anorexia nervosa (AN) or atypical anorexia nervosa (AAN) and premorbid overweight or obesity, we examined unique relationships between premorbid and presenting weight status and medical sequelae in youth with AN/AAN requiring medical hospitalization. DESIGN AND METHODS: We performed a retrospective study of 150 youth aged mean [SD] of 14.1[2.3] years, hospitalized for AN/AAN. Independent t-tests and Fischer's exact tests assessed differences in demographic and clinical characteristics by premorbid weight status. Logistic regressions assessed associations between premorbid and presenting weight status and vital sign or laboratory abnormalities. RESULTS: Compared to youth with premorbid 'normal' weights, youth with premorbid overweight/obesity demonstrated greater percent (p = .042) and faster rate (p < .001) of weight loss and had 10.9 times the odds of having anemia (p = .025). Youth with AN (<5th percentile for body mass index [BMI]) were more likely to experience hypoglycemia (p < .018) than youth with AAN (≥5th percentile BMI). Greater percent of weight loss significantly predicted bradycardia (p < .001) and hypoglycemia (p = .002), independent of premorbid or presenting weight status. CONCLUSION: Acute medical management of AN/AAN should be commensurate for hospitalized patients, regardless of premorbid weight status. However, those with more significant weight loss and those presenting as underweight may warrant particular monitoring for complications such as bradycardia and hypoglycemia. PRACTICE IMPLICATIONS: In youth with AN/AAN, high percent of weight loss warrants closer monitoring for medical complications during hospitalization. Those with premorbid overweight/obesity may need additional monitoring for anemia, as there may be additional contributors to anemia aside from malnutrition.

Evaluation of Malaria Rapid Diagnostic Test Performance and pfhrp2 Deletion in Tanzania School Surveys, 2017.

As part of malaria nationwide monitoring and evaluation initiatives, there is an increasing trend of incorporating malaria rapid diagnostic tests (mRDTs) in surveys conducted within primary schools to detect malaria parasites. However, mRDTs based on the detection of histidine-rich protein 2 (HRP2) are known to yield false-positive results due to persistent antigenemia, and false-negative results may result from low parasitemia or Plasmodium falciparum hrp2/3 gene deletion. We evaluated diagnostic performance of an HRP2 and pan-parasite lactate dehydrogenase (HRP2/pLDH) mRDT against polymerase chain reaction (PCR) for detection of P. falciparum among 17,051 primary school-age children from eight regions of Tanzania in 2017. According to PCR, the prevalence of P. falciparum was 19.2% (95% CI: 18.6-19.8). Using PCR as reference, the sensitivity and specificity of mRDT was 76.2% (95% CI: 74.7-77.7) and 93.9% (95% CI: 93.5-94.3), respectively. Test agreement was lowest in low transmission areas, where true-positive mRDTs were outnumbered by false-negatives due to low parasitemia. Discordant samples (mRDT-negative but PCR-positive) were screened for pfhrp2/3 deletion by real-time PCR. Among those with a parasite density sufficient for analysis, pfhrp2 deletion was confirmed in 60 samples, whereas pfhrp3 deletion was confirmed in two samples; one sample had both pfhrp2 and pfhrp3 deletions. The majority of samples with gene deletions were detected in the high-transmission Kagera region. Compared with mRDTs, PCR and other molecular methods offer increased sensitivity and are not affected by pfhrp2/3 deletions, making them a useful supplement to mRDTs in schools and other epidemiological surveys.

Differentiating anorexia nervosa and atypical anorexia nervosa with absolute weight cut-offs results in a skewed distribution for premorbid weight among youth.

OBJECTIVE: Anorexia nervosa (AN) and atypical AN are conceptualized as distinct illnesses, despite similar characteristics and sequelae. Whereas DSM-5 differentiates youth with AN and atypical AN by the presence of clinical 'underweight' (i.e., 5th BMI percentile for age-and-sex (BMI%)), we hypothesized that using this weight cut-off to discern diagnoses creates a skewed distribution for premorbid weight. METHOD: Participants included hospitalized youth with AN (n = 165, 43.1%) and atypical AN (n = 218, 56.9%). Frequency analyses and chi-square tests assessed the distribution of premorbid BMI z-scores (BMIz) for diagnosis. Non-parametric Spearman correlations and Stepwise Linear regressions examined relationships between premorbid BMIz, admission BMIz, and weight loss in kg. RESULTS: Premorbid BMIz distributions differed significantly for diagnosis (p < .001), with an underrepresentation of 'overweight/obesity' (i.e., BMI% ≥ 85th) in AN. Despite commensurate weight loss in AN and atypical AN, patients with premorbid 'overweight/obesity' were 8.31 times more likely to have atypical AN than patients with premorbid BMI% < 85th. Premorbid BMIz explained 57% and 39% of the variance in admission BMIz and weight loss, respectively. DISCUSSION: Findings support a homogenous model of AN and atypical AN, with weight loss predicted by premorbid BMI in both illnesses. Accordingly, premorbid BMI and weight loss (versus presenting BMI) may better denote the presence of an AN-like phenotype across the weight spectrum. Findings also suggest that differentiating diagnoses with BMI% < 5th requires that youth with higher BMIs lose disproportionately more weight for an AN diagnosis. This is problematic given unique treatment barriers experienced in atypical AN. PUBLIC SIGNIFICANCE: Anorexia nervosa (AN) and atypical AN are considered distinct conditions in youth, with differential diagnosis hinging upon a presenting weight status of 'underweight' (i.e., BMI percentile for age-and-sex (BMI%) < 5th). In our study, youth with premorbid 'overweight/obesity' (BMI% ≥ 85th) disproportionately remained above this threshold, despite similar weight loss. Coupled with prior evidence for commensurate characteristics and sequelae in both diagnoses, we propose that DSM-5 differentiation of AN and atypical AN inadvertently reinforces weight stigma and may contribute to treatment disparities in atypical AN.

Efficacy and Safety of Dose-Escalated Alectinib in Patients With Metastatic ALK-Positive NSCLC and Central Nervous System Relapse on Standard-Dose Alectinib.

Introduction: Central nervous system (CNS) metastases remain a common challenge in patients with ALK-positive NSCLC. We previously reported reinduction of CNS responses using dose-intensified alectinib in two patients with CNS progression on standard-dose alectinib. Nevertheless, this strategy has not been assessed in larger cohorts. Methods: Patients were eligible for this retrospective study if they had metastatic ALK-positive NSCLC with CNS relapse on alectinib 600 mg twice daily dosing and subsequently received escalated dosing (900 mg twice daily) of alectinib. CNS efficacy was assessed per the modified Response Evaluation Criteria in Solid Tumors version 1.1. Results: Among 27 patients, median duration of dose-escalated alectinib was 7.7 months (95% confidence interval [CI]: 4.8-10.9), with median overall time-to-progression (TTP) of 7.1 months (95% CI: 4.4-9.6). Among 25 CNS response-assessable patients, CNS objective response rate was 12.0% (95% CI: 2.5-31.2) and CNS disease control rate was 92.0% (95% CI: 74.0-99.0), with median CNS duration of disease control of 5.3 months (95% CI: 3.4-8.3) and median CNS TTP of 7.1 months (95% CI: 4.4-9.6). Among four patients with measurable CNS disease at baseline, three experienced a best intracranial response of stable disease and one experienced intracranial partial response with CNS TTP ranging from 4.1 to 7.7 months. No patient required drug discontinuation due to treatment-related adverse event or experienced grade 3 or higher treatment-related adverse events. Conclusions: Dose-intensified alectinib was found to have tolerability and activity in patients with ALK-positive NSCLC who experienced CNS relapse on standard-dose alectinib and represents one clinically viable strategy for this population.

Discovery of TRPA1 Antagonist GDC-6599: Derisking Preclinical Toxicity and Aldehyde Oxidase Metabolism with a Potential First-in-Class Therapy for Respiratory Disease.

Transient receptor potential ankyrin 1 (TRPA1) is a nonselective calcium ion channel highly expressed in the primary sensory neurons, functioning as a polymodal sensor for exogenous and endogenous stimuli, and has been implicated in neuropathic pain and respiratory disease. Herein, we describe the optimization of potent, selective, and orally bioavailable TRPA1 small molecule antagonists with strong in vivo target engagement in rodent models. Several lead molecules in preclinical single- and short-term repeat-dose toxicity studies exhibited profound prolongation of coagulation parameters. Based on a thorough investigative toxicology and clinical pathology analysis, anticoagulation effects in vivo are hypothesized to be manifested by a metabolite─generated by aldehyde oxidase (AO)─possessing a similar pharmacophore to known anticoagulants (i.e., coumarins, indandiones). Further optimization to block AO-mediated metabolism yielded compounds that ameliorated coagulation effects in vivo, resulting in the discovery and advancement of clinical candidate GDC-6599, currently in Phase II clinical trials for respiratory indications.

Knowledge of Pre- and Postexposure Prophylaxis for HIV Prevention Among Internal Medicine Residents in the United States.

Prescription rates of pre-exposure prophylaxis (PrEP) have remained low among noninfectious disease providers in the United States despite almost a decade since their introduction. For future primary care doctors, residency is the optimal time to build practice patterns around HIV prevention. We assessed baseline knowledge of PrEP in specific pre- and post-exposure prophylaxis content areas among internal medicine trainees who completed the Physician Education and Assessment Center HIV learning module between 2013 to 2020 (N = 12,060). Resident baseline PrEP knowledge was universally low; despite rising awareness of antiretroviral therapy for PrEP in successive years following the nadir of 41% in 2014, still only 56% of residents affirmed this means of HIV prevention by 2020. Knowledge remained limited regardless of academic year, local HIV prevalence, or training program type. Online module completion increased competence across all content areas. There is still a deficit in HIV prevention knowledge across U.S. internal medicine residents, suggesting insufficient education and exposure to HIV-related care.