Impact of efavirenz on hormone-positive breast cancer survival in women living with HIV.

Women living with HIV and breast cancer have poorer survival than HIV-negative women. Efavirenz-estrogen interactions are documented; however, the survival impact is unknown. Survival between women with estrogen-receptor positive breast cancer taking efavirenz (n = 38) and nonefavirenz regimens (n = 51) were compared. The 5-year overall-survival was 48.9% [95% confidence interval (CI) 33.0-72.2 and 51.1% (95% CI 34.0-76.8)] in the efavirenz and nonefavirenz groups, respectively suggesting efavirenz is unlikely driving poorer survival in women living with HIV and estrogen-receptor positive breast cancer.

Micrometeorite collections: a review and their current status.

Micrometeorites are estimated to represent the main part of the present flux of extraterrestrial matter found on the Earth's surface and provide valuable samples to probe the interplanetary medium. Here, we describe large and representative collections of micrometeorites currently available to the scientific community. These include Antarctic collections from surface ice and snow, as well as glacial sediments from the eroded top of nunataks-summits outcropping from the icesheet-and moraines. Collections extracted from deep-sea sediments (DSS) produced a large number of micrometeorites, in particular, iron-rich cosmic spherules that are rarer in other collections. Collections from the old and stable surface of the Atacama Desert show that finding large numbers of micrometeorites is not restricted to polar regions or DSS. The advent of rooftop collections marks an important step into involving citizen science in the study of micrometeorites, as well as providing potential sampling locations over all latitudes to explore the modern flux. We explore their strengths of the collections to address specific scientific questions and their potential weaknesses. The future of micrometeorite research will involve the finding of large fossil micrometeorite collections and benefit from recent advances in sampling cosmic dust directly from the air. This article is part of the theme issue 'Dust in the Solar System and beyond'.

State of the science and future directions for research on HIV and cancer: Summary of a joint workshop sponsored by IARC and NCI.

An estimated 38 million people live with human immunodeficiency virus (HIV) worldwide and are at excess risk for multiple cancer types. Elevated cancer risks in people living with HIV (PLWH) are driven primarily by increased exposure to carcinogens, most notably oncogenic viruses acquired through shared transmission routes, plus acceleration of viral carcinogenesis by HIV-related immunosuppression. In the era of widespread antiretroviral therapy (ART), life expectancy of PLWH has increased, with cancer now a leading cause of co-morbidity and death. Furthermore, the types of cancers occurring among PLWH are shifting over time and vary in their relative burden in different parts of the world. In this context, the International Agency for Research on Cancer (IARC) and the US National Cancer Institute (NCI) convened a meeting in September 2022 of multinational and multidisciplinary experts to focus on cancer in PLWH. This report summarizes the proceedings, including a review of the state of the science of cancer descriptive epidemiology, etiology, molecular tumor characterization, primary and secondary prevention, treatment disparities and survival in PLWH around the world. A consensus of key research priorities and recommendations in these domains is also presented.

Nonfucosylation of an anti-TIGIT antibody enhances FcγR engagement, driving innate immune activation and antitumor activity.

TIGIT is an immune checkpoint receptor expressed on activated and memory T cells, immunosuppressive T regulatory cells, and natural killer (NK) cells. TIGIT has emerged as an attractive target for antitumor therapies, due to its proposed immunosuppressive effects on lymphocyte function and T cell activation. We generated an anti-TIGIT monoclonal antibody (mAb) that binds with high affinity to human, non-human primate, and murine TIGIT and through multiple experimental methodologies demonstrated that checkpoint blockade alone is insufficient for antitumor activity. Generating anti-TIGIT mAbs with various Fc backbones we show that muting the Fc-Fcγ receptor (FcγR) interaction failed to drive antitumor activity, while mAbs with Fc functional backbones demonstrate substantial antitumor activity, mediated through activation of antigen-presenting cells (APCs), T cell priming, and NK-mediated depletion of suppressive Tregs and exhausted T cells. Further, nonfucosylation of the Fc backbone resulted in enhanced immune responses and antitumor activity relative to the intact IgG1 backbone. The improved activity correlated with the biased FcγR interaction profile of the nonfucosylated anti-TIGIT mAb, which supports that FcγRIIIa binding with decreased FcγRIIb binding favorably activates APCs and enhances tumor-specific CD8+ T cell responses. The anti-TIGIT mAbs with intact FcγR interacting backbones also demonstrated synergistic enhancement of other standard antitumor treatments, including anti-PD-1 treatment and a model monomethyl auristatin E antibody-drug conjugate. These findings highlight the importance of the anti-TIGIT mAb's Fc backbone to its antitumor activity and the extent to which this activity can be enhanced through nonfucosylation of the backbone.

HER2-Selective and Reversible Tyrosine Kinase Inhibitor Tucatinib Potentiates the Activity of T-DM1 in Preclinical Models of HER2-positive Breast Cancer.

The oncogenic receptor HER2 is overexpressed in many cancers, including up to 20% of breast cancers. Despite the availability of HER2-targeted treatments, patients' disease often progresses during therapy, underscoring the need for novel treatment strategies. The addition of tucatinib, a reversible, highly selective HER2 tyrosine kinase inhibitor (TKI), to treatment with trastuzumab and capecitabine significantly improved survival outcomes of patients with HER2-positive metastatic breast cancer, including those with active brain metastases. We rationalized that combining tucatinib with other HER2-targeting agents with complementary mechanisms of action would further increase efficacy against tumors. We characterized the activity of tucatinib with the antibody­drug conjugate T-DM1 in preclinical models of breast cancer, including HER2-positive breast cancer cells and patient-derived xenograft (PDX) models. Mechanistic details on tucatinib activity were obtained in internalization and catabolism studies. In combination, tucatinib and T-DM1 showed an enhanced, often synergistic, cytotoxic response and demonstrated improved antitumor activity in vivo, including in PDX models refractory to T-DM1 single-agent activity. Mechanistically, tucatinib mediated an increase in inactive HER2 molecules at the cell surface through inhibition of HER2 ubiquitination, resulting in increased internalization and catabolism of T-DM1. The combination was correlated with enhanced HER2 pathway inhibition, decreased proliferation, and increased apoptosis. In a xenograft model of brain metastasis, tucatinib penetrated intracranial tumor tissues, inhibiting tumor growth and improving survival. These results suggest that tucatinib may be the optimal TKI partner for HER2-targeted therapies and support clinical studies of its combination with T-DM1, including in patients with brain metastases. SIGNIFICANCE: The preclinical findings in breast cancer models presented here demonstrate that combining tucatinib with T-DM1 enhances the antitumor activity of either agent alone, supporting clinical studies of the combination in HER2-positive breast cancer, including in patients with brain metastases, which remains an important unmet medical need.

Personalized Response of Parkinson's Disease Gut Microbiota to Nootropic Medicinal Herbs In Vitro: A Proof of Concept.

Parkinson's disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic neurons. Although the etiology of PD remains elusive, it has been hypothesized that initial dysregulation may occur in the gastrointestinal tract and may be accompanied by gut barrier defects. A strong clinical interest in developing therapeutics exists, including for the treatment of gut microbiota and physiology. We previously reported the impact of healthy fecal microbiota anaerobic cultures supplemented with nootropic herbs. Here, we evaluated the effect of nootropic Ayurvedic herbs on fecal microbiota derived from subjects with PD in vitro using 16S rRNA sequencing. The microbiota underwent substantial change in response to each treatment, comparable in magnitude to that observed from healthy subjects. However, the fecal samples derived from each participant displayed unique changes, consistent with a personalized response. We used genome-wide metabolic reconstruction to predict the community's metabolic potential to produce products relevant to PD pathology, including SCFAs, vitamins and amino acid degradation products. These results suggest the potential value of conducting in vitro cultivation and analyses of PD stool samples as a means of prescreening patients to select the medicinal herbs for which that individual is most likely to respond and derive benefit.

Alteration of Community Metabolism by Prebiotics and Medicinal Herbs.

Several studies have examined the impact of prebiotics on gut microbiota and associated changes in host physiology. Here, we used the in vitro cultivation of human fecal samples stimulated with a series of chemically related prebiotics and medicinal herbs commonly used in Ayurvedic medicine, followed by 16S rRNA sequencing. We applied a genome-wide metabolic reconstruction of enumerated communities to compare and contrast the structural and functional impact of prebiotics and medicinal herbs. In doings so, we examined the relationships between discrete variations in sugar composition and sugar linkages associated with each prebiotic to drive changes in microbiota composition. The restructuring of microbial communities with glycan substrates alters community metabolism and its potential impact on host physiology. We analyzed sugar fermentation pathways and products predicted to be formed and prebiotic-induced changes in vitamin and amino acid biosynthesis and degradation. These results highlight the utility of combining a genome-wide metabolic reconstruction methodology with 16S rRNA sequence-based community profiles to provide insights pertaining to community metabolism. This process also provides a rational means for prioritizing in vivo analysis of prebiotics and medicinal herbs in vivo to test hypotheses related to therapeutic potential in specific diseases of interest.

Oral Antiviral Therapy Utilization Among Adults with Recent COVID-19 in the United States.

BACKGROUND: This is the first study, to our knowledge, to assess uptake of oral antiviral treatment (OAV) for COVID-19 in the US and assess whether it is reaching recommended groups. OBJECTIVE: The study evaluated uptake among persons of all ages, with emphasis on utilization among individuals ages 65 + who comprise 75% of all COVID-19 deaths. To maximize public health outreach and benefit, we sought to understand reasons for use and non-use of OAV among individuals 65 + with at least mild COVID-19 symptoms. DESIGN: Data were collected from phase 3.5 of the US Census Household Pulse Survey, during three 2022 time periods: June 1-13, June 29-July 11, and July 27-August 8. PARTICIPANTS: Respondents (n = 12,299) were ages 18 + with active or resolved COVID-19 within the last 4 weeks of their survey participation. MAIN MEASURE(S): Comparisons of demographic variables were made for OAV uptake using the chi-square test of independence. A logistic regression was conducted to identify characteristics of participants independently associated with receipt of an OAV. Comparisons were made with chi-square testing, between those ages 65 + with at least mild symptoms who endorsed one of a number of specific reasons for not using OAV. KEY RESULTS: Utilization was low-17.9% of all respondents, 20.5% of respondents ages 50-64, and 33.9% of respondents 65 years and older received guideline-concordant treatment for their infection. Receipt did not differ by income or sex. The average response across the three phases was 5.4%. Most common reasons for not receiving treatment included having minimal symptoms, not thinking that they needed treatment, and not receiving a recommendation from their healthcare provider. CONCLUSIONS: A minority of increased-risk US residents have accessed early therapy for COVID-19 despite being made available without cost. Responses suggest that efforts to improve patient and provider knowledge could improve utilization to mitigate future COVID-19 hospitalizations.

Nirmatrelvir Plus Ritonavir for Early COVID-19 in a Large U.S. Health System : A Population-Based Cohort Study.

BACKGROUND: In the EPIC-HR (Evaluation of Protease Inhibition for Covid-19 in High-Risk Patients) trial, nirmatrelvir plus ritonavir led to an 89% reduction in hospitalization or death among unvaccinated outpatients with early COVID-19. The clinical impact of nirmatrelvir plus ritonavir among vaccinated populations is uncertain. OBJECTIVE: To assess whether nirmatrelvir plus ritonavir reduces risk for hospitalization or death among outpatients with early COVID-19 in the setting of prevalent SARS-CoV-2 immunity and immune-evasive SARS-CoV-2 lineages. DESIGN: Population-based cohort study analyzed to emulate a clinical trial using inverse probability-weighted models to account for anticipated bias in treatment. SETTING: A large health care system providing care for 1.5 million patients in Massachusetts and New Hampshire during the Omicron wave (1 January to 17 July 2022). PATIENTS: 44 551 nonhospitalized adults (90.3% with ≥3 vaccine doses) aged 50 years or older with COVID-19 and no contraindications for nirmatrelvir plus ritonavir. MEASUREMENTS: The primary outcome was a composite of hospitalization within 14 days or death within 28 days of a COVID-19 diagnosis. RESULTS: During the study period, 12 541 (28.1%) patients were prescribed nirmatrelvir plus ritonavir, and 32 010 (71.9%) were not. Patients prescribed nirmatrelvir plus ritonavir were more likely to be older, have more comorbidities, and be vaccinated. The composite outcome of hospitalization or death occurred in 69 (0.55%) patients who were prescribed nirmatrelvir plus ritonavir and 310 (0.97%) who were not (adjusted risk ratio, 0.56 [95% CI, 0.42 to 0.75]). Recipients of nirmatrelvir plus ritonavir had lower risk for hospitalization (adjusted risk ratio, 0.60 [CI, 0.44 to 0.81]) and death (adjusted risk ratio, 0.29 [CI, 0.12 to 0.71]). LIMITATION: Potential residual confounding due to differential access to COVID-19 vaccines, diagnostic tests, and treatment. CONCLUSION: The overall risk for hospitalization or death was already low (1%) after an outpatient diagnosis of COVID-19, but nirmatrelvir plus ritonavir reduced this risk further. PRIMARY FUNDING SOURCE: National Institutes of Health.

The impact of break duration, time of break onset, and prior shift duration on the amount of sleep between shifts in heavy vehicle drivers.

This study aimed to examine the impact of break duration between consecutive shifts, time of break onset, and prior shift duration on total sleep time (TST) between shifts in heavy vehicle drivers (HVDs), and to assess the interaction between break duration and time of break onset. The sleep (actigraphy and sleep diaries) and work shifts (work diaries) of 27 HVDs were monitored during their usual work schedule for up to 9 weeks. Differences in TST between consecutive shifts and days off were assessed. Linear mixed models (followed by pairwise comparisons) assessed whether break duration, prior shift duration, time of break onset, and the interaction between break duration and break onset were related to TST between shifts. Investigators found TST between consecutive shifts (mean [SD] 6.38 [1.38] h) was significantly less than on days off (mean [SD] 7.63 [1.93] h; p < 0.001). Breaks starting between 12:01 and 8:00 a.m. led to shorter sleep (p < 0.05) compared to breaks starting between 4:01 and 8:00 p.m. Break durations up to 7, 9, and 11 h (Australian and European minimum break durations) resulted in a mean (SD) of 4.76 (1.06), 5.66 (0.77), and 6.41 (1.06) h of sleep, respectively. The impact of shift duration prior to the break and the interaction between break duration and time of break were not significant. HVDs' sleep between workdays is influenced independently by break duration and time of break onset. This naturalistic study provides evidence that current break regulations prevent sufficient sleep duration in this industry. Work regulations should evaluate appropriate break durations and break onset times to allow longer sleep opportunities for HVDs.

At-home Testing and Risk Factors for Acquisition of SARS-CoV-2 Infection in a Major US Metropolitan Area.

Background: Unbiased assessment of the risks associated with acquisition of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical to informing mitigation efforts during pandemics. The objective of our study was to understand the risk factors for acquiring coronavirus disease 2019 (COVID-19) in a large prospective cohort of adult residents in a large US metropolitan area. Methods: We designed a fully remote longitudinal cohort study involving monthly at-home SARS-CoV-2 polymerase chain reaction (PCR) and serology self-testing and monthly surveys. Results: Between October 2020 and January 2021, we enrolled 10 289 adults reflective of the Boston metropolitan area census data. At study entry, 567 (5.5%) participants had evidence of current or prior SARS-CoV-2 infection. This increased to 13.4% by June 15, 2021. Compared with Whites, Black non-Hispanic participants had a 2.2-fold greater risk of acquiring COVID-19 (hazard ratio [HR], 2.19; 95% CI, 1.91-2.50; P < .001), and Hispanics had a 1.5-fold greater risk (HR, 1.52; 95% CI, 1.32-1.71; P < .016). Individuals aged 18-29, those who worked outside the home, and those living with other adults and children were at an increased risk. Individuals in the second and third lowest disadvantaged neighborhood communities were associated with an increased risk of acquiring COVID-19. Individuals with medical risk factors for severe disease were at a decreased risk of SARS-CoV-2 acquisition. Conclusions: These results demonstrate that race/ethnicity and socioeconomic status are the biggest determinants of acquisition of infection. This disparity is significantly underestimated if based on PCR data alone, as noted by the discrepancy in serology vs PCR detection for non-White participants, and points to persistent disparity in access to testing. Medical conditions and advanced age, which increase the risk for severity of SARS-CoV-2 disease, were associated with a lower risk of COVID-19 acquisition, suggesting the importance of behavior modifications. These findings highlight the need for mitigation programs that overcome challenges of structural racism in current and future pandemics.

Bebtelovimab for High-Risk Outpatients With Early COVID-19 in a Large US Health System.

There are limited data for the clinical efficacy of bebtelovimab in preventing severe coronavirus disease 2019. Among outpatients unable to take nirmatrelvir-ritonavir at a large health system, 10 of 377 (2.7%) patients who received bebtelovimab and 17 of 377 (4.5%) matched untreated patients were hospitalized or died. The 43% observed risk reduction with bebtelovimab was not statistically significant (P = 0.14).

Concreteness and levels of processing: a test of the dual-coding hypothesis using dynamic visual noise.

Concreteness and levels of processing (LOP) effects have been attributed to the differential availability of visual images for concrete words, and at deeper levels of processing, respectively. Interestingly, the concreteness effect has been shown to disappear under conditions involving dynamic visual noise (DVN), which is thought to suppress the generation of visual images from long-term memory. The present study further investigated the role of visual imagery in concreteness and LOP effects. Across four experiments, DVN was manipulated during study, and participants' memory for concrete and abstract words was measured using recall and recognition tests. Although some support for dual-coding was found, concreteness and LOP effects were not fully explained by visual imagery because they were present under DVN conditions. We conclude that concreteness and LOP effects may be better explained by an "extended dual-coding theory" that incorporates the role of context availability in accounting for this pattern of results.

Service learning and self-efficacy in exercise science: outcomes of a community fitness training program involving undergraduate Exercise Science students.

There is increasing awareness of the importance of civic engagement in higher education. Service-learning activities in undergraduate programs, in particular, have been linked to positive academic outcomes and gains in various forms of self-efficacy. Exercise Science students at our university complete two service-learning courses as part of the curriculum, each of which involves implementing a structured 12-week individualized fitness training program with a community member client. The aim of this study was to investigate the effect of these service-learning experiences on Exercise Science students' self-efficacy for fitness assessment and exercise prescription. Students completed a seven-item self-efficacy questionnaire administered at both the beginning and end of each service-learning course and reflected on their experience using an end-of-course survey. Our results showed significant improvements in self-efficacy from pretest to posttest for each of the two service-learning experiences, with the second experience producing additional gains in self-efficacy over and above the first. Students also reported improved confidence in their fitness assessment and exercise prescription skills in the end-of-course survey. Community members involved in the fitness training program reported a positive experience with students' knowledge of fitness assessment and exercise prescription as well as their own progression to independence in a home exercise program. Our findings highlight the benefits of including a structured service-learning experience in the Exercise Science curriculum.NEW & NOTEWORTHY This study was done to investigate the effect of a structured fitness training experience on Exercise Science students' self-efficacy for fitness assessment and exercise prescription. Our results indicate a significant improvement in self-efficacy from pretest to posttest. Students also reported improved confidence in their fitness assessment and exercise prescription skills. Community members reported a positive experience with students' knowledge of fitness assessment and exercise prescription and their progression to independence in a home exercise program.

Feasibility and lessons learned on remote trial implementation from TestBoston, a fully remote, longitudinal, large-scale COVID-19 surveillance study.

Longitudinal clinical studies traditionally require in-person study visits which are well documented to pose barriers to participation and contribute challenges to enrolling representative samples. Remote trial models may reduce barriers to research engagement, improve retention, and reach a more representative cohort. As remote trials become more common following the COVID-19 pandemic, a critical evaluation of this approach is imperative to optimize this paradigm shift in research. The TestBoston study was launched to understand prevalence and risk factors for COVID-19 infection in the greater Boston area through a fully remote home-testing model. Participants (adults, within 45 miles of Boston, MA) were recruited remotely from patient registries at Brigham and Women's Hospital and the general public. Participants were provided with monthly and "on-demand" at-home SARS-CoV-2 RT-PCR and antibody testing using nasal swab and dried blood spot self-collection kits and electronic surveys to assess symptoms and risk factors for COVID-19 via an online dashboard. Between October 2020 and January 2021, we enrolled 10,289 participants reflective of Massachusetts census data. Mean age was 47 years (range 18-93), 5855 (56.9%) were assigned female sex at birth, 7181(69.8%) reported being White non-Hispanic, 952 (9.3%) Hispanic/Latinx, 925 (9.0%) Black, 889 (8.6%) Asian, and 342 (3.3%) other and/or more than one race. Lower initial enrollment among Black and Hispanic/Latinx individuals required an adaptive approach to recruitment, leveraging connections to the medical system, coupled with community partnerships to ensure a representative cohort. Longitudinal retention was higher among participants who were White non-Hispanic, older, working remotely, and with lower socioeconomic vulnerability. Implementation highlighted key differences in remote trial models as participants independently navigate study milestones, requiring a dedicated participant support team and robust technology platforms, to reduce barriers to enrollment, promote retention, and ensure scientific rigor and data quality. Remote clinical trial models offer tremendous potential to engage representative cohorts, scale biomedical research, and promote accessibility by reducing barriers common in traditional trial design. Barriers and burdens within remote trials may be experienced disproportionately across demographic groups. To maximize engagement and retention, researchers should prioritize intensive participant support, investment in technologic infrastructure and an adaptive approach to maximize engagement and retention.

Nirmatrelvir plus ritonavir for early COVID-19 and hospitalization in a large US health system.

Background: In the EPIC-HR trial, nirmatrelvir plus ritonavir led to an 88% reduction in hospitalization or death among unvaccinated outpatients with early COVID-19. Clinical impact of nirmatrelvir plus ritonavir among vaccinated populations is uncertain. Objective: To assess whether nirmatrelvir plus ritonavir reduces risk of hospitalization among outpatients with early COVID-19 in the setting of prevalent SARS-CoV-2 immunity and immune evasive SARS-CoV-2 lineages. Design: Population-based cohort study analyzed to emulate a clinical trial utilizing two-stage, inverse-probability weighted models to account for anticipated bias in testing and treatment. Setting: A large healthcare system providing care for 1.5 million patients in Massachusetts and New Hampshire during Omicron wave (January 1 to May 15, 2022) with staged access and capacity to prescribe nirmatrelvir plus ritonavir. Patients: 30,322 non-hospitalized adults (87.2% vaccinated) aged 50 and older with COVID-19 and without contraindications to nirmatrelvir plus ritonavir. Measurement: Primary outcome was hospitalization within 14 days of COVID-19 diagnosis. Results: During the study period, 6036 (19.9%) patients were prescribed nirmatrelvir plus ritonavir and 24,286 (80.1%) patients were not. Patients prescribed nirmatrelvir were more likely to be older, have more comorbidities, and be unvaccinated. Hospitalization occurred in 40 (0.66%) and 232 (0.96%) patients prescribed and not prescribed nirmatrelvir plus ritonavir, respectively. The adjusted risk ratio was 0.55 (95% confidence interval 0.38 to 0.80, p = 0.002). Observed risk reduction was greater among unvaccinated patients and obese patients. Limitations: Potential for residual confounding due to differential access and uptake of COVID-19 vaccines, diagnostics, and treatment. Conclusions: The overall risk of hospitalization was already low (<1%) following an outpatient diagnosis of COVID-19, but this risk was 45% lower among patients prescribed nirmatrelvir plus ritonavir. Funding: National Institutes of Health (P30 AI060354 and R01 CA236546).

Mechanistic Modeling of Central Nervous System Pharmacokinetics and Target Engagement of HER2 Tyrosine Kinase Inhibitors to Inform Treatment of Breast Cancer Brain Metastases.

PURPOSE: This study evaluated the central nervous system (CNS) pharmacokinetics and target engagement of lapatinib, neratinib, and tucatinib in patients with cancer, using a physiologically based pharmacokinetic (PBPK) modeling approach. EXPERIMENTAL DESIGN: Drug-specific parameters for in vitro metabolism, binding to plasma proteins and brain tissues, transcellular passive permeability, and interactions with efflux transporters were determined. Whole-body PBPK models integrated with a 4-compartment permeability-limited brain model was developed and verified for predicting plasma and CNS pharmacokinetics. Target engagement ratio (TER), defined as the ratio of the average steady-state unbound drug brain concentration (Css,ave,br) to in vitro IC50 for HER2 inhibition, was used as a predictor of intracranial efficacy. RESULTS: PBPK models predicted that following 1 cycle of standard dosing, tucatinib and lapatinib achieved similar Css,ave,br (14.5 vs. 16.8 nmol/L), while neratinib Css,ave,br (0.68 nmol/L) was 20-fold lower. Tucatinib and neratinib were equally potent for HER2 inhibition (IC50, 6.9 vs. 5.6 nmol/L), while lapatinib was less potent (IC50, 109 nmol/L). The model-predicted population mean TER in the human normal brain was 2.1 for tucatinib, but < 0.20 for lapatinib and neratinib. CONCLUSIONS: The PBPK modeling suggests that tucatinib induces sufficient HER2 inhibition (TER > 2.0) in not only brain metastases with a disrupted blood-brain barrier (BBB), but also micrometastases where the BBB largely remains intact. These findings, in line with available clinical pharmacokinetics and efficacy data, support the therapeutic value of tucatinib for treatment of brain metastases and warrant further clinical investigation for the prevention of brain metastases in patients with HER2-positive breast cancer.

Improving identification of symptomatic cancer at primary care clinics: A predictive modeling analysis in Botswana.

In resource-limited settings, augmenting primary care provider (PCP)-based referrals with data-derived algorithms could direct scarce resources towards those patients most likely to have a cancer diagnosis and benefit from early treatment. Using data from Botswana, we compared accuracy of predictions of probable cancer using different approaches for identifying symptomatic cancer at primary clinics. We followed cancer suspects until they entered specialized care for cancer treatment (following pathologically confirmed diagnosis), exited from the study following noncancer diagnosis, or died. Routine symptom and demographic data included baseline cancer probability assessed by the primary care provider (low, intermediate, high), age, sex, performance status, baseline cancer probability by study physician, predominant symptom (lump, bleeding, pain or other) and HIV status. Logistic regression with 10-fold cross-validation was used to evaluate classification by different sets of predictors: (1) PCPs, (2) Algorithm-only, (3) External specialist physician review and (4) Primary clinician augmented by algorithm. Classification accuracy was assessed using c-statistics, sensitivity and specificity. Six hundred and twenty-three adult cancer suspects with complete data were retained, of whom 166 (27%) were diagnosed with cancer. Models using PCP augmented by algorithm (c-statistic: 77.2%, 95% CI: 73.4%, 81.0%) and external study physician assessment (77.6%, 95% CI: 73.6%, 81.7%) performed better than algorithm-only (74.9%, 95% CI: 71.0%, 78.9%) and PCP initial assessment (62.8%, 95% CI: 57.9%, 67.7%) in correctly classifying suspected cancer patients. Sensitivity and specificity statistics from models combining PCP classifications and routine data were comparable to physicians, suggesting that incorporating data-driven algorithms into referral systems could improve efficiency.

Btla signaling in conventional and regulatory lymphocytes coordinately tempers humoral immunity in the intestinal mucosa.

The Btla inhibitory receptor limits innate and adaptive immune responses, both preventing the development of autoimmune disease and restraining anti-viral and anti-tumor responses. It remains unclear how the functions of Btla in diverse lymphocytes contribute to immunoregulation. Here, we show that Btla inhibits activation of genes regulating metabolism and cytokine signaling, including Il6 and Hif1a, indicating a regulatory role in humoral immunity. Within mucosal Peyer's patches, we find T-cell-expressed Btla-regulated Tfh cells, while Btla in T or B cells regulates GC B cell numbers. Treg-expressed Btla is required for cell-intrinsic Treg homeostasis that subsequently controls GC B cells. Loss of Btla in lymphocytes results in increased IgA bound to intestinal bacteria, correlating with altered microbial homeostasis and elevations in commensal and pathogenic bacteria. Together our studies provide important insights into how Btla functions as a checkpoint in diverse conventional and regulatory lymphocyte subsets to influence systemic immune responses.

Short-Chain Fatty Acids Modulate Healthy Gut Microbiota Composition and Functional Potential.

Many studies have focused on the metabolic capacity of human gut microbiota to produce short-chain fatty acids and subsequent effects on host physiology. Given scarce data on how SCFAs produced by gut bacteria participate in cross-feeding to influence community structure and function, we evaluated the potential of SCFAs to modulate human gut microbiota in vitro. We employed anaerobic fecal cultivation in chemically defined medium supplemented with one of nine SCFAs to determine effects on both gut microbial community structure via 16S rRNA sequencing and function via genome reconstruction analysis. Each SCFA displayed significant and unique modulatory potential with respect to the relative abundance of bacterial taxa. Analysis of SCFA-supplemented communities revealed that alterations of individual closely related phylotypes displayed coherent changes, although exceptions were also observed which suggest strain-dependent differences in SCFA-induced changes. We used genome reconstruction to evaluate the functional implications of SCFA-mediated restructuring of fecal communities. We note that some SCFA-supplemented cultures displayed a reduction in the predicted abundance of SCFA producers, which suggests a possible undefined negative feedback mechanism. We conclude that SCFAs are not simply end-products of metabolism but also serve to modulate the gut microbiota through cross-feeding that alters the fitness of specified taxa. These results are important in the identification of prebiotics that elevate specific SCFAs for therapeutic benefit and highlight SCFA consumers as a salient part of the overall metabolic flux pertaining to bacterial fermentative processes.