Informational Postcards Increase Engagement with Remote Monitoring Among Veterans with Pacemakers and Implantable Cardioverter-Defibrillators: a Stepped-Wedge Randomized Controlled Trial.

BACKGROUND: Remote monitoring (RM) of pacemakers and implantable cardioverter-defibrillators (ICDs) reduces morbidity and mortality. However, many patients are not adherent to RM. OBJECTIVE: To test the effect of informational postcards on RM adherence. DESIGN/PATIENTS: Stepped-wedge randomized controlled trial among Veterans with pacemakers and ICDs. INTERVENTION: In wave 1, Veterans who had sent at least 1 transmission within the past 2 years but had become non-adherent were randomly assigned to receive a postcard or no postcard. Those receiving postcards were randomized to 1 of 2 messages: (1) a"warning" postcard describing risks of non-adherence or (2) an "encouraging" postcard describing benefits of adherence. In wave 2, Veterans who had either not received a postcard in wave 1 or had since become non-adherent were mailed a postcard (again, randomized to 1 of 2 messages). Patients who did not send an RM transmission within 1 month were mailed a second, identical postcard. MAIN MEASURES: Transmission within 70 days. KEY RESULTS: Overall, 6351 Veterans were included. In waves 1 and 2, postcards were mailed to 5657 Veterans (2821 "warning" messages and 2836 "encouraging" messages). Wave 1 included 2178 Veterans as controls (i.e., not mailed a postcard), some of whom received a postcard in wave 2 if they remained non-adherent. In wave 2, 3473 postcards were sent. Of the 5657 patients mailed a postcard, 2756 (48.7%) sent an RM transmission within 70 days, compared to 530 (24.3%) of 2178 controls (absolute difference 24.4%, 95% confidence interval [CI] 22.2%, 26.6%). Of those who sent a transmission, 71.8% did so after the first postcard. Transmission rates at 70 days did not significantly differ between "warning" and "encouraging" messages (odds ratio 1.04, 95% CI 0.92, 1.18). CONCLUSIONS: Informational postcards led to a 24.4% absolute increase in adherence at 70 days among Veterans with pacemakers and ICDs who were non-adherent to RM.

XTX301, a Tumor-Activated Interleukin-12 Has the Potential to Widen the Therapeutic Index of IL12 Treatment for Solid Tumors as Evidenced by Preclinical Studies.

IL12 is a proinflammatory cytokine, that has shown promising antitumor activity in humans by promoting the recruitment and activation of immune cells in tumors. However, the systemic administration of IL12 has been accompanied by considerable toxicity, prompting interest in researching alternatives to drive preferential IL12 bioactivity in the tumor. Here, we have generated XTX301, a tumor-activated IL12 linked to the human Fc protein via a protease cleavable linker that is pharmacologically inactivated by an IL12 receptor subunit beta 2 masking domain. In vitro characterization demonstrates multiple matrix metalloproteases, as well as human primary tumors cultured as cell suspensions, can effectively activate XTX301. Intravenous administration of a mouse surrogate mXTX301 demonstrated significant tumor growth inhibition (TGI) in inflamed and non-inflamed mouse models without causing systemic toxicities. The superiority of mXTX301 in mediating TGI compared with non-activatable control molecules and the greater percentage of active mXTX301 in tumors versus other organs further confirms activation by the tumor microenvironment-associated proteases in vivo. Pharmacodynamic characterization shows tumor selective increases in inflammation and upregulation of immune-related genes involved in IFNγ cell signaling, antigen processing, presentation, and adaptive immune response. XTX301 was tolerated following four repeat doses up to 2.0 mg/kg in a nonhuman primate study; XTX301 exposures were substantially higher than those at the minimally efficacious dose in mice. Thus, XTX301 has the potential to achieve potent antitumor activity while widening the therapeutic index of IL12 treatment and is currently being evaluated in a phase I clinical trial.

Implementing Heart Plus: Design and Early Results of a Novel Comanagement Clinic for Patients With Stimulant-associated Cardiomyopathy.

We describe the methodology, design, and early results of a novel multidisciplinary co management clinic model with Addiction Medicine and Cardiology providers using contingency management to engage patients with stimulant-associated cardiomyopathy (SA-CMP). Stimulant use, including methamphetamine and cocaine, is increasing in prevalence nationally and is associated with cardiovascular complications. People with SA-CMP have higher rates of mortality and acute care use (eg, emergency department visits, hospital admissions) and lower rates of outpatient care engagement than individuals with non-SA-CMP. This population also has disproportionately elevated rates of mental health and other medical comorbidities, challenges with social determinants of health, including housing and food insecurity, and representation from communities of color. This multidisciplinary comanagement care delivery model, called Heart Plus, was developed and funded as a quality improvement project. It led to a 5-fold increase in outpatient care engagement with a concomitant 53% decrease in acute care use. All participants reported a decrease in stimulant use. With increased clinical stability, patients were able to better engage with outpatient resources for social determinants of health, such as case management, social work, and housing and food service programs. Patients were also empowered to take control over their health while knowing that health care providers cared about their well-being.

Genome-wide CRISPR-Cas9 screen analyzed by SLIDER identifies network of repressor complexes that regulate TRIM24.

TRIM24 is an oncogenic chromatin reader that is frequently overexpressed in human tumors and associated with poor prognosis. However, TRIM24 is rarely mutated, duplicated, or rearranged in cancer. This raises questions about how TRIM24 is regulated and what changes in its regulation are responsible for its overexpression. Here, we perform a genome-wide CRISPR-Cas9 screen by fluorescence-activated cell sorting (FACS) that nominated 220 negative regulators and elucidated a regulatory network that includes the KAP1 corepressor, CNOT deadenylase, and GID/CTLH E3 ligase. Knocking out required components of these three complexes caused TRIM24 overexpression, confirming their negative regulation of TRIM24. Our findings identify regulators of TRIM24 that nominate previously unexplored contexts for this oncoprotein in biology and disease. These findings were enabled by SLIDER, a new scoring system designed and vetted in our study as a broadly applicable tool for analysis of CRISPR screens performed by FACS.

Cardiovascular health among persons with HIV without existing atherosclerotic cardiovascular disease.

OBJECTIVES: We sought to characterize atherosclerotic cardiovascular disease (ASCVD) risk and metrics of cardiovascular health in persons with HIV (PWH) eligible for primary prevention of ASCVD. DESIGN: A cross-sectional study of PWH 40 years and older without documented ASCVD who received care at three HIV clinics in San Francisco from 2019 to 2022. METHODS: We used ICD-10 codes and electronic health record data to assess ASCVD risk and cardiovascular health, as defined by the American Heart Association's Life's Essential 8 (LE8) metrics for nicotine exposure, BMI, lipids, glucose, and blood pressure (BP). RESULTS: Among 2567 PWH eligible for primary prevention of ASCVD, the median age was 55 years, 14% were women, and 95% were on antiretroviral therapy. Seventy-seven percent had undergone complete assessment of ASCVD risk factors, and 50% of these patients had intermediate-high ASCVD risk (≥7.5%). Of those with hypertension, 39% were prescribed an antihypertensive. Among those eligible, 43% were prescribed a statin. The mean LE8 cardiovascular health score [0--100 (best health)] was 55.1 for nicotine exposure, 71.3 for BMI, 70.4 for lipids, 81.2 for blood glucose, 56.0 for BP, with an average score of 66.2 across the five metrics. Patients with Medicare insurance, black patients, and those with sleep apnea and chronic kidney disease had on average lower cardiovascular health scores; patients with undetectable viral loads had higher cardiovascular health scores. CONCLUSION: We highlight opportunities for improving primary prevention of ASCVD among PWH, especially in the areas of guideline-based therapy, nicotine exposure, and BP control.

Impact of Enhanced Recovery After Surgery pathway for cesarean delivery on postoperative pain.

BACKGROUND: Enhanced Recovery After Surgery pathways provide evidence-based recommendations to optimize perioperative care. OBJECTIVE: This study aimed to holistically investigate the effect of implementing an Enhanced Recovery After Surgery pathway for all cesarean deliveries on postoperative pain experience. STUDY DESIGN: This was a prepost study comparing subjective and objective measures of postoperative pain before and after the implementation of an Enhanced Recovery After Surgery pathway for cesarean delivery. The Enhanced Recovery After Surgery pathway was developed by a multidisciplinary team and included preoperative, intraoperative, and postoperative components, with emphasis on preoperative preparation, hemodynamic optimization, early mobilization, and multimodal analgesia. All individuals undergoing cesarean delivery, whether scheduled, urgent, or emergent, were included. Demographic, delivery, and inpatient pain management data were obtained through medical record review. Of note, 2 weeks after discharge, patients were surveyed about their delivery experience, analgesic usage, and complications. The primary outcome was inpatient opioid use. RESULTS: The study included 128 individuals, 56 in the preimplementation cohort and 72 in the Enhanced Recovery After Surgery cohort. Baseline characteristics between the 2 groups were similar. The survey response rate was 73% (94/128). Opioid use in the first 48 hours postoperatively was significantly lower in the Enhanced Recovery After Surgery group than the preimplementation group (9.4 vs 21.4 morphine milligram equivalents 0-24 hours after delivery [P<.001]; 14.1 vs 25.4 morphine milligram equivalents 24-48 hours after delivery [P<.001]) with no increase in either average or maximum postoperative pain scores. Individuals in the Enhanced Recovery After Surgery group used fewer opioid pills after discharge (10 vs 20; P<.001). Patient satisfaction and complication rates did not change after the implementation of an Enhanced Recovery After Surgery pathway. CONCLUSION: The implementation of an Enhanced Recovery After Surgery pathway for all cesarean deliveries decreased both inpatient and outpatient postpartum opioid use without increasing pain scores or decreasing patient satisfaction.

Cholestatic Pruritus Treatments in Primary Biliary Cholangitis and Primary Sclerosing Cholangitis: A Systematic Literature Review.

BACKGROUND AND AIMS: We conducted a systematic literature review to understand the evidence supporting treatment decisions for cholestatic pruritus associated with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC). METHODS: Studies that enrolled ≥ 75% participants with PBC or PSC and reported ≥ 1 endpoint(s) related to efficacy, safety, health-related quality of life (HRQoL) or other patient-reported outcomes were included. Bias was assessed using the Cochrane risk of bias tool for randomised controlled trials (RCTs) and the Quality of Cohort studies tool for non-RCTs. RESULTS: Thirty-nine publications were identified, covering 42 studies and six treatment classes (including investigational and approved products): anion-exchange resins, antibiotics (rifampicin/derivatives), opiates, selective serotonin reuptake inhibitors, fibrates, ileal bile acid transporter inhibitors and other agents not categorised in these six classes. Across studies, median sample size was small (n = 18), 20 studies were over 20 years old, 25 followed patients for ≤ 6 weeks, only 25 were RCTs. Pruritus was assessed using several different tools, with inconsistencies in their application. Cholestyramine, considered first-line therapy for moderate-severe cholestatic pruritus, was assessed in six studies (two RCTs) including 56 patients with PBC and 2 with PSC, with evidence of efficacy demonstrated in only three studies, among which, two RCTs were assessed as having a high risk of bias. Findings were similar for other drug classes. CONCLUSIONS: There is a lack of consistent and reproducible evidence available on efficacy, impact on HRQoL, and safety of cholestatic pruritus treatments, leaving physicians to rely on clinical experience rather than evidence-based medicine for treatment selection.

Japanese subgroup analysis of GLIMMER: A global Phase IIb study of linerixibat for the treatment of cholestatic pruritus in patients with primary biliary cholangitis.

AIM: To compare patient characteristics and outcomes between the overall and Japanese populations of GLIMMER. METHODS: GLIMMER was a multicenter, double-blind, randomized, placebo-controlled, Phase IIb study evaluating linerixibat for the treatment of pruritus in patients with primary biliary cholangitis. RESULTS: In total, 147 patients were randomized in the GLIMMER overall population with 38 patients comprising the Japanese population. Demographics and baseline clinical characteristics were similar across treatment groups and between both populations. A reduction in mean worst daily itch score from baseline to week 16 (primary endpoint) was seen in all groups, with the largest reduction observed with linerixibat 40 mg twice daily (BID; -2.92 [95% confidence interval: -5.07, -0.76] and -2.86 [95% confidence interval: -3.76, -1.95] for Japanese and overall populations, respectively). The highest proportion of responders was generally in the 40 mg BID group in both populations regardless of the responder definition applied. Improvements in health-related quality of life were generally consistent in both populations. In the Japanese and overall populations, on-treatment drug-related adverse events were reported in 25% and 19% of patients in the placebo group and 0%-86% and 31%-78% of patients in the linerixibat groups, respectively. Consistent with the mechanism of action, the most common events were gastrointestinal in nature. The effects of linerixibat on pharmacodynamic biomarkers favored BID dosing. CONCLUSIONS: Therapeutic responses and safety of linerixibat were consistent between the Japanese and overall populations of GLIMMER. Linerixibat may provide an effective treatment option for cholestatic pruritus in patients with primary biliary cholangitis. CLINICAL TRIAL REGISTRATION: NCT02966834.

GLIMMER: A Randomized Phase 2b Dose-Ranging Trial of Linerixibat in Primary Biliary Cholangitis Patients With Pruritus.

BACKGROUND & AIMS: GLIMMER assessed dose-response, efficacy, and safety of linerixibat, an ileal bile acid transporter inhibitor in development for cholestatic pruritus associated with primary biliary cholangitis (PBC). METHODS: GLIMMER was a Phase 2b, multicenter, randomized, parallel-group study in adults with PBC and moderate-to-severe pruritus (≥4 on 0-10 numerical rating scale [NRS]). After 4 weeks of single-blind placebo, patients with NRS ≥3 were randomized (3:1) to double-blind linerixibat/placebo for 12 weeks (to week 16), followed by single-blind placebo (to week 20). The primary objective was to investigate dose-related changes in mean worst daily itch (MWDI) score. RESULTS: One hundred forty-seven patients received placebo (n = 36) or linerixibat (once daily: 20 mg, n = 16; 90 mg, n = 23; 180 mg, n = 27; twice daily: 40 mg, n = 23; 90 mg, n = 22). Linerixibat groups exhibited ≥2-point mean reductions in MWDI from baseline at week 16; however, differences from placebo were not significant. Post hoc analysis of change from baseline in monthly itch score over the treatment period (Phase 3 endpoint) showed significant differences between placebo and linerixibat 180 mg once daily (P = .0424), 40 mg twice daily (P = .0105), and 90 mg twice daily (P = .0370). A significant relationship between total daily dose and response was observed post hoc in the per protocol population (P = .0542). Consistent with mechanism of action, diarrhea was the most frequent adverse event, and incidence increased with dose. CONCLUSIONS: Linerixibat effect on itch was not significantly different versus placebo in the primary intent-to-treat analysis but was associated with a significant dose-dependent reduction in itch in the per protocol population. A well-tolerated dose was identified for Phase 3 investigation for cholestatic pruritus in PBC. CLINICALTRIALS: gov ID: NCT02966834.

Impact of Pruritus on Quality of Life and Current Treatment Patterns in Patients with Primary Biliary Cholangitis.

BACKGROUND AND AIMS: Patients with primary biliary cholangitis (PBC) often suffer with pruritus. We describe the impact of pruritus on quality of life and how it is managed in a real-world cohort. METHODS: TARGET-PBC is a longitudinal observational cohort of patients with PBC across the USA. Data include information from medical records for three years prior to the date of consent up to 5 years of follow-up. Enrolled patients were asked to complete patient-reported outcome surveys: PBC-40, 5-D itch, and the PROMIS fatigue survey. Kruskal-Wallis tests were used to compare differences in symptoms between groups. RESULTS: A total of 211 patients with completed PRO surveys were included in the current study. PRO respondents were compared with non-respondents in the TARGET-PBC population and were broadly similar. Pruritus was reported in 170 patients (81%), with those reporting clinically significant pruritus (30%) scoring worse across each domain of the PBC-40 and 5-D itch, more frequently having cirrhosis, and having significantly greater levels of fatigue. Patients reporting clinically significant pruritus were more likely to receive treatment, but 33% had never received treatment (no itch = 43.9%, mild itch = 38.3%). CONCLUSIONS: The prevalence of pruritus was high in this population, and those reporting clinically significant pruritus had a higher likelihood of having advanced disease and worse quality of life. However, this study found that pruritus in PBC is under-treated. This may be due in part to ineffectiveness of current treatments, poor tolerance, or the lack of FDA-approved medications for pruritus.

Development of text messages for primary prevention of cardiovascular disease in persons with HIV.

Objective: Persons with HIV (PWH) have increased risk for atherosclerotic cardiovascular disease (CVD). Despite this increased risk, perceived cardiovascular risk among PWH is low, and interventions that are known to be beneficial in the general population, such as statins, have low uptake in this population. We sought to develop a bank of text messages about (1) the association between HIV and CVD and (2) advice on reducing cardiovascular risk. Methods: We developed an initial bank of 162 messages. We solicited feedback from 29 PWH recruited from outpatient clinics providing HIV care at a large urban tertiary medical center and a public hospital in San Francisco, California. Participants reviewed 7-10 messages each and rated message usefulness, readability, and potential impact on behavior on a scale from 1 (least) to 5 (most). We also collected open-ended feedback on the messages and data on preferences about message timing. Results: The average score for the messages was 4.4/5 for usefulness, 4.4/5 for readability, and 4.0/5 for potential impact on behavior. The text messages were iteratively revised based on participant feedback, and lowest-rated messages were removed from the message bank. The final message bank included 116 messages on diet (30.2%), physical activity (24.8%), tobacco (11.2%), the association between HIV and cardiovascular disease (9.5%), general heart health (6.9%), cholesterol (5.2%), blood pressure (4.3%), blood sugar (2.6%), sleep (2.6%), and weight (2.6%). Conclusion: We describe an approach for developing educational text messages on primary prevention of cardiovascular disease among PWH.

XTX101, a tumor-activated, Fc-enhanced anti-CTLA-4 monoclonal antibody, demonstrates tumor-growth inhibition and tumor-selective pharmacodynamics in mouse models of cancer.

INTRODUCTION: The clinical benefit of the anti-CTLA-4 monoclonal antibody (mAb) ipilimumab has been well established but limited by immune-related adverse events, especially when ipilimumab is used in combination with anti-PD-(L)1 mAb therapy. To overcome these limitations, we have developed XTX101, a tumor-activated, Fc-enhanced anti-CTLA-4 mAb. METHODS: XTX101 consists of an anti-human CTLA-4 mAb covalently linked to masking peptides that block the complementarity-determining regions, thereby minimizing the mAb binding to CTLA-4. The masking peptides are designed to be released by proteases that are typically dysregulated within the tumor microenvironment (TME), resulting in activation of XTX101 intratumorally. Mutations within the Fc region of XTX101 were included to enhance affinity for FcγRIII, which is expected to enhance potency through antibody-dependent cellular cytotoxicity. RESULTS: Biophysical, biochemical, and cell-based assays demonstrate that the function of XTX101 depends on proteolytic activation. In human CTLA-4 transgenic mice, XTX101 monotherapy demonstrated significant tumor growth inhibition (TGI) including complete responses, increased intratumoral CD8+T cells, and regulatory T cell depletion within the TME while maintaining minimal pharmacodynamic effects in the periphery. XTX101 in combination with anti-PD-1 mAb treatment resulted in significant TGI and was well tolerated in mice. XTX101 was activated in primary human tumors across a range of tumor types including melanoma, renal cell carcinoma, colon cancer and lung cancer in an ex vivo assay system. CONCLUSIONS: These data demonstrate that XTX101 retains the full potency of an Fc-enhanced CTLA-4 antagonist within the TME while minimizing the activity in non-tumor tissue, supporting the further evaluation of XTX101 in clinical studies.

Overcoming Barriers to Successful Climate and Health Adaptation Practice: Notes from the Field.

State and local public health agencies are at the forefront of planning and responding to the health challenges of climate hazards but face substantial barriers to effective climate and health adaptation amidst concurrent environmental and public health crises. To ensure successful adaptation, it is necessary to understand and overcome these barriers. The U.S. Centers for Disease Control and Prevention Climate-Ready States and Cities Initiative (CRSCI) provides funding to state and local health departments to anticipate and respond to health impacts from climate change using the Building Resilience Against Climate Effects (BRACE) framework. This paper explores the barriers to and enablers of successful adaptation projects among BRACE West CRSCI grantees, including Arizona, California, Oregon, and the city and county of San Francisco. The barriers included competing demands such as the COVID-19 pandemic, dependence on partners with similar challenges, staff and leadership turnover, uncertain and complex impacts on at-risk populations, and inadequate resources. The enablers included effective partnerships, leadership support, dedicated and skilled internal staff, and policy windows enabling institutional change and reprioritization. These findings highlight effective strategies in the field that state and local health departments may use to anticipate potential barriers and establish their work in an environment conducive to successful adaptation.

Injection and Sexual Behavior Profiles among People Who Inject Drugs in Miami, Florida.

BACKGROUND: The dynamics of injection drug use and higher-risk sexual practices compound the risk of HIV and HCV acquisition. Published literature on people who inject drugs (PWID) has examined risk of infection assuming homogeneity of cohort behavior. Categorizing subgroups by injection and sexual risk can inform a more equitable approach to how syringe services programs (SSPs) adapt harm reduction resources and implementation of evidence-based interventions. We explored injection and sexual risk profiles among PWID to determine significant predictors of class membership. METHODS: Data were collected from 1,272 participants at an SSP in Miami-Dade County. Latent Class Analysis (LCA) examined how 10 injection/sexual behavior indicators cluster together to create profiles. Model fit statistics and multivariable multinomial latent class regression identified the optimal class structure and significant predictors of class membership. We assessed SSP visits, naloxone access, HIV/HCV testing and prevalence, and incidence of self-reported wounds. RESULTS: Three distinct profiles of injection/sexual risk were determined: Low Injection/High Sexual (LIHS) (9.4%); High Injection/Moderate Sexual (HIMS) (18.9%); and Low Injection/Low Sexual (LILS) (71.7%). Participants reporting gay/bisexual orientation and methamphetamine injection more likely belonged to the LIHS class. LIHS class members had higher prevalence of HIV, while those of HIMS reported increased hepatitis C prevalence. Compared to members of LILS, those of HIMS more likely experienced unstable housing, gay/bisexual orientation, heroin or speedball injection, and identifying as women. HIMS cohort members had more SSP visits, naloxone accessed, and higher wound incidence than those of LILS. CONCLUSIONS: Understanding PWID subgroups amplifies the importance of implementing evidencebased interventions such as PrEP for those engaging in highest risk behavior, with focused interventions of antiretroviral management and access to condoms for members of the LIHS class and HCV screening with wound care for those belonging to HIMS.

Discovery of putative tumor suppressors from CRISPR screens reveals rewired lipid metabolism in acute myeloid leukemia cells.

CRISPR knockout fitness screens in cancer cell lines reveal many genes whose loss of function causes cell death or loss of fitness or, more rarely, the opposite phenotype of faster proliferation. Here we demonstrate a systematic approach to identify these proliferation suppressors, which are highly enriched for tumor suppressor genes, and define a network of 145 such genes in 22 modules. One module contains several elements of the glycerolipid biosynthesis pathway and operates exclusively in a subset of acute myeloid leukemia cell lines. The proliferation suppressor activity of genes involved in the synthesis of saturated fatty acids, coupled with a more severe loss of fitness phenotype for genes in the desaturation pathway, suggests that these cells operate at the limit of their carrying capacity for saturated fatty acids, which we confirm biochemically. Overexpression of this module is associated with a survival advantage in juvenile leukemias, suggesting a clinically relevant subtype.

Pharmacokinetics and ADME Characterization of Intravenous and Oral [14C]-Linerixibat in Healthy Male Volunteers.

Linerixibat, an oral small-molecule ileal bile acid transporter inhibitor under development for cholestatic pruritus in primary biliary cholangitis, was designed for minimal absorption from the intestine (site of pharmacological action). This study characterized the pharmacokinetics, absorption, metabolism, and excretion of [14C]-linerixibat in humans after an intravenous microtracer concomitant with unlabeled oral tablets and [14C]-linerixibat oral solution. Linerixibat exhibited absorption-limited flip-flop kinetics: longer oral versus intravenous half-life (6-7 hours vs. 0.8 hours). The short intravenous half-life was consistent with high systemic clearance (61.9 l/h) and low volume of distribution (16.3 l). In vitro studies predicted rapid hepatic clearance via cytochrome P450 3A4 metabolism, which predicted human hepatic clearance within 1.5-fold. However, linerixibat was minimally metabolized in humans after intravenous administration: ∼80% elimination via biliary/fecal excretion (>90%-97% as unchanged parent) and ∼20% renal elimination by glomerular filtration (>97% as unchanged parent). Absolute oral bioavailability of linerixibat was exceedingly low (0.05%), primarily because of a very low fraction absorbed (0.167%; fraction escaping first-pass gut metabolism (fg) ∼100%), with high hepatic extraction ratio (77.0%) acting as a secondary barrier to systemic exposure. Oral linerixibat was almost entirely excreted (>99% recovered radioactivity) in feces as unchanged and unabsorbed linerixibat. Consistent with the low oral fraction absorbed and ∼20% renal recovery of intravenous [14C]-linerixibat, urinary elimination of orally administered radioactivity was negligible (<0.04% of dose). Linerixibat unequivocally exhibited minimal gastrointestinal absorption and oral systemic exposure. Linerixibat represents a unique example of high CYP3A4 clearance in vitro but nearly complete excretion as unchanged parent drug via the biliary/fecal route. SIGNIFICANCE STATEMENT: This study conclusively established minimal absorption and systemic exposure to orally administered linerixibat in humans. The small amount of linerixibat absorbed was eliminated efficiently as unchanged parent drug via the biliary/fecal route. The hepatic clearance mechanism was mispredicted to be mediated via cytochrome P450 3A4 metabolism in vitro rather than biliary excretion of unchanged linerixibat in vivo.

Comprehensive Assessment of the Relationship Between Site-2 Specificity and Helix α2 in the Erbin PDZ Domain.

PDZ domains are key players in signalling pathways. These modular domains generally recognize short linear C-terminal stretches of sequences in proteins that organize the formation of complex multi-component assemblies. The development of new methodologies for the characterization of the molecular principles governing these interactions is critical to fully understand the functional diversity of the family and to elucidate biological functions for family members. Here, we applied an in vitro evolution strategy to explore comprehensively the capacity of PDZ domains for specific recognition of different amino acids at a key position in C-terminal peptide ligands. We constructed a phage-displayed library of the Erbin PDZ domain by randomizing the binding site-2 and adjacent residues, which are all contained in helix α2, and we selected for variants binding to a panel of peptides representing all possible position-2 residues. This approach generated insights into the basis for the common natural class I and II specificities, demonstrated an alternative basis for a rare natural class III specificity for Asp-2, and revealed a novel specificity for Arg-2 that has not been reported in natural PDZ domains. A structure of a PDZ-peptide complex explained the minimum requirement for switching specificity from class I ligands containing Thr/Ser-2 to class II ligands containing hydrophobic residues at position-2. A second structure explained the molecular basis for the specificity for ligands containing Arg-2. Overall, the evolved PDZ variants greatly expand our understanding of site-2 specificities and the variants themselves may prove useful as building blocks for synthetic biology.

Development and Validation of Manually Modified and Supervised Machine Learning Clinical Assessment Algorithms for Malaria in Nigerian Children.

It is currently estimated that 67% of malaria deaths occur in children under-five years (WHO, 2020). To improve the identification of children at clinical risk for malaria, the WHO developed community (iCCM) and clinic-based (IMCI) protocols for frontline health workers using paper-based forms or digital mobile health (mHealth) platforms. To investigate improving the accuracy of these point-of-care clinical risk assessment protocols for malaria in febrile children, we embedded a malaria rapid diagnostic test (mRDT) workflow into THINKMD's (IMCI) mHealth clinical risk assessment platform. This allowed us to perform a comparative analysis of THINKMD-generated malaria risk assessments with mRDT truth data to guide modification of THINKMD algorithms, as well as develop new supervised machine learning (ML) malaria risk algorithms. We utilized paired clinical data and malaria risk assessments acquired from over 555 children presenting to five health clinics in Kano, Nigeria to train ML algorithms to identify malaria cases using symptom and location data, as well as confirmatory mRDT results. Supervised ML random forest algorithms were generated using 80% of our field-based data as the ML training set and 20% to test our new ML logic. New ML-based malaria algorithms showed an increased sensitivity and specificity of 60 and 79%, and PPV and NPV of 76 and 65%, respectively over THINKD initial IMCI-based algorithms. These results demonstrate that combining mRDT "truth" data with digital mHealth platform clinical assessments and clinical data can improve identification of children with malaria/non-malaria attributable febrile illnesses.

DNA polymerase ι compensates for Fanconi anemia pathway deficiency by countering DNA replication stress.

Fanconi anemia (FA) is caused by defects in cellular responses to DNA crosslinking damage and replication stress. Given the constant occurrence of endogenous DNA damage and replication fork stress, it is unclear why complete deletion of FA genes does not have a major impact on cell proliferation and germ-line FA patients are able to progress through development well into their adulthood. To identify potential cellular mechanisms that compensate for the FA deficiency, we performed dropout screens in FA mutant cells with a whole genome guide RNA library. This uncovered a comprehensive genome-wide profile of FA pathway synthetic lethality, including POLI and CDK4 As little is known of the cellular function of DNA polymerase iota (Pol ι), we focused on its role in the loss-of-function FA knockout mutants. Loss of both FA pathway function and Pol ι leads to synthetic defects in cell proliferation and cell survival, and an increase in DNA damage accumulation. Furthermore, FA-deficient cells depend on the function of Pol ι to resume replication upon replication fork stalling. Our results reveal a critical role for Pol ι in DNA repair and replication fork restart and suggest Pol ι as a target for therapeutic intervention in malignancies carrying an FA gene mutation.