New Drug Formulary Management and Utilization: Evidence in Sex, Race, and Ethnicity: 2019-2020.

BACKGROUND: It is well established that females and persons of racial and ethnic minorities are frequently underrepresented in clinical trials. These disparities are potentially important aspects of evidence-based formulary management and drug utilization review (DUR) processes. OBJECTIVE: The purpose of this study was to review the demographic composition of pivotal trials and post-approval study requirements for recent FDA-approved drugs, analyzing the representation of minority groups and its generalizability to the US population or corresponding disease state. METHODS: Drugs approved between July 2019 and June 2020 were identified and demographic data including race, ethnicity, and sex was extracted from their pivotal trials. Demographic data was compared to US demographics and/or the disease state demographics for the respective approved drug. RESULTS: There were a total of 85 drugs and 142 pivotal trials included in the study. Compared to the estimated US population, the minority groups with a statistically significant underrepresentation across all pivotal trials included Black or African Americans and American Indian or Alaska Natives. The Hispanic/Latinx population had a statistically significant underrepresentation in 55.4% of trials. Females had a statistically significant underrepresentation in 21.2% of trials when compared to the disease state demographics of the respective approved drug. CONCLUSION AND RELEVANCE: Persons of minorities are underrepresented in the generation of evidence of safety and efficacy for many new drugs. Formulary management and DUR offer an integrated strategic opportunity for the clinical community to formally and carefully consider the data on sex, race, and ethnicity to address disparities in health care.

The Adam family metalloprotease Kuzbanian regulates the cleavage of the roundabout receptor to control axon repulsion at the midline.

Slits and their Roundabout (Robo) receptors mediate repulsive axon guidance at the Drosophila ventral midline and in the vertebrate spinal cord. Slit is cleaved to produce fragments with distinct signaling properties. In a screen for genes involved in Slit-Robo repulsion, we have identified the Adam family metalloprotease Kuzbanian (Kuz). Kuz does not regulate midline repulsion through cleavage of Slit, nor is Slit cleavage essential for repulsion. Instead, Kuz acts in neurons to regulate repulsion and Kuz can cleave the Robo extracellular domain in Drosophila cells. Genetic rescue experiments using an uncleavable form of Robo show that this receptor does not maintain normal repellent activity. Finally, Kuz activity is required for Robo to recruit its downstream signaling partner, Son of sevenless (Sos). These observations support the model that Kuz-directed cleavage is important for Robo receptor activation.

Functional modulation of cardiac form through regionally confined cell shape changes.

Developing organs acquire a specific three-dimensional form that ensures their normal function. Cardiac function, for example, depends upon properly shaped chambers that emerge from a primitive heart tube. The cellular mechanisms that control chamber shape are not yet understood. Here, we demonstrate that chamber morphology develops via changes in cell morphology, and we determine key regulatory influences on this process. Focusing on the development of the ventricular chamber in zebrafish, we show that cardiomyocyte cell shape changes underlie the formation of characteristic chamber curvatures. In particular, cardiomyocyte elongation occurs within a confined area that forms the ventricular outer curvature. Because cardiac contractility and blood flow begin before chambers emerge, cardiac function has the potential to influence chamber curvature formation. Employing zebrafish mutants with functional deficiencies, we find that blood flow and contractility independently regulate cell shape changes in the emerging ventricle. Reduction of circulation limits the extent of cardiomyocyte elongation; in contrast, disruption of sarcomere formation releases limitations on cardiomyocyte dimensions. Thus, the acquisition of normal cardiomyocyte morphology requires a balance between extrinsic and intrinsic physical forces. Together, these data establish regionally confined cell shape change as a cellular mechanism for chamber emergence and as a link in the relationship between form and function during organ morphogenesis.

Icm/dot-independent entry of Legionella pneumophila into amoeba and macrophage hosts.

Legionella pneumophila, the causative agent of Legionnaires' disease, expresses a type IVB secretion apparatus that translocates bacterial proteins into amoeba and macrophage hosts. When stationary-phase cultures are used to infect hosts, the type IVB apparatus encoded by the icm/dot genes is required for entry, delay of phagosome-lysosome fusion, and intracellular multiplication within host cells. Null mutants with mutations in icm/dot genes are defective in these phenotypes. Here a new model is described in which hosts are infected with stationary-phase cultures that have been incubated overnight in pH 6.5 buffer. This model is called Ers treatment because it enhances the resistance to acid, hydrogen peroxide, and antibiotic stress beyond that of stationary-phase cultures. Following Ers treatment entry into amoeba and macrophage hosts does not require dotA, which is essential for Legionella virulence phenotypes when hosts are infected with stationary-phase cultures, dotB, icmF, icmV, or icmX. Defective host entry is also suppressed for null mutants with mutations in the KatA and KatB catalase-peroxidase enzymes, which are required for proper intracellular growth in amoeba and macrophage hosts. Ers treatment-induced suppression of defective entry is not associated with increased bacterial adhesion to host cells or with morphological changes in the bacterial envelope but is dependent on protein expression during Ers treatment. By using proteomic analysis, Ers treatment was shown to induce a protein predicted to contain eight tetratricopeptide repeats, a motif previously implicated in enhanced entry of L. pneumophila. Characterization of Ers treatment-dependent changes in expression is proposed as an avenue for identifying icm/dot-independent factors that function in the entry of Legionella into amoeba and macrophage hosts.

Intracellular accumulation of pIgA-R and regulators of transcytotic trafficking in cholestatic rat hepatocytes.

Bile duct ligation (BDL) impairs basolateral-to-apical transcytosis in hepatocytes, causing accumulation of transcytotic carriers for the polymeric IgA receptor (pIgA-R) and redistribution of secretory component (SC) from bile to blood. To gain insight into the mechanisms regulating transcytosis and the pathophysiology of cholestasis, we investigated nascent protein trafficking in control and BDL livers using cell fractionation in the context of in vivo pulse-chase experiments and immunoblot analysis. Control and cholestatic hepatocytes trafficked [35S]-labeled serum proteins and the pIgA-R along the secretory pathway with identical kinetics. However, BDL impaired transcytosis, causing (1) accumulation of the pIgA-R, rab3D, rab11a, and other candidate regulators of apical-directed secretion in a crude vesicle carrier fraction (CVCF) enriched in transcytotic carriers; (2) slow delivery of [35S]-labeled SC to bile; and (3) paracellular reflux of SC from bile to blood. In conclusion, these data indicate that the secretory and transcytotic pathways remain polarized in cholestatic hepatocytes and suggest that the pIgA-R traffics through postendosomal rab3D-, rab11a-, and syntaxin 2-associated compartments, implicating these proteins in the regulation of transcytosis.

Mutation of weak atrium/atrial myosin heavy chain disrupts atrial function and influences ventricular morphogenesis in zebrafish.

The embryonic vertebrate heart is composed of two major chambers, a ventricle and an atrium, each of which has a characteristic size, shape and functional capacity that contributes to efficient circulation. Chamber-specific gene expression programs are likely to regulate key aspects of chamber formation. Here, we demonstrate that epigenetic factors also have a significant influence on chamber morphogenesis. Specifically, we show that an atrium-specific contractility defect has a profound impact on ventricular development. We find that the zebrafish locus weak atrium encodes an atrium-specific myosin heavy chain that is required for atrial myofibrillar organization and contraction. Despite their atrial defects, weak atrium mutants can maintain circulation through ventricular contraction. However, the weak atrium mutant ventricle becomes unusually compact, exhibiting a thickened myocardial wall, a narrow lumen and changes in myocardial gene expression. As weak atrium/atrial myosin heavy chain is expressed only in the atrium, the ventricular phenotypes in weak atrium mutants represent a secondary response to atrial dysfunction. Thus, not only is cardiac form essential for cardiac function, but there also exists a reciprocal relationship in which function can influence form. These findings are relevant to our understanding of congenital defects in cardiac chamber morphogenesis.