Safety of Perflutren Ultrasound Contrast Agents: A Disproportionality Analysis of the US FAERS Database

Potential Signals of COVID-19 as an Effect Modifier of Adverse Drug Reactions

PURPOSE

COVID-19 infection may interact with patients' medical conditions or medications. The objective of this study was to identify potential signals of effect modification of adverse drug reactions by statistical reporting interactions with COVID-19 infection (SRIsCOVID-19) in a large spontaneous reporting database.

METHODS

Data from the US Food and Drug Administration Adverse Event Reporting System through the second quarter of 2020 were used. Three-dimensional disproportionality analyses were conducted to identify drug-event-event (DEE) combinations, for which 1 of the events was COVID-19 infection, that were disproportionately reported. Effect size was quantified by an interaction signal score (INTSS) when COVID-19 was coreported as an adverse event or an indication (INTSSCOVID-19). An SRICOVID-19 exists when the calculated INTSSCOVID-19 is >2. The analyses focused on pandemic-emergent SRIsCOVID-19. Screening for extreme duplication of cases was applied. To assess possible reporting artifacts during the early pandemic as an alternative explanation for pandemic-emergent SRICOVID-19, we repeated the analyses with an additional year of data to gauge temporal stability of our findings.

FINDINGS

When examining DEE interactions, 193 emergent SRIsCOVID-19 were identified, involving 44 drugs and 88 events, in addition to COVID-19 infection. Of the 44 drugs recorded, most were immunosuppressant or modulatory drugs, followed by antivirals. Seven drugs (eg, azithromycin) were identified in emergent SRIsCOVID-19 with preferred terms representing off-label use for prevention or treatment of COVID-19 infection. These drugs were in fact repurposed for COVID-19 treatment, supporting assay sensitivity of our procedure. Infections and infestations were the most frequently observed system organ class, followed by the general disorders and respiratory disorders. The psychiatric system organ class had only a few emergent SRIsCOVID-19 but contained the largest INTSSs. Less commonly reported manifestations of COVID-19 (e.g., skin events) were also identified. After excluding DEE combinations that were highly suggestive of extreme duplication, there remained a more robust set of emergent SRIsCOVID-19, which were supported by biological plausibility considerations. Our findings indicate a relative temporal stability, with >90% of SRIsCOVID-19 persisting after updating the analysis with an additional year of data.

IMPLICATIONS

The signals identified in the analyses could be critical in refining our understanding of the causality of spontaneously reported adverse drug events and thus informing the ongoing care of patients with COVID-19. Our findings also underscore the importance of undetected report duplication as a distorting influence on disproportionality analysis.

Lytic Release of Cellular ATP: Physiological Relevance and Therapeutic Applications

The lytic release of ATP due to cell and tissue injury constitutes an important source of extracellular nucleotides and may have physiological and pathophysiological roles by triggering purinergic signalling pathways. In the lungs, extracellular ATP can have protective effects by stimulating surfactant and mucus secretion. However, excessive extracellular ATP levels, such as observed in ventilator-induced lung injury, act as a danger-associated signal that activates NLRP3 inflammasome contributing to lung damage. Here, we discuss examples of lytic release that we have identified in our studies using real-time luciferin-luciferase luminescence imaging of extracellular ATP. In alveolar A549 cells, hypotonic shock-induced ATP release shows rapid lytic and slow-rising non-lytic components. Lytic release originates from the lysis of single fragile cells that could be seen as distinct spikes of ATP-dependent luminescence, but under physiological conditions, its contribution is minimal <1% of total release. By contrast, ATP release from red blood cells results primarily from hemolysis, a physiological mechanism contributing to the regulation of local blood flow in response to tissue hypoxia, mechanical stimulation and temperature changes. Lytic release of cellular ATP may have therapeutic applications, as exemplified by the use of ultrasound and microbubble-stimulated release for enhancing cancer immunotherapy in vivo.

Contrast-Enhanced Ultrasound: A Technology Primer

Contrast-enhanced ultrasound (CEUS) is a relatively new addition to the diagnostic armamentarium in the United States. The pairing of intravenously injected contrast agents with advanced ultrasound image processing techniques permits improved detection and characterization of different tissue types compared with conventional sonography. The use and efficacy of CEUS is well established in echocardiographic applications in the United States and in many other applications worldwide. Recent approval by the U.S. Food and Drug Administration of an ultrasound contrast agent for use in evaluating adult and pediatric hepatic pathology opens the door to a new era in sonographic diagnosis. An understanding of the underlying physical and technical principles of CEUS is essential for the accurate interpretation of the information obtained from this exciting emerging modality.

An exploratory factor analysis of the spontaneous reporting of severe cutaneous adverse reactions

BACKGROUND

Severe cutaneous adverse reactions (SCARs) are prominent in pharmacovigilance (PhV). They have some commonalities such as nonimmediate nature and T-cell mediation and rare overlap syndromes have been documented, most commonly involving acute generalized exanthematous pustulosis (AGEP) and drug rash with eosinophilia and systemic symptoms (DRESS), and DRESS and toxic epidermal necrolysis (TEN). However, they display diverse clinical phenotypes and variations in specific T-cell immune response profiles, plus some specific genotype-phenotype associations. A question is whether causation of a given SCAR by a given drug supports causality of the same drug for other SCARs. If so, we might expect significant intercorrelations between SCARs with respect to overall drug-reporting patterns. SCARs with significant intercorrelations may reflect a unified underlying concept.

METHODS

We used exploratory factor analysis (EFA) on data from the United States Food and Drug Administration Adverse Event Reporting System (FAERS) to assess reporting intercorrelations between six SCARs [AGEP, DRESS, erythema multiforme (EM), Stevens-Johnson syndrome (SJS), TEN, exfoliative dermatitis (ExfolDerm)]. We screened the data using visual inspection of scatterplot matrices for problematic data patterns. We assessed factorability via Bartlett's test of sphericity, Kaiser-Myer-Olkin (KMO) statistic, initial estimates of communality and the anti-image correlation matrix. We extracted factors via principle axis factoring (PAF). The number of factors was determined by scree plot/Kaiser's rule. We also examined solutions with an additional factor. We applied various oblique rotations. We assessed the strength of the solution by percentage of variance explained, minimum number of factors loading per major factor, the magnitude of the communalities, loadings and crossloadings, and reproduced- and residual correlations.

RESULTS

The data were generally adequate for factor analysis but the amount of variance explained, shared variance, and communalities were low, suggesting caution in general against extrapolating causality between SCARs. SJS and TEN displayed most shared variance. AGEP and DRESS, the other SCAR pair most often observed in overlap syndromes, demonstrated modest shared variance, along with maculopapular rash (MPR). DRESS and TEN, another of the more commonly diagnosed pairs in overlap syndromes, did not. EM was uncorrelated with SJS and TEN.

CONCLUSIONS

The notion that causality of a drug for one SCAR bolsters support for causality of the same drug with other SCARs was generally not supported.