The mechanism of thrombocytopenia caused by cholesterol-conjugated antisense oligonucleotides

Physiological platelet aggregation assay to mitigate drug-induced thrombocytopenia using a microphysiological system

Developing a reliable method to predict thrombocytopenia is imperative in drug discovery. Here, we establish an assay using a microphysiological system (MPS) to recapitulate the in-vivo mechanisms of platelet aggregation and adhesion. This assay highlights the role of shear stress on platelet aggregation and their interactions with vascular endothelial cells. Platelet aggregation induced by soluble collagen was detected under agitated, but not static, conditions using a plate shaker and gravity-driven flow using MPS. Notably, aggregates adhered on vascular endothelial cells under gravity-driven flow in the MPS, and this incident increased in a concentration-dependent manner. Upon comparing the soluble collagen-induced aggregation activity in platelet-rich plasma (PRP) and whole blood, remarkable platelet aggregate formation was observed at concentrations of 30 µg/mL and 3 µg/mL in PRP and whole blood, respectively. Moreover, ODN2395, an oligonucleotide, induced platelet aggregation and adhesion to vascular endothelial cells. SYK inhibition, which mediated thrombogenic activity via glycoprotein VI on platelets, ameliorated platelet aggregation in the system, demonstrating that the mechanism of platelet aggregation was induced by soluble collagen and oligonucleotide. Our evaluation system partially recapitulated the aggregation mechanisms in blood vessels and can contribute to the discovery of safe drugs to mitigate the risk of thrombocytopenia.

A real-world pharmacovigilance analysis for transthyretin inhibitors: findings from the FDA adverse event reporting database

Objective

The purpose of this study is to investigate the drug safety of three Transthyretin (TTR) inhibitors in the real world using the United States Food and Drug Administration Adverse Event Reporting System (FAERS) database.

Methods

This study extracted reports received by the FAERS database from the first quarter of 2018 to the third quarter of 2023 for descriptive analysis and disproportionality analysis. Safety signal mining was conducted at the Preferred Term (PT) level and the System Organ Class (SOC) level using reporting odds ratio (ROR). The characteristics of the time-to-onset curves were analyzed using the Weibull Shape Parameter (WSP). The cumulative incidence of TTR inhibitors was evaluated using the Kaplan-Meier method. Subgroup analyses were conducted based on whether the reporter was a medical professional.

Results

A total of 3,459 reports of adverse events (AEs) caused by TTR inhibitors as the primary suspect (PS) drug were extracted. The top three reported AEs for patisiran were fatigue, asthenia, and fall, with the most unexpectedly strong association being nonspecific reaction. The top three reported AEs for vutrisiran were fall, pain in extremity and malaise, with the most unexpectedly strong association being subdural haematoma. The top three reported AEs for inotersen were platelet count decreased, blood creatinine increased, and fatigue, with the most unexpectedly strong association being blood albumin decreased. Vitamin A decreased, arthralgia, and dyspnea were the same AEs mentioned in the drug labels of all three drugs, while malaise and asthenia were the same unexpected significant signals. This study offers evidence of the variability in the onset time characteristics of AEs associated with TTR inhibitors, as well as evidence of differences in adverse event reporting between medical professionals and non-medical professionals.

Conclusion

In summary, we compared the similarities and differences in drug safety of three TTR inhibitors in the real world using the FAERS database. The results indicate that not only do these three drugs share common AEs, but they also exhibit differences in drug safety profiles. This study contributes to enhancing the understanding of medical professionals regarding the safety of TTR inhibitors.

APOC3 siRNA and ASO therapy for dyslipidemia

PURPOSE OF REVIEW

The aim of this review is to present the clinical indications of apolipoprotein C-III (apoC3) inhibition in the therapeutic arsenal for the treatment of lipid disorders and associated risks and to compare the most advanced modalities of apoC3 inhibition currently available or in development, specifically APOC3 antisense oligonucleotides (ASO) and small interfering RNA (siRNA).

RECENT FINDINGS

ApoC3 inhibition significantly decreases triglyceride levels by mechanisms coupling both lipoprotein lipase (LPL) upregulation and LPL-independent mechanisms. The main apoC3 inhibitors in advanced clinical development are the GalNAc-ASO olezarsen and the GalNAc-siRNA plozasiran. Clinical studies conducted with volanesorsen, the olezarsen precursor, showed a favorable effect on hepatic steatosis (nonalcoholic fatty liver disease, NAFLD). Olezarsen does not appear to be associated with the main side effects attributed to volanesorsen including thrombocytopenia. Plozasiran is in advanced clinical development and requires subcutaneous injection every 3 months and present to-date an efficacy and safety profile comparable to that of the monthly ASO.

SUMMARY

Inhibition of apoC3 is effective across all the spectrum of hypertriglyceridemia, might have a favorable effect on hepatic steatosis (NAFLD) and the effect of apoC3 inhibition on cardiovascular risk is not limited to its effect on plasma triglycerides. APOC3 GalNAc-conjugated ASO and siRNA are both effective in decreasing plasma apoC3 and triglyceride levels.