Subcutaneous Selatogrel Inhibits Platelet Aggregation in Patients With Acute Myocardial Infarction.

BACKGROUND: Oral P2Y12 receptor antagonists exhibit delayed onset of platelet inhibition in patients with acute myocardial infarction (AMI). Selatogrel is a potent, highly selective, and reversible P2Y12 receptor antagonist with a rapid onset and short duration of action. OBJECTIVES: This study sought to assess inhibition of platelet aggregation following subcutaneous administration of selatogrel in patients with AMI. METHODS: Patients with AMI were randomized to a single subcutaneous dose of selatogrel of 8 or 16 mg. The primary endpoint was response to treatment (P2Y12 reaction units <100; measured by VerifyNow) at 30 min post-dose. Safety was assessed up to 48 h post-injection. RESULTS: Forty-seven patients received selatogrel 8 mg (n = 24) or 16 mg (n = 23) followed by ticagrelor (n = 43) or clopidogrel (n = 1). The proportion of responders 30 min post-dose was 91% (one-sided 97.5% confidence interval [CI]: 80% to 100%) and 96% (97.5% CI: 87% to 100%) with 8 and 16 mg, respectively (p values for responders >85% target; p = 0.142 and p = 0.009, respectively). Response rates were independent from type of AMI presentation, age, or sex. A similar response rate was observed at 15 min (8 mg: 75% [97.5% CI: 58% to 100%]; 16 mg: 91% [97.5% CI: 80% to 100%]), which was sustained at 60 min post-dose (8 mg: 75% [97.5% CI: 58% to 100%]; 16 mg: 96% [97.5% CI: 87% to 100%]). At 15 min, median P2Y12 reaction units was 51 (range: 4 to 208) for 8 mg and 9 (range: 2 to 175) for 16 mg. Selatogrel was well tolerated, without major bleeding complications. CONCLUSIONS: Single-dose subcutaneous administration of selatogrel in patients with AMI was safe and induced a profound, rapid, and dose-related antiplatelet response. (A Medical Research Study to Evaluate the Effects of ACT-246475 in Adults With Heart Attack; NCT03487445, 2018-000765-36 [EudraCT]).

Pharmacodynamics, pharmacokinetics, and safety of single-dose subcutaneous administration of selatogrel, a novel P2Y12 receptor antagonist, in patients with chronic coronary syndromes.

AIMS: To study the pharmacodynamics and pharmacokinetics of selatogrel, a novel P2Y12 receptor antagonist for subcutaneous administration, in patients with chronic coronary syndromes (CCS). METHODS AND RESULTS: In this double-blind, randomized study of 345 patients with CCS on background oral antiplatelet therapy, subcutaneous selatogrel (8 mg, n = 114; or 16 mg, n = 115) was compared with placebo (n = 116) (ClinicalTrials.gov: NCT03384966). Platelet aggregation was assessed over 24 h (VerifyNow assay) and 8 h (light transmittance aggregometry; LTA). Pharmacodynamic responders were defined as patients having P2Y12 reaction units (PRU) <100 at 30 min post-dose and lasting ≥3 h. At 30 min post-dose, 89% of patients were responders to selatogrel 8 mg, 90% to selatogrel 16 mg, and 16% to placebo (P < 0.0001). PRU values (mean ± standard deviation) were 10 ± 25 (8 mg), 4 ± 10 (16 mg), and 163 ± 73 (placebo) at 15 min and remained <100 up to 8 h for both doses, returning to pre-dose or near pre-dose levels by 24 h post-dose. LTA data showed similarly rapid and potent inhibition of platelet aggregation. Selatogrel plasma concentrations peaked ∼30 min post-dose. Selatogrel was safe and well-tolerated with transient dyspnoea occurring overall in 7% (16/229) of patients (95% confidence interval: 4-11%). CONCLUSIONS: Selatogrel was rapidly absorbed following subcutaneous administration in CCS patients, providing prompt, potent, and consistent platelet P2Y12 inhibition sustained for ≥8 h and reversible within 24 h. Further studies of subcutaneous selatogrel are warranted in clinical scenarios where rapid platelet inhibition is desirable.

Efficacy and Safety of Selexipag in Adults With Raynaud's Phenomenon Secondary to Systemic Sclerosis: A Randomized, Placebo-Controlled, Phase II Study.

OBJECTIVE: To determine the effect of selexipag, an oral, selective IP prostacyclin receptor agonist, on the frequency of attacks of Raynaud's phenomenon (RP) in patients with systemic sclerosis (SSc). METHODS: Patients with SSc-related RP were randomized 1:1 to placebo (n = 38) or selexipag (n = 36) in individualized doses (maximum of 1,600 µg twice daily) during a 3-week titration period. The primary end point was the weekly average number of RP attacks during the study maintenance period, analyzed using a Bayesian approach with a negative binomial model adjusted for baseline number of RP attacks. Other outcome measures included Raynaud's Condition Score (RCS), RP attack duration, and treatment-emergent adverse events (AEs). RESULTS: Baseline characteristics were comparable between treatment groups. For 83.3% of patients, the individualized maintenance dosage of selexipag was ≤800 µg twice daily. No significant difference was observed between placebo and selexipag in weekly average number of electronic diary (eDiary)-recorded RP attacks during the maintenance period (14.2 attacks during the maintenance period and 21.5 attacks during the baseline week in the placebo group [n = 32] versus 18.0 attacks during the maintenance period and 22.4 attacks during the baseline week in the selexipag group [n = 27]; adjusted mean treatment difference of 3.4 in favor of placebo). No significant treatment effect was observed on RCS or RP attack duration. In the double-blind period, 86.8% of placebo-treated patients and 100% of selexipag-treated patients reported ≥1 AE; 55.3% and 91.7%, respectively, reported ≥1 prostacyclin-associated AE. CONCLUSION: Treatment with selexipag did not reduce the number of RP attacks compared with placebo. The safety profile of selexipag was similar to that previously reported. This study provides important information about the feasibility of eDiary reporting of RP attacks in clinical trials.

Lipid remodeling of murine epididymosomes and spermatozoa during epididymal maturation.

We have isolated vesicular structures from mouse epididymal fluid, referred to as epididymosomes. Epididymosomes have a roughly spherical aspect and a bilayer membrane, and they are heterogeneous in size and content. They originate from the epididymal epithelium, notably from the caput region, and are emitted in the epididymal lumen by way of apocrine secretion. We characterized their membranous lipid profiles in caput and cauda epididymidal fluid samples and found that epididymosomes were particularly rich in sphingomyelin (SM) and arachidonic acid. The proportion of SM increased markedly during epididymal transit and represented half the total phospholipids in cauda epididymidal epididymosomes. The cholesterol:phospholipid ratio increased from 0.26 in the caput to 0.48 in the cauda epididymidis. Measures of epididymosomal membrane anisotropy revealed that epididymosomes became more rigid during epididymal transit, in agreement with their lipid composition. In addition, we have characterized the membrane lipid pattern of murine epididymal spermatozoa during their maturation. Here, we have shown that mouse epididymal spermatozoa were distinguished by high percentages of SM and polyunsaturated membranous fatty acids (PUFAs), principally represented by arachidonic, docosapentanoic, and docosahexanoic acids. Both SM and PUFA increased throughout the epididymal tract. In particular, we observed a threefold rise in the ratio of docosapentanoic acid. Epididymal spermatozoa had a constant cholesterol:phospholipid ratio (average, 0.30) during epididymal transit. These data suggest that in contrast with epididymosomes, spermatozoal membranes seem to become more fluid during epididymal maturation.

Changes in serum lipoprotein lipids and their fatty acid compositions and lipid peroxidation in growing rats fed soybean protein versus casein with or without cholesterol.

OBJECTIVE: We compared the effects of diets based on soybean protein and casein supplemented or not supplemented with 0.1% cholesterol on plasma lipoprotein lipid amounts and their fatty acid compositions, lecithin:cholesterol acyl-transferase activity, and lipid peroxidation. METHODS: The composition and concentration of lipid and apolipoprotein in different lipoprotein classes, plasma LCAT activity, and lipid peroxidation were determined in rats fed 20% highly purified soybean protein or casein with or without 0.1% cholesterol for 2 mo. RESULTS: Soybean protein and casein diets with or without cholesterol had similar plasma total cholesterol concentrations. Soybean protein consumption diminished very low-density lipoprotein particle number, as measured by diminished contents of very low-density lipoprotein triacylglycerol, phospholipid, and apolipoprotein-B100. Lecithin:cholesterol acyl-transferase activity was not significantly modified by either protein. The soybean protein diet decreased the linoleate desaturation index (20:4[omega-6]/18:2[omega-6]) in liver and high-density lipoprotein fraction 2-3-phospholipids but enhanced red blood cell resistance against free radical attack. Addition of cholesterol to both protein diets decreased concentrations of high-density lipoprotein fraction 2-3 cholesterol. Lecithin:cholesterol acyl-transferase activity tended to be greater after cholesterol feeding, likely due to the enhanced high-density lipoprotein fraction 2-3 apolipoprotein-AI, a cofactor activator for lecithin:cholesterol acyl-transferase. Regardless of dietary protein source, cholesterol supplementation decreased the linoleate desaturation index in liver and plasma lipoprotein lipids and red blood cell resistance to free radical attack. CONCLUSIONS: Our results suggest that the dietary protein origin affects lipid peroxidation and polyunsaturated fatty acid biosynthesis and distribution among liver and different lipoprotein lipid classes, but plays only a minor role in the regulation of plasma and lipoprotein cholesterol concentrations. Providing dietary cholesterol (0.1%) with casein or soybean protein attenuates the effects of these proteins, with the exception of plasma cholesterol.

Very high alpha-tocopherol diet diminishes oxidative stress and hypercoagulation in hypertensive rats but not in normotensive rats.

BACKGROUND: Oxidative stress is closely related to cardiovascular diseases, such as atherosclerosis. Increasing dietary antioxidants, such as alpha-tocopherol, may prevent these diseases. However, in some pathologies, such as hypertension, oxidative stress is enhanced, thus alpha-tocopherol requirements may be raised. MATERIAL/METHODS: In eleven-week-old spontaneously hypertensive rats and normotensive Wistar Kyoto rats, we investigated the effects of a four-week very high alpha-tocopherol dietary enrichment (1,200 mg/kg diet, VH) on blood pressure, resistance to free radical aggression, and VLDL+LDL resistance to lipid peroxidation. Platelet aggregation and plasma lipid profile were also investigated. RESULTS: With either diet, hypertensive rats were more protected against oxidative stress than normotensive rats. Their capacity to withstand free radical aggression was better, and their VLDL+LDL particles were less sensitive to lipid peroxidation. In either group, the VH diet did not modify blood pressure values when resistance to free radical aggression was increased, but not the resistance of VLDL+LDL to lipid peroxidation. With the control diet, platelet aggregation was faster and higher in hypertensive rats vs. normotensive rats. It was decreased with the VH diet in hypertensive rats but increased in normotensive rats, when compared to their respective controls. Whatever the diet, plasma triacylglycerol, phospholipid and cholesterol concentrations were lower in hypertensive than in normotensive rats. Only cholesterol concentrations were diminished with the VH diet in hypertensive rats, but not in normotensive rats. CONCLUSIONS: These results indicate that very high alpha-tocopherol dietary amounts decrease cardiovascular risk in hypertensive rats with high oxidative stress, but have less effect on normotensive rats.