Use and Misuse of Aspirin in Primary Cardiovascular Prevention

New oral protease-activated receptor 4 antagonist BMS-986120: tolerability, pharmacokinetics, pharmacodynamics, and gene variant effects in humans

BMS-986120 is a novel first-in-class oral protease-activated receptor 4 (PAR4) antagonist exhibiting robust antithrombotic activity that has shown low bleeding risk in monkeys. We sought to assess pharmacokinetics, pharmacodynamics, and tolerability of BMS-986120 in healthy participants and platelet responses to BMS-986120 in participants carrying PAR4 A120T variants. Phase I, randomized, double-blind, placebo-controlled single-ascending-dose (SAD; N = 56) and multiple-ascending-dose (MAD; N = 32) studies were conducted. Exposure was approximately dose-proportional: maximum concentrations 27.3 and 1536 ng/mL, areas under the curve (AUC) to infinity of 164 and 15,603 h*ng/mL, and half-lives of 44.7 and 84.1 hours for 3.0 and 180 mg, respectively. The accumulation index suggested an ~2-fold AUC increase at steady state. Single doses of 75 and 180 mg BMS-986120 produced ≥80% inhibition of 12.5 μM PAR4 agonist peptide (AP)-induced platelet aggregation through at least 24 hours postdose, and doses ≥10 mg for ~7 days inhibited aggregation completely through 24 hours. No differences in PAR4-mediated platelet response were seen between AA120 versus TT120 PAR4 variants. In cells expressing A120 or T120 PAR4 proteins, no differences in half-maximal effective concentration in receptor activation by PAR4-AP were observed. BMS-986120 was well tolerated with dose-proportional pharmacokinetics and concentration-dependent pharmacodynamics in healthy participants over a wide dose range.ClinicalTrials.gov ID: NCT02208882.

Spurious Hyperchloremia in the Presence of Elevated Plasma Salicylate: A Cohort Study

BACKGROUND

Acute metabolic acidosis is rarely associated with a reduced or negative anion gap (AG), but several case reports have described such an abnormality occurring in the setting of acute salicylate intoxication. The underlying cause of this phenomenon is unclear.

METHODS

In this retrospective cohort study, we reviewed our institutional database to identify all patients admitted for salicylate intoxication at Mayo Clinic (Rochester, MN, USA) from January 2010 through December 2012. Serum chloride was measured with the Cobas INTEGRA 400 plus electrode (expedited laboratory test) or Cobas 6000 (routine laboratory test). We compared blood chloride levels measured by the 2 devices in the presence of positive blood salicylate level.

RESULTS

Twelve adult patients with salicylate levels >20 mg/dL had markedly elevated chloride concentrations. The median (interquartile range) chloride level at admission was 120 (107-145) mmol/L on their initial laboratory studies, resulting in reduced or even negative AGs. None of the patients had bromide toxicity, nor did they have any other identifiable cause of hyperchloremia or decreased AG. Further testing of the same blood samples with an alternative measurement system (Roche Cobas 6000) yielded normal chloride values, indicating that falsely elevated chloride values with the initial testing led to the diminished or negative AG values.

CONCLUSION

Circulating levels of salicylate can interfere with chloride measured by using routine techniques, resulting in spurious hyperchloremia outcomes and erroneous AG values. In patients with acute metabolic acidosis and abnormally reduced or negative AG, salicylate interference with chloride measurement should be suspected.