Atopaxar and its effects on markers of platelet activation and inflammation: results from the LANCELOT CAD program

Atopaxar is a reversible protease activated receptor (PAR)-1 thrombin receptor antagonist that interferes with platelet signaling. The effects of PAR-1 antagonists on biomarkers remain unknown. The primary objective was to assess the effects of atopaxar on biomarkers of inflammation and platelet activation. The LANCELOT-CAD trial randomized 720 subjects to atopaxar (50, 100, or 200 mg daily) or matching placebo for 24 weeks. Biomarkers were assessed at serial time points. A linear mixed model to account for repeated measures was used to evaluate the change in biomarker concentration from randomization across time to week 24. Least square means were determined from the linear mixed models. The concentration of sCD40L decreased on average over time by −553 (95 % CI −677, −429) ng/L in the combined atopaxar group versus −30.3 (−249 to 189) ng/L fall in the placebo arm (P < 0.001) and a dose-dependent trend was seen across treatment groups (P < 0.001 for trend). In contrast, Lp-PLA₂ mass rose on average over time by 12.6 (95 % CI 10.0, 15.3) ng/ml in the combined atopaxar group as compared with 2.6 (95 % CI −2.1, 7.3) ng/ml in the placebo arm (P < 0.001). Similarly, the concentration of IL-18 rose by 17.5 (95 % CI 12.4, 22.6) pg/ml in the atopaxar group versus a −1.2 (95 % CI −10.2, 7.8) pg/ml fall in the placebo group (P < 0.001). The effects of atopaxar on Lp-PLA₂ and IL-18 appeared to be dose-dependent (P < 0.001 for trend) and were observed in J-LANCELOT. Atopaxar did not have a significant effect on other inflammatory markers. In conclusion, atopaxar appeared to decrease sCD40L, but did not demonstrate an anti-inflammatory effect in patients with stable CAD. Although atopaxar increased the concentration of Lp-PLA₂ and IL-18, the clinical relevance of these findings remains unknown and warrants further investigation and validation.