mdl-100907 and Intermittent-Claudication

This was a multinational, multicentre, double-blind Phase II study in Europe to evaluate the efficacy and safety of two dose regimens (200 mg bid and 200 mg tid) of sarpogrelate (MCI-9042, 5-HT2A receptor antagonist) compared to placebo in patients with stable, moderately severe intermittent claudication. Following a single-blind placebo run-in period of 6 weeks, 364 (309 male and 55 female) patients (59.2 +/- 8.4 years, mean +/- SD) were randomized to receive sarpogrelate 200 mg bid, 200 mg tid or placebo for 24 weeks with a follow-up of 8 weeks. The primary objective was the increase of absolute claudication distance (ACD) at the end of treatment (week 24) compared to placebo. Analysis of covariance (ANCOVA) was performed on the log-transformed percentage of baseline ACD: loge(ACD/baseline). A responder analysis (defined as a > or = 50% improvement in ACD) was also performed. There was a marked training/placebo effect on the ACD which persisted up to 16 weeks. At 24 weeks the primary objective did not reach statistical significance (200mg bid vs placebo, p = 0.225; 200mg tid vs placebo, p = 0.580). In the responder analysis, 200 mg bid showed a statistically significant difference vs placebo (p = 0.035). In the exploratory analysis with completers (patients completing all treadmill tests), there was a statistical difference in ACD/baseline change for 200 mg bid (p = 0.035) and in the responder analysis for 200 mg tid (p = 0.044) at 24 weeks compared to placebo. Both treatments showed a carry-over effect for ACD during the 8-week follow-up (weeks 28-32). The treatment was well tolerated and no clinically significant safety concerns were reported. In conclusion, the study results confirm that sarpogrelate is well tolerated and although the primary endpoint failed to reach statistical significance, the responder analysis showed an increased absolute walking distance, which makes a further trial warranted, including a larger population, and possibly also a longer treatment period.

Topics: Adult; Aged; Double-Blind Method; Europe; Exercise Test; Female; Humans; Intermittent Claudication; Lower Extremity; Male; Middle Aged; Receptor, Serotonin, 5-HT2A; Serotonin 5-HT2 Receptor Antagonists; Serotonin Antagonists; Succinates; Treatment Outcome; Walking

AT-1015 is a novel selective 5-HT2A serotonin receptor antagonist that is known to impair platelet aggregation and vasoconstriction. Serotonin has been hypothesized to contribute to claudication symptoms in individuals with peripheral arterial disease (PAD) via microvascular vasoconstrictor and thrombotic effects. AT-1015 was thus evaluated in 439 patients with claudication who were randomized in a double-blind, placebo-controlled trial comparing 10 mg, 20 mg, and 40 mg BID versus placebo for 24 weeks. Treadmill walking performance was assessed by peak walking time (PWT) and pain-free walking time (PFWT). Quality of life (QoL) was measured by the Walking Impairment Questionnaire (WIQ) and the Health Status Survey SF-36. Limb hemodynamics was assessed with the ankle-brachial index (ABI). The 40 mg arm was terminated prematurely by recommendation of the Data Safety Monitoring Committee due to an excess number of non-fatal myocardial infarctions. At study conclusion, there were no statistically significant differences in the mean change of PWT, PFWT, ABI and QoL between the 10 mg and 20 mg BID treatment groups compared with placebo. The proportion of patients who experienced an adverse event (AE) was similar across all treatment groups. Antimuscarinic and gastrointestinal AEs were more common in the AT-1015 treatment groups. Two deaths occurred: one in the placebo group and the other in the AT-1015 20 mg group. Although a prolongation of the QTc interval was observed in all groups, this was not clinically significant (QTc > 500 ms). Mean supine pulse rates were significantly increased in all AT-1015 treatment groups, consistent with predicted antimuscarinic effects. Population pharmacokinetic analysis fit a one-compartment model with first-order absorption and elimination. These data indicate that selective serotonin receptor blockade does not improve exercise tolerance or quality of life in individuals with claudication.

Topics: Aged; Dose-Response Relationship, Drug; Double-Blind Method; Exercise Tolerance; Female; Humans; Intermittent Claudication; Isonipecotic Acids; Male; Middle Aged; Quality of Life; Serotonin 5-HT2 Receptor Antagonists; Walking