Suppression of pseudointimal hyperplasia by a novel prostacyclin analogue: beraprost

Beraprost: a review of its pharmacology and therapeutic efficacy in the treatment of peripheral arterial disease and pulmonary arterial hypertension

Beraprost sodium (beraprost) is a stable, orally active prostacyclin analogue with vasodilatory, antiplatelet and cytoprotective effects. Beraprost acts by binding to prostacyclin membrane receptors ultimately inhibiting the release of Ca2+ from intracellular storage sites. This reduction in the influx of Ca2+ has been postulated to cause relaxation of the smooth muscle cells and vasodilation. Data from a large, randomised, double-blind, multicentre study indicated that beraprost was as efficacious as ticlopidine in the treatment of patients with peripheral arterial disease (Buerger's disease and arteriosclerosis obliterans). Most patients receiving beraprost exhibited reduction of ulcer size, reported improvement of granulation appearance of the tissue and showed improvement of pain at rest and sensation of cold in the extremities. In a large pivotal clinical trial in patients with intermittent claudication, beraprost treatment was associated with statistically significant increases in pain-free and absolute walking distances compared with those in patients receiving placebo. Statistically significant differences in the incidence of critical cardiovascular events among both treatment groups were not observed but patients receiving beraprost were more likely to be satisfied with changes in their quality of life. However, while preliminary unpublished data from a large, phase III, placebo-controlled study in the US suggested a trend toward fewer critical cardiovascular events (no specific data presented), this study did not confirm the positive results from the European phase III trial and statistical significance was not achieved in the study's endpoints relating to exercise. A series of small, noncomparative clinical trials of patients with the rare condition of pulmonary arterial hypertension (PAH) demonstrated that substantial reductions of pulmonary arterial pressure and resistance, increase of cardiac output, and increase of exercise capacity appeared to be associated with beraprost therapy; however, these data are very limited and in most instances are not fully published. Beraprost is a well tolerated agent. Overall, the main adverse events include headache, hot flushes, diarrhoea and nausea. However, patients with PAH showed higher incidence of adverse events than those with peripheral arterial disease.

CONCLUSION

Beraprost, an orally administered PGI2 analogue, is generally well tolerated and appears to be an effective agent in the treatment of patients with Buerger's disease and arteriosclerosis obliterans. Comparative data from a large randomised trial indicated that the drug appears as effective as ticlopidine in patients with these conditions. In patients with intermittent claudication, significant benefits of beraprost compared with placebo were reported in a randomised clinical trial; however, the use of beraprost in these patients is not supported by recent preliminary unpublished data from a large, phase III, placebo-controlled study. Limited data suggest some efficacy with long-term beraprost treatment of patients with PAH, where options are few and where oral administration of the drug could be a considerable advantage over intravenous prostacyclin (PGI2) therapy. Additional well-designed and, where possible, large trials with active comparators are necessary to define more precisely the place of beraprost in the treatment of patients with PAH, Buerger's disease and arteriosclerosis obliterans.