Epidemiological studies have demonstrated an association between apolipoprotein-(apo)-B containing particles [lipoprotein (Lp) (a), LpE:B; LpC-III:B] and coronary heart disease (CHD). The effect of fluvastatin, a novel competitive inhibitor of HMG-CoA reductase, on these plasma lipoprotein levels was studied in patients with hypercholesterolaemia after 14 weeks of standard dietary therapy. The results of a placebo-controlled, dose-response study and of the combined data of the European double-blind, controlled studies on the effect of fluvastatin are presented. The patients were selected according to the following criteria of inclusion: plasma low-density-lipoprotein (LDL) cholesterol levels > 160 mg dL-1 and premature CHD and/or two associated risk factors, or LDL cholesterol > 190 mg dL-1 and no CHD, plus triglycerides < 300 mg dL-1. All measurements were performed at the Pasteur Institute Central Laboratory. Lp(a), LpE:B and LpC-III:B particles were measured by double-site ELISA. In the placebo-controlled, dose-response study, 429 subjects were randomly assigned to one of the following treatment groups: placebo, fluvastatin 2.5 mg q.p.m., 5 mg q.p.m., 10 mg q.p.m. and 20 mg q.p.m. Treatment with fluvastatin for 6 weeks was associated with a dose-dependent reduction of LDL cholesterol, apoB, LpE:B and LpCIII:B levels. In addition, treatment with fluvastatin 5 mg and 20 mg q.p.m. was associated with a significant reduction in median Lp(a) concentrations (3.2%, P < 0.05 and 6.4%, P < 0.05 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)