Efficacy of once-daily extended-release lovastatin as compared to immediate-release lovastatin in patients with hypercholesterolemia.

Objective: to compare the efficacy and safety of 20 mg of lovastatin when administered once daily as an extended-release (ER) tablet or as an immediate-release (IR) tablet.

Research Design And Methods: Male or female patients aged 21-70 years with hypercholesterolemia who provided written informed consent and met the inclusion criteria were screened. A total of 179 patients were enrolled: 100 male and 79 female; 153 were Caucasian, eight Black and 18 other races; the mean age was 56 years. Patients were generally in good health as evidenced by medical history, physical and laboratory examination. Patients were required to not exceed specific low-density lipoprotein cholesterol (LDL-C) levels depending on their risk category. The trial was conducted as a multi-center, randomized, double-blind, positive-controlled, double-dummy, two-way crossover study. Patients were washed-out of any prior lipid-lowering medications (period 1) and then received one ER or one IR lovastatin tablet for 12 weeks (period 2) and then washed out with placebo for 6 weeks (period 3). They then received the alternate treatment for an additional 12 weeks (period 4).

Main Outcome Measures: The primary efficacy variable was the combined mean percent change in LDL-C from baseline to endpoint for periods 2 and 4. Secondary variables included the mean percent change from baseline in high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), and triglycerides (TG) for periods 2 and 4 combined. Least-square mean differences between ER and IR treated groups were estimated at both treatments. All tests were two-sided and a p-value of < 0.05 was considered statistically significant.

Results: Both ER and IR lovastatin tablets produced statistically significant changes in the lipid profile from baseline. Differences in HDL-C (4.1% and 4.3% for ER and IR, respectively) and TG (7.4% and 10.4% for ER and IR, respectively) were not significant between treatments. TC (19.1% and 17.2% for ER and IR, respectively) and LDL-C (26.4% and 23.1% for ER and IR, respectively) were also reduced significantly from baseline by both treatments. However the ER lovastatin reduced TC by an additional 1.9% (p = 0.0355) and LDL-C by a further 3.3% decrease (p = 0.0028) as compared to the IR formulation. The increase in LDL-C efficacy is equivalent to an increase of 50% in the dose of IR lovastatin, suggesting that 20 mg ER is equivalent to about 30 mg IR in LDL-C-lowering capacity. No apparent difference in the safety profile between the two formulations was noted.

Conclusions: The data show that 20 mg of ER lovastatin was about one and one-half times as effective at lowering LDL-C than the same dose of IR lovastatin. Both regimens were tolerated well.