In a double-blind, randomized, multicenter, multi-national, active-controlled, 24-week study, the lipid effects of a combination tablet of NIASPAN and simvastatin were compared to simvastatin 20 mg and 80 mg in 641 patients with type II hyperlipidemia or mixed dyslipidemia. Following a lipid qualification phase, patients were eligible to enter one of two treatment groups. In Group A, patients on simvastatin 20 mg monotherapy, with elevated non-HDL levels and LDL-C levels at goal per the NCEP guidelines, were randomized to one of three treatment arms: combination tablet of NIASPAN and simvastatin 1000/20 mg, combination tablet of NIASPAN and simvastatin 2000/20 mg, or simvastatin 20 mg. In Group B, patients on simvastatin 40 mg monotherapy, with elevated non-HDL levels per the NCEP guidelines regardless of attainment of LDL-C goals, were randomized to one of three treatment arms: combination tablet of NIASPAN and simvastatin 1000/40 mg, combination tablet of NIASPAN and simvastatin 2000/40 mg, or simvastatin 80 mg. Therapy was initiated at the 500 mg dose of combination tablet of NIASPAN and simvastatin and increased by 500 mg every four weeks. Thus patients were titrated to the 1000 mg dose of combination tablet of NIASPAN and simvastatin after four weeks and to the 2000 mg dose of combination tablet of NIASPAN and simvastatin after 12 weeks. All patients randomized to simvastatin monotherapy received 50 mg immediate-release niacin daily in an attempt to keep the study from becoming unblinded due to flushing in the combination tablet of NIASPAN and simvastatin groups. Patients were instructed to take one 325 mg aspirin or 200 mg ibuprofen 30 minutes prior to taking the double-blind medication to help minimize flushing effects. 

In Group A, the primary efficacy analysis was a comparison of the mean percent change in non-HDL levels between the combination tablet of NIASPAN and simvastatin 2000/20 mg and simvastatin 20 mg groups, and if statistically significant, then a comparison was conducted between the combination tablet of NIASPAN and simvastatin 1000/20 mg and simvastatin 20 mg groups. In Group B, the primary efficacy analysis was a determination of whether the mean percent change in non-HDL in the combination tablet of NIASPAN and simvastatin 2000/40 mg group was non-inferior to the mean percent change in the simvastatin 80 mg group, and if so, whether the mean percent change in non-HDL in the combination tablet of NIASPAN and simvastatin 1000/40 mg group was non-inferior to the mean percent change in the simvastatin 80 mg group. 

In Group A, the non-HDL-C lowering with combination tablet of NIASPAN and simvastatin 2000/20 and combination tablet of NIASPAN and simvastatin 1000/20 was statistically significantly greater than that achieved with simvastatin 20 mg after 24 weeks (p<0.05; Table 12). The completion rate after 24 weeks was 72% for the combination tablet of NIASPAN and simvastatin arms and 88% for the simvastatin 20 mg arm. In Group B, the non-HDL-C lowering with combination tablet of NIASPAN and simvastatin 2000/40 and combination tablet of NIASPAN and simvastatin 1000/40 was non-inferior to that achieved with simvastatin 80 mg after 24 weeks (Table 13). The completion rate after 24 weeks was 78% for the combination tablet of NIASPAN and simvastatin arms and 80% for the simvastatin 80 mg arm.

The combination tablet of NIASPAN and simvastatin was not superior to simvastatin in lowering LDL-C in either Group A or Group B. However, the combination tablet of NIASPAN and simvastatin was superior to simvastatin in both groups in lowering TG and raising HDL (Tables 14 and 15).