Patients were randomized to simvastatin or placebo using a covariate adaptive method which considered the distribution of 10 important baseline characteristics of patients already enrolled.
The Study HPS results showed that simvastatin 40 mg/day significantly reduced: total and CHD mortality; and non-fatal MI, stroke, and revascularization procedures (coronary and non-coronary) (see Table 5).
Two composite endpoints were defined to have enough events to assess relative risk reductions across a range of baseline characteristics:
Major coronary events (MCE) was comprised of CHD mortality and non-fatal MI. Analyzed by time-to-first event; 898 patients (8.7%) treated with simvastatin had events and 1,212 patients (11.8%) treated with placebo had events.
Major vascular events (MVE) was comprised of MCE, stroke, and revascularization procedures including coronary, peripheral and other non-coronary procedures. Analyzed by time-to-first event; 2,033 patients (19.8%) treated with simvastatin had events and 2,585 patients (25.2%) on placebo had events.
Simvastatin use led to significant relative risk reductions for both composite endpoints (27% for MCE and 24% for MVE, p<0.0001) and for all components of the composite endpoints. The risk reductions produced by simvastatin in both MCE and MVE were evident and consistent regardless of cardiovascular disease related medical history at study entry (i.e., CHD alone; or peripheral vascular disease, cerebrovascular disease, diabetes or treated hypertension, with or without CHD), gender, age, baseline levels of LDL-C, baseline concomitant cardiovascular medications (i.e., aspirin, beta blockers, or calcium channel blockers), smoking status, or obesity. Patients with diabetes showed risk reductions for MCE and MVE due to simvastatin treatment regardless of baseline HbA1c levels or obesity.
Primary Hyperlipidemia in Adults
The effects of simvastatin on total-C and LDL-C were assessed in controlled clinical studies in adult patients with heterozygous familial and non-familial forms of hyperlipidemia and in mixed hyperlipidemia. Simvastatin significantly decreased total-C, LDL-C, and TG, and increased HDL-C (see Table 6). Maximal to near maximal response was generally achieved within 4-6 weeks and maintained during chronic therapy.
Table 6: Mean Changes in Lipid Levels in Adult Patients with Primary Hyperlipidemia and Combined (mixed) Hyperlipidemia (Mean Percent Change from Baseline After 6 to 24 Weeks)
| TREATMENT | N | TOTAL-C | LDL-C | HDL-C | TG* |
| Lower Dosage Comparative Study
†(Mean % Change at Week 6)
|
| Simvastatin 5 mg once at night | 109 | -19% | -26% | +10% | -12% |
| Simvastatin 10 mg once at night | 110 | -23% | -30% | +12% | -15% |
| Scandinavian Simvastatin Survival Study
‡(Mean % Change at Week 6)
|
| Placebo | 2223 | -1% | -1% | 0% | -2% |
| Simvastatin 20 mg once at night | 2221 | -28% | -38% | +8% | -19% |
| Upper Dosage Comparative Study
§(Mean % Change Averaged at Weeks 18 and 24)
|
| Simvastatin 40 mg once at night | 433 | -31% | -41% | +9% | -18% |
| Simvastatin 80 mg once at night
¶ | 664 | -36% | -47% | +8% | -24% |
| Combined Hyperlipidemia Study
#(Mean % Change at Week 6)
|
| Placebo | 125 | 1% | 2% | +3% | -4% |
| Simvastatin 40 mg once at night | 123 | -25% | -29% | +13% | -28% |
| Simvastatin 80 mg once at night | 124 | -31% | -36% | +16% | -33% |
* median percent change
†mean baseline LDL-C = 244 mg/dL and median baseline TG = 168 mg/dL
‡mean baseline LDL-C = 188 mg/dL and median baseline TG = 128 mg/dL
§mean baseline LDL-C = 226 mg/dL and median baseline TG = 156 mg/dL
¶21% and 36% median reduction in TG in patients with TG ≤200 mg/dL and TG >200 mg/dL, respectively. Patients with TG >350 mg/dL were excluded
#mean baseline LDL-C = 156 mg/dL and median baseline TG = 391 mg/dL.
Hypertriglyceridemia in Adults
The results of a subgroup analysis in 74 adult patients with hypertriglyceridemia from a 130-patient, double-blind, placebo-controlled, 3-period crossover study are similar to those presented in Table 6 for the Combined Hyperlipidemia Study. Simvastatin decreased TC, LDL-C, and TG in these patients.
Dysbetalipoproteinemia in Adults
The results of a subgroup analysis in 7 adult patients with dysbetalipoproteinemia (apo E2/2) (very-low-density lipoprotein cholesterol [VLDL-C]/TG>0.25) from a 130-patient, double-blind, placebo-controlled, 3-period crossover study are presented in Table 7. Simvastatin decreased total-C, LDL-C + intermediate-density
lipoprotein (IDL), VLDL-C + IDL, and TG compared to placebo.
Table 7: Lipid Effects in Adult Patients with Dysbetalipoproteinemia Over Six Weeks [Median Percent Change (min, max) from Baseline]*
| TREATMENT | N | Total-C | LDL-C + IDL | HDL-C | TG | VLDL-C + IDL | Non-HDL-C |
| Placebo | 7 | -8% | -8% | -2% | +4% | -4% | -8% |
| (-24, +34) | (-27, +23) | (-21, +16) | (-22, +90) | (-28, +78) | (-26, -39) |
| Simvastatin 40 | 7 | -50% | -50% | +7% | -41% | -58% | -57% |
| mg/day | (-66, -39) | (-60, -31) | (-8, +23) | (-74, -16) | (-90, -37) | (-72, -44) |
| Simvastatin 80 | 7 | -52% | -51% | +7% | -38% | -60% | -59% |
| mg/day | (-55, -41) | (-57, -28) | (-5, +29) | (-58, +2) | (-72, -39) | (-61, -46) |
* The median baseline values (mg/dL) were: total-C = 324, LDL-C = 121, HDL-C = 31, TG = 411, VLDL-C = 170, and non-HDL-C = 291.
Homozygous Familial Hypercholesterolemia
In a controlled clinical study, 12 patients 15-39 years of age with homozygous familial hypercholesterolemia (HoFH) received simvastatin 40 mg/day in a single dose, or 80 mg/day in 3 divided doses. In 12 patients the mean LDL-C changes at 9 weeks for the 40- and 80-mg doses were -13.7% (range -22.5% to -4.9%) and -24.6% (range -37.3% to -11.9%), respectively.
Pediatric Patients 10 Years of Age and Older with HeFH
In a double-blind, placebo-controlled study, 175 pediatric patients (99 boys and 76 post-menarchal girls) 10 years of age and older (mean age 14 years old) with heterozygous familial hypercholesterolemia (HeFH) were randomized to simvastatin (n=106) or placebo (n=67) for 24 weeks (base study). To be included in the study, patients were required to have a baseline LDL-C level between 160 and 400 mg/dL and at least one parent with an LDL-C level >189 mg/dL. The dosage of simvastatin (once daily in the evening) was 10 mg for the first 8 weeks, 20 mg for the second 8 weeks, and 40 mg thereafter. In a 24- week extension, 144 patients elected to continue therapy with simvastatin 40 mg or placebo.
Simvastatin significantly decreased plasma levels of total-C, LDL-C, and apolipoprotein B (ApoB) (see Table 8) in the HeFH study. Results from the extension at 48 weeks were comparable to the results at Week 24.
The safety and effectiveness of dosages above 40 mg daily have not been studied in pediatric patients with HeFH. The long-term efficacy of simvastatin therapy in pediatric patients to reduce morbidity and mortality in adulthood has not been established.
Table 8: Lipid Effects in Pediatric Patients 10 Years of Age and Older with Heterozygous Familial Hypercholesterolemia (Mean Percent Change from Baseline)
| Dosage | Duration | N | | Total-C | LDL-C | HDL-C | TG* | ApoB |
| Placebo | 24 Weeks | 67 | % Change from Baseline (95% CI) | +1.6% (-2.2, 5.3) | +1.1% (-3.4, 5.5) | +3.6% (-0.7, 8.0) | -3.2% (-11.8, 5.4) | -0.5% (-4.7, 3.6) |
| Mean baseline, mg/dL (SD) | 279 (52) | 212 (49) | 47 (12) | 90 (51) | 186 (38) |
| Simvastatin | 24 Weeks | 106 | % Change from Baseline (95% CI) | -26.5% (-29.6, -23.3) | -36.8% (-40.5, -33.0) | +8.3% (4.6, 11.9) | -7.9% (-15.8, 0.0) | -32.4% (-35.9, -29.0) |
| Mean baseline, mg/dL (SD) | 270 (44) | 204 (42) | 48 (9) | 78 (46) | 180 (34) |
*median percent change