Rosuvastatin Efficacy in South Asian Patients: Documented Gaps, Dosing, and Pharmacogenomics

What does the Crestor label say about Asian patients?

Crestor (rosuvastatin calcium) was approved in 2003 and generic rosuvastatin tablets are widely available [5]. Its dosing section carries a separate line for Asian patients: initiate at 5 mg once daily, and consider the risks and benefits of treatment if LDL-C is not adequately controlled at doses up to 20 mg once daily [2]. The label's stated reason is increased rosuvastatin plasma concentrations. Pharmacokinetic studies cited in the label, including one conducted in the US, showed roughly 2-fold higher median exposure (AUC and Cmax) in Asian subjects than in White controls [2]. The same section says there are no clinically relevant pharmacokinetic differences among White, Hispanic or Latino, and Black or Afro-Caribbean groups [2].

Two details matter here. The dosing line applies to "Asian patients" as one group, without separate advice for South Asian, East Asian or Southeast Asian ancestry. And the label's myopathy warning lists Asian patients among those who may be at higher risk, alongside age 65 or older, uncontrolled hypothyroidism, renal impairment, certain interacting drugs and higher doses [2].

How much higher is exposure in Asian-Indian patients?

The most direct comparison comes from Lee 2005, a single-dose study of rosuvastatin 40 mg in 36 White, 36 Chinese, 35 Malay and 35 Asian-Indian subjects living in Singapore [4]. Compared with the White group, AUC ratios were 2.31 in Chinese, 1.91 in Malay and 1.63 in Asian-Indian participants; Cmax ratios were 2.36, 2.00 and 1.68 [4]. Asian-Indian participants therefore had the smallest increase of the three groups, and it was still well above the White reference. This was one dose in volunteers, not steady-state dosing in patients with high cholesterol.

Do SLCO1B1 variants explain the difference?

The label names OATP1B1 (SLCO1B1) and BCRP (ABCG2) among the transporters that handle rosuvastatin, and lists cyclosporine as an inhibitor of both [2]. The genetic findings are limited: the variants tested in one study did not explain the Asian-White exposure difference, and the clinical impact of reduced-function SLCO1B1 has not been established [2][4].

The label says very small groups (n=3 to 5) with two reduced-function SLCO1B1 521C alleles had higher rosuvastatin concentrations, and that the genotype occurs in under 5% of most groups [2]. Lee 2005 genotyped two SLCO1B1 variants, A388G and T521C, and reported that SLCO1B1 genotypes did not account for the difference between Asian and White subjects [4].

What have studies in South Asian patients measured?

In a study of Indian men aged 40 to 60 with dyslipidemia, 52 received rosuvastatin and 52 received atorvastatin for six months [1]. In the rosuvastatin group, total cholesterol, LDL-C and HDL-C all fell significantly (P<0.05), while 25-hydroxyvitamin D did not change significantly [1]. In the atorvastatin group, 25-hydroxyvitamin D fell significantly and the LDL-C reduction correlated with vitamin D concentration [1].

A smaller South Asian study measured blood vessel function and blood lipids during treatment with rosuvastatin alone or with omega-3 fatty acids [6]. Thirty South Asian adults with dyslipidemia and endothelial dysfunction were randomized to rosuvastatin 10 mg with omega-3 fatty acids 4 g, or rosuvastatin 10 mg alone [6]. Rosuvastatin alone for four weeks did not improve endothelial-dependent or endothelial-independent vasodilation compared with baseline; after omega-3 fatty acids were added, endothelial-dependent vasodilation rose from -0.66% to 14.73% (P=0.001) and endothelial-independent vasodilation from 11.02% to 24.5% (P=0.001) [6]. In the group given the combination first, the improvement was lost when omega-3 fatty acids were withdrawn (11.36% to 0.59%, P=0.003) [6]. Adding omega-3 fatty acids also lowered triglycerides from 139 to 91 mg/dL (P=0.006) and LDL-C from 116 to 88 mg/dL (P=0.014) [6]. Endothelial function is a surrogate measure, and 30 people over eight weeks cannot show whether rosuvastatin prevents heart attacks.

Where do the cardiovascular outcome numbers come from?

JUPITER randomized 17,802 apparently healthy men aged 50 and older and women aged 60 and older with LDL-C under 130 mg/dL and hsCRP of 2.0 mg/L or higher to rosuvastatin 20 mg daily or placebo, and was stopped at a median of 1.9 years [3]. LDL-C fell 50% and hsCRP 37%; the primary end point occurred at 0.77 versus 1.36 per 100 person-years (hazard ratio 0.56, 95% CI 0.46 to 0.69) [3]. The label reports the same trial as 142 versus 252 events, a 44% relative risk reduction and a 1.2% absolute risk reduction [2].

A 2009 review of rosuvastatin's effects on LDL noted that outcome trials in specific ethnic groups, including South Asian populations, formed part of the ongoing GALAXY program at the time of writing [7].

The trial's entry criterion is worth knowing because C-reactive protein differs by ancestry. A meta-analysis of 221,287 people from 89 studies found a geometric mean CRP of 2.34 mg/L in South Asian participants (n=1,053) versus 2.03 mg/L in White participants (n=104,949), a difference not explained by study design or assay and preserved after adjustment for age and body mass index [8]. The authors concluded that a single 2 mg/L threshold for statin eligibility could produce unequal treatment thresholds across ancestries [8].

What does the label say about dosing and monitoring?

For adults, the Crestor label lists 5 to 40 mg once daily, at any time of day, with or without food, and LDL-C is assessed as early as 4 weeks after starting [2]. For severe renal impairment (creatinine clearance under 30 mL/min/1.73 m2, not on hemodialysis), the label says to start at 5 mg and not exceed 10 mg daily; exposure in that group is about 3-fold higher [2]. The label says to take Crestor at least 2 hours before an aluminum or magnesium hydroxide antacid; taking them together reduced rosuvastatin exposure by about 50% [2]. With cyclosporine the label limit is 5 mg daily (AUC rose about 7-fold in a 10-patient heart transplant study) [2][9]; with gemfibrozil the label says avoid, or if unavoidable start at 5 mg and do not exceed 10 mg daily [2][10].

The label's myopathy warning notes that risk is greater at 40 mg than at lower doses, and says patients should be told to report unexplained muscle pain, tenderness or weakness promptly, particularly with malaise or fever [2]. Transaminases above 3 times the upper limit of normal occurred in 1.1% of patients on Crestor versus 0.5% on placebo in pooled trials, and proteinuria or hematuria was more frequent on 40 mg, generally transient and not linked to worsening kidney function [2]. HbA1c and fasting glucose can rise; in JUPITER, diabetes mellitus was reported in 2.8% on rosuvastatin versus 2.3% on placebo, with mean HbA1c 0.1% higher [2][3].

What is still unresolved?

Two things. The label gives one 5 mg starting dose for Asian patients as a group, while the exposure increase in Lee 2005 ranged from 1.63-fold in Asian-Indian to 2.31-fold in Chinese participants [2][4]. And the label states that the clinical impact of reduced-function SLCO1B1 has not been established [2].