| Pharmacotherapeutic group: nicotinic acid and derivatives, ATC code: C10AD52.Tredaptive contains nicotinic acid, which at therapeutic doses is a lipid-modifying agent, and laropiprant, a potent, selective antagonist of the prostaglandin D2 (PGD2) receptor subtype 1 (DP1). Nicotinic acid lowers the levels of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), very low density lipoprotein cholesterol (VLDL-C), apolipoprotein B (apo B, the major LDL protein), triglycerides (TG), and lipoprotein(a) (Lp(a), a modified LDL particle) and elevates the levels of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (apo A-I, the major protein component of HDL). Laropiprant suppresses PGD2 mediated flushing associated with administration of nicotinic acid. Laropiprant has no effect on lipid levels nor does it interfere with the effects of nicotinic acid on lipids. Nicotinic acid Mechanism of action The mechanisms by which nicotinic acid modifies the plasma lipid profile are not fully understood. Nicotinic acid inhibits release of free fatty acids (FFA) from adipose tissue, which may contribute to the reduced plasma LDL-C, TC, VLDL-C, apo B, TG, and Lp(a), as well as elevated HDL-C, and apo A-I, all of which are associated with lower cardiovascular risk. Additional explanations that do not invoke plasma FFA reduction as the central driver of lipid profile modification include nicotinic acid-mediated inhibition of de novo lipogenesis or esterification of fatty acids into TG in the liver.Pharmacodynamic effects Nicotinic acid causes a relative shift in the distribution of LDL subclasses from small, dense (most atherogenic) LDL particles to larger LDL particles. Nicotinic acid also elevates the HDL2 subfraction to a greater extent than the HDL3 subfraction, thereby increasing the HDL2:HDL3 ratio, which is associated with decreased cardiovascular disease risk. HDL is hypothesised to participate in the transport of cholesterol from tissues back to the liver, to suppress vascular inflammation associated with atherosclerosis, and to have anti-oxidative and anti-thrombotic effects.Like LDL, cholesterol-enriched triglyceride-rich lipoproteins, including VLDL, intermediate-density lipoproteins (IDL), and remnants, can also promote atherosclerosis. Elevated plasma TG levels are frequently found in a triad with low HDL-C levels and small LDL particles, as well as in association with non-lipid metabolic risk factors for coronary heart disease (CHD).Treatment with nicotinic acid reduces the risk of death and cardiovascular events, and slows progression or promotes regression of atherosclerotic lesions. The Coronary Drug Project, a five year study completed in 1975, showed that nicotinic acid had a statistically significant benefit in decreasing nonfatal, recurrent myocardial infarctions (MI) in men 30 to 64 years old with a history of MI. Though total mortality was similar in the two groups at five years, in a fifteen-year cumulative follow-up there were 11 % fewer deaths in the nicotinic acid group compared to the placebo cohort.Laropiprant Mechanism of action Nicotinic acid-induced flushing is mediated primarily by release of prostaglandin D2 (PGD2) in the skin. Genetic and pharmacologic studies in animal models have provided evidence that PGD2, acting through DP1, one of the two receptors for PGD2, plays a key role in nicotinic acid-induced flushing. Laropiprant is a potent and selective antagonist of DP1. Laropiprant is not expected to inhibit the production of prostaglandins.Pharmacodynamic effects Laropiprant has been shown to be effective in reducing flushing symptoms induced by nicotinic acid. The reduction in flushing symptoms (assessed by patient questionnaires) was correlated with a reduction in nicotinic acid-induced vasodilatation (assessed by measurements of skin blood flow). In healthy subjects receiving Tredaptive, pretreatment with acetylsalicylic acid 325 mg had no additional beneficial effects in reducing nicotinic acid-induced flushing symptoms compared to Tredaptive alone (see section 4.8).Laropiprant also has affinity for the thromboxane A2 receptor (TP) (although it is substantially less potent at TP as compared to DP1). TP plays a role in platelet function; however, therapeutic doses of laropiprant had no clinically relevant effect on bleeding time and collagen-induced platelet aggregation (see section 4.5).Clinical studies Effect on lipids Tredaptive was consistently efficacious across all prespecified patient subpopulations defined by race, gender, baseline LDL-C, HDL-C and TG levels, age and diabetes status.In a multicentre, double-blind, 24-week placebo-controlled study, patients taking Tredaptive (2000 mg/40 mg) with or without a statin, when compared to placebo, had significantly decreased LDL-C (-18.9 % vs. -0.5 %), TG (-21.7 % vs. 3.6 %), LDL-C:HDL-C (-28.9 % vs. 2.3 %), non-HDL-C (-19.0 % vs. 0.8 %), apo B (-16.4 % vs. 2.5 %), TC (-9.2 % vs. -0.6 %), Lp(a) (-17.6 % vs. 1.1 %), and TC:HDL-C (-21.2 % vs. 1.9 %) and also had significantly increased HDL-C (18.8 % vs. -1.2 %), and apo A-I (11.2 % vs. 4.3 %) as measured by percent change from baseline. In general, the between-group treatment effects on all lipid parameters were consistent across all patient subgroups examined. Patients receiving Tredaptive, nicotinic acid (prolonged-released formulation), or placebo were also taking statins (29 % atorvastatin [5-80 mg], 54 % simvastatin [10-80 mg], 17 % other statins [2.5-180 mg] (pravastatin, fluvastatin, rosuvastatin, lovastatin)), of which 9 % were also taking ezetimibe [10 mg]. The effect on lipids was similar whether Tredaptive was given as monotherapy or was added to ongoing statin therapy with or without ezetimibe.The placebo-adjusted LDL-C, HDL-C and TG responses appeared greater among women compared to men and appeared greater among elderly patients ( 65 years) compared to younger patients (< 65 years).In a multicentre, double-blind, 12-week factorial study, Tredaptive 1000 mg/20 mg co-administered with simvastatin, when compared with simvastatin alone or Tredaptive 1000 mg/20 mg alone, for 4 weeks, significantly lowered LDL-C (-44.2 %, -37.4 %, -8.2 % respectively), TG (-25.8 %, -15.7 %, -18.7 % respectively), TC (-27.9 %, -25.8 %, -4.9 % respectively) and significantly increased HDL-C (19.2 %, 4.2 %, 12.5 % respectively). Tredaptive (2000 mg/40 mg) co-administered with simvastatin when compared with simvastatin alone or Tredaptive (2000 mg/40 mg) alone for 12 weeks, significantly lowered LDL-C (-47.9 %, -37.0 %, -17.0 % respectively), TG (-33.3 %, -14.7 %, -21.6 % respectively), apo B (-41.0 %, -28.8 %, -17.1 % respectively), and TC (-29.6 %, -24.9 %, -9.1 % respectively), as well as LDL-C:HDL-C (-57.1 %, -39.8 %, -31.2 % respectively), non-HDL-C (-45.8 %, -33.4 %, -18.1 % respectively), and TC:HDL-C (-43.0 %, -28.0 %, -24.9 % respectively), and significantly increased HDL-C (27.5 %, 6.0 %, 23.4 % respectively). Further analysis showed Tredaptive (2000 mg/40 mg) co-administered with simvastatin when compared with simvastatin alone significantly increased apo A-I (8.6 %, 2.3 % respectively) and significantly decreased Lp(a) (-19.8 %, 0.0 % respectively ). Efficacy and safety of Tredaptive in combination with simvastatin > 40 mg were not included in this study.Flushing In two large clinical trials measuring patient-reported flushing symptoms, patients taking Tredaptive experienced less flushing than those taking nicotinic acid (prolonged-release formulations). In patients continuing in the first study (24 weeks), the frequency of moderate or greater flushing in patients treated with Tredaptive declined and approached that of patients receiving placebo (see Figure 1), whereas in patients treated with nicotinic acid (prolonged-release formulation) the flushing frequency remained constant (after Week 6).Flushing efficacy of laropiprant has not been established past 24 weeks.Figure 1. Average number of days per week with Moderate or greater* flushing symptoms across weeks 1-24 ●Tredaptive (1000 mg/20 mg to 2000 mg/40 mg at week 5)▲Nicotinic acid (prolonged-release 1000 mg to 2000 mg at week 5)○Placebo*Includes patients with moderate, severe, or extreme flushing symptomsDose advancement at Week 5In the second study (16 weeks) where acetylsalicylic acid was allowed, patients taking Tredaptive experienced significantly fewer days per week with moderate or greater flushing compared to nicotinic acid (prolonged-release formulation taken as a 12-week multi-step 500 mg to 2000 mg titration) (p< 0.001).The European Medicines Agency has waived the obligation to submit the results of studies with Tredaptive in all subsets of the paediatric population in homozygous familial hypercholesterolaemia and in paediatric patients less than 7 years old in heterozygous familial hypercholesterolaemia.The European Medicines Agency has deferred the obligation to submit the results of studies with Tredaptive in paediatric patients from 7-18 years old in heterozygous familial hypercholesterolaemia (see section 4.2 for information on paediatric use). | |