Gary Swergold

Effect of a monoclonal antibody to PCSK9 on LDL cholesterol.

BACKGROUND Proprotein convertase subtilisin/kexin 9 (PCSK9), one of the serine proteases, binds to low-density lipoprotein (LDL) receptors, leading to their accelerated degradation and to increased LDL cholesterol levels. We report three phase 1 studies of a monoclonal antibody to PCSK9 designated as REGN727/SAR236553 (REGN727). METHODS In healthy volunteers, we performed two randomized, single ascending-dose studies of REGN727 administered either intravenously (40 subjects) or subcutaneously (32 subjects), as compared with placebo. These studies were followed by a randomized, placebo-controlled, multiple-dose trial in adults with heterozygous familial hypercholesterolemia who were receiving atorvastatin (21 subjects) and those with nonfamilial hypercholesterolemia who were receiving treatment with atorvastatin (30 subjects) (baseline LDL cholesterol, >100 mg per deciliter [2.6 mmol per liter]) or a modified diet alone (10 subjects) (baseline LDL cholesterol, >130 mg per deciliter [3.4 mmol per liter]). REGN727 doses of 50, 100, or 150 mg were administered subcutaneously on days 1, 29, and 43. The primary outcome for all studies was the occurrence of adverse events. The principal secondary outcome was the effect of REGN727 on the lipid profile. RESULTS Among subjects receiving REGN727, there were no discontinuations because of adverse events. REGN727 significantly lowered LDL cholesterol levels in all the studies. In the multiple-dose study, REGN727 doses of 50, 100, and 150 mg reduced measured LDL cholesterol levels in the combined atorvastatin-treated populations to 77.5 mg per deciliter (2.00 mmol per liter), 61.3 mg per deciliter (1.59 mmol per liter), and 53.8 mg per deciliter (1.39 mmol per liter), for a difference in the change from baseline of -39.2, -53.7, and -61.0 percentage points, respectively, as compared with placebo (P<0.001 for all comparisons). CONCLUSIONS In three phase 1 trials, a monoclonal antibody to PCSK9 significantly reduced LDL cholesterol levels in healthy volunteers and in subjects with familial or nonfamilial hypercholesterolemia. (Funded by Regeneron Pharmaceuticals and Sanofi; ClinicalTrials.gov numbers, NCT01026597, NCT01074372, and NCT01161082.).

Potential of Proprotein Convertase Subtilisin/Kexin Type 9 Based Therapeutics

The link between proprotein convertase subtilisin/kexin type 9 (PCSK9) and cholesterol metabolism was established only in 2003 when genetic mapping and positional cloning in patients with autosomal dominant hypercholesterolemia in which linkage to the loci coding for the LDL receptor and apolipoprotein B had been excluded identified the genetic defect missense as mutations in PCSK9, a protein/enzyme previously unknown to be related to lipid metabolism. Laboratory-based investigations confirmed that these were gain-of-function mutations. Further studies in cohorts with low LDL cholesterol (LDLc) levels from large epidemiological cardiovascular studies reported that loss-of-function mutations in PCSK9 were associated with protection from cardiovascular disease. An additional critical observation provided evidence that the interaction of PCSK9 and the LDL receptor was through circulating, not intracellular, PCSK9, which bound to the receptor, and then mediated the recycling of the LDL receptor. These findings established PSCK9 as a potential therapeutic target and resulted in biopharmaceutical companies developing interventions designed to lower LDLc levels. Clinical development programs for monoclonal antibodies against PCSK9 have advanced rapidly with completion of comprehensive phase 1 and 2 trials with both REGN727/SAR236553 (REGN727) and AMG 145, clearly demonstrating substantial reductions in LDLc levels in patients receiving diet alone, low, moderate, and high doses of statins, or statin combined with ezetimibe, and both heterozygous familial hypercholesterolemia and nonfamilial hypercholesterolemia subjects. Concomitant and parallel reductions in the levels of apolipoprotein B and its related lipoproteins, and small but significant increases in HDL cholesterol levels were seen as anticipated. An unanticipated and robust decrease in lipoprotein(a) levels was also noted. Although these trials have been relatively short term, no significant safety issues or target organs of interest have emerged. Larger and much longer phase 3 trials are now in progress to assess the long-term tolerability, safety, and impact on cardiovascular disease events of these very effective LDLc lowering compounds.

Cardiovascular safety and gastrointestinal tolerability of etoricoxib vs diclofenac in a randomized controlled clinical trial (The MEDAL study)

OBJECTIVE To compare cardiovascular (CV) and other safety and efficacy parameters of etoricoxib 60 and 90 mg, and diclofenac 150 mg. METHODS This double-blind study randomized OA patients to etoricoxib 90 mg, then to 60 mg once daily vs diclofenac 75 mg twice daily; RA patients were randomized to etoricoxib 90 mg once daily or diclofenac 75 mg twice daily. The primary endpoint was non-inferiority of etoricoxib vs diclofenac for thrombotic CV events (95% CI upper bound of hazard ratio <1.30). Other safety and efficacy parameters were evaluated in cohorts of patients based on etoricoxib dose and disease. RESULTS A total of 23 504 patients were randomized with mean treatment duration from 19.4 to 20.8 months. The thrombotic CV risk hazard ratio (HR) (etoricoxib to diclofenac) was 0.96 (95% CI 0.81, 1.15), consistent with non-inferiority of etoricoxib to diclofenac. The cumulative gastrointestinal (GI)/liver adverse events (AEs) discontinuation rate was significantly lower for etoricoxib than diclofenac in each patient cohort; HR (95% CI) of 0.46 (0.39, 0.54), 0.52 (0.42, 0.63) and 0.49 (0.39, 0.62) for the 60 mg OA, 90 mg OA and RA cohorts. The maximum average change in systolic blood pressure (BP) with etoricoxib was 3.4-3.6 mmHg (diastolic BP: 1.0-1.5 mmHg), while diclofenac produced a maximum average change of 0.9-1.9 mmHg (diastolic BP: 0.0-0.5 mmHg). Both agents resulted in similar efficacy regardless of etoricoxib dose. CONCLUSION Long-term etoricoxib use is associated with a risk of thrombotic CV events comparable with that of diclofenac. Compared with diclofenac, etoricoxib demonstrated a greater risk of renovascular AEs, but a more favourable GI/liver tolerability profile.

Characterization of Autosomal Dominant Hypercholesterolemia Caused by PCSK9 Gain of Function Mutations and its Specific Treatment with Alirocumab, a PCSK9 Monoclonal Antibody

Background—Patients with PCSK9 gene gain of function (GOF) mutations have a rare form of autosomal dominant hypercholesterolemia. However, data examining their clinical characteristics and geographic distribution are lacking. Furthermore, no randomized treatment study in this population has been reported. Methods and Results—We compiled clinical characteristics of PCSK9 GOF mutation carriers in a multinational retrospective, cross-sectional, observational study. We then performed a randomized placebo-phase, double-blind study of alirocumab 150 mg administered subcutaneously every 2 weeks to 13 patients representing 4 different PCSK9 GOF mutations with low-density lipoprotein cholesterol (LDL-C) ≥70 mg/dL on their current lipid-lowering therapies at baseline. Observational study: among 164 patients, 16 different PCSK9 GOF mutations distributed throughout the gene were associated with varying severity of untreated LDL-C levels. Coronary artery disease was common (33%; average age of onset, 49.4 years), and untreated LDL-C concentrations were higher compared with matched carriers of mutations in the LDLR (n=2126) or apolipoprotein B (n=470) genes. Intervention study: in PCSK9 GOF mutation patients randomly assigned to receive alirocumab, mean percent reduction in LDL-C at 2 weeks was 62.5% (P<0.0001) from baseline, 53.7% compared with placebo-treated PCSK9 GOF mutation patients (P=0.0009; primary end point). After all subjects received 8 weeks of alirocumab treatment, LDL-C was reduced by 73% from baseline (P<0.0001). Conclusions—PCSK9 GOF mutation carriers have elevated LDL-C levels and are at high risk of premature cardiovascular disease. Alirocumab, a PCSK9 antibody, markedly lowers LDL-C levels and seems to be well tolerated in these patients. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01604824.

Factors associated with blood pressure changes in patients receiving diclofenac or etoricoxib : results from the MEDAL study

Objective To evaluate the hypertensive effects of etoricoxib and diclofenac relative to baseline hypertension risk factors in arthritis patients. Methods Multivariate analysis of data from the Multinational Etoricoxib and Diclofenac Arthritis Long-term (MEDAL) study (n = 23 504). We evaluated risk factors for change in systolic blood pressure (BP) (SBP) and diastolic BP (DBP) at 4 months versus baseline; exceeding predefined limits of change (PLoC) in BP anytime during the study; and the effect of concomitant antihypertensive class on SBP and exceeding SBP PLoC. Results Increased SBP was most highly associated with history of hypertension (+3.04 mmHg; P < 0.0001), as were increased DBP (+1.28 mmHg; P < 0.0001), and exceeding DBP PLoC [odds ratio (OR) = 1.83; P < 0.0001]. Exceeding SBP PLoC (OR = 1.50; P < 0.0001) was most highly associated with age at least 65 years. Etoricoxib (vs. diclofenac) was also significantly associated with increased SBP (P < 0.0001), DPB (P < 0.0001 to P = 0.0015), and exceeding SBP PLoC (P < 0.0001 to P = 0.002). Compared with no antihypertensive medication, background calcium channel blockers (CCB) were associated with a small, nonsignificant decrease in SBP (−0.60 mmHg) and no increased odds of exceeding SBP PLoC [OR = 1.00 (95% CI 0.71, 1.42)]. All other antihypertensive classes were associated with either no change or numerically or statistically significantly increased SBP and increased odds of exceeding PLoC. Conclusion History of hypertension and age at least 65 years were most strongly associated with increased BP. Treatment with etoricoxib vs. diclofenac was also a significant factor for increased BP. CCBs appear to maintain antihypertensive effects with concurrent NSAID therapy better than other examined antihypertensive drug classes.