Tenshang Joh

A Phase I Randomized Study of a Specifically Engineered, pH‐Sensitive PCSK9 Inhibitor RN317 (PF‐05335810) in Hypercholesterolemic Subjects on Statin Therapy

This phase I study assessed the safety, tolerability, pharmacokinetics, and pharmacodynamics of RN317 (PF‐05335810), a specifically engineered, pH‐sensitive, humanized proprotein convertase subtilisin kexin type 9 (PCSK9) monoclonal antibody, in hypercholesterolemic subjects (low‐density lipoprotein cholesterol (LDL‐C) ≥ 80 mg/dl) 18–70 years old receiving statin therapy. Subjects were randomized to: single‐dose placebo, RN317 (subcutaneous (s.c.) 0.3, 1, 3, 6, or intravenous (i.v.) 1, 3, 6 mg/kg), or bococizumab (s.c. 1, 3, or i.v. 1 mg/kg); or multiple‐dose RN317 (s.c. 300 mg every 28 days; three doses). Of 133 subjects randomized, 127 completed the study. RN317 demonstrated a longer half‐life, greater exposure, and increased bioavailability vs. bococizumab. RN317 was well tolerated, with no subjects discontinuing because of treatment‐related adverse events. RN317 lowered LDL‐C by up to 52.5% (day 15) following a single s.c. dose of 3.0 mg/kg vs. a maximum of 70% with single‐dose bococizumab s.c. 3.0 mg/kg. Multiple dosing of RN317 produced LDL‐C reductions of ∼50%, sustained over an 85‐day dosing interval.

Effects of Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Inhibition with Bococizumab on Lipoprotein Particles in Hypercholesterolemic Subjects

PURPOSE Monoclonal antibody inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9) elicit significant reductions in serum LDL-C levels. However, little is known about their effects on lipoprotein particles. The purpose of this analysis was to evaluate the effect of PCSK9 inhibition with bococizumab (RN316/PF-04950615), a humanized monoclonal antibody to PCSK9, on LDL, VLDL, and HDL particle concentration and size in hypercholesterolemic subjects. METHODS Data from 3 double-blind, placebo-controlled, randomized studies were analyzed. In study 1, a total of 67 hypercholesterolemic subjects received IV placebo or bococizumab 0.25, 0.5, 1, or 1.5 mg/kg weekly for 4 weeks. In studies 2 and 3, a total of 135 hypercholesterolemic subjects taking statins received IV placebo or bococizumab 0.25, 1, 3, or 6 mg/kg monthly for 12 weeks. Lipoprotein particle concentration and size were measured by using nuclear magnetic resonance spectroscopy. FINDINGS Overall, the majority of subjects were men (51.9%) aged >50 years of age and of white ethnic origin. In total, 189 subjects with both baseline and 2-week posttreatment data were included in the analysis. After PCSK9 inhibition with bococizumab 0.5, 1, 1.5, 3, and 6 mg/kg, concentrations of total LDL, total small LDL, and small VLDL particles decreased significantly versus baseline and placebo (P < 0.05), whereas concentrations of HDL particles increased (P < 0.05). The size of the LDL, VLDL, and HDL particles increased after PCSK9 inhibition. Reductions in LDL-C and total LDL particle concentrations were highly correlated. IMPLICATIONS The effect of inhibiting PCSK9 with bococizumab on lipoprotein particle concentration and size are consistent with the general mechanism of PCSK9 inhibitors in blocking PCSK9-mediated downregulation of LDL receptors. PCSK9 inhibition has the potential to provide a clinical benefit through the modulation of atherogenic lipoprotein particles in addition to LDL-C lowering, and this effect will likely be assessed in future analyses of data from cardiovascular outcomes trials of PCSK9 monoclonal antibodies that are currently being conducted. ClinicalTrials.gov identifiers: NCT01243151, NCT01342211, and NCT01350141.

EFFECTS OF RN316 (PF-04950615), A HUMANIZED IGG2ΔA MONOCLONAL ANTIBODY BINDING PROPROTEIN CONVERTASE SUBTILISIN KEXIN TYPE 9, ON LIPOPROTEIN PARTICLES IN HYPERCHOLESTEROLEMIC SUBJECTS

RN316 binds to Proprotein Convertase Subtilisin Kexin type 9 (PCSK9), preventing PCSK9-mediated down-regulation of the low density lipoprotein (LDL) receptor (R), improving LDL cholesterol (C) clearance from serum, and reducing LDL-C levels. High concentrations of small LDL particles contribute to

A Mechanism‐Based Pharmacokinetic/Pharmacodynamic Model for Bococizumab, a Humanized Monoclonal Antibody Against Proprotein Convertase Subtilisin/Kexin Type 9, and Its Application in Early Clinical Development

Bococizumab (RN316/PF‐04950615), a humanized monoclonal antibody, binds to secreted proprotein convertase subtilisin/kexin type 9 (PCSK9) and prevents its downregulation of low‐density lipoprotein receptor, leading to improved clearance and reduction of low‐density lipoprotein cholesterol (LDL‐C) in plasma. A mechanism‐based drug‐target binding model was developed, accounting for bococizumab, PCSK9, and LDL‐C concentrations and the effects of concomitant administration of statins. This model was utilized to better understand the pharmacokinetic/pharmacodynamic (PK/PD) data obtained from 3 phase 1 and 2 phase 2a clinical studies. First, simulations performed with this model demonstrated that the conventional method of the area‐under‐the‐curve ratio for bioavailability determination underestimated the subcutaneous bioavailability of bococizumab due to its target‐mediated disposition. Second, a covariate model component for statin effects on bococizumab PK/PD was characterized, including a description of the decreased baseline LDL‐C, increased baseline PCSK9, and increased LDL‐C lowering with concomitant use of statins. Last, the impact of the dosing regimens with and without a dose holiday on bococizumabs LDL‐C–lowering effectiveness was shown to be predictable due to the well‐characterized PK‐PD relationship.

Single and multiple ascending-dose study of glucagon-receptor antagonist RN909 in type 2 diabetes: a phase 1, randomized, double-blind, placebo-controlled trial

PurposeThis first-in-human study assessed safety, immunogenicity, pharmacokinetics, and pharmacodynamics of RN909, a monoclonal antibody antagonist of the glucagon receptor, in type 2 diabetes (T2DM) subjects.MethodsThis study enrolled 84 T2DM subjects receiving stable metformin regimens. Forty-four subjects were randomized to receive single escalating doses of RN909 (0.3 to 6 mg/kg subcutaneously (SC), or 1 mg/kg intravenously (IV)), or placebo; 40 subjects were randomized to receive multiple escalating doses (50 to 150 mg SC) or placebo every 4 weeks for 12 weeks.ResultsRN909 was well tolerated; treatment-related elevated liver function tests (LFTs) were observed in 4/33 (12.1%) and 5/32 (15.6%) subjects treated with single and multiple doses, respectively, versus 1/10 (10%) and 0 in the respective placebo groups. RN909 dose-normalized AUCinf increased more than dose-proportionally following single SC doses, and after multiple doses, accumulation ratios ranged from 1.3 to 3.4. The incidence of antidrug antibodies (ADA) was 33% after single doses and 50% after multiple doses. RN909 produced dose-dependent, durable fasting plasma glucose (FPG)-lowering at day 29 (mean change −20.6 to −97.5 mg/dL) and day 85 (mean change; −27.2 to −43.5 mg/dL) after single and multiple doses, respectively. HbA1c also was reduced after single (mean change −0.30% to −1.44%), and multiple doses (−0.83% to −1.56%).ConclusionRN909 was well tolerated after single and multiple doses in T2DM subjects, with diarrhea and elevated LFTs the most frequent adverse events. The appearance of ADA did not affect pharmacokinetics or efficacy. Robust lowering of FPG and HbA1c was observed.