Human Anti-PCSK9 Recombinant Antibody (clone mAb1)

(A) mAb1 induced LDLR protein in HepG2 cells after 24 and 48 h, as assessed by Western blot analysis. (B) mAb1 increased LDLR protein in a HepG2 stable cell line overexpressing PCSK9. Cells were incubated with mAb1 for 24 h. The fold change in a and b was calculated as the ratio of LDLR in the presence of mAb1 to LDLR in the absence of mAb1, after normalization of LDLR to β-actin in each lane. (C) A combination of mAb1 with mevinolin induces LDLR protein more than either treatment alone. HepG2 cells were incubated with mAb1 (1, 3, or 10 μg/mL) with or without mevinolin (0.2 or 1 μg/mL) for 48 h, followed by Western blot analysis of whole-cell lysates. The fold change in c was calculated as the ratio of LDLR in the presence of mAb1 and/or mevinolin to LDLR in the untreated cells, after normalization of LDLR to β-actin in each lane.

(A) Injection of 10 mg/kg mAb1 caused a statistically significant decrease in TC. Results are expressed as the mean ± SEM, n = 7 per group. (B) mAb1 induced hepatic LDLR protein expression, as assessed by Western blot analysis of pooled liver lysates. The fold change was calculated as the ratio of LDLR in the presence or absence of mAb1 for each time point after normalization of the LDLR to β-actin in each lane. (C) mAb1 dose-dependently lowered serum non-HDL-C in mice expressing huPCSK9 by adeno-associated virus (AAV) (n = 7 per treatment group). Results are expressed as the mean ± SEM. *P < 0.05; **P < 0.01 vs. anti-KLH control antibody at the same time point and dose.

A single injection of mAb1 led to (A) a significant lowering of serum TC, observed as early as 8 h after administration of mAb1; (B) a significant lowering in serum LDL-C, with maximal lowering observed at 10 days after injection; and (C) a significant lowering of HDL-C at day 3 and day 7. Results are expressed as mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001 vs. anti-KLH control antibody at the same time point, n = 4 per group. (D) Temporal relationship between free circulating PCSK9 levels and serum LDL-C after administration of mAb1.