Generation and Characterization of a Novel Small Biologic Alternative to Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Antibodies, DS-9001a, Albumin Binding Domain–Fused Anticalin Protein

Abstract

Since it was recently reported that an antibody for proprotein convertase subtilisin/kexin type 9 (PCSK9) reduces the risk of cardiovascular events in a clinical context, PCSK9 inhibition is thought to be an attractive therapy for dyslipidemia. In the present study, we created a novel small biologic alternative to PCSK9 antibodies called DS-9001a, comprising an albumin binding domain fused to an artificial lipocalin mutein (ABD-fused Anticalin protein), which can be produced by a microbial production system. DS-9001a strongly interfered with PCSK9 binding to low-density-lipoprotein receptor (LDL-R) and PCSK9-mediated degradation of LDL-R. In cynomolgus monkeys, single DS-9001a administration significantly reduced the serum LDL-C level up to 21 days (62.4% reduction at the maximum). Moreover, DS-9001a reduced plasma non-high-density-lipoprotein cholesterol and oxidized LDL levels, and their further reductions were observed when atorvastatin and DS-9001a were administered in combination in human cholesteryl ester transfer protein/ApoB double transgenic mice. Additionally, their reductions on the combination of atorvastatin and DS-9001a were more pronounced than those on the combination of atorvastatin and anacetrapib. Besides its favorable pharmacologic profile, DS-9001a has a lower molecular weight (about 22 kDa), yielding a high stoichiometric drug concentration that might result in a smaller administration volume than that in existing antibody therapy. Since bacterial production systems are viewed as more suited to mass production at low cost, DS-9001a may provide a new therapeutic option to treat patients with dyslipidemia. In addition, considering the growing demand for antibody-like drugs, ABD-fused Anticalin proteins could represent a promising new class of small biologic molecules.

Development and Differentiation in Monobodies Based on the Fibronectin Type 3 Domain

“…Unfortunately in humans this construct reduced LDL-C by only 47% at the highest intravenous dose, or by 48% as a subcutaneous dose in combination with statins [82], in stark contrast to the efficacy of approved antibodies such as Evolocumab which reduce cholesterol by 60% or more with similar doses [79]. Alongside this work, an affibody non-antibody domain which targeted PCSK9 was fused with serum albumin for longer half-life [79,83]. In a similar application, and to further improve efficacy, a serum albumin domain was also fused to the Adnectin-anti-PCSK9 construct to improve circulation half-life to match that of antibodies ( Figure 3E) [79].…”

Novel strategies to target proprotein convertase subtilisin kexin 9: beyond monoclonal antibodies

“…A recent alternative biologic approach was to use a 22 kDa albuminbinding domain (ABD)-fused Anticalin protein DS-9001a produced in bacteria (Figure 2). 34 In cynomolgus monkeys, a single subcutaneous injection of such ABD-fused Anticalin protein was reported to have a somewhat longer half-life in plasma (120h) 34 compared to mAbs (60-120 h) 91 and BMS-962476 (74-108 h). 33 Such treatment resulted in a sustained 50-60% reduction of LDL-C lasting up to 21 days (Table 1), and its effect was significantly potentiated by atorvastatin.…”

Progress and prospects of biological approaches targeting PCSK9 for cholesterol-lowering, from molecular mechanism to clinical efficacy

“…Adenoviral overexpression of AnxA2 in the liver results in an increase of LDLR expression [26]; (2) DS-9001a is a small biologic molecule, composed of an albumin-binding domain fused with an artificial lipocalin mutein enabling high specific recognition of the target protein. DS-9001a inhibits the binding of the PCSK9 to LDLR, preventing LDLR degradation [27]; (3) Adnectin, BMS-962,476 is a PCSK9-targeting polypeptide conjugated with polyethylene glycol which enhances its pharmacokinetic profile, binding to human PCSK9 with subnanomolar affinity. Adnectin hinders the interaction between the EGF-A domain of LDLR and extracellular PCSK9, thus preventing the PCSK9-induced degradation of LDLR [28].…”