SAP variants and their use

Inventors

Willett, W. Scott

Assignees

Promedior Inc

Abstract

Polypeptides are susceptible to denaturation or enzymatic degradation in the blood, liver or kidney. Due to the low stability of some polypeptides, it has been required to administer polypeptide drugs in a sustained frequency to a subject in order to maintain an effective plasma concentration of the active substance. Furthermore, pharmaceutical compositions of therapeutic peptides preferably have a shelf-life of several years in order to be suitable for common use. However, peptide compositions are inherently unstable due to sensitivity towards chemical and physical degradation. In part, the invention provides SAP variant proteins, compositions, pharmaceutical preparations and formulations having a prolonged in vivo half-life, prolonged shelf-life, or rather increased in vitro stability, or increased manufacturing efficiency compared to human SAP. Advantages of increased plasma half-life include, but are not limited to, reducing the amount and/or frequency of dosing.

Core Innovation

The invention describes Serum Amyloid P (SAP) variant proteins comprising five SAP protomers, where each SAP protomer comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 1. A key variant feature is substitution at position 32 of SEQ ID NO: 1 so that the residue at position 32 is not asparagine (N), which functions to inhibit N-linked glycosylation. The described variants include substantially glycan-free protomers.

The invention further describes SAP variant features intended to improve stability and functional performance. Protease-resistance is addressed by substitutions at positions 144 and 145, and resistance to calcium-dependent autoaggregation is addressed by a substitution at position 167. Covalent conjugation to inert polymers is described, including PEG or dextran, with site-specific attachment using introduced cysteines or glutamine-mediated transglutaminase.

In addition to variant proteins, the invention describes covalently crosslinked SAP oligomers having multi-pentamer structures. Therapeutic use is described for SAP-responsive disorders, and the variants and oligomers are linked to inhibiting Macrophage-Derived Chemokine (MDC) production. The overview also reports improved stability including prolonged plasma/in vivo half-life and increased in vitro/in vivo stability, as well as improved manufacturing efficiency versus human serum-derived SAP.

Claims Coverage

The independent claim defines a SAP variant made from five SAP protomers with specified sequence identity constraints and a defined position-32 substitution, together with a functional inhibition of MDC production. Dependent claims add sequence-identity refinements, specific position-32 substitutions, comparative functional constraints such as protease-cleavage resistance and calcium-dependent autoaggregation resistance, and covalent PEG or dextran conjugation details.

Overall, the claim set centers on a five-protomer SAP variant with a SEQ ID NO: 1 identity threshold, a position-32 substitution that avoids asparagine at that position, and a functional requirement of greater inhibition of MDC production than serum-derived human SAP. Dependent claims refine sequence identity and specify particular position-32 substitutions, and they add comparative functional properties and covalent PEG conjugation to cysteine residues.

Stated Advantages

Documented Applications