TGF-alpha/epiregulin monoclonal antibody(Eli Lilly)

Two phase 1 studies (TGAA and TGAB) evaluated the safety, pharmacokinetics, pharmacodynamics, and efficacy of LY3016859 (LY), a monoclonal antibody that binds epiregulin and transforming growth factor α (TGF‐α), administered intravenously or subcutaneously. In TGAA, 56 healthy subjects received a single dose of LY (0.1–750 mg intravenously, 50 mg subcutaneously) or placebo. In TGAB part A, 15 patients with diabetic nephropathy (DN) received 2 doses of LY (10–750 mg intravenously) or placebo, and in TGAB part B, 45 patients with DN received 5 doses of LY (50–750 mg intravenously) or placebo. Pharmacokinetics, pharmacodynamics, anti‐LY antibodies, and change in proteinuria and albuminuria were evaluated. Single and multiple doses of LY administered 3 weeks apart were well tolerated. Pharmacokinetics were nonlinear in healthy subjects and patients with DN, indicating target‐mediated drug disposition. Epiregulin level increased in both studies, and TGF‐α levels increased in the TGAB study, consistent with target engagement; however, LY treatment did not significantly reduce proteinuria or albuminuria in patients with DN. There was no obvious effect of LY on the disease‐related biomarkers monocyte chemoattractant protein‐1, synaptopodin, or transferrin. Although LY administration resulted in a high frequency of anti‐LY antibodies, pharmacokinetics, target engagement, and efficacy were not impacted.

Recent studies have implicated a role of the epidermal growth factor receptor (EGFR) pathway in kidney disease. Skin toxicity associated with therapeutics which completely block the EGFR pathway precludes their use in chronic dosing. Therefore, we developed antibodies which specifically neutralize the EGFR ligands TGFα (transforming growth factor‐alpha) and epiregulin but not EGF (epidermal growth factor), amphiregulin, betacellulin, HB‐EGF (heparin‐binding epidermal growth factor), or epigen. The epitope of one such neutralizing antibody, LY3016859, was characterized in detail to elucidate the structural basis for ligand specificity. Here we report a crystal structure of the LY3016859 Fab fragment in complex with soluble human TGFα. Our data demonstrate a conformational epitope located primarily within the C‐terminal subdomain of the ligand. In addition, point mutagenesis experiments were used to highlight specific amino acids which are critical for both antigen binding and neutralization, most notably Ala41, Glu44, and His45. These results illustrate the structural basis for the ligand specificity/selectivity of LY3016859 and could also provide insight into further engineering to alter specificity and/or affinity of LY3016859.