Affibody Announces Termination of ABY-039 (FcRn) Program

Solna, Sweden, June 15, 2020. Affibody AB (“Affibody”), a clinical stage biopharmaceutical company today announced the completion of its adaptive, double-blind, placebo-controlled Phase 1 study investigating safety, tolerability, pharmacokinetics, and pharmacodynamics of its novel FcRn inhibitor ABY-039 (FcRn) in healthy volunteers.

ABY-039 is a bivalent antibody-mimetic that targets the neonatal Fc receptor and that has shown potent lowering of plasma IgG titers and very long half-life in healthy volunteers in Phase 1. Its main competitor, efgartigimod, has recently demonstrated the benefit of IgG lowering in patients with myasthenia gravis in Phase 3. Affibody today announced the completion of the ABY-039 Phase 1 trial, and the termination of the ABY-039 program due to tolerability observations that would limit the target product profile of subcutaneous high dose once monthly maintentance injections. Based on these observations Alexion has terminated the co-development agreement with Affibody. The termination will become effective June 18, 2020.

“In light of the successful development of efgartigimod, with a risk for a less than optimal product profile, and with note of a challenging target biology, including for instance the dual functionality of albumin and IgG binding, we will focus on other proprietary projects in our pipeline” said David Bejker, CEO of Affibody.

ABY-039 has been specifically designed to utilize the advantages of Affibody’s technology platform to differentiate from competing antibody and Fc-based approaches by binding both to albumin and FcRn. ABY-039 is a small protein ligand (19 kDa, an eighth of the size of an antibody) and has an in vivo half-life exceeding that of antibody-based approaches.

“We have seen clear evidence that our protein engineering efforts were successful in terms of the efficacy and potency of ABY-039. Although we are disappointed that the ABY-039 program will not continue, it is reassuring to note that our ABY-035 Phase 2 study has exceeded two years of high dose administration in psoriasis patients with excellent safety and tolerability. The Phase 2 study is investigating our bispecific IL-17A inhibitor, ABY-035, that shares the molecular format and has a high sequence similarity to ABY-039” said Fredrik Frejd, CSO of Affibody.