Alexion and Affibody Announce Partnership to Co-Develop Anti-FcRn Affibody® Molecule

Solna, Sweden & Boston, USA, March 20, 2019. Affibody AB and Alexion Pharmaceuticals, Inc. (NASDAQ: ALXN) today announced a partnership to co-develop ABY-039 for rare Immunoglobulin G (IgG)-mediated autoimmune diseases.

• Agreement provides opportunity to expand Alexion’s clinical-stage anti-FcRn portfolio with ABY-039
• Affibody to receive $25 million upfront payment with potential for additional milestone-dependent and royalty payments, and option for U.S. co-promote
• Affibody’s technology offers potential for extended half-life compared to other anti-FcRn therapies and low volume subcutaneous administration

Currently in Phase 1 development, ABY-039 is a bivalent antibody-mimetic that targets the neonatal Fc receptor (FcRn). ABY-039 has been specifically designed to combine Affibody’s protein therapeutics platform (Affibody® molecules) and Albumod™ technology to achieve a long half-life, which, along with its small size provides the potential for less frequent, convenient, at-home subcutaneous administration.

“We believe there is significant opportunity to transform patient care with FcRn-targeted therapies and are thrilled to add a second clinical-stage anti-FcRn medicine to our pipeline with this collaboration,” said John Orloff, M.D., Executive Vice President and Head of Research & Development at Alexion. “While clinical development is still early, we are excited by ABY-039’s potential to be an optimal subcutaneous therapy across a number of IgG-mediated diseases, providing patients with the possibility of a convenient self-administered treatment option.”

“ABY-039 offers an innovative and novel approach to treating IgG-mediated diseases. Its rapid onset, sustained response, long half-life and potential for low volume administration hold great promise as a self-administered subcutaneous anti-FcRn therapy of choice,” said David Bejker, Chief Executive Officer of Affibody. “We look forward to building our partnership with Alexion and leveraging their significant development and commercial experience to accelerate the development of ABY-039. This collaboration is another key step in the evolution of our company that is aligned with our key strategic objectives.”

ABY-039 is being evaluated in a Phase 1 study in healthy volunteers. This adaptive, double-blind, placebo-controlled study is evaluating the safety, tolerability, pharmacokinetics, and pharmacodynamics of ABY-039 and will aid in dose selection for future studies. The companies are assessing potential indications for future development.

Under the terms of the agreement, Alexion will provide Affibody with an upfront payment of $25 million, with the potential for additional development- and sales-based milestones of up to $625 million and tiered low double-digit royalty payments. Alexion will lead joint clinical development of ABY-039 and commercialization activities. Affibody has the option to co-promote ABY-039 in the U.S. and will lead clinical development for an undisclosed indication.

The companies expect to close the transaction in the second quarter of 2019, subject to clearance under the Hart-Scott Rodino Antitrust Improvements Act.

Alexion will discuss the partnership further during Alexion’s Investor Day event and webcast on March 20, 2019.

About FcRn

Antibodies play an important role in a healthy body’s defense by fighting infections from bacteria and other invaders. In autoimmune diseases, however, the body mistakenly attacks itself through the production of pathogenic (disease-causing) antibodies of the Immunoglobulin G (IgG) subtype. Neonatal Fc receptor (FcRn) rescues IgGs from lysosomal degradation by binding them to endosomes and returning them to the bloodstream. This helps prolong the half-life of IgG. In healthy individuals, this function contributes to a normal immune response. In many autoimmune conditions, however, FcRn prevents lysosomal degradation of pathogenic IgGs associated with driving the disease. Therefore, blocking the FcRn-IgG interaction has the potential to drive degradation of IgG within cells and rapidly reduce circulating pathogenic IgG.

About ABY-039

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