The acquisition of early-phase biotech Syntimmune is “part and parcel” to Alexion Pharmaceuticals’ plan to build up its pipeline, says the firm’s CFO.

Alexion Pharmaceuticals has entered into an agreement to buy Syntimmune for an upfront payment of $400 million (€342 million), though milestone payments could see the firm shell out a further $800 million.

The deal brings Alexion SYNT001, a humanized monoclonal antibody candidate that inhibits the interaction of FcRn with Immunoglobulin G (IgG) and IgG immune complexes. The candidate is in Phase Ib/IIa studies in patients with warm autoimmune hemolytic anemia (WAIHA) and in patients with pemphigus vulgaris (PV) or pemphigus foliaceus (PF).

Syntimmune is the second acquisition for Alexion this year after the firm bought Wilson Therapeutics in May.

“This acquisition is an excellent step in building our clinical stage pipeline and fits well with our strategy and our approach to disciplined capital allocation,” Alexion’s CFO Paul Clancy said on a conference call discussing the deal (see transcript here).

“This is part and parcel to the business plan that we have laid out with one of the key objectives of rebuilding the pipeline,” he continued, adding the firm will continue to focus on growing its pipeline, while retaining the financial capacity to do so.

In May, Alexion completed the acquisition of Swedish biotech Wilson Therapeutics, adding Phase III candidate WTX101, a first-in-class oral copper-binding agent with a unique mechanism of action and ability to access and bind copper from serum and promote its removal from the liver.

The Syntimmune and the Wilson transactions “are great examples of pulling through in executing on that plan. And we intend to continue to rebuild the pipeline looking for transformative therapies and terrible rare diseases. And we’ll do that in a disciplined way as we’ve always intended to do.”

The acquisition is expected to close in the fourth quarter of 2018.

Alexion’s top selling product is the monoclonal antibody Soliris (eculizumab), approved to treat orphan diseases atypical hemolytic uremic syndrome (aHUS). The basis of the product is the IgG4 scaffold, the firm said, and one of the reasons Alexion targeted SYNT001, which is also based on the IgG4 scaffold.

“Soliris is one of the least immunogenic marketed proteins out there with 11 years in marketed experience in the single-digits,” head of R&D John Orloff said on the call. “So we’re very confident about the IgG4 scaffold.”