Syntimmune Snares $50M to Test Autoimmune Drug in Two Rare Diseases

Xconomy New York — 

Although antibodies play a key role in neutralizing invading bacteria and viruses, sometimes these protective proteins can turn against the body’s own tissues, sparking an autoimmune disorder.

Syntimmune’s leaders believe their company has found a way to block the immune system’s attack on the body. And now the biotech has $50 million to advance its lead drug through clinical trials in two rare diseases. Apple Tree Partners led the Series B investment round with a $48 million commitment. Earlier backers also joined in the financing for the New York-based company, which has now raised $78 million total from investors.

David de Graaf, CEO of Syntimmune, says the company’s drug SYNT001 blocks a molecule called neonatal Fc receptor (FcRn). That molecule regulates a blood protein called immunoglobulin G (IgG), which has a role in fighting infections. In autoimmune diseases, antibodies target the body’s tissue, making IgG pathogenic. De Graaf says the Syntimmune drug disables the protein interaction in a way that doesn’t affect the other things that FcRn does.

“We leave the whole immune system in place,” he says. “We’re only removing IgG’s role in these diseases.”

Syntimmune is focusing its research on two autoimmune diseases. The first is pemphigus, a group of rare skin disorders that cause blisters and sores on the skin or mucus membranes. The second is warm autoimmune hemolytic anemia, a disorder in which healthy red blood cells are destroyed by the body’s own antibodies.

De Graaf says that when he joined Syntimmune last fall, he identified 50 autoimmune disorders that the company’s drug could target. He chose pemphigus and warm autoimmune hemolytic anemia because they are rare diseases with no treatments, other than steroids. He adds that by targeting a skin disease and a blood disease, Syntimmune can demonstrate the potential breadth of the company’s technology to address a range of disorders. At least, that’s the hope.

Syntimmune has started to identify clinical trial sites, and de Graaf says he hopes to begin enrolling patients in two Phase1b/2a clinical trials testing SYNT001 soon.

Other companies are in various stages of development with drugs that also target the FcRn-IgG interaction. Argenx (NASDAQ: ARGX), a Netherlands-based biotech, is in a Phase 2 trial testing its IgG-blocking drug as a treatment for myasthenia gravis, a muscle weakness disease, and immune thrombocytopenia, a blood clotting disorder. Cambridge, MA-based Momenta Pharmaceuticals (NASDAQ: MNTA) expects to report data from a Phase 1 trial of its antibody drug in the second half of this year.

Syntimmune was formed in 2013, based on the research of Laurence and Richard Blumberg. The brothers previously founded hemophilia drug developer Syntonix Pharmaceuticals, a company that was acquired by Biogen (NASDAQ: BIIB) in 2007.

Syntimmune has a second office in Waltham, MA.

Public domain image of immunoglobulin G by Wikimedia user Jawahar Swaminathan.