Rare Diseases

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

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…