Canadian researchers and their colleagues in the U.S. report this week in The New England Journal of Medicine that AMG-157, a human monoclonal antibody that targets a protein called thymic stromal lymphopoietin (TSLP), attenuated most allergen-induced asthmatic responses, both early and late, in a small number of patients with mild allergic asthma. This is the first study to show that TSLP is a viable therapeutic target in managing allergic asthma, a chronic inflammatory disease of the airways. Nearly 40 million Americans suffer from asthma, a condition that in 2010 killed over 3,400 and resulted in more than 400,000 hospitalizations, according to the U.S. Centers for Disease Control and Prevention.

Current asthma treatments are taken daily, but AMG-157 is given every four weeks by intravenous injection. Less frequent medication is attractive to patients, as many as 15 percent of which show no benefit at all to currently available treatment options.

“I’ve never seen anything quite like this,” said Paul O’Byrne, lead study scientist. “It’s too early to say if it’s going be effective in treatment but if it is, it can be a game-changer.”

AMG-157 is a “fully human anti-TSLP monoclonal immunoglobulin G2gamma that specifically binds human TSLP and prevents interaction with its receptor,” according to the report. The target, TSLP, is a cytokine, a class of proteins involved in inflammatory signaling, that is released in response to allergens and other pro-inflammatory agents. The TSLP then triggers responses in several different types of the body’s immune cells. Scientists have speculated on the potential of targeting TSLP for inhibition to manage asthma.

The next step for AMG-157 investigation is a Phase II clinical trial and although Amgen has not revealed a timeline, patient recruitment has begun.

“We are encouraged by these early results,” said Cuyler Mayer, a spokesman for Amgen. They “add to the growing body of evidence suggesting that inhibiting TSLP could be beneficial.”