The US Food and Drug Administration (FDA) has granted clearance to Tourmaline Bio’s investigational new drug (IND) application enabling initiation of a Phase IIb trial of TOUR006 to treat thyroid eye disease (TED) also known as Graves’ ophthalmopathy.

The planned study intends to assess TOUR006 20mg and 50mg doses against placebo in moderate to severe TED patients who are in the active phase of disease.

Nearly 81 participants will be enrolled and divided into three arms of 27 each. They will receive subcutaneous injections every eight weeks.

The study's primary endpoint includes proptosis response, or reduction of abnormal eye protrusion, as measured at week 20.

Tourmaline CEO Sandeep Kulkarni said: “We believe TOUR006 could be an ideal treatment option for patients suffering from TED, in light of its anti-inflammatory mechanism of action, established tolerability profile, attractive dosing schedule, and convenient subcutaneous administration.

“We anticipate top-line data from this trial in the first half of 2025 and expect to further expand the development of TOUR006 into atherosclerotic cardiovascular disease (ASCVD) and other indications.

“We are also looking forward to the expected closing of our merger with Talaris Therapeutics and listing on Nasdaq in the fourth quarter of 2023.”

The company’s lead programme TOUR006 is a fully-human, anti-IL-6 antibody with a naturally long half-life and has high binding affinity towards IL-6.

It treats the autoimmune disease by reducing eye-bulging and inflammation. These observations were shown in patients with off-label use of IL-6 pathway inhibitors.

In addition, key biomarkers such as levels of pathogenic autoantibodies were found to be impacted.