Initiation of phase III trial in Japan evaluating Tepezza in adults with chronic/low clinical activity score (CAS) thyroid eye disease

The trial includes patients with an initial diagnosis of TED between two to 10 years prior to the study and low levels of disease activity. Findings from this study will build on a separate Phase III clinical trial (OPTIC-J) that is currently underway in Japan and is evaluating Tepezza for the treatment of TED patients with disease duration of nine months or less and higher levels of disease activity.

TED is a serious, progressive and potentially vision-threatening rare autoimmune disease that can cause proptosis (eye bulging), diplopia (double vision), eye pain, redness and swelling. Tepezza was approved by the FDA in January 2020 and is the first and only medicine for TED, regardless of TED activity or duration. Tepezza has not been approved for commercial use in Japan. There are no medicines approved for the treatment of TED in Japan.

This randomized, double-masked, placebo-controlled, parallel-group, multicenter trial will be evaluating the efficacy, safety and tolerability of Tepezza compared to placebo in adults with chronic TED and low CAS. All study participants will be required to have a CAS of less than 2 at the screening and baseline visits, two to 10 years since initial diagnosis of TED, and no worsening in proptosis, diplopia or inflammatory symptoms of TED for at least one year. Adult participants who meet the trial eligibility criteria will be randomized in a 2:1 ratio to receive an infusion of either Tepezza or placebo, 10 mg/kg for the first infusion and 20 mg/kg for the remaining seven infusions, once every three weeks, for a total of eight infusions.

The primary efficacy endpoint is proptosis response rate at Week 24, defined as the percentage of participants with at least a 2 mm reduction in proptosis from baseline in the study eye, without deterioration in the fellow eye (? 2 mm increase). Study participants who complete the treatment period and are proptosis non-responders at Week 24 may choose to enter an open-label extension period to receive an additional eight infusions of Tepezza.