Horizon's Tepezza becomes first treatment for thyroid eye disease approved in US

The FDA said Tuesday that it cleared Horizon Therapeutics' filing for Tepezza (teprotumumab-trbw) to treat adults with thyroid eye disease, making it the first drug approved in the US for this indication. "Currently, there are very limited treatment options for this potentially debilitating disease," noted Wiley Chambers, deputy director of the Division of Transplant and Ophthalmology Products in the FDA's Center for Drug Evaluation and Research, adding that Tepezza "has the potential to alter the course of the disease, potentially sparing patients from needing multiple invasive surgeries by providing an alternative, non surgical treatment option." 

The decision, which follows unanimous backing from an FDA advisory panel last month, was based on the confirmatory Phase III OPTIC study, as well as positive data from a mid-stage clinical trial. OPTIC results demonstrated that a significant 82.9% of Tepezza-treated patients achieved at least a 2-mm reduction in proptosis, versus 9.5% for placebo, without deterioration in the fellow eye at week 24. Horizon said additional secondary endpoints were also met, including a change from baseline of at least one grade in diplopia in 67.9% of patients receiving Tepezza, compared to 28.6% of those on placebo at week 24. 

In a related analysis of the mid- and late-stage studies, Horizon said 53% of patients administered Tepezza achieved complete resolution of diplopia, versus 25% for placebo. Further, the majority of adverse events reported with Tepezza treatment were graded as mild-to-moderate in nature and were deemed "manageable," with few discontinuations or therapy interruptions, the company noted. 

Horizon said it will conduct a post-marketing study to evaluate the safety of Tepezza in a larger patient population. The study will also look at retreatment rates relative to how long patients receive the medicine, which is administered once every three weeks for a total of eight infusions. Earlier this month, the company increased its sales expectations for Tepezza, which it has priced at $14,900 per vial, saying it believes the IGF-1R inhibitor has the potential for more than $1 billion in peak US annual net revenues, compared with a prior forecast of more than $750 million.

Horizon gained the drug in 2017 via its acquisition of River Vision Development Corporation, to whom Roche had licensed it out previously.

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