Horizon Therapeutics has won a speedy approval for its thyroid eye disease (TED) treatment Tepezza in the US.
The US Food and Drug Administration (FDA) was due to deliver a verdict on Tepezza (teprotumumab-trbw) on 8 March. Yet, the agency reached a decision well ahead of that target, giving Horizon the green light to sell the insulin-like growth factor type 1 receptor inhibitor on Tuesday.
The speed of the decision reflects the unmet need in TED. Tepezza is the first medicine approved in the rare autoimmune disease, which can cause eye bulging, facial disfigurement and vision loss.
Horizon demonstrated the potential for Tepezza to help these patients in phase 2 and 3 clinical trials that linked the monoclonal antibody to statistically significant reductions in eye bulging.
The trials also generated evidence that Tepezza improves double vision. More than half of patients who received Tepezza across the trials experienced the complete resolution of their double vision, as compared to one quarter of the placebo cohort.
Horizon looked to be on track to win approval for Tepezza last month when the FDA's Dermatologic and Ophthalmic Drugs Advisory Committee voted 12-0 in favour of the therapeutic when asked if its benefits outweigh its risks.
Having secured the FDA approval, Horizon will now turn its attention to making a commercial success of Tepezza. Horizon reset its expectations for the drug shortly before the FDA decision.
In light of the phase 3 data and further assessments of the TED market, Horizon increased its peak sales forecast for Tepezza from $750m (€677m) to $1bn. Horizon raised its revenue expectations for Krystexxa (pegloticase injection), a gout therapy that is already on the market, by the same amount.
There is scope to further grow Tepezza sales by moving into new indications. Shao-Lee Lin, chief scientific officer at Horizon, set out the opportunity in the statement regarding the reset sales targets.
“We believe teprotumumab may impact underlying mechanisms of fibrosis and could demonstrate utility beyond thyroid eye disease, including diffuse cutaneous scleroderma, a rare autoimmune disease with central characteristics of inflammation and fibrosis,” Lin said.
Horizon plans to begin its pursuit of those opportunities by initiating an exploratory clinical trial in the coming months. The study will “evaluate objective biomarker and clinical endpoints to inform potential subsequent larger and longer duration clinical trials”, according to Horizon.