Teprotumumab is currently in development for Thyroid Eye Disease (TED), a rare, autoimmune disorder which causes the eye muscles and fatty tissue behind the eye to become inflamed.
“The acquisition is an important step in our strategy of pursuing and acquiring development-stage medicines targeting rare diseases,” said Horizon Pharma CEO, Timothy Walbert.
The agreement accords Horizon Pharma all outstanding equity of River Vision for an upfront cash payment of $145m (€133m).
Horizon Pharma will also be eligible for potential future milestone and earn-out payments dependent on the achievement of certain regulatory milestones and sales thresholds.
If approved, Horizon predicts potential sales for teprotumumab in excess of $250m (€229.9m) in the US.
Teprotumumab, a human mAb inhibitor of insulin-like growth hormone, is currently being examined in a Phase III trial.
It has received Orphan Drug, Fast Track and Breakthrough Therapy designations from the US Food and Drug Adminstration (FDA).
“With no approved medicines to treat Thyroid Eye Disease, there is a significant unmet treatment need among the approximately 10,000 patients in the United States with moderate to severe disease and we look forward to beginning the pivotal study with Teprotumumab in the second half of the year.”
Horizon Pharma said assuming positive trial results, a submission for Biologics License Application (BLA) is expected in the second half of 2019.
A Phase II study evaluating the efficacy and safety of teprotumumab in patients with recent onset, moderate-to-severe TED, illustrated that therapeutic effects of the drug were rapid, and that teprotumumab was more effective than placebo in reducing proptosis.
River Vision was founded by Narrow River Management LP for the sole purpose of developing Teprotumumab. The medicine was developed by Genmab, and later licensed from Roche.