Horizon Pharma PLC closed a public offering of 14,081,632 ordinary shares priced at $24.50 each.
Shares sold include the additional 1,836,734 stocks the offering's underwriters could have bought as part of their overallotment option.
Net proceeds from the offering are about $326.8 million. The company previously said it plans to use net proceeds, along with cash on hand, to repay about $550 million of its outstanding debt.
The debt includes a portion of the loans under Horizon Pharma's credit agreement and a portion of an amount of its 6.625% senior notes due 2023.
Citigroup, Morgan Stanley, Goldman Sachs & Co. LLC and Cowen acted as joint book-running managers for the offer.
Dublin-based Horizon Pharma develops medicines that address rare and rheumatic diseases.