Shares in Dublin-based Prothena surge as it seeks to raise $67.8m

Nasdaq-listed company was spun out of Irish drugmaker Elan back in 2012

Shares in Dublin-based, Nasdaq-listed biotech company Prothena jumped by almost 17 per cent on Wednesday after it said it intends to raise $67.8 million (€57.3 million) through a public offering.

The company, which was spun out of Irish drugmaker Elan in 2012, specialises in developing immune system-based drugs to fight progressive diseases. The company has expertise in protein dysregulation and a pipeline of novel investigational therapeutics for rare peripheral amyloid and neurodegenerative diseases.

Prothena has priced an underwritten public offering of 3,500,000 of its ordinary shares at a price to the public of $20.75 per ordinary share. In addition, the company has granted underwriters a 30-day option to purchase up to an additional 525,000 of shares.

The offering is expected to close on Friday.


Citigroup, Jefferies and Cantor are acting as lead book-running managers, Oppenheimer is acting as book-running manager, and BTIG and HC Wainwright are acting as co-lead managers for the offering.

Prothena, which was previously backed by disgraced British investor Neil Woodford, found itself in difficulties three years ago when a drug it was developing for treating a rare disease called AL amyloidosis failed in a crucial clinical trial.

News of the failure led to the company’s shares plunging 70 per cent in one day. The drug was subsequently discontinued.