By Katherine Hamilton

Prothena shares fell after the company reported unfavorable trial results and said it would shrink its workforce.

The stock was down 27% to $4.81 in pre-market trading Tuesday.

The Irish biotechnology company said Friday its Phase 3 trial of a blood-disorder treatment had not met its primary or secondary endpoints. As a result, it was ending the trial, it said.

Oppenheimer analysts downgraded the Prothena stock to perform from outperform, and removed its price target. The analyst said they are still optimistic about the company's internal and partnered programs, but the trial was a main driver behind their thesis.

"We're moving to the sidelines for now," they said in a research note.

Chief Executive Daniel Welch called the results disappointing. He said Prothena is now planning what it called a substantial job cut in an effort to reduce expenses. It is also evaluating business options that it thinks could be in the best interest for shareholders.

The company expects to share more details about workforce reduction and business plans in June once they are more fleshed out.

Write to Katherine Hamilton at katherine.hamilton@wsj.com

(END) Dow Jones Newswires

May 27, 2025 08:28 ET (12:28 GMT)

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