Prothena Plummets 60% After Lead Drug Fails Phase 2 Trial

Prothena Corporation PLC PRTA plummeted 60 percent Monday morning after a disappointing update relating to the company's treatment for AL amyloidosis.

What Happened

Prothena, a clinical-stage biopharmaceutical company that focuses on therapies in the neuroscience and orphan categories, said a Phase 2b study of its therapy called NEOD001 failed to achieve its primary or secondary endpoints.

Prothena's Phase 2b study explored its NEOD001 therapy versus a placebo in previously-treated patients with AL amyloidosis and persistent cardiac dysfunction. Unfortunately, there were no statistically significant difference between the two treatment groups.

Prothena also asked independent data monitors to examine data from its ongoing Phase 3 trial of newly diagnosed AL amyloidosis patients. The monitors found that the company's therapy is not likely to show a benefit for patients. Accordingly, the company will discontinue all development of the therapy and end all studies.

Why It's Important

Prothena's update is "not pretty" and there's no "hunt for silver linings" for the therapy that had high expectations, Endpoints News' John Carroll wrote. The update also serves as "brutally bad news" for investors, especially after the company signed a licensing deal with Celgene Corporation CELG to boost up its neurosciences pipeline.

Prothena's experimental Parkinson's drug, PRX002/RG7935 is the company's remaining clinical stage program, Carroll said. The company holds $422 million in cash as of the end of 2017 in addition to Celgene's $150 million injection as part of its preclinical licensing deal.

At time of publication, the stock was trading down 65 percent at $12.80.

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