In a stock exchange announcement, the Dublin-based biotech firm, specialising in discovering and developing protein immunotherapies, confirmed that Sarah Noonberg had decided to resign as CMO and would be providing transitional support until 15 March 2018.
It said former CMO Martin Koller would step into lead the clinical and medical units as a consultant while the firm hunts for Noonberg’s replacement.
Despite the departure being confirmed last Friday, its shares, listed on the Nasdaq, did not slide until Monday morning. At the time of writing, they were down 16% at $33.45 per share.
The latest pitfall for Prothena comes just over a week after Neil Woodford, one of the firm’s largest shareholders, blasted US hedge fund Kerrisdale Capital for its criticisms of the biotech firm’s stability.
Last November, Kerrisdale predicted Prothena would be “the next big biotech blow-up” in a 29-page report, outlining its reasons for shorting the Irish company. Chief among them was that Prothena’s main drug under development, used to treat a rare disease called amyloidosis, would fail several key trials.
“In the words of one amyloid antibody co-inventor, the probability of NEOD001 succeeding in its Phase 3 trial is ‘almost zero’,” the hedge fund said in the report.
When asked about Kerrisdale’s opinion on Prothena at the Winterflood Securities event in London in January, Woodford was quoted as saying: “Their job is to scare the market when the market is prepared to be scared. It doesn’t matter if what they said about Allied Minds and Prothena is totally inaccurate and unsubstantiated.
“What matters is Bloomberg and others giving them the oxygen of publicity and, hey presto, there is a self-fulfilled prophecy and the share price falls.”
In response to Woodford’s remarks, the New York-based hedge fund retaliated with a searing tweet: “Neil, you’ll lose money on your bad investments regardless of whether we write on them. But hopefully our work helps the widows and orphans who invest in your Patient Capital Trust recognise just how poor your diligence is on the stocks you pick.”
Like several of his major holdings, Prothena endured a difficult 2017 even without the bad publicity from Kerrisdale. Over the last 12-months, it has seen 34% of its share price shaved off, which weighed heavily on Woodford’s Patient Capital Trust, where it is now the second largest holding (9.22%).