Woodford-backed company Prothena’s share price bombs by 70 per cent after failed drugs trial

A biotechnology company backed by investor Neil Woodford saw its share price fall off a cliff today after announcing the withdrawal of a new drug.

Prothena, which is nearly 29 per cent owned by a fund controlled by Woodford, saw its share price plunge by 70 per cent, wiping more than $1bn (£720m) from its market capitalisation.

The Irish-based Nasdaq-listed biotech business announced that it was discontinuing development of a drug to treat amyloidosis after examining test results.

The news is another blow for Woodford who saw his fund shrink by a fifth – £1.6bn – in the first three months of the year.

Read more: Woodford flagship flounders as fund falls by a fifth this year alone

Woodford said: “Despite the disappointment that we feel, that our investors will feel, and indeed the company feels more acutely, there is a lot of value in Prothena.”

He said that Prothena is a “much broader business” which has “multiple shots on goal” and a “technology platform that we think is extremely valuable”.

After launching in June 2014, Woodford’s main fund last registered assets under management of less than £7bn in June 2015. They peaked in May 2017 at a mammoth £10.2bn.

Woodford has been on the wrong end of a number of poor trades in recent months, with big sell-offs in the likes of Provident Financial, Capita and the AA demolishing performance.

It has not all been doom and gloom for Woodford of late, with a Welsh biotechnology firm that he backs announcing it had treated its first UK cancer patient using proton beam technology earlier this month.