The failure of a high-profile clinical trial at biotech business Opthea has rattled investors in Phil King’s Regal Partners, who fear the eye treatment play will collapse and wipe off $220 million in funds under management.

Regal is Opthea’s largest shareholder, with a 30 per cent stake. Its exposure has rocked the fund manager’s own stock, which closed down 15 per cent on Monday after Opthea warned that it could collapse because a negative trial result could force it to repay more than $1 billion in development funding.