Shares in Irish drugmaker Amarin haver fallen almost 30 per cent in two days after US health regulators rejected a preset testing process that was critical to the company seeking broader use of its blood fat-lowering drug.

The Irish drugmaker said it planned to appeal the decision.

Advisers to the Food and Drug Administration had in October recommended that the agency not approve Vascepa for the new use until the larger 8,000-patient trial shows that lowering blood fats leads to reduced cardiovascular risk.

The FDA had in October also revoked a Special Protocol Assessment agreement covering a late-stage trial code-named ANCHOR, saying that a substantial scientific issue essential to determining the effectiveness of Vascepa in the expanded population was identified only after the trial began.– (Reuters)