Shares of Amarin (AMRN) lost more than half their value in after-hours trading Monday after a federal judge ruled patents on one of its medications were invalid, according to a published report.
Amarin shares fell $9.08, or 67%, to $4.50 in after-hours action.
The slide comes after a federal judge in Nevada found that patents on Amarin’s Vascepa drug were invlaid, STAT reported.
Generic drugmakers Hikma Pharmaceuticals and Dr. Reddy's Laboratories Limited (RDY) , sought to overturn the patents so they can begin making generic versions of the medication, which is partially based on fish oil.
The ruling found that the patent claims held by Amarin were “obvious,” according to the report, making them invalid.
"Amarin strongly disagrees with the ruling and will vigorously pursue all available remedies, including an appeal of the Court’s decision,” said John F. Thero, president and chief executive officer of Amarin, in a statement late Monday.
Elsewhere, biotech stocks were generally higher Monday.
Johnson & Johnson JNJ shares rose Monday, after it said it has identified a lead coronavirus vaccine candidate which it hopes to begin testing by September. Shares ended up $9.85, or 8%, at $133.01, and continued rising in after-hours action.
The SPDR S&P Biotech (XBI) ETF rose $2.07, or 2.73%, to $78.03.
In the broader markets, stocks were generally higher Monday with all three major indexes ending in the green.
The S&P 500 index rose 85.18 points, or 3.35%, to 2,626.65.
The Nasdaq Composite Index rose 271.77 points, or 3.62%, to 7,774.15.
All of the major S&P 500 sub-sectors rose, led by the healthcare sector index which gained 46.29, or 4.67%, to 1036.98.