Biogen tanks 8% after Samsung denies report it was in talks to buy the drugmaker

• Biogen stock dropped 8% on Thursday after Samsung denied it was seeking to buy the drugmaker.
• Samsung Biologics said in filing it wasn't true that it was aiming to buy the Massachusetts-based company.
• Korea Economic Daily had reported Samsung was in talks to buy Biogen.

Biogen stock dropped sharply Thursday after South Korean conglomerate Samsung said it wasn't aiming to buy the neuroscience-focused biotech company.

Shares shot up 9.5% on Wednesday after the Korea Economic Daily reported that Samsung Group was in negotiations to acquire the Massachusetts-based drugmaker.

The Wednesday news report cited investment banking sources and said Biogen could land a valuation of more than $42 billion.

But on Thursday, Samsung's biotech division, Samsung Biologics, disputed the report in a filing in South Korea, calling it "not true," according to a translated version.

Biogen stock fell by as much as 8.2% to $237.15 Thursday then pared the decline to 7.4%. The drop pushed Biogen's year-to-date performance into the red, down by nearly 3%.

Earlier this year, shares had been up about 70% after the US Food and Drug Administration approved Aduhelm, Biogen's controversial Alzheimer's therapy, in June.

But Biogen gave up those gains as the drug, which hasn't shown evidence of reversing or curing Alzheimer's disease, has seen little uptake by doctors who are skeptical of its effectiveness and the high price tag of $56,000.