Amgen said on Wednesday there was no link between its experimental weight-loss drug and changes in bone density, a day after those concerns wiped off more than $12 billion from the company's market value.

After a research note raised potential safety concerns with Amgen's lead obesity candidate, the company defended its drug and has asked the journal to issue a correction and add in the finalized data.

Amgen addresses safety concerns for its weight loss drug MariTide after new data suggests a potential 4% reduction in bone density at the highest dose.

Amgen has rebuffed claims made by an analyst suggesting that its obesity drug MariTide is associated with reductions in bone mineral density that could undermine its ability to compete in the fast-growing sector.

Analysts cited data from a phase one study showing the highest dose of Amgen’s MariTide was linked to roughly 4% loss of bone mineral density over 12 weeks.

Amgen (NASDAQ:AMGN) shares spiked in the premarket on Wednesday after the company ruled out concerns over loss of bone mineral density linked to its obesity candidate MariTide, which led to a ~7% decline in its share price in the previous session.