Cosmetics products maker Obagi Medical Products Inc. has reached agreement to a revised $24-per-share takeover offer from Valeant Pharmaceuticals International Inc. following a bid raised by Germany's Merz Pharma Group.

Shares in Obagi increased by 9% at $25.03 in early trading as shareholders geared up for a buyout fight over a firm that manufacturers specialized skin care products for skin aging, sun damage and acne.

Last month, Obagi agreed to be acquired by Canada's Valeant for $19.75 per share. However, Merz Pharma responded with a $22 per share offer to top Valeant's.

In released statement, Obagi's board has approved its latest offer which values the Cosmetics maker at $418 million.