Shares of Osiris Therapeutics Inc. slipped in premarket trading Tuesday, a day after the stem cell therapy developer announced that President and CEO C. Randal Mills will leave for personal reasons.

The Columbia, Md., company said Monday after markets closed that Chief Operating Officer Lode Debrabandere will take over as president and CEO, pending board confirmation.

Debrabandere joined Osiris in 2006, and the former Bristol Myers Squibb global marketing vice president became COO last year.

Mills joined Osiris in 2004 and will remain an adviser to the company.

Osiris develops treatments that use stem cells for the orthopedic, sports medicine and wound care markets. Its products include Grafix and Ovation for the treatment of acute and chronic care wounds and Cartiform, a mesh used for cartilage repair.

Last month, the company said its third-quarter loss narrowed to $1.7 million from $2.9 million in the previous year's quarter as revenue more than tripled to $6.9 million. It also said it expected to report a profit in the fourth quarter and for the full year.

Osiris shares slipped 4 cents to $16.68 before markets opened Tuesday. The stock had dropped nearly 5 percent, or 86 cents, on Monday but was still up 86 percent so far this year.