Ocata Therapeutics (named Advanced Cell Technology, Incorporated (ACT) until November 2014) is a biotechnology company located in Marlborough, Massachusetts, United States. The company specializes in the development and commercialization of cell therapies for the treatment of a variety of diseases. Ocata is primarily developing stem cell-based technologies, both adult and human embryonic, and other methods and treatments in the area of regenerative medicine.

In November 2015 the company announced it would be acquired by Astellas Pharma for $379 million, which was finally completed in February 2016.

Formed in 1994, the company was led from 2005 to late 2010 by William M. Caldwell IV, Chairman and Chief Executive Officer. Upon Mr. Caldwell's death on December 13, 2010, Gary Rabin, a member of ACT's board of directors with experience in investment and capital raising, assumed the role of Chairman and CEO.

In 2007 the company's Chief Scientific Officer (CSO), Michael D. West, PhD, also founder of Geron (NASDAQ: GERN) left Ocata to join a regenerative medicine firm, BioTime (AMEX: BTX) as CEO. In 2008, for $250,000 plus royalties up to a total of $1 million, the company licensed its "ACTCellerate" technology to BioTime. Robert Lanza was appointed CSO.

On November 22, 2010, the company announced that it had received approval from the U.S. Food and Drug Administration (FDA) to initiate the first human clinical trial using embryonic stem cells to treat retinal diseases. A preliminary report of the trial published in 2012, and a follow-up article was published in February 2015.

In July 2014, Ocata announced that Paul K. Wotton, previously of Antares Pharma Inc (ATRS:NASDAQ CM), became President and Chief Executive Officer.

On August 27, 2014, Ocata announced a 1-100 reverse stock split of its common stock. Ocata was listed on NASDAQ in February 2015.

On November 30, 2010, Ocata filed an Investigational New Drug application with the U.S. FDA for the first clinical trial using embryonic stem cells to regenerate retinal pigment epithelium to treat Dry Age-Related Macular Degeneration (Dry AMD). Dry AMD is the most common form of macular degeneration and represents a market size of $25–30 Billion in the U.S. and Europe.

In November 2010 the FDA allowed Ocata to begin a Phase I/II human clinical trial to use its retinal pigment epithelium cell therapy to treat Stargardt disease, a form of inherited juvenile macular degeneration.