Cytori Therapeutics said Tuesday it has halted trials of its experimental stem cell therapy for heart failure after three patients developed blood flow problems.
The San Diego-based company said it placed the hold on two studies after the patients developed problems with blood flow to the brain. Two of the patients' symptoms resolved in a short period of time and a third was still recovering, the company said in a statement.
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Cytori said it is working with the Food and Drug Administration and the study's safety monitoring board to understand how the problems occurred.
The study hold means the company will not complete enrollment of its lead study for the treatment by the end of 2014, as previously stated.
Cytori makes equipment that separates adult stem cells from fat tissue using a combination of spinning motions and chemical reactions. Company researchers are studying the use of these purified stem cells in treating a variety of medical conditions, including heart disease.
Adult stem cells are found in bone, fat and other tissue throughout the body and can be manipulated into several different cell types. They differ from embryonic stem cells, whose use has been long- debated because they are derived from human embryos.
Cytori's procedure involves harvesting stem cells from fat removed during liposuction procedures and injecting the cells into the heart.
Shares of Cytori Therapeutics Inc. fell 60 cents, or 29 percent, to $1.50 in afterhours trading.