Geron's first-mover disadvantage: first-ever human stem cell study held up

It's not easy being first. Biotech company Geron (GERN) had to wait more than a year before getting the green light from federal regulators in January to begin the first study using human embryonic stem cell-based therapies in humans. The early-stage trial is looking at the safety of its drug GRNOPC1, which is designed to treat patients with spinal cord injuries.

Now the company, which is in the spotlight because of the groundbreaking nature of the treatment, has hit another speed bump after the U.S. Food and Drug Administration put the study on hold in August. The reason? Animals injected with the experimental drug candidate developed microscopic cysts.