California-based Geron Corporation has been given the green light to proceed with its trial on a therapy for patients with spinal-cord injury. The trial involves injecting a stem-cell treatment into patients with severe spinal cord injury with the hope that it would help damaged nerve cells regrow and eventually allow patients to regain movement.

Both opponents and proponents of embryonic stem cell research highlight the fact that the FDA had originally approved the study in January 2009 and the trial was scheduled to begin last summer. But Geron found that animals used in a preclinical study had developed small cysts that appeared with “a higher frequency” than other studies, resulting in the FDA ...