If IPS cells work in humans, they could eliminate one of the biggest problems with embryonic stem cell therapy: Patients need to take immune-suppressing drugs, so that their bodies won't reject and attack the cells as foreign. In the Geron trial, patients will take low-level immune-suppressing drugs for six months. Adult stem cells also have been used to grow organs, including bladders, of the same type of cells. That way, they don't need to differentiate into the right kind of cell, as embryonic cells do.
"We look forward to everyone seeing that we want to do this research in an ethical way," says Harvard's Melton, who is working with stem cells to create pancreatic beta cells, which could be injected into patients with type 1 diabetes to replace cells destroyed by the immune system. "No one should think that because the restrictions might be lifted in January, that cure will be available this summer, or even years from now. These cures take years of research. But if they take years of research, why not start now?"