Happy days are here again for the embryonic stem cell (ESC) research community, or at least they should be. The day after Barack Obama was inaugurated as president in January, the U.S. Food and Drug Administration green-lighted an application from Geron Corporation to pursue the first phase I clinical trial of an ESC-based therapy (in this case, for spinal cord injury).
President Obama, who ran on a pro-ESC research platform, cannot take credit for that regulatory first, which was largely a coincidence of timing. But he has already made good on his promise to lift the burdensome restrictions on federally funded ESC studies imposed by his predecessor in 2001. Laboratories receiving federal money are once again free to work on the cell lines of their choice (with some important restrictions).
So scientists at last mostly have what they have been asking for. And the public should now prepare to be disappointed.
Perhaps “disappointed” is an overstatement, but a realistic recalibration of expectations is surely in order. The problem with turning a scientific issue into a political football is that the passionate rough-and-tumble of the game can leave the science itself rather scuffed. When opponents of ESC research likened it to genocide and Nazi concentration camp experiments, its proponents countered by emphasizing how irreplaceable ESCs were and how miraculous the cures arising from them could be. Whether or not those claims wandered into rhetorical excess, at least a few false hopes and misimpressions have probably been left behind.
To address the most obvious one first: practicable ESC-based therapies are years away. The upcoming tests of Geron’s paralysis treatment, for example, will look only at how safely it is tolerated by patients; tests of its effectiveness are further off. The therapeutic cells helped mice to partially recover from spinal injuries, but in humans they might fail to do the same or, worse, might induce tumors. It will take time to find out. New drugs often take five to nine years to progress from phase I testing to market.
Moreover, many if not most of those future therapies based on ESC research may not actually involve ESCs. Patients, after all, will not be able to supply embryonic cells directly from their own body. Therapeutic ESCs would either have to come from immunologically matched stockpiles (the equivalent of blood banks) or be cloned for each patient individually. Both solutions would involve technological and legal headaches. Using adult stem cells or others reprogrammed for versatility from a patient’s own tissues may therefore prove much easier. (Adult stem cells are indeed already used to treat some blood-related and orthopedic disorders.)
Opponents of ESC research may howl that these facts only vindicate their long-standing position that it would be better simply to concentrate on adult stem cell therapies. But the hard-fought campaign against restricting ESC research was well worth it: ESCs will most likely be essential for developing sophisticated stem cell therapies of any kind because they offer the best clues to how the body naturally grows, repairs and regenerates demandingly intricate tissues.
Anyone who thinks that the public debate over ESCs is nearing an end is also in for a rude awakening. In March, 10 out of 18 members of former president George W. Bush’s Council on Bioethics issued a press release criticizing the Obama administration’s policy as unethical. Days after the president’s executive order, the Georgia State Senate approved the Ethical Treatment of Human Embryos Act, which would bar the deliberate creation of embryos for ESCs. Expect more of the same.
Stem cell research continues to be a pawn in a larger political game being fought over abortion, women’s reproductive autonomy, and the tension between individual rights and notions of public morality. And that fact, however inescapable, may be the most disappointing one of all.
Note: This article was originally published with the title, "Reality Check for Stem Cells".