Stem Cell Year-in-Review 2016
If we picked one word to define the past year in the stem cell field, it would have to be ‘therapy.’
While many important developments impacted the field, two that garnered significant public, political and scientific attention in 2016 were the proliferation of clinics using unproven stem cell “therapies,” and the steps forward in therapeutic modification of human oocytes (unfertilized eggs) through a process called mitochondrial replacement therapy (MRT).
Within the stem cell field, unproven stem cell therapies, or “treatments” that lack rigorous scientific proof of their safety and effectiveness, have been a growing concern. Clinics often offer these types of treatments directly to consumers, marketing them online or in recruiting seminars, often at substantial cost. The treatments typically use autologous stem cells (those obtained from one’s body) to treat everything from bad knees to incurable disease such as ALS or Parkinson’s. In some countries, this phenomenon traditionally has been called stem cell tourism because it involved travel to another country with less stringent regulations to obtain treatment. Two publications1,2 in 2016 debunked that concept, showing these clinics are found throughout the world. The U.S. alone has an estimated 570 clinics. That puts the U.S. among the countries with the highest number of such clinics, along with India, Mexico, China, Australia, United Kingdom, Thailand, Malaysia and Germany.
Like many countries, the U.S. struggles to regulate unproven stem cell therapies. In 2016, the Food and Drug Administration (FDA), the branch of government charged with regulating cellular therapies, took action to address these issues, proposing revised guidelines that could change how stem cells, especially autologous stem cells, are regulated. The ISSCR was among the organizations and individual scientists that supported the need for careful oversight and regulation of the therapeutic application of stem cells. The FDA has yet to issue a final ruling, but a Perspective article written by three FDA executives published in the New England Journal of Medicine may provide insight into their thinking.
Another big story in 2016 was the first reported use of MRT in humans. This relatively new technology has shown to be effective in animal models for intercepting mitochondrial disease before it’s passed from mother to child. The approach works by replacing the mother’s mutant mitochondria responsible for disease with healthy mitochondria from a donor. The chimeric oocytes (that contain the mother’s nuclear DNA and the donor’s mitochondria) then undergo fertilization through standard IVF methods.
A U.S. fertility specialist reported the birth of a baby boy from a mother who was a carrier for mitochondrial disease that lead to the death of her previously-born children. The MRT procedure is not approved in the U.S., so doctors performed it in Mexico, which led to many concerns within and outside the scientific community. Among them, how do regulatory agencies and the scientific community deal with procedures approved in some countries but not others? Whether and how should we advance human health using technology that alters a natural state? How far should science be applied in influencing health-related outcomes?
This concern was also brought to the forefront of the scientific and public consciousness when a report by Chinese scientists described the use of CRISPR-Cas to modify a gene in human embryos making them resistant to HIV infection [to learn more about CRISPR-Cas, read our previous blog]. Although the embryos were not viable and not intended for clinical use, this proof-of-principle research raised ethical concerns and emphasized the need to continue to have discussions on the scientific and social impact of this technology and its use in countries around the world.
While 2016 saw many articles on unproven stem cell therapies, and the controversial use of MRT, there were many positive stories about potential stem cell-derived therapies that are successfully moving into the clinic for testing. Interventions for macular degeneration, stoke, cancers, and sickle cell disease, among others, are in approved clinical trials in California (U.S.), London, Japan, and elsewhere. These trials, unlike the unproven therapies, have been approved by the appropriate regulatory agencies and will be rigorously tested so that the risks and benefits are more fully understood before (hopefully) being made available to patients. We look forward to continued advances in 2017 that support the rigorous, ethical standards set forth in the 2016 Guidelines for Stem Cell Research and Clinical Translation, and help address issues of human health around the world.