78-year-old Jack Nicklaus has suffered from chronic back pain throughout his life, caused by a condition known as facet joint syndrome. While cortisone relieved the symptoms temporarily, the underlying disorder remained. Recently, the retired golf pro was interviewed on CNN, during which he extolled the benefits of a controversial and largely untested therapy he underwent two years ago, using stem cells harvested from abdominal body fat.

The experimental treatment, developed by German scientists and administered at a facility in Munich, has drawn attention here at home and is being offered by two U.S. companies, Florida-based U.S. Stem Cell Clinic and the Cell Surgical Network in California. This week, the Department of Justice, acting at the behest of the Food and Drug Administration, filed lawsuits in both states, asking that they cease and desist.

These filings come after the FDA received reports that the new stem cell treatment has caused some injuries to some patients, including permanent blindness. According to the complaints, these companies have been touting the new stem cell treatment as a cure for everything from cancer and heart disease to COPD and Parkinson’s, despite the lack of clinical evidence of efficacy and safety.

During the procedure, a patient undergoes liposuction in order to harvest adipose tissue from the abdomen, which contains an abundance of blood vessels. This adipose tissue is strained with a proprietary enzyme known as Matrase, which breaks it down in order to release the stem cells. These are then processed in a centrifuge and checked for contamination before being injected into the treatment site. The treatment is based on the theory that stem cells will repair the damage, whether caused by trauma, degeneration or a pathogen.

This new stem cell treatment is scheduled to undergo formal clinical trials within the next few years, with the goal of winning FDA approval. However, some companies have been forging ahead, eager to exploit the commercial potential. According to the FDA, U.S. Stem Cell Clinic marketed the unapproved, untested treatment to patients desperate for a cure, “violating current good manufacturing practice requirements, including some that could impact the sterility of their products, putting patients at risk.” The company received a warning letter from the FDA in August 2017, but those warnings were disregarded. At the time, Kristin Cornella said that FDA approval was not required since the treatment consisted of the patients own cells, which are not considered to be a drug and therefore not subject to regulation.

Nonetheless, three patients who underwent the treatment for their macular degeneration now suffer from permanent, total blindness. Meanwhile, Dr. Peter Marks, who heads up the FDA’s Center for Biologics Evaluation and Research, notes that there are still several hundred “rogue clinics” offering the new treatment – and enforcement will be difficult. “We simply don’t have the bandwidth to go after all of them,” he says. Because of this, enforcement efforts will focus on clinics that perform the procedure in the areas of the patient other than the joints, including the central nervous system, the bloodstream or the eyes.

Anyone considering undergoing this stem cell therapy is advised to exercise caution until the procedure has been thoroughly tested under clinical conditions and subject to peer review.