A team of a Kyoto University laboratory has said it has found two compounds that curb the progress of a rare disease that causes bone fragments to grow all over the body.

Fibrodysplasia ossificans progressiva, known as FOP, is a rare disease without an established cure. There are only about 80 patients in Japan.

Using induced pluripotent stem, or iPS, cells, the team of the university’s Center for iPS Cell Research and Application (CiRA) discovered that the compounds curb bone formation in muscles and other areas where bone is not normally present.

The study was published online in the U.S. journal Stem Cell Reports on Friday.

The team identified seven promising compounds by screening nearly 5,000 compounds using mouse cells with the disease.

After examining the seven using iPS cells produced from tissue of FOP patients, the team confirmed that two of them are effective in curbing the progress of the disease.

In August last year, the team started a clinical trial using the immune-suppressing drug rapamycin, marketed as Rapamune, after confirming that the drug was effective in curbing abnormal bone formation in FOP sufferers.