Kyoto University in Japan has acquired the world's first patent for induced pluripotent stem (iPS) cells. The university paid registration fees for the patent (2008-131577), which is of only limited coverage and applies only in Japan, on 2 September, after it was approved by the Japanese patent office.

Shinya Yamanaka, a stem-cell researcher at the university, created the first iPS cells in 2006 by using four genetic factors to 'reprogram' adult cells from mice into an embryonic-stem-cell-like state. A year later he achieved the same in human cells, publishing the research the same day as a US team led by James Thomson of the University of Wisconsin. Thomson's group used a different set of genetic factors to make its human iPS cells.

iPS cells have the potential to develop into almost any of the body's cell types, and hold great promise in therapy and disease modelling. Kyoto University applied for an international patent (PCT/JP2006/324881) in December 2006. A US patent application is in Yamanaka's name.

Kyoto University expects the international patent to cover iPS cells from all species — "any cell, besides a germ cell, of any type of organism," says Hideya Hayashi of the university's iPS Cell Research and Application office.

The international patent has many claims in it, so it will probably take another year or longer for the various patent offices to process and approve it, says Hayashi. Kyoto University did not want to wait, so it fast-tracked the Japanese patent application for the most basic claim, covering the "method" of using Yamanaka's four genetic factors to reprogram a cell. "A lot of people were wondering what was happening with these patents. We wanted to make it clear," Hayashi says.

Other claims in the international patent still need to be worked out, especially that covering the product, the iPS cells themselves. It's not certain whether Yamanaka's patents cover iPS cells created by reprogramming with different genetic factors. Itsuki Shimbo, a patent attorney with the Tokyo-based firm Tsubame says it is unclear whether the patent will be able to restrict scientists using other combinations.

Hayashi says the university does not plan to restrict others from doing iPS cell research. Rather, it wants to ensure that people, including Yamanaka, are not restricted by other patents and can freely use iPS cell technology. "We want to remove any potential obstacles to the quick clinical application of iPS technology," Hayashi says. "We are not trying to confine its use."

Shimbo says that Yamanaka's patent might prevent future restrictive iPS patents based on different combinations of genetic factors. "It will be very hard to claim that such a change was truly novel," he says.

The Japanese patent will be valid until 6 December 2026, 20 years from the application date.