Japanese startup PorMedTec announced on Tuesday that it has produced three clone piglets that have organs that can be transplanted to humans with less risk of immune rejection, paving the way for future cross-species organ transplants.

The piglets, which were born Sunday using cells imported from U.S biotech startup eGenesis, will be provided to medical institutions in Japan for pre-clinical research, the firm said.

PorMedTec, a spinoff of Meiji University, imported gene-edited pig cells from eGenesis in September and took their nuclei into egg cells, creating genetically modified embryos. They were then implanted into the uterus of a mother pig to produce clone piglets.

¡°The realization of xenotransplantation has been long awaited in Japan for several years, but it remained in the basic research stage because pigs that could withstand clinical application were still under development,¡± the firm said in a statement.

However, eGenesis has advanced research in this field by producing pigs that have a smaller chance of immune rejection by human recipients by manipulating 10 related pig genes, it added.

The U.S. firm has also succeeded in creating pigs in which genes of porcine endogenous retroviruses (PERVs) are inactivated. PERVs, which are viruses that exist in the genome of all pigs and which can infect human cells, have long been a major stumbling block for xenotransplantation using pig cells, tissues and organs.

Last year, a team of researchers in the U.S., including those from eGenesis, announced that a monkey with a kidney transplanted from a genetically engineered pig survived for more than two years, making it one of the longest survival periods for a cross-species organ transplant.

¡°The successful cloning in Japan of a genetically engineered pig with such a track record will help accelerate efforts to realize clinical applications in the nation,¡± PorMedTec said.

The shortage of organ donors is global issue, but the situation is particularly dire in Japan. Only 400 people receive organ transplants per year, while 16,000 people are on waiting lists to receive them, according to the Japan Organ Transplant Network.

Earlier this month, a separate team of researchers was reported to be planning to start a clinical study to temporarily transplant a pig¡¯s kidney into a human fetus with a severe kidney disease.

The team, led by Jikei University School of Medicine, is seeking to apply for approval of the study later this year, pending an ethical review at a hospital where the transplant would be performed.