The first patient who received a kidney transplant from a genetically engineered pig has been released from the hospital.

Richard "Rick" Slayman got the organ in March, following a four-hour operation at Massachusetts General Hospital (MGH) in Boston, USA.

PHOTO | COURTESY Richard "Rick" Slayman

The 62-year-old has end-stage renal failure, a chronic condition in which the kidneys can no longer work on their own.

When the 62-year-old Massachusetts Department of Transportation manager was diagnosed with end-stage renal disease last year, his physicians recommended that he try a pig kidney.

In a hospital statement, Slayman said, “This moment – leaving the hospital today with one of the cleanest bills of health I’ve had in a long time – is one I wished would come for many years. Now, it’s a reality and one of the happiest moments of my life.”

His doctors indicated last month that they believed Slayman's new kidney would live for years but that there are many unknowns with animal-to-human transplants.

PHOTO | COURTESY Richard "Rick" Slayman

His procedure marks the third xenotransplant of a pig organ into a living person. The first two transplants were hearts placed into living patients who had exhausted all other transplant options.

The organs were transplanted following specific regulations, allowing for the compassionate use of experimental medicines for patients in severe circumstances.

Upon his release, Slayman thanked all the medical personnel who had cared for him before and after his "historic transplant."

He said, "I'm excited to resume spending time with my family, friends, and loved ones free of the burden of dialysis, which has harmed my quality of life for many years."

PHOTO | COURTESY Richard "Rick" Slayman

"I want to thank anyone who has seen my story and sent well-wishes, especially patients waiting for a kidney transplant. Today marks a new beginning not just for me, but for them, as well."

The Massachusetts-based company eGenesis customized the kidney Mr Slayman received.

It was genetically modified with technology to eliminate damaging pig genes and introduce some human genes to increase its compatibility with people.