Surgeons removed a genetically engineered pig’s kidney from an Alabama woman after she experienced acute organ rejection, NYU Langone Health officials said on Friday.

Towana Looney, 53, lived with the kidney for 130 days, which is longer than anyone else has tolerated an organ from a genetically modified animal. She has resumed dialysis, hospital officials said.

Dr. Robert Montgomery, Ms. Looney’s surgeon and the director of the NYU Langone Transplant Institute, said that the so-called explant was not a setback for the field of xenotransplantation — the effort to use organs from animals to replace those that have failed in humans.

“This is the longest one of these organs has lasted,” he said in an interview, adding that Ms. Looney had other medical conditions that might have complicated her prognosis.

“All this takes time,” he said. “This game is going to be won by incremental improvements, singles and doubles, not trying to swing for the fences and get a home run.”

Further treatment of Ms. Looney might have salvaged the organ, but she and her medical team decided against it, Dr. Montgomery said.

“No. 1 is safety — we needed to be sure that she was going to be OK,” he said.

Another patient, Tim Andrews of Concord, N.H., has been living with a kidney from a genetically modified pig since Jan. 25. He has been hospitalized twice for biopsies, doctors at Massachusetts General Hospital in Boston said.

Two other patients who received similar kidneys in recent years died, as did two patients given hearts from genetically modified pigs.

Ms. Looney, who has returned to her home in Alabama after coming to New York for treatment and was not available for comment, said in a statement that she was grateful for the opportunity to participate in the groundbreaking procedure.

“For the first time since 2016, I enjoyed time with friends and family without planning around dialysis treatments,” Ms. Looney said in a statement provided by NYU Langone.

“Though the outcome is not what anyone wanted, I know a lot was learned from my 130 days with a pig kidney — and that this can help and inspire many others in their journey to overcome kidney disease,” she said.

Hospital officials said that Ms. Looney’s kidney function dropped after she experienced rejection of the organ. The cause was being investigated, Dr. Montgomery said.

But the response followed a reduction in immunosuppressive medications she had been taking, done in order to treat an unrelated infection, he added.

The first sign of trouble was a blood test done in Alabama that showed Ms. Looney had elevated levels of creatinine, a waste product that is removed from the blood through the kidneys. Elevated levels signal there may be a problem with kidney function.

Ms. Looney was admitted to the hospital, but when her creatinine levels continued to climb, she flew to New York, where doctors biopsied the kidney and found clear signs of rejection, Dr. Montgomery said.

The kidney was removed last Friday, hospital officials said.

“The decision was made by Ms. Looney and her doctors that the safest intervention would be to remove the kidney and return to dialysis rather than giving additional immunosuppression,” Dr. Montgomery said in a statement.

United Therapeutics Corporation, the biotech company that produced the pig that provided Ms. Looney’s kidney, thanked her for her bravery and said that the organ appeared to function well until the rejection.

The company expects to start a clinical trial of pig-kidney transplantation this year, starting with six patients and eventually growing to 50 patients.

Pig organs are seen as a potential solution to the shortage of donated organs, especially kidneys. More than 550,000 Americans have kidney failure and require dialysis, and about 100,000 of them are on a waiting list to receive a kidney.

But there is an acute need for human organs, and fewer than 25,000 transplants were performed in 2023. Many patients die while waiting.