Two people who received genetically engineered pig kidneys have now gone on to receive human donor organs, a result that suggests a temporary animal transplant does not block a conventional one later. A xenograft, the medical term for a transplant between different species, had functioned as a bridge rather than a barrier. eGenesis, a biotech company working to develop interspecies transplants, announced the outcome on Thursday evening.
One of the central concerns in this field has been the immune response. When a patient receives an organ from another species, the question is whether their body will generate antibodies, proteins the immune system produces to identify and attack foreign material, that could then complicate a human transplant later. This was not a trivial worry. A patient who needed a human kidney could conceivably end up in a worse position if a prior xenograft created a new immunological obstacle. eGenesis scientists did not believe that would happen, based on what they saw in primate studies. Thursday's announcement confirmed it in two human patients.
The transition back to human organs was not without difficulty. In both cases, doctors removed the pig kidney, and the patients went back on dialysis for months before a human organ became available. Dialysis is the process of filtering waste from the blood that a functioning kidney handles on its own. Still, both patients had spent the better part of a year free of that routine, relying on an engineered pig kidney in the meantime. For patients who can spend years on waiting lists and sometimes never receive a human organ at all, that stretch of time is not incidental.
The shortage that makes this research matter
There are not enough human donor organs for everyone who needs one. Many die on waiting lists. The whole project of placing pig kidneys into people is motivated by that gap. eGenesis is among a handful of biotechs racing to develop the approach.
Thursday's announcement does not resolve how long pig organs reliably function inside a human body or which patients make the best candidates. What it does establish is that a patient can receive a pig kidney and then move on to a human organ. That sequence had not been confirmed before.