By her 50th birthday, Els van der Heijden felt sicker than ever. Born with the hereditary disorder cystic fibrosis (CF), she had managed to work around her illness, finishing college and landing a challenging job in consulting. But Van der Heijden, who lives in a small Dutch town, says she always felt "a dark cloud hanging over my head." When she began feeling exhausted and easily out of breath in 2015, she thought it was the beginning of the end.

Then she read a newspaper article about a child with CF named Fabian whose life had been saved after scientists grew a "mini-organ" from a tissue sample snipped from his colon, one organ that CF affects. Doctors had used the mini-organ to test ivacaftor (Kalydeco), a drug so expensive that Dutch insurers refuse to cover it without evidence that it will help an individual CF patient. No such data existed for Fabian, whose CF was caused by an extremely rare mutation. But his minigut responded to ivacaftor, and he improved within hours of taking it. His insurance eventually agreed to pay for the drug.

Van der Heijden's doctor arranged to have a minigut made for her as well; it responded to a drug marketed as Orkambi that combines ivacaftor and another compound, lumacaftor. Within weeks after she began taking that combination, "I had an enormous amount of energy," she says. "For the first time ever, I felt like my body was functioning like it should."

The life-altering test was developed in the lab of Hans Clevers, director of the Hubrecht Institute here. More than a decade ago, Clevers identified a type of mother cell in the gut that can give birth to all other intestinal cells. With the right nutrition, his team coaxed such stem cells to grow into a 3D, pencil tip-sized version of the gut from which it came. The minigut was functionally similar to the intestine and replete with all its major cell types—an organoid.

To read more, click here.