MPNs are chronic blood cancers that begin when a mutation arises in the DNA of a blood stem cell. Over time, some patients progress to myelofibrosis, a serious condition marked by scarring of the bone marrow and anemia.

In roughly 1 in 5 cases, the disease transforms into an aggressive leukemia-like phase where survival may be measured in months. For most patients, there are no curative treatments available.

CAR T-cell therapy works by reprogramming a patient’s own immune cells to target specific cells in the body and is already a successful treatment in other blood cancers. In this study, published in Science Translational Medicine, the engineered cells were designed to recognize a mutation found in around a third of MPN patients called CALR.