Gene-Editing Platform Lets Doctors Control Cell Therapies with Existing Drugs

A team of Australian clinician-researchers has developed a gene-editing platform designed to give doctors more control over cell therapies, aiming to make them more workable for patients with complex immune conditions.

Published in Blood and led by WEHI, the approach uses prime editing to let clinicians treat existing immunosuppressive drugs as a control dial for cell therapies, helping corrected cells survive once returned to the body. It targets patients who need ongoing immunosuppression, including those with rare immune disorders, organ or stem cell transplants, and cell therapy for cancer.

Cell and gene therapies generally work by removing a patient’s immune cells, modifying them outside the body, and reinfusing them—but once those cells are back, doctors have few ways to selectively boost or suppress them. That’s a particular problem for patients on continuous immunosuppression, since the same drugs protecting a transplant or managing disease can also suppress the therapeutic cells meant to help.

Co-senior author Miles Horton said prime editing was chosen to solve a problem seen in real clinical care. “We’ve used genetic engineering to rewire these cells so clinicians could use existing drugs, already sitting in the hospital pharmacy, as a control dial.” He added: “Some approaches being explored elsewhere would require doctors to adopt a new cell therapy and a new drug at the same time. Our aim was to build a platform around clinical reality, using medicines that clinicians already know and use.”

The team engineered T cells to resist tacrolimus, a common immunosuppressive drug, while keeping them sensitive to cyclosporin, a related alternative—giving clinicians a way to protect the edited cells with one drug while still having the other in reserve if the cells needed to be reined in.

The work centered on SPTCL-HLH, a rare and serious immune-linked blood cancer affecting children and young adults. Using patient-derived cells, researchers applied prime editing to correct the disease-causing mutation and add tacrolimus resistance, then tested the same platform in virus-specific T cells and CAR T cells used in cancer treatment.

Tom Lew, the study’s other co-senior author, said the project was shaped around clinical needs: “As clinicians, we are always thinking about whether a promising technology could realistically fit into patient care. Our approach is built around medicines that are already part of routine clinical practice, which could make translation more practical.”

First author Esther Bandala-Sanchez explained that the platform was built for both precision and flexibility: “We showed this strategy could be applied across different types of therapeutic T cells, not just one disease setting. The edited cells stayed functional under immunosuppression, and importantly, remained sensitive to other drugs. That precision is what makes the platform so promising as a foundation for future cell therapies.”