mRNA CAR T aims to spare autoimmunity from cancer risk

mRNA-encoded CAR – Gene-therapy researchers are pushing CAR T treatments designed to act temporarily—using mRNA to encode cancer-targeting cells—in hopes of reducing the hard-to-measure long-term risks that make autoimmune use so fraught.

In cancer care. a grim trade-off can sometimes be tolerated: allowing a serious side effect so long as the disease that’s killing a patient can be stopped.. But in autoimmune disease. where severity can vary widely. the same bargain is far harder to justify—especially when the risk of future cancers and other late complications is difficult to put a clear number on.

Matt Lunning. medical director for gene and cellular therapy at Nebraska Medicine in Omaha. puts it bluntly: causing a secondary cancer may be acceptable when treating a life-threatening cancer. but probably not for autoimmunity.. That uncertainty—how to balance an autoimmune’s impact against the difficult-to-quantify risk of future side effects or cancers—remains a major open question for the field.

One bet toward answering that question is building the next versions of CAR T. with researchers already working on second- and third-generation approaches expected to be safer for both cancer and autoimmunity.. A notable example comes from James Howard. a neuromuscular neurologist at the University of North Carolina at Chapel Hill. who is testing a technology from a company called Cartesian Therapeutics.

Instead of encoding the CAR using long-lasting DNA. Cartesian’s approach uses molecules of mRNA—the short-lived genetic messenger used in Covid-19 vaccines—to carry the instructions.. In this design. the CAR T cells should wipe out B cells for only as long as the mRNA persists. then lose their B cell-targeting abilities.. Howard’s reasoning is straightforward: with no chance for genetically modified T cells to hang around long-term. there should be no cancer risk.

There’s also another practical safety argument built into how physicians administer the therapy. Howard says the cells are infused in sufficient numbers that they don’t need to reproduce inside the patient’s body. He thinks that reduces risk for inflammation.

In a recent trial of the Cartesian CAR T treatment, 15 people with autoimmune diseases received the therapy. Two-thirds saw their symptoms improve, and none suffered long-term serious side effects.

Yet even if safety concerns can be addressed. CAR T still faces a separate hurdle—one that has nothing to do with biology and everything to do with access.. The treatment’s price tag reaches hundreds of thousands of dollars, including hospital stays, cell engineering, and other expenses.. The financial weight is part of why researchers are looking for ways to streamline the manufacturing process.

Lunning says the treatment would likely be cheaper and simpler if scientists could eliminate personalized engineering for each patient’s own cells and instead use donor cells.. Another possibility is cutting out the step of engineering and growing the cells in a laboratory.. He’s also watching up-and-coming procedures that would modify a person’s T cells within their own body. rather than doing the genetic engineering in a lab.

The needle-threading challenge shows up in the way today’s CAR T promises two different paths at once: Lunning’s concern centers on hard-to-quantify future risks when autoimmune disease isn’t always immediately fatal. while Howard’s mRNA-based design tries to limit that uncertainty by shortening how long CAR-targeting lasts—paired with trial results showing symptom improvement in two-thirds of 15 patients and no long-term serious side effects.. Even as the biology aims for temporary action. the treatment’s scale and cost still hinge on complex engineering steps that researchers are trying to replace or move closer to the patient.

For autoimmunity, the stakes are high precisely because the risk is so difficult to measure.. And for CAR T. the promise hinges on whether the next generation can stay effective without turning late complications into the next chapter of patients’ lives—while also becoming realistic in cost and manufacturing.

CAR T mRNA autoimmune disease B cells gene therapy Cartesian Therapeutics inflammation Nebraska Medicine UNC Chapel Hill gene and cellular therapy