mRNA Rewrites the Rules of Cancer Cell Therapy

Myeloid's in-body mRNA tech aims to make cancer treatment faster, cheaper, and more widely available.

2 Jun 2025

A US biotechnology company has presented early-stage clinical results suggesting that messenger RNA could significantly reduce the cost and complexity of cancer cell therapy.

Myeloid Therapeutics, a privately held firm based in Cambridge, Massachusetts, said it had developed a method to reprogram immune cells inside the body using intravenously delivered mRNA. The announcement came at the annual meeting of the American Society of Clinical Oncology.

The approach differs from traditional CAR-T therapy, which involves extracting a patient's immune cells, modifying them in a laboratory, and reinfusing them. This process is both time-consuming and expensive. Myeloid's method, by contrast, injects mRNA nanoparticles into the bloodstream, where they deliver genetic instructions directly to immune cells.

"If successful, in-vivo programming could democratize cell therapy, bringing it from niche centers into community hospitals," said one cancer research executive familiar with the field.

Initial results from the first human trial showed signs of immune cell reprogramming, though the study remains in its early stages. The company has not yet released detailed efficacy data, and long-term safety will be a key focus for regulators.

Cell therapy has transformed treatment for some blood cancers but has had limited success with solid tumors, which are more difficult to target. By activating immune cells already present at tumor sites, in-vivo mRNA techniques could offer a new strategy.

The use of mRNA in medicine gained widespread attention during the Covid-19 pandemic, when it was deployed in vaccines by Pfizer-BioNTech and Moderna. Since then, the technology has been rapidly adopted in oncology and rare disease research.

Myeloid's work adds to a growing list of early efforts aimed at delivering gene instructions without removing cells from the patient. If proven effective, such treatments could reduce reliance on complex manufacturing systems and significantly lower costs.

Investors and researchers will be watching closely as more data emerges. For now, the promise of in-vivo cell therapy remains unproven but potentially transformative.