Recent preclinical data published in Molecular Therapy suggest the company may be closer than ever to answering that question. Its platform did not emerge from a single discovery programme, but from a sequence of acquisitions that brought together the key ingredients for in vivo cell engineering: mRNA payloads, lipid nanoparticle delivery, and targeted immune-cell guidance. Across big pharma, companies are increasingly assembling in vivo CAR-T platforms piece by piece, raising a broader question about whether the next generation of cell therapy will be built in-house, or bought.