A single dose of a new cancer drug made a brain tumor almost disappear in just 5 days In early 2024, doctors at Massachusetts General Hospital treated three people with recurrent glioblastoma brain tumour using a brand-new type of CAR T-cell therapy called CARv3-TEAM-E. The treatment is made from each patient’s own immune cells, which are taken out, genetically rewired in the lab to recognize two different markers commonly found on glioblastoma cells, and then infused directly into the fluid spaces of the brain through a single procedure. The results were stunning and much faster than anyone expected: In one patient, MRI scans taken just five days after the single infusion showed the tumor had almost completely vanished. A second patient had more than 60 % of the tumor disappear, and that shrinkage lasted for over six months. The third patient also had clear tumor reduction within days. These responses happened far more quickly and dramatically than anything seen before with immunotherapy for this type of brain cancer. Doctors described the early images as “jaw-dropping.