I try to avoid sensationalizing early clinical trial results presented at medical conferences, what’s commonly known as “hype over hope.” But at this year’s annual meeting of the American Society of Hematology (ASH) in New Orleans I was struck by the thought that I was a witness to the beginning of a revolution in the treatment of blood cancers.
Switzerland-based Novartis and Seattle-based Juno Therapeutics are blazing the trail to bring novel therapies to market based on modifying a patient’s own white blood cells known as T lymphocytes, central to the immune process and fighting cancer.
After harvesting T cells from a patient, gene therapy is used to express chimeric antigen receptors (CARs) onto their surface, resulting in T cells that are redirected to target tumor cells.
Dramatic results have been seen in acute lymphoblastic leukemia (ALL).
Stephan Grupp, the director of translational research for the center for childhood cancer research at The Children’s Hospital of Philadelphia (CHOP) presented data at ASH that showed complete remissions for 19 out of 22 children with relapsed, treatment-resistant forms of ALL who got the new form of therapy. All five adults treated with the Novartis CTL019 chimeric antigen receptor (CAR) modified T cells also achieved a complete remission. This data, although still preliminary, was worthy of being presented in the plenary session of the ASH meeting.
Renier Brentjens, director of cell therapeutics at Memorial Sloan-Kettering Cancer Center in New York, and one of the scientific founders of Juno Therapeutics put this data in context:
“I see a therapy that now offers life-saving treatment to patients with e.g. relapsed B-cell ALL,” Brentjens said. “It really is a heart-warming story and it’s an incredible experience to have one of your own patient’s that was basically doomed to die, make it to transplant, then run into them in the hallways two years later. It’s fantastic! “
Significant challenges remain with CAR modified T cell therapy.
“I think the current iteration of CAR T cell therapy is a little bit like the model A Ford and ultimately we are looking for a Ferrari,” Brentjens said.
Researchers are already on the third generation of chimeric antigen receptors and a fourth generation is in development.
There’s still a lot we don’t understand, such as
