SAN FRANCISCO (TheStreet) -- Treatment with re-engineered immune cells designed to kill leukemia has led to complete remissions in more than 90% of a small group of children and young adults with an aggressive form of the disease enrolled in an ongoing, early-stage study.
More than two-thirds of the patients remain cancer free six months following treatment and 75% of patients are still alive, said researchers from the University of Pennsylvania and Novartis (NVS) , speaking during a media briefing Saturday at the American Society of Hematology (ASH) annual meeting taking place here.
This new form of cancer immunotherapy, which scientists refer to as CAR-T for the receptor added to killer T cells in the lab, promises to radically change the way certain blood cancers are treated. CAR-T therapies are also generating tremendous commercial and investor interest. The UPenn-Novartis joint venture is competing with Juno Therapeutics, a red-hot private company expected to price a $150 million initial public offering early next year.
The study updated today enrolled 39 children and young adults with relapsed, treatment-resistant acute lymphocytic leukemia (ALL). After the experimental UPenn-Novartis treatment known as CTL019 was given, 36 of 39 patients, or 92%, went into complete remission, meaning there was no evidence of disease in their bodies. Six months after receiving CTL019, 70% of patients remain cancer free, and only five patients have required subsequent treatment. Seventy-five percent of the patients are still alive.
"With this longer followup, we now have children who remain in remission a year or more after treatment solely because of this T cell therapy," said lead study investigator Dr. Stephan Grupp of The Children's Hospital of Philadelphia. "Our next step is to conduct a Phase II, multi-site trial to assess the safety and efficacy of this treatment in multiple centers and to further evaluate its long-term potential to become a replacement for stem cell transplant for children with relapsed, treatment-resistant disease."
CAR-T therapies are personalized for each patient. The process starts by harvesting T cells from the patient's blood. In a lab, scientists add a chimeric antigen receptor (CAR) to the surface of the T cells. This receptor allows the T cells to recognize a protein known as CD19 found on the most leukemic cells. The T cells are also programmed to multiply once attached to the CD19 protein. Once this engineering work is done, the T cells are infused back into the patient where they seek out and destroy leukemic cells.
CAR-T is not without risks. All the patients who respond suffer from severe flu-like symptoms resulting from the engineered T cells attacking leukemic cells. In some cases, the side effects are life threatening unless managed carefully.
The commercial process necessary to make personalized CAR-T treatments is complex and may not be as profitable as off-the-shelf cancer treatments. Dendreon (DNDN) went bankrupt, in part, because of the difficulty making and selling a personalized prostate cancer vaccine.
And when researchers have tested CAR-T therapies in other blood cancers like chronic lymphocytic leukemia, the response rates have not been as robust as those seen in acute lymphocytic leukemia.