The latest results of clinical trials of more than 125 patients testing an investigational personalized cellular therapy known as CTL019 were presented at the 56th annual meeting of the American Society of Hematology in San Francisco, California.
Highlights of the new trial results included a response rate of more than 90% among pediatric patients with acute lymphoblastic leukemia (ALL), and results from the first lymphoma trials testing the approach, including a 100% response rate among follicular lymphoma patients and 45% response rate among those with diffuse large B-cell lymphoma.
“We have now treated more than 125 patients in our trials of the chimeric antigen receptor (CAR) therapy CTL019, and with each patient, we learn more and more about the potential of this therapy,” said the research team’s leader, Carl June, MD, the Richard W. Vague Professor in Immunotherapy in the department of Pathology and Laboratory Medicine in Penn’s Perelman School of Medicine, and director of Translational Research in the Abramson Cancer Center in Philadelphia, Pennsylvania.
“We are continuing to refine our approach to ensure the best outcomes for patients who may be eligible for this experimental therapy, and we hope our findings will contribute to the emerging field of cellular therapy as a whole.”
This personalized cellular therapy approach begins with patients’ own immune cells, collected through a procedure similar to dialysis. The cells are then engineered in a laboratory and infused back into patients’ bodies after being trained to hunt and kill their cancer cells. All patients who enroll in the trials have cancers that have progressed despite multiple conventional therapies.
Updated results of a CTL019 trial for children and young adults with relapsed, treatment-resistant acute lymphocytic leukemia who were treated at the Children’s Hospital of Philadelphia includes data on 39 patients.
Among them, 36 of the 39 children (92%) achieved a complete response (CR) after receiving an infusion of the modified cells. After a median follow-up of 6 months, more than two-thirds (70%) of children who responded remained in remission and 75% were alive, including the first patient to receive the therapy, in the spring of 2012. These results were achieved with only three of the patients continuing on to stem cell transplant while in remission.
All pediatric patients who responded to the therapy experienced a cytokine release syndrome (CRS) within a few days after receiving their infusions, which is a key indicator that the engineered cells have begun proliferating and killing tumor cells in the body; however, this is also a known potentially lethal type of toxicity. Patients who experience a CRS typically have varying degrees of flu-like symptoms, with high fevers, nausea, muscle pain, and sometimes low blood pressure and breathing difficulties. Some patients require treatment with anticytokine agents and steroids to manage these symptoms.
In July 2014, the US Food and Drug Administration granted CTL019 a breakthrough therapy designation for the treatment of relapsed and refractory adult and pediatric ALL, a step which is intended to expedite the development and review of new medicines that treat serious or life-threatening conditions, if a therapy has demonstrated substantial advantages over available treatments. CTL019 is the first personalized cellular therapy to receive the designation.