Seattle Children s Opens CD22 CAR T-Cell Immunotherapy Trial for Children and Youthfull Adults Whose Leukemia Escapes CD19 CAR T-Cell Therapy – Massachusetts Biotechnology Council
Seattle Children’s Opens CD22 CAR T-Cell Immunotherapy Trial for Children and Youthfull Adults Whose Leukemia Escapes CD19 CAR T-Cell Therapy
After eyeing promising results in phase one of the Pediatric Leukemia Adoptive Therapy (PLAT-02) trial with ninety three percent of patients with relapsed or refractory acute lymphoblastic leukemia (ALL) achieving accomplish initial remission, researchers at Seattle Children’s are continuing their quest to improve the experimental therapy and reduce the rate of relapse, which is about fifty percent. Researchers have now opened a phase one clinical trial, PLAT-04, for children and youthful adults with relapsed or refractory CD22-positive ALL. They will examine the safety and feasibility of administering cancer-fighting chimeric antigen receptor (CAR) T cells that have been reprogrammed to target the CD22 protein voiced by some leukemia cells.
“We’re at a pivotal point where we’re building upon what we’ve learned in the PLAT-02 trial and opening fresh trials, like PLAT-04, with the aim of improving this therapy to the point that it becomes a long-term cure for all of our leukemia patients,” said Dr. Corinne Summers, an oncologist at Seattle Children’s and the lead investigator of the PLAT-04 trial.
Summers and the research team, led by Dr. Mike Jensen at the Ben Towne Center for Childhood Cancer Research at Seattle Children’s Research Institute, are opening PLAT-04 after discovering that of the patients who relapsed in the PLAT-02 trial, approximately forty percent of them relapsed with a leukemia that evolved to circumvent the CAR T cells that were reprogrammed to detect and ruin cancer.
In PLAT-02, the CAR T cells are reprogrammed to recognize and target the CD19 protein that is voiced by most precursor B acute lymphoblastic leukemia cells. However, in some patients, the leukemia recurred without the CD19 target and voiced a protein that the CAR T cells were incapable to recognize – CD22. With the PLAT-04 trial, researchers will now be able to reprogram CAR T cells to detect and ruin leukemia cells that express the CD22 protein. Researchers hope to enroll more than thirty patients in the trial over the next two to three years.
“Leukemia cells evolve in order to find ways to sustain,” said Summers. “For the patients who relapse with CD22-positive leukemia, we are very pleased to now be able to suggest a treatment option that will hopefully lead them to ultimately achieving long-term remission.”
The PLAT-04 trial goes after the PLAT-03 trial that Seattle Children’s opened in May. PLAT-03 institutes another strategy aimed at enlargening long-term remission – introducing T-cell “boosters” intended to improve the persistence of CAR T cells. Researchers are also working to develop a trial where they will reprogram CAR T cells to identify the CD19 and CD22 proteins at the same time, enabling them to target the cancer cells from more than one angle with the initial round of T-cell immunotherapy.
“We believe T-cell immunotherapy has tremendous potential,” said Summers. “This is why we’re diligently working to employ several strategies that we hope will lead us to reaching our ultimate objective of developing the best therapy possible – a therapy that can be given to patients as a very first line of defense, greatly reducing the side effects of cancer treatment and leading to a cure.”
The T-cell immunotherapy trials at Seattle Children’s are funded in part by Strong Against Cancer, a national philanthropic initiative with worldwide implications for potentially curing childhood cancers. If you are interested in supporting the advancement of immunotherapy and cancer research, please visit Strong Against Cancer’s donation page.
For more information on immunotherapy research trials at Seattle Children’s, please call (206) 987-2106 or email [email protected].
Seattle Children’s mission is to provide hope, care and cures to help every child live the healthiest and most fulfilling life possible. Together, Seattle Children’s Hospital, Research Institute and Foundation supply superior patient care, identify fresh discoveries and treatments through pediatric research, and raise funds to create better futures for patients.