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Trial assesses CD22 CAR T-cell therapy for children, young adults with acute lymphoblastic leukemia
The PLAT-04 clinical trial is underway to evaluate the use of CD22 chimeric antigen receptor T-cell immunotherapy for children and young adults with relapsed or refractory CD22-positive acute lymphoblastic leukemia.
Study participants will receive CD22 chimeric antigen receptor (CAR) T cells that have been reprogrammed to target the CD22 protein expressed by certain leukemia cells.
“We are at a pivotal point where we are building upon what we have learned in the PLAT-02 trial and opening new trials, like PLAT-04, with the goal of improving this therapy to the point that it becomes a long-term cure for all of our leukemia patients,” Corinne Summers, MD, principal investigator in Ben Towne Center at Seattle Children’s Hospital, said in a press release. “We believe T-cell immunotherapy has tremendous potential. This is why we are diligently working to employ several strategies that we hope will lead us to reaching our ultimate goal of developing the best therapy possible — a therapy that can be given to patients as a first line of defense, greatly reducing the side effects of cancer treatment and leading to a cure.”
HemOnc Today spoke with Summers about how the study will be conducted, when data may be available, and the broader potential for CAR T-cell therapy for children and young adults with leukemia.
Question: What prompted this research?
Answer: Much of what we do from a research perspective is work on enhancing T-cell therapy. Part of this includes identifying additional targets. CD19 CAR T-cell immunotherapy has been quite successful in the clinic; however, there are some patients who relapse after CAR T-cell immunotherapy, and their disease no longer express the CD19 target. We thought the CD22 CAR would be potentially useful in these cases. Often, B-cell leukemia continues to express the CD22 marker, and this could be an additional therapy for patients with CD19-negative relapse.
Q: Earlier this year, the FDA approved the first CAR T-cell therapy for childhood leukemia . What does that approval mean for this patient population?
A: We are very encouraged about this new approval. It will increase the availability of the therapy, which is incredibly important to pediatric patients with high-risk leukemia. With more patients receiving CD19-directed therapy, we will have an increased number of patients with negative relapse, making CD22 directed therapy an important potential option.
Q: How will the PLAT-04 trial be conducted?
A: It is a phase 1 trial designed to evaluate the feasibility and safety of patient-derived CD22 CAR T cells for pediatric and young adult patients with relapsed or refractory leukemia that expresses the CD22 target.
Q: What is the timeline for patient enrollment and when might data become available?
A: We began patient enrollment in late July. We anticipate it will take 3 to 4 years to enroll approximately 35 patients.
Q: Can you describe the broader potential for CAR T-cell therapy for children and young adults with leukemia?
A: Targeted therapy is important for growing and developing pediatric patients, potentially limiting long-term side effects observed with chemotherapy. We hope that, with additional research, we can move this therapy upfront in the treatment landscape, closer to initial diagnosis.
Q: Is there anything else that you would like to mention?
A: Cellular immunotherapy is an important treatment modality. Moreover, targeted therapy is an important option for pediatric patients to potentially prevent long-term side effects observed with conventional therapy. The CD22 CAR T-cell trial offers a targeted therapy for pediatric and young adult patients with CD22-positive leukemia. This is particularly useful for patients who have developed CD19-negative relapse following CD19 directed therapy. – by Jennifer Southall
For more information:
Corinne Summers, MD, can be reached at Seattle Children’s Hospital, MB.8.501 — Hematology-Oncology, 4800 Sand Point Way NE, Seattle, WA 98105; email: immunotherapy@seattlechildrens.org.
Disclosure: Summers reports no relevant financial disclosures.