A new Phase 1 clinical trial is underway at Children’s Hospital Colorado, evaluating a dual-target CAR T-cell therapy for pediatric patients with relapsed or refractory pre B-cell acute lymphoblastic leukemia (B-ALL). This innovative approach, which targets both CD19 and CD22 proteins on leukemia cells, aims to improve outcomes for patients who have relapsed after initial treatment. The trial represents a significant step forward in personalized cancer therapy, leveraging the body's own immune system to fight the disease.
Addressing Relapse in B-ALL
B-ALL is the most common childhood malignancy, with generally positive outcomes. However, a subset of patients experience relapse, presenting a significant challenge. The newly developed CAR T-cell therapy, known as CD19x22, targets two proteins frequently found on the surface of leukemia cells. This dual-targeting strategy is designed to overcome a common resistance mechanism where leukemia cells lose the CD19 protein, allowing them to evade conventional CAR T-cell therapies.
Terry Fry, MD, executive director of Gates Institute, who initially developed the technology, explained that initial CAR T-cells targeted the CD19 receptor, but about half of patients who had achieved remission eventually relapsed because the leukemia had lost the CD19 protein. A similar issue was observed when targeting CD22. The CD19x22 CAR T-cell places the targets in separate places on the cell surface to improve efficacy.
Novel CAR T-Cell Design
Unlike previous attempts to target both CD19 and CD22 with a single CAR, this new approach utilizes two separate CARs introduced into the same T cell. This design is intended to enhance the therapy's ability to effectively target both proteins simultaneously. A clinical trial at UCHealth University of Colorado Hospital is also evaluating this CAR T-cell in adults with B-cell lymphomas, with initial results to be presented by Manali Kamdar, MD, at an upcoming American Society of Hematology meeting.
The Role of the Gates Institute and Biomanufacturing Facility
The Gates Institute plays a crucial role in this research, providing expertise in cell and gene therapy clinical trial design, regulatory strategy, and trial operations. The Gates Biomanufacturing Facility (GBF) is the only GMP-compliant facility at an academic medical campus in the Rocky Mountain region equipped to produce CAR T cells. This on-site manufacturing capability allows for customized treatments and accelerates the development of novel therapies.
Trial Design and Patient Monitoring
The Phase 1 study will enroll patients from 3 months to 30 years of age. Patients undergo apheresis to collect T cells, which are then engineered at the GBF to recognize cancer cells. The engineered T cells are multiplied and infused back into the patient. The trial aims to determine the optimal dose of CAR T cells, with patients receiving one infusion and being monitored for 12 months for safety and side effects. Long-term follow-up will continue for 15 years, as required by the FDA.
Vanessa Fabrizio, MD, MS, principal investigator of the trial, emphasizes the importance of offering more choices to patients with limited options. This investigator-initiated trial, with CAR T cells manufactured at the GBF, positions CU Anschutz as a leader in cell therapy research.
Potential Risks and Benefits
CAR T-cell therapy can cause severe side effects, such as cytokine release syndrome (CRS), which can lead to high fevers and require oxygen or blood pressure support. However, the potential benefits of this therapy, particularly in patients with relapsed or refractory B-ALL, are significant. By leveraging the immune system to specifically target cancer cells, CAR T-cell therapy offers a more targeted approach compared to traditional chemotherapy, which can indiscriminately kill both cancer and healthy cells.
