CAR T cells show potential for treatment of pediatric solid tumors
Researchers at Stanford University School of Medicine have used chimeric antigen receptor T cells targeting B7-H3 to attack certain solid tumors in several pediatric cancer models.
“The treatment has yet to be tested in humans, but is quickly moving toward clinical trials,” Robbie G. Majzner, MD, of the division of pediatric hematology-oncology at Stanford University School of Medicine, said in a press release.
Results from studies conducted in mice have laid the groundwork for a trial in adults and children.
HemOnc Today spoke with Majzner about this experimental therapy, the potential timeline for trials in humans, and when this approach — if proven effective and safe — could be adopted in clinical practice.
Question: What is the rationale for this research ?
Answer: The idea is to translate the success that has already been seen with CAR T cells for leukemia and lymphoma, specifically pediatric leukemia, into new therapies for children with incurable solid tumors and brain tumors.
Q: Why did you choose B7-H3 as a target?
A: Based on our clinical experience targeting CD19 and CD22 in leukemia, we wanted a target that was homogeneously expressed at high levels on an array of pediatric solid tumors. B7-H3 fit that description — we found it on more than 80% of the tumor samples that we analyzed, and expression levels were almost always significantly increased. Additionally, B7-H3 has been safely targeted with other types of antibody-based therapeutics for many years, so we were encouraged by the early safety data. Finally, because the target is expressed across many different types of pediatric cancer, we were hopeful that we could create a therapeutic that would be viable for several rare diseases.
Q: How will you conduct the trial in humans?
A: This CAR T cell will be tested first in adults with recurrent brain tumors. We are starting with brain tumors because we can give the CAR T cells locally into the central nervous system, where it potentially could be safer. Soon after this trial in adults begins, we will start testing it in children. We will inject the CAR T cells into the spinal fluid of patients and then watch for an antitumor response. This is in very early planning stages right now. We plan to start the trial by the end of 2020.
Q: What do you hypothesize that you will find?
A: We hope that we will begin to see the CAR T cells attack the tumor cells within the CNS and kill the tumor or slow its growth. We are hopeful that the CAR T cell will not attack normal tissues in the process. There is not much expression of this target in the CNS, but we hope that the T cells will not go after normal tissue that has low levels of B7-H3. The first human trial will assess the safety of administering these CAR T cells.
Q: When might this approach — if proven safe and effective—be adopted in clinical practice?
A: If we see promising results in our first clinical trial, we will work to quickly and safely roll this therapy out into trials at many centers treating children with cancer. – by Jennifer Southall
For more information:
Robbie G. Majzner, MD, can be reached at Stanford University School of Medicine, 291 Campus Drive, Room LK3C02, Stanford, CA 94305; email: email@example.com.
Disclosure: Majzner reports no relevant financial disclosures.