Immunotherapy spurs a growth spurt for Alfonso

Whenever he comes to St. Jude for a checkup, Alfonso Reyes Juan heads to the Makerspace. Tucked into a glass-walled corner of the patient-and-family-only area called the Family Commons, the Makerspace is home to technology that would appeal to any curious, tech-savvy 12-year-old like Alfonso. He homes in on the pair of 3D printers at the back of the room — aptly named Danny and Marlo — ready to create whatever he can dream up.

Sean Winfrey, a Makerspace staff member, has mentored Alfonso for the past two years as Alfonso’s passion for technology blossomed. The pair have been designing increasingly complex digital models and bringing them to life with the 3D printers.

“Alfonso is a master of creating decals and 3D prints, and now he’s making a chessboard and Lego blocks. He’s grown so much,” Winfrey says.

But Alfonso has grown in other ways, too, since he first came to St. Jude. Between February and August 2025, he grew five centimeters — an unremarkable growth spurt for most boys, but significant for Alfonso. When he and his family first arrived at St. Jude, then 8-year-old Alfonso had spent the previous three years receiving treatment for the most common type of pediatric leukemia, B-cell acute lymphoblastic leukemia (B-ALL).

Diagnosed at age 5, Alfonso received chemotherapy followed by bone marrow transplantation, but still, his cancer returned. Having exhausted the available care options at home in Mexico City, Mexico, Alfonso and his family were referred to St. Jude.

Pediatric oncologist Aimee Talleur, MD, Department of Bone Marrow Transplantation & Cellular Therapy, recognized the potential to treat Alfonso with immunotherapy, a treatment that uses a patient’s own immune system against the cancer.

One type of immunotherapy, called chimeric antigen receptor (CAR) T–cell therapy, has been successful at treating blood cancers. It works by modifying a patient’s T cells to find and attach to specific proteins on the surface of cancer cells, triggering a targeted immune response that destroys the cancer.

Talleur told Alfonso and his family about a study called SJCAR19, the first clinical trial at St. Jude to study CAR T–cell therapy in patients with B-ALL who did not respond to treatment or whose cancer came back. Alfonso enrolled in the trial.

Almost two years after receiving CAR T–cell therapy, he is still in remission. While the treatment stopped his cancer from growing, Alfonso has grown physically, mentally and emotionally. The digital modeling skills he learned in the Makerspace have evolved into a passion for robotics programming. This past year, he and other kids from home competed in their first-ever robotics competition, placing fifth out of 14 groups. Encouraged by the win, his goal now is to form an official robotics team at his school so he and his classmates can continue to grow.