One-year-old Korean baby with leukemia successfully recovers after CAR-T therapy

A patient who is in complete remission after CAR-T treatment is being treated by Im Ho-joon, professor of Pediatric Hematology and Oncology at Asan Medical Center in Seoul. [Photo provided by Asan Medical Center]

The CAR-T Center at Asan Medical Center in Seoul has successfully treated a one-year-old infant suffering from relapsed B-cell acute lymphoblastic leukemia, a type of malignant blood cell cancer.

The hospital recently said that the infant’s bone marrow tests showed complete remission of leukemia and microscopic examination of residual leukemia cells showed that they had been reduced to 0 percent. The infant was diagnosed with B-cell acute lymphoblastic leukemia in July 2021, just one month after birth, when his parents noticed the baby had developed blue bruises on his face and body.

CAR-T therapy uses the patient’s own T-cells engineered with a substance that can attack tumor cells and reintroduced into the patient’s body. It is a cutting-edge treatment method that has shown great promise in treating leukemia.

Leukemia is a type of cancer where the normal blood cells produced by the bone marrow are converted into tumor cells and proliferate in the body. The exact cause of leukemia is still unknown in modern medicine.

The doctor, Professor Im Ho-joon, division of Pediatric Hematology and Oncology at Asan Medical Center, first gave chemotherapy to the baby, followed by a hematopoietic stem cell transplant taken from his mother in January 2022.

While there were no complications after the transplant, his leukemia relapsed in August. The relapse rate after hematopoietic stem cell transplantation is known to be about 20 percent.

If leukemia comes back after a stem cell transplant, chemotherapy and a stem cell transplant can be tried again, but the risk of serious side effects is very high.

There were very few cases of CAR-T therapy being used to treat leukemia in infants under one year old worldwide, but it was the only option to save the baby’s life.

The medical team performed the CAR-T treatment in October, in which T-cells taken from the baby’s blood. They carefully monitored the baby for potential side effects, including neurotoxicity and cytokine release syndrome.

One month after the CAR-T therapy, bone marrow and microscopic residual disease tests conducted in November showed the leukemia was in complete remission and the baby remains healthy with no side effects.

Asan Medical Center opened the country’s first CAR-T center in April last year. Eligible patients include those with relapsed or refractory B-cell acute lymphoblastic leukemia who are 25 years old or younger, and those with relapsed or refractory diffuse large B-cell lymphoma after two or more systemic therapies who are 19 years old or older.

Both diseases are difficult to treat as patients have only six months to live after diagnosis, but CAR-T has shown to completely treat cancer in about 80 percent of patients with B-cell acute lymphoblastic leukemia under the age of 25 and about half of patients with diffuse large B-cell lymphoma over the age of 19.

The hospital’s CAR-T Center is collaborating with other departments, including the intensive care unit, neurology and infectious diseases to develop guidelines for early detection and safe treatment of possible side effects from CAR-T therapy.

“I think this is the result of our experience in treating pediatric blood cancers, having performed one out of five pediatric hematopoietic stem cell transplants in Korea, and safe treatment through the multidisciplinary clinic at the CAR-T Center,” said Im. “Since CAR-T treatment does not completely remove the possibility of recurrence, we will do our best to ensure that patients continue to receive treatment.”

Asan Medical Center has performed more than 1,100 pediatric hematopoietic stem cell transplants, giving new life to children with cancer and incurable blood diseases.

In 2013, the hospital successfully performed the world’s first half-matched stem cell transplant for more than 10 children with severe aplastic anemia, leading the way in pediatric half-matched stem cell transplantation.

The success rate of haploidentical stem cell transplantation for patients with severe aplastic anemia at Asan Medical Center is 93 percent, which is higher than the global average of 70 percent to 80 percent, providing hope for children in urgent need of stem cell transplantation.