Relapsed Refractory B-Cell ALL: Patient Prognosis

Elias J. Jabbour, MD: Hello, and welcome to this OncLive® Insights® program titled “Adult Relapsed/Refractory B-cell Acute Lymphoblastic Leukemia: 2021 Updates.”

My name is Elias Jabbour, and I’m a professor in the department of leukemia, the division of cancer medicine, at [The University of Texas] MD Anderson Cancer Center in Houston, Texas. I’m joined by my esteemed colleague Dr Jae Park. I’d like to welcome him to introduce himself.

Jae Park, MD: Hello, everyone. My name is Jae Park. I’m an associate professor at Memorial Sloan Kettering Cancer Center in New York, part of a leukemia and cellular therapeutic service.

Elias J. Jabbour, MD: Welcome, and thank you for joining me. We’re going to discuss a number of recent updates in the treatment of adults with refractory/relapsed acute lymphoblastic leukemia [ALL] that were presented at key conferences. We’ll discuss the data in the context of guidelines, the treatment landscape, and its impact on clinical practice.

Let’s get started on our first topic. Jae, ALL is a rare disease, and we don’t see relapsed/refractory quite often. How common is this disease? If you can, please give a background of ALL in general.

Jae Park, MD: As you said, ALL is a rare disease for adults. It’s 1 of the most common cancers in pediatrics, but for adult patients, it’s 1 of the rare cancers, even among the hematologic malignancies. In the United States, we typically see 2000 to 3000 new cases of adult ALL in a year, so it’s a rare disease. From the frontline therapy in the majority of patients, the cure rate typically has been 40% to 60%, although that’s improving and we’re getting better. It seems that the majority of the patients are being cured, which is an excellent trend. This means that among the newly diagnosed patients in the relapsed/refractory setting, we may see roughly 40%, and even higher in the higher-risk patients.

There are 2 major phenotypes of ALL that we think about. They’re divided into B-cell or T-cell subtype based on the markers these ALL cells express, or the immunophenotypes. B-cell ALL is the predominant type. Typically, about 80% of ALL cases will be B-cell, and the other 20% will be T-ALL [T-cell acute lymphoblastic leukemia]. There are different age distributions. The younger patients may have a slightly higher incidence of T-cell ALL, but it’s roughly 80% to 20%.

Among the B-cell subtype, we further divide the disease based on the Philadelphia chromosome [Ph] presence, which is translocation of the chromosome 9 and 22 or BCR-ABL translocation. We call that Ph-positive or Ph-negative disease based on the presence of this mutation. Incidence of the Ph-positive mutation also increases with age, so about 40% of ALL will belong to that category, but it may be even higher in those over age 60. The younger you are, the less the incidence of the Ph positivity. These are generally the phenotypes we think about. The absolute minimum we need at the time of diagnosis is to see whether they’re B vs T. If they’re B, it’s Ph-positive vs Ph-negative.

Elias J. Jabbour, MD: Great. Thank you very much for this brief overview.

Transcript edited for clarity.