How Is CLL Treatment Guided by Cytogenetic Testing?

Our recent CLL Global Research Foundation virtual town hall featured CLL Global President, Dr. William Wierda, and Dr. Patrick Reville, Assistant Professor in the Department of Leukemia at The University of Texas MD Anderson Cancer Center. CLL patient advocate Jeff Folloder moderated the event. Watch the full webinar.

Transcript

Jeff Folloder:

I’ve got a question for Dr. Wierda from Susan. This is a great question. “Does cytogenic testing direct doctors to the best method of treatment?”

Dr. William Wierda:

So, I would say yes. I would say, if I were to choose yes or no, I would say yes, and the reason I say yes is when we talk about cytogenetic testing, cytogenetic can fall into several categories. Metaphase karyotyping is a form of cytogenetic testing, meaning we generate chromosomes in the lab that we can look at and count and determine if there is a change in the number or the structure of the chromosomes.

Another genetic test would be FISH. That tests for specific chromosome abnormalities. The one that is the one that we key into for the FISH test result is the 17p deletion. That’s a high-risk feature. That’s loss of part of chromosome 17, and that’s also frequently associated with a mutation in the gene that’s lost when you lose part of that chromosome, which is TP53. Patients with 17p deletion and mutated TP53 are high risk. They should not receive any chemotherapy. The target therapies improve outcomes for those patients, but we still have work to do in patients with that feature of 17p mutated TP53.

They’re at risk for developing resistance, they’re at risk for developing Richter’s transformation. Those are patients we don’t like to be in remission and off treatment if their disease has been active.

So, the answer to the question, and the very specific answer is yes, chromosome studies do matter. 17p deletion particularly will direct us to a maintenance strategy with a BTK inhibitor in preference over a fixed duration, venetoclax-based therapy. So, it is useful in terms of treating patients and managing the disease.