Authored by Ann Liu, PhD
Medically Reviewed by Brian Koffman, MDCM (retired), MSEd
The Bottom Line:
Patients with CLL who had genetic testing done before starting treatment were more likely to have better clinical outcomes than patients who were not tested.
Who Performed the Research and Where Was it Presented:
Dr. Brian Koffman from CLL Society and colleagues presented the results at the American Society for Hematology (ASH) Annual Meeting in 2025.
Background:
Not all chronic lymphocytic leukemia (CLL) / small lymphocytic lymphoma (SLL) cells are the same, and they may behave in different ways depending on their genetic makeup. Doctors can get useful information by running genetic tests on your CLL / SLL cells. Genetic tests are key to understanding how aggressive your disease might be, and they can help doctors understand how your body might react to different medications.
Three important genetic marker tests include FISH, IGHV, and TP53. FISH (fluorescence in situ hybridization) testing looks for structural changes in chromosomes and, therefore, in genes. Testing for IGHV and TP53 identifies whether the gene is mutated or unmutated. Patients who have deletions in chromosome 17 (del17p), unmutated IGHV, or mutated TP53 are considered higher-risk, because their disease tends to be more aggressive and does not respond well to chemoimmunotherapy. This study looked at whether genetic testing influenced first-line treatment choices and patient outcomes.
Methods and Participants:
This was a retrospective study using de-identified electronic health record data from a US database. It included patients with CLL who started first-line treatment between 2020 and 2024.
Results:
- A total of 5481 patients were included in the study, and prior to starting treatment:
- 82% had FISH testing
- 52% had IGHV testing
- 27% had TP53 testing
- Patients who received genetic testing were more likely to be younger, male, White, and have commercial insurance.
- Patients who received genetic testing had better outcomes.
- In patients who were tested for del17p / TP53, real-world time to next treatment was 42 months vs. 30 months in untested patients.
- In patients who were tested for IGHV, the real-world time to next treatment was 45 months vs. 35 months in untested patients.
- Patients who were not tested before treatment were less likely to receive National Comprehensive Cancer Network (NCCN)-guideline-preferred therapies (acalabrutinib, zanubrutinib, venetoclax-based regimens) and more likely to receive chemoimmunotherapy.
- Median real-world time to next treatment was 60 months for patients receiving NCCN-guideline-preferred therapies vs. 10 months for patients receiving chemoimmunotherapy.
Conclusions:
Patients with CLL who had genetic testing done prior to starting treatment were more likely to have better clinical outcomes than patients who were not tested. Genetic testing seems to be a surrogate marker for the quality of care, as doctors who know enough about CLL to order the tests are likely providing better care. While it was good to that the number of patients tested appropriately has been growing so that now most patients are getting FISH testing done, there is still more work to do to make sure patients also receive TP53 and IGHV testing, which are equally as important. Here at the CLL Society, we provide a Test Before Treat™ handout that explains biomarker testing, which can be shared with your healthcare provider.
Links and Resources:
Watch the interview on the abstract here:
You can read the actual ASH abstract here: Impact of testing for genetic markers on treatment selection and clinical outcomes among patients with chronic lymphocytic leukemia
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