Real-World Analysis of Race in CLL Treatment Patterns

At the American Society of Clinical Oncology annual meeting, researchers presented results of a study using informCLL, the first multicenter U.S. chronic lymphocytic leukemia (CLL) registry, that aimed to better understand real-world treatment practices among Black patients primarily treated in a community-based setting.

In this exclusive MedPage Today video, lead author Jacqueline Barrientos, MD, of the CLL Research and Treatment Program of Northwell Health Cancer Institute in New Hyde Park, New York, briefly discusses the study.

Following is a transcript of her remarks:

So our key questions and analysis are what are the baseline demographics and clinical characteristics by line of therapy for Black patients fully enrolled in the informCLL registry — what proportion of Black patients underwent prognostic marker testing, which baseline characteristics including race were associated with likelihood of undergoing prognostic biomarker testing, and how did the choice of index treatment evolve over the registrant enrollment period? And how does it compare to the other population?

So as an introduction, CLL is the most common chronic form of leukemia in adults in the United States. However, for patients that are known white, this is different. Black patients represent by SEER [Statistics Epidemiology and End Results] registry approximately 6 to 7% of newly diagnosed cases of CLL in the United States. This is the reason why participation in clinical trials is usually limited because the incidence is much lower. Prior observational studies from academic centers have reported younger diagnosis and shorter time to initial treatment compared to non-black patients with a diagnosis of CLL.

Our registry was the first multicenter U.S. registry with CLL, which represented a valuable opportunity for exploring greater real-world treatment practices in a larger cohort of patients — doing that primarily in a community-based setting. So our method was we went back to the informCLL registry; the patients were enrolled from October 2015 to June 2019. And it was just a descriptive analysis of who were the patients that participated in this trial.

We summarized the data descriptively by previously untreated or relapsed/refractory. And so out of the 1,462 patients that enrolled in the registry, 106 patients were Black, which is 7% — similar to what has been reported in SEER registry databases.

The community-based practice enrolled 87% of all the patients, similar to the overall population. Black patients were predominantly enrolled in the South, which is actually different from what we have seen in some other clinical trials where most of the patients are enrolled in the North. Among Black patients, the median age was 66 years old with 64% of them having a right stage of three or four, kind of like more advanced at the time of presentation. And the median time from initial diagnosis to treatment registry was 40 months.

In the overall registry population, the median age was older at 71 years, with 51% of them having a right stage III or IV at presentation, and a median time to treatment from the initial diagnosis at 41 months.

In the frontline or the first-line treated cohort of patients, the median time from initial diagnosis to first treatment on the registry was only 7 months compared to 19 months for the overall registry population. So we don’t understand quite now from this data whether the patients waited to come and see and get the diagnosis, or if there was any other reason, or if it’s just that the biology of the disease is more aggressive and that’s the reason why they require therapy much faster.

In terms of the FISH [fluorescence in situ hybridization] testing, it was performed only in 25% of Black patients, but this is similar to the testing rate in the overall population, which was 28%. The testing rate for patients for TP53 mutation and IGHV mutation was performed in 13% and 17% of Black patients, which is similar to what we found in the registry population.

So we could be doing a better job in terms of testing and characterizing who are the patients at higher risk for progression of disease or evolution. As you know, patients with a TP53 mutation tend to have a shorter progression-free survival compared to other patients when treated with certain drugs such as a BCL2 inhibitor.

Similar to the overall registry population, ibrutinib was the most common and frequent treatment amongst Black patients, both in frontline and in relapse/refractory followed by chemotherapy in frontline treatment with ibrutinib generally increased over time, while chemo-immunotherapy use tended to persist through the later years of enrollment in the developed population and Black patient population.

And even though the sample sizes with the treatment groups by year or small chemoimmunotherapy used in frontline appear to be persistent to a greater degree among Black patients, which was 36% in 2019 than the overall registered population, which was 26% in 2019. So it seemed to be a little bit of a disparity in terms of first initial therapy in pre-relapse/refractory patients, the use of ibrutinib tended to decrease over time while immunotherapy remained consistent and treatment with other novel agents increased in the overall population and Black patient population.

This pattern of treatment selections over time deferred from the overall registry population where ibrutinib use tended to remain consistent over time. The potential limitation of our study is that this is a real-world observation registry, and it relies on site-reported data. So the data may be subject to missing or incomplete data points and data entry error. And unfortunately, because of the limited number of patients that were of Black ancestry, the interpretation of the data can be also limited.

So in conclusion, from our study in these 106 patients, the patients with the diagnoses of CLL tended to present at a younger age with worse ECOG performance status, more advanced disease, and shorter time to initial therapy compared to the rest of the informCLL registry population. And while ibrutinib was the most common treatment in Black patients, the use of chemoimmunotherapy in frontline remained persistent over time, despite the fact that most of us in the community setting and in the academic center are moving away from chemoimmunotherapy.

And similar to the observational registry population, we are doing work with prognostic testing rate because they’re suboptimal both in the general population and the Black population.

So these results highlight the importance of prognostic testing and the need for more closely monitoring disease status in Black patients at the time of initial diagnosis, because they might need initial therapy earlier than their non-Black counterparts.