Treatment Outcomes Among Chronic Lymphocytic Leukemia Patients with 17p Deletion or TP53 Mutation in Argentina: A Retrospective Chart Review

Introduction

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in Western countries. CLL patients with 17p deletion and/or TP53 mutation have poor treatment outcomes with standard chemoimmunotherapy. Real-world treatment outcomes among CLL patients with 17p deletion and/or TP53 mutation in countries outside USA and Europe are unclear. In South America the CLL treatment follows international guidelines, but outcomes may vary due to differences in patients profile or other variables.

Methods

This was a retrospective, multisite, longitudinal medical chart review study for adults (≥18 years) diagnosed with CLL between January 1, 2011 and December 31, 2014 in Argentina. Patients' medical records were reviewed and CLL patients with 17p deletion and/ or TP53 mutation were identified. The primary outcomes of this study were overall survival (OS) and treatment response in terms of best response to line of treatment. Categorical and continuous variables were evaluated using the chi-square, Fisher exact test, or the Mann-Whitney test, as appropriate. Survival distributions were estimated using Kaplan-Meier plots. Univariable comparisons were made using the log rank test. The Cox proportional hazards regression model was used to assess the effect of 17p deletion and TP53 mutation on OS while controlling for other covariates. All statistical analyses were performed using SAS 9.4.

Results

Chart abstraction was completed for 97 patients with CLL. Almost half of the patients (53 %) had 17p deletion and/or TP53 mutation. The mean age of the patients with 17p deletion and/or TP53 mutation was 67 years, majority (70.59%) were males, married (66.67%), and covered by private/supplemental insurance (62.75%). Across the cohort only 37% of the patients with 17p deletion and/or TP53 mutation and 19% of the patients without 17p deletion and/or TP 53 mutation received treatment with novel oral agents. Median OS for patients with 17p deletion and/or TP53 mutation was 54 months (median follow up time: 30 months) and the median OS for patients without 17p deletion and/or TP 53 mutation was not reached (median follow up time: 36 months) (Figure 1). Results from the Cox proportional hazard model indicated that the presence of 17p deletion and/or TP53 mutation was significantly associated with all-cause mortality (HR: 7.301; 95% CI: 2.149 - 24.806; p- value: 0.0014). For patients receiving first line of treatment, 74% of the patients without 17p deletion and/or TP53 mutation achieved complete response (CR), while 55% patients with 17p deletion and/or TP53 mutation achieved CR. For patients receiving second line of treatment, 31% of patients without 17p deletion and/or TP53 mutation and only 16% of patients with 17p deletion and/or TP53 mutation achieved CR.

Conclusions

CLL patients with 17p deletion and/or TP53 mutation in Argentina experienced poorer survival and inferior treatment responses compared with patients without 17p deletion and/or TP53 mutation. This indicates that in the Argentinean population this genetic alteration induces a poor prognosis leading to inferior outcomes.

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