A novel 17-gene expression signature may help guide the choice of initial treatment in patients with IGHV-unmutated chronic lymphocytic leukemia (CLL), according to findings of a retrospective dual cohort study.
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“[Fludarabine, cyclophosphamide, and rituximab] was the first regimen to improve progression-free survival and overall survival in patients with chronic lymphocytic leukaemia, and has become a gold-standard chemoimmunotherapy regimen in physically fit patients,” wrote the investigators, who were led by Carmen D. Herling, MD, of the Center for Integrated Oncology, Cologne, Germany; and Kevin R. Coombes, PhD, of Ohio State University, Columbus.
While several studies demonstrate that young, fit patients with mutated IGHV gene and no high-risk cytogenetic abnormalities achieve durable remission with the FCR (fludarabine, cyclophosphamide, and rituximab) regimen, there have been no studies to identify if this is true for patients with unmutated IGHV gene, they reported in the Lancet Oncology.
The investigators performed transcriptional profiling using peripheral blood samples collected from two cohorts of patients with CLL who were treated with frontline FCR.
The discovery and training cohort consisted of 101 patients (65% with IGHV-unmutated disease) treated at the MD Anderson Cancer Center who had a median follow-up of about 12 years. The validation cohort consisted of 109 patients with IGHV-unmutated disease treated on the German CLL8 single-arm trial who had a median follow-up of about 6 years.
A total of 1,136 genes showed a significant univariate association with time to progression. Ultimately, 17 of these genes – most of them involved in purine metabolism and oxidative phosphorylation – were included in the expression signature.
Among patients with IGHV-unmutated CLL, the 17-gene signature discriminated between two groups having differing time to progression after their frontline FCR chemoimmunotherapy: an unfavorable prognosis group and an intermediate prognosis group.
The unfavorable prognosis group had a significantly higher relative risk of progression in both the discovery/training cohort (hazard ratio, 3.83; P less than .0001) and the validation cohort (HR, 1.90; P = .008). In the validation cohort, the median time to progression was 39 months among patients with a signature-defined unfavorable prognosis, compared with 59 months among patients with a signature-defined intermediate prognosis.
“We would recommend testing the value of the 17-gene signature in a prospective study that compares FCR treatment with alternative therapies, such as ibrutinib, as part of a randomised clinical trial,” the investigators wrote.
Dr. Herling reported financial disclosures related to Hoffmann-La Roche, and Dr. Coombes reported grants from the National Institutes of Health. The study was funded by the Chronic Lymphocytic Leukaemia Global Research Foundation and the National Institutes of Health/National Cancer Institute.
SOURCE: Herling CD et al. Lancet Oncol. 2019;20(11):1576-86.