Ibrutinib monotherapy prolongs progression-free survival (PFS) and overall survival (OS) among patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) with deletion 17p (del(17p)) mutations, according to a study published in the British Journal of Haematology.1

CLL/SLL characterized by del(17p) — a cytogenetic abnormality that develops over the course of the disease — is difficult to treat and responds very poorly to chemoimmunotherapy. Data from previous studies showed that ibrutinib may improve survival outcomes in this patient population.

In this retrospective analysis, researchers evaluated the outcomes of patients with R/R del(17p) CLL previously enrolled in 3 clinical studies (ClinicalTrials.gov Identifier: NCT01105247 [with long term follow-up data from ClinicalTrials.gov Identifier: NCT01109069], ClinicalTrials.gov Identifier: NCT01578707, ClinicalTrials.gov Identifier: NCT01744691) that assessed the efficacy of ibrutinib alone. A total of 230 patients were included in the analysis; all participants received ibrutinib 420 mg once daily and had del(17p) status assessed by fluorescence in situ hybridization (FISH) assays.

After a median-follow up of 28 months, 108 patients (47%) remained on treatment.

Results showed that the overall response rate (ORR) was 85%, with 10%, 3%, 67%, and 6% of patients achieving complete response with or without incomplete bone marrow recovery (CR/CRi), nodular partial response, partial response (PR), and PR with lymphocytosis (PR-L), respectively.  A multivariate analysis demonstrated that ORR was similar among participants regardless of all risk factors except for advanced age.

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The estimated 30-month PFS rate was 57% (95% CI, 50-64) and the OS rate 69% (95% CI, 61-75).

Factors associated with the most favorable survival outcomes were normal lactate dehydrogenase and no bulky disease.

Hematological improvements for hemoglobin, platelet count, and absolute neutrophil counts occurred in 61%, 67%, and 70% of patients with baseline cytopenia, respectively, and were found to be sustainable. The rate of new onset infection and severe cytopenias decreased over time.

The authors concluded that “results of the present analysis serve to further support the conclusion that ibrutinib is among the most effective treatments for patients with del(17p) CLL, with 30‐month survival estimates that surpass other available therapies.”

Reference

  1. Jones J, Mato A, Coutre S, et al. Evaluation of 230 patients with relapsed/refractory deletion 17p chronic lymphocytic leukaemia treated with ibrutinib from 3 clinical trials [published online June 5, 2018]. Br J Haematol. doi: 10.1111/bjh.15421