Long-Term Outcomes With Chemoimmunotherapy Regimen in IGHV-Mutated CLL

By: Julia Fiederlein
Posted: Tuesday, August 9, 2022

Nitin Jain, MD, of The University of Texas MD Anderson Cancer Center, Houston, and colleagues conducted a phase II trial to investigate the role of ibrutinib plus fludarabine, cyclophosphamide, and obinutuzumab (FCG) in previously untreated patients with IGHV-mutated chronic lymphocytic leukemia (CLL). The long-term results, which were presented during the European Hematology Association (EHA) 2022 Congress (Abstract S149), revealed this combination of chemoimmunotherapy and targeted therapy achieves a high undetectable measurable residual disease (MRD) rate and a favorable 5-year progression-free survival rate compared with standard regimens. 

A total of 45 patients without a 17p deletion or TP53 mutation were treated with ibrutinib plus FCG. After three courses, those who achieved undetectable MRD in the marrow and complete remission with or without incomplete blood cell count recovery received ibrutinib plus obinutuzumab for three cycles followed by ibrutinib monotherapy for 6 months; all other patients were administered ibrutinib plus obinutuzumab for nine cycles. After 12 cycles, those with undetectable MRD in the marrow discontinued all therapy. Follow-up data were provided for a median of 56.8 months.

A total of 87% of patients achieved undetectable MRD in the marrow after three cycles. After 6 and 12 cycles, 89% and 91% achieved undetectable MRD in the marrow, respectively. Nearly all patients (98%) achieved undetectable MRD in the marrow as best response at any time during the study. The 5-year progression-free survival rate was 97.7%, and the 5-year overall survival rate was 97.8%. No patients experienced disease progression or Richter transformation. On both progression-free and overall survival curves, death from heart failure was the sole reported event.

All 41 patients who completed 12 cycles of treatment achieved undetectable MRD in the marrow with 10^-4 sensitivity and, per protocol, discontinued ibrutinib. At a median follow-up of 44.2 months after treatment discontinuation, six patients experienced an MRD recurrence at a median of 27.2 months after stopping all therapy.

Disclosure: For full disclosures of the study authors, visit library.ehaweb.org.

EHA 2022 Congress

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