Long-term results of the sequential combination of cladribine and rituximab in Hairy cell leukemia

Abstract

We report on the long-term efficacy and safety of a phase 2 trial of sequential cladribine and rituximab in hairy cell leukemia (HCL). One-hundred and thirty-nine patients were enrolled: 111 in the frontline setting, 18 in first relapse, and 10 with variant HCL (HCLv). A complete response (CR) was achieved in 133 of 137 evaluable participants (97%) with measurable residual disease (MRD) negativity in 102 (77%). MRD status was not associated with significant differences in event-free survival (EFS) or overall survival (OS). With a median follow-up of 7.8 years (range: 0.40–18.8), eight patients have experienced disease relapse (5.8%), 4/111 with newly diagnosed HCL (3·6%) and 4/10 with HCLv (40%) (p = 0.002). The 10-year EFS and OS rates were 86.7% and 91.1%, respectively. Grade 3 adverse events were observed in 28 participants (20·1%), mostly due to infections. Treatment of HCL with sequential cladribine followed by rituximab is associated with excellent efficacy and safety results both in the frontline and relapsed settings.

Keywords:

• HCL
• HCLv
• cladribine
• rituximab
• clinical trial

Ethical approval

This study was approved by the institutional review board of The University of Texas MD Anderson Cancer Center (2004-0223).

Author contributions statement

FR designed the study. DM, JMP and W-YJ collected the data. JMP and W-YJ analyzed the data and wrote the manuscript. HK, FH, WW, AF, JB, and SO treated patients on the study. JJ, SW, KP, SL reviewed flow cytometry and molecular data. All authors reviewed and approved the final version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data sharing

The study details are available online on ClinicalTrials.gov, reference number 00412594. The study data is not publicly available to respect participant confidentiality. Requests for sharing of deidentified data should be directed to the corresponding author.

Additional information

Funding

This research is supported in part by the Charif Souki Cancer Research Fund.