Long-term follow-up after purine analogue therapy in hairy cell leukaemia

Abstract

Since 2006 when we last reviewed the literature concerning the use of purine analogues in hairy cell leukaemia (HCL), results from several new and updated series have been published. Here we examine these reports and consider their implications for patient management. The two purine analogues pentostatin and cladribine remain the first-line treatments of choice for all patients with HCL. Although they have not been compared in randomised trials, they appear to be equally effective. A complete response is important for the long-term outcome and we look at how best this can be achieved. Evidence is emerging which supports the use of either purine analogue plus an anti-CD20 monoclonal antibody after relapse, though questions remain concerning the scheduling of the monoclonal antibody. Patients refractory to the purine analogues may require alternative agents.

Keywords: Chemoimmunotherapy; Cladribine; Hairy cell leukaemia; Pentostatin; Purine analogue; Rituximab; Survival.

Fig. 1

Relapse-free survival (RFS) by response to first-line single-agent treatment with either pentostatin or cladribine, showing a significant difference between patients achieving a complete response (CR) versus a partial response (PR). The median RFS was 16 years overall: 20 + years (not reached) for patients attaining a CR and 4 years after a PR (log-rank p < 0.0001). There was no difference in RFS by type of treatment (pentostatin or cladribine). Reprinted from: Dearden et al.; Leuk Lymphoma. 2011; 52 Suppl 2: 21–24 .

Fig. 2

Relapse-free survival (RFS) following treatment with the combination of a purine analogue plus rituximab compared with the RFS of these same 26 patients following their earlier first-line therapy with a purine analogue (cladribine or pentostatin) alone (log-rank p < 0.0001).