Early Autologous Stem Cell Transplantation (autoSCT) May Overcome the Adverse Impact of Del 11q- in Poor-Risk Chronic Lymphocytic Leukemia (CLL): Results From the GCLLSG CLL3 Trial.

The protocol comprised optional cytoreduction with CHOP, fludarabine, or FC; PBSC mobilization using the Dexa-BEAM regimen; and myeloablative therapy with TBI/CY followed by reinfusion of purged (CD34+) stem cells. Inclusion criteria were age <61 years, stage Binet B/C or poor-risk stage A as defined by short lymphocyte doubling time plus elevated TK, and one line of pretreatment or less. From December 1996 through September 2002, 216 patients were registered with the protocol. As 47 cases had to be excluded due to screening failure (n=21), withdrawn consent (n=19) or other reasons (n=7), 169 patients were eligible for the current analysis. Male to female ratio was 5:1 and the median age at diagnosis was 51 years (range 27-60).

SCT was performed in 131 patients (78%) at a median time of 17 months (range 4-159) after initial diagnosis, whereas 38 patients did not proceed to SCT due to mobilization failure (n=14), disease progression (n=4), early death (n=3), patients preference (n=6), or unknown reasons (n=11). At a median follow-up of 99 months (range 4-137) after initiation of first cytoreductive therapy within the protocol, median OS of all 169 patients was 10.5 years, with 10.5 years for those treated with and 6.1 years for those treated without autoSCT, yielding a hazard ratio of 0.26 (95% CI 0.13-0.54; p<.0001). Median PFS was 6.3 years, with 6.8 years for those treated with and 4.8 years for those treated without autoSCT (HR 0.39; 95% CI 0.23-0.67; p=0.0007). The 10-year incidence rate of t-MDS/ t-AML was 9% (1-18%).

Diagnostic samples for assessment of the IGHV mutational status were available for 143 of 169 patients (85%). An unfavorable (unmutated of V3-21-containing) IGHV rearrangement was present in 104 patients (73%). Compared to the 39 patients with favorable IGHV, those with unfavorable VH had significantly worse PFS and OS (median PFS 5.1 years vs not reached, hazard ratio (HR) 2.47 (1.56-3.92), p=0.0001; median OS 9.1 years vs not reached, HR 2.0 (1.14-3.68), p=0.017). FISH was possible in 160 patients (95%) with results as follows: del 17p- 4 patients (3%), del 11q- without del 17p 40 patients (25%), trisomy 12 without del 17p- and del 11q- 20 patients (13%), del 13q- as sole abnormality 48 patients (30%), other karyotypes 20 patients (13%), normal karyotype 28 patients (17%). All 4 patients with del 17p- showed progressive disease after Dexa-BEAM mobilization and did not proceed to autoSCT. Whereas PFS (p <0.0001) and OS (p <0.0001) thus was strongly reduced in the 4 patients with del 17p-, no significant differences between the other subsets became evident: median PFS 1.0 years (del 17p-), 5.9 years (del 11q), 4.8 years (+12), 7.5 years (del 13q-), 7.7 years (normal); median OS 1.5 years (del 17p-), 10.5 years (del 11q-), not reached (+12), not reached (del 13q-), 10.3 years (normal).

Unmutated IGHV remains an adverse prognostic factor after dose-escalated first-line therapy with autoSCT. In contrast, this strategy may overcome the unfavorable impact of the FISH karyotype del 11q- seen with conventional therapy.

Hopfinger:Roche: Honoraria. Schmitz:Roche: Honoraria, Research Funding. Stilgenbauer:BayerScheringAG: Honoraria, Research Funding.