Prognostic Factors in the UK LRF CLL4 Trial.

Abstract

The CLL4 trial randomised 777 previously untreated patients between Chlorambucil (Chlor), Fludarabine (Fluda) and Fludarabine with Cyclophosphamide (FC). The median follow-up is 21 months. VH gene mutation status using a 98% cut off, CD38 expression using a 7% cut off, ZAP70 expression (Orchard et al Lancet 2004) and interphase FISH were measured on samples taken at randomisation. In an interim analysis 253/397 patients had unmutated VH genes. 32 patients utilised the VH3-21 gene, of whom 27 showed restricted HCDR3 usage. 343/535 were CD38 positive and 131/261 were ZAP70 positive. 10/24 VH 3-21 cases were ZAP 70 positive, of whom 7 were unmutated. There was no significant association between VH genes and age, sex or a positive DAT. There were significant correlations between VH gene mutations and CD38, ZAP70 and FISH results.Association of VH genes with CD38, ZAP70 and FISH results.CD38+ZAP 70+p53 lossDel 11qDel 6q21Del 13qTrisomy 12VH Unmutated119 (58%)110 (72%)21 (9%)48 (22%)18 (10%)109 (45%)50 (21%)VH Mutated30 (25%)17 (16%)3 (2%)13 (11%)6 (6%)97 (73%)13 (10%)p=<0.0001<0.00010.02<0.0090.2<0.00010.008% = % of all cases with known VH mutation statusLogistic regression including age, stage, gender, VH mutations and genetic factors shows that stage (p=0.002), VH genes (p=0.05), p53 loss (p=0.02) and del 11q (p=0.01) affect response. Response rates by VH gene mutation status and treatment arm are given in table 2.Response rates according to VH mutation status and treatment armChlor UnmutChlor MutFluda UnmutFluda MutF/C UnmutF/C MutCR/NPR24 (25%)23 (42%)25 (43%)18 (55%)37 (58%)23 (70%)PR43 (45%)19 (34%)21 (36%)10 (30%)21 (33%)10 (30%)NR/PD29 (30%)13 (24%)12 (21%)5 (15%)6 (9%)0 (0%)p (trend)0.070.30.1%=% of all unmutated or mutated cases receiving a particular treatmentAnalysis of variance shows that both VH genes (p=0.01) and treatment (p<0.0001) have an effect on response with no significant interaction. Among 104 patients with unmutated VH genes and both ZAP 70 expression and response data available, there was no significant difference in response rates between ZAP positive and negative cases. In univariate analysis p53 loss (p<0.00005), unmutated VH genes (p=0.003), CD38 positivity (p=0.06) but not ZAP70 positivity correlate with poor overall survival. In multivariate Cox regression analyses, age (p<0.0001) stage (p=0.01) and p53 loss (p<0.0001) are significant for survival. When patients with p53 loss are excluded unmutated VH genes (p=0.007) but not CD38 or ZAP70 positivity are significant. In conclusion p53 loss identifies a small group of patients with both poor response to treatment and short survival. In the remaining cases, unmutated VH genes are associated with a relatively poor response independent of treatment arm, and with a shorter survival.