High fluorescence in situ hybridization percentage of deletion 11q in patients with chronic lymphocytic leukemia is an independent predictor of adverse outcome

Chronic Lymphocytic Leukemia Patients With Deletion 11q Have a Short Time to Requirement of First-Line Therapy, But Long Overall Survival: Results of a Population-Based Cohort in British Columbia, Canada

BACKGROUND

Chronic lymphocytic leukemia (CLL) patients with 11q22.3 deletion (11q-) have an aggressive clinical course, and thus selection of first-line therapy in this group is important. This study aimed to improve our understanding of real-world practice patterns and outcomes of CLL patients with 11q- in a population-based setting.

PATIENTS AND METHODS

The British Columbia CLL Database was used to identify patients with 11q-. Overall survival (OS) and treatment-free survival (TFS) were assessed after adjustment for prognostic factors.

RESULTS

Of 1044 patients in the database, 125 had 11q- (12%). Sixty-nine patients had 11q- identified before therapy initiation and had a median OS and TFS of 14.7 (95% confidence interval [CI], 11.3-18.1) and 2.5 (95% CI, 1.5-3.6) years. Patient with copresence of 11q- and deletion 17p had a markedly worse prognosis, with median OS of 4.9 versus 14.7 years (P < .001). Most treated patients (33 of 52) received fludarabine with or without rituximab (FR). Patients treated with FR had a median OS of 12.8 years (standard error, 1.0), which was not statistically different from those treated with alkylator-containing therapy (P = .35).

CONCLUSION

Although median TFS of 11q- patients in this cohort was short at 2.5 years, OS remains long at 14.7 years, even when most patients received initial treatment without alkylators.

The Dohner fluorescence in situ hybridization prognostic classification of chronic lymphocytic leukaemia (CLL): the CLL Research Consortium experience

This study revisited the Dohner prognostic hierarchy in a cohort of 1585 well-documented patients with chronic lymphocytic leukaemia. The duration of both time to first treatment (TTFT) and overall survival (OS) were significantly longer than observed previously, and this is at least partly due to improved therapeutic options. Deletion 13q remains the most favourable prognostic group with median TTFT and OS from fluorescence in situ hybridization (FISH) testing of 72 months and >12 years, respectively. Deletion 11q had the poorest median TTFT (22 months) and 17p deletion the poorest median OS (5 years). The percentages of abnormal nuclei were significantly associated with differential TTFT for the trisomy 12, 13q and 17p deletion cohorts but not for the 11q deletion cohort. From the date of the first FISH study, patients with >85% 13q deletion nuclei had a notably shorter TTFT (24 months). Patients with ≤20% 17p deletion nuclei had longer median TTFT and OS from the date of the first FISH study (44 months and 11 years), and were more likely to be IGHV mutated.

Chronic lymphocytic leukemia (CLL)-Then and now

The field of chronic lymphocytic leukemia (CLL) has witnessed considerable change since the time clinical staging was introduced in clinical practice in 1975. Over the years, the prognostication in CLL has expanded with the addition in late 90s of mutational status of variable region of immunoglobulin heavy chain (IGHV), and chromosomal analyses using fluorescent in situ hybridization (FISH). More recently, stereotypy of BCR (B cell receptor) and whole exome sequencing (WES) based discovery of specific mutations such as NOTCH1, TP53, SF3B1, XPO-1, BIRC3, ATM, and RPS15 further refined the current prognostication system in CLL. In therapy, the field of CLL has seen major changes from oral chlorambucil and steroids prior to 1980s, to chemo-immunotherapy (CIT) with fludarabine, cyclophosphamide, rituximab (FCR) to the orally administered targeted therapeutic agents inhibiting kinases in the B cell receptor (BCR) signaling pathway such as Ibrutinib (BTK inhibitor) and Idelalisib (p110 PI3Kδ inhibitor) and novel anti-CD20 mAb's (monoclonal antibodies) such as obinutuzumab. This progress is continuing and other targeted therapeutics such as Bcl2 antagonists (Venetoclax or ABT-199) and finally chimeric antigen receptor against T cells (CART) are in the process of being developed. This review is an attempt to summarize the major benchmarks in the prognostication and in the therapy of CLL. The topic allocated to us by Dr Ayalew Tefferi and Dr Carlo Brugnara is very appropriate to reminisce what our understanding of chronic lymphocytic leukemia (CLL) was in 1976 and how rapidly have the advances occurring in this field affected the patients with CLL.

A Low Frequency of Losses in 11q Chromosome Is Associated with Better Outcome and Lower Rate of Genomic Mutations in Patients with Chronic Lymphocytic Leukemia

To analyze the impact of the 11q deleted (11q-) cells in CLL patients on the time to first therapy (TFT) and overall survival (OS), 2,493 patients with CLL were studied. 242 patients (9.7%) had 11q-. Fluorescence in situ hybridization (FISH) studies showed a threshold of 40% of deleted cells to be optimal for showing that clinical differences in terms of TFT and OS within 11q- CLLs. In patients with ≥40% of losses in 11q (11q-H) (74%), the median TFT was 19 months compared with 44 months in CLL patients with <40% del(11q) (11q-L) (P<0.0001). In the multivariate analysis, only the presence of 11q-L, mutated IGHV status, early Binet stage and absence of extended lymphadenopathy were associated with longer TFT. Patients with 11q-H had an OS of 90 months, while in the 11q-L group the OS was not reached (P = 0.008). The absence of splenomegaly (P = 0.02), low LDH (P = 0.018) or β2M (P = 0.006), and the presence of 11q-L (P = 0.003) were associated with a longer OS. In addition, to detect the presence of mutations in the ATM, TP53, NOTCH1, SF3B1, MYD88, FBXW7, XPO1 and BIRC3 genes, a select cohort of CLL patients with losses in 11q was sequenced by next-generation sequencing of amplicons. Eighty % of CLLs with 11q- showed mutations and fewer patients with low frequencies of 11q- had mutations among genes examined (50% vs 94.1%, P = 0.023). In summary, CLL patients with <40% of 11q- had a long TFT and OS that could be associated with the presence of fewer mutated genes.