Key Points• Small TP53 mutated subclones have the same unfavorable prognostic impact as clonal TP53 defects in chronic lymphocytic leukemia.TP53 mutations are strong predictors of poor survival and refractoriness in chronic lymphocytic leukemia (CLL) and have direct implications for disease management. Clinical information on TP53 mutations is limited to lesions represented in >20% leukemic cells. Here, we tested the clinical impact and prediction of chemorefractoriness of very small TP53 mutated subclones. The TP53 gene underwent ultra-deep-next generation sequencing (NGS) in 309 newly diagnosed CLL. A robust bioinformatic algorithm was established for the highly sensitive detection of few TP53 mutated cells (down to 3 out of ∼1000 wild-type cells). Minor subclones were validated by independent approaches. Ultra-deep-NGS identified small TP53 mutated subclones in 28/309 (9%) untreated CLL that, due to their very low abundance (median allele frequency: 2.1%), were missed by Sanger sequencing. Patients harboring small TP53 mutated subclones showed the same clinical phenotype and poor survival (hazard ratio 5 2.01; P 5 .0250) as those of patients carrying clonal TP53 lesions. By longitudinal analysis, small TP53 mutated subclones identified before treatment became the predominant population at the time of CLL relapse and anticipated the development of chemorefractoriness. This study provides a proof-of-principle that very minor leukemia subclones detected at diagnosis are an important driver of the subsequent disease

Analysis of the chronic lymphocytic leukemia (CLL) coding genome has recently disclosed that the NOTCH1 proto-oncogene is recurrently mutated at CLL presentation. Here, we assessed the prognostic role of NOTCH1 mutations in CLL. Two series of newly diagnosed CLL were used as training (n ‫؍‬ 309) and validation (n ‫؍‬ 230) cohorts. NOTCH1 mutations occurred in 11.0% and 11.3% CLL of the training and validation series, respectively. In the training series, NOTCH1 mutations led to a 3.77-fold increase in the hazard of death and to shorter overall survival (OS; P < .001). Multivariate analysis selected NOTCH1 mutations as an independent predictor of OS after controlling for confounding clinical and biologic variables. The independent prognostic value of NOTCH1 mutations was externally confirmed in the validation series. The poor prognosis conferred by NOTCH1 mutations was attributable, at least in part, to shorter treatment-free survival and higher risk of Richter transformation. Although NOTCH1 mutated patients were devoid of TP53 disruption in more than 90% cases in both training and validation series, the OS predicted by NOTCH1 mutations was similar to that of TP53 mutated/deleted CLL. NOTCH1 mutations are an independent predictor of CLL OS, tend to be mutually exclusive with TP53 abnormalities, and identify cases with a dismal prognosis. (Blood. 2012;119(2): 521-529) IntroductionChronic lymphocytic leukemia (CLL) is the most common leukemia in adults. [1][2][3][4] The clinical course of CLL ranges from very indolent, with a nearly normal life expectancy, [5][6][7][8][9] to rapidly progressive leading to death and occasionally undergoing transformation to aggressive lymphoma, known as Richter syndrome (RS). [10][11][12][13][14][15][16][17][18] At presentation, several clinical and biologic features may help to predict, at least in part, the clinical course of CLL. [19][20][21] Of the biologic prognosticators that have been developed, current guidelines for clinical practice recommend screening only for TP53 disruption by mutation, deletion, or both of the locus, that identifies a fraction of high-risk CLL destined to experience a very short survival. 2,[21][22][23][24][25][26][27][28] High-risk CLL, however, cannot be fully recapitulated by TP53 disruption, and other lesions of cancer genes may be implicated in this aggressive phenotype. 29 Recently, two independent investigations of the CLL coding genome have revealed that activating mutations of the NOTCH1 proto-oncogene are recurrently associated with CLL. 30,31 Based on current knowledge, NOTCH1 mutations occur in ϳ 10% CLL at diagnosis and their frequency increases in advanced disease phases, as exemplified by the case of RS. 30,31 The relevance of NOTCH1 mutations in CLL is reinforced by knowledge of activation of the NOTCH1 pathway in this leukemia, 32 and by the possibility of targeting NOTCH1 with drugs currently under development in other clinical contexts. 33 Although not designed to fully assess clinical correlates, the pivotal studies that have ident...

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, characterized by immunodeficiency. Hence, patients with CLL might be considered more susceptible to severe complications from COVID-19. We undertook this retrospective international multicenter study to characterize the course of COVID-19 in patients with CLL and identify potential predictors of outcome. Of 190 patients with CLL and confirmed COVID-19 diagnosed between 28/03/2020 and 22/05/2020, 151 (79%) presented with severe COVID-19 (need of oxygen and/or intensive care admission). Severe COVID-19 was associated with more advanced age (≥65 years) (odds ratio 3.72 [95% CI 1.79-7.71]). Only 60 patients (39.7%) with severe COVID-19 were receiving or had recent (≤12 months) treatment for CLL at the time of COVID-19 versus 30/39 (76.9%) patients with mild disease. Hospitalization rate for severe COVID-19 was lower (p < 0.05) for patients on ibrutinib versus those on other regimens or off treatment. Of 151 patients with severe disease, 55 (36.4%) succumbed versus only 1/38 (2.6%) with mild disease; age and comorbidities did not impact on mortality. In CLL, (1) COVID-19 severity increases with age; (2) antileukemic treatment (particularly BTK inhibitors) appears to exert a protective effect; (3) age and comorbidities did not impact on mortality, alluding to a relevant role of CLL and immunodeficiency.

Purpose: Del17p13 predicts poor outcome and chemorefractoriness in chronic lymphocytic leukemia (CLL). Conversely, it is unknown whether TP53 mutations carry any prognostic value independent of del17p13.We tested the independent prognostic value of TP53 mutations in CLL. Experimental Design: The study was based on a consecutive series of 308 CLL. DNA sequencing of TP53 exons 2 to 10 and del17p13 interphase fluorescence in situ hybridization were done at CLL diagnosis. Study end points were survival and chemorefractoriness. Results: At diagnosis, TP53 mutations (n = 32) occurred in 31 of 308 (10.0%) patients. Of all CLL showing TP53 disruption by either mutation and/or deletion (n = 44), 10 cases (22.7%) showed TP53 mutations in the absence of del17p13. Multivariate analysis selected TP53 mutations (hazard ratio, 3.20; P = 0.002) as an independent predictor of overall survival after adjustment for del17p13. Also, multivariate analysis selected TP53 mutations (hazard ratio, 3.97; P < 0.001) as an independent predictor of chemorefractoriness after adjustment for del17p13.Compared with cases without TP53 alterations, CLL harboring any type of TP53 disruption (mutation only, del17p13 only, or both mutation and del17p13) uniformly displayed a high prevalence of unfavorable prognosticators and poor outcome. Analysis of sequential CLL samples showed the acquisition of new or additional TP53 alterations at the time of chemorefractoriness. Conclusions: These data show that (a) TP53 mutations are an independent predictor of short survival and chemorefractoriness, and (b) that CLL presenting withTP53 mutations without del17p13 fare as poorly as CLL carrying del17p13. Because CLL harboringTP53 mutations without del17p13 are currently not recognized by conventional diagnostic strategies, these results may be relevant for a comprehensive prognostic characterization of CLL.

Summary Predictors of chronic lymphocytic leukaemia (CLL) transformation to Richter syndrome (RS) are not established and were investigated in 185 consecutive CLL cases. Actuarial incidence of RS (n = 17; all diffuse large B‐cell lymphomas) at 10 years was 16·2% (95% confidence interval: 8·0–24·4%). At CLL diagnosis, prognosticators of RS by univariate analysis were IGHV homology ≥98% (P = 0·006), IGHV4‐39 usage (P < 0·001), del13q14 absence (P = 0·004), expression of CD38 (P < 0·001) and ZAP70 (P = 0·004), size (P < 0·001) and number (P < 0·001) of lymph nodes, advanced Binet stage (P = 0·002), and lactate dehydrogenase (P < 0·001). Multivariate analysis, performed separately for biological and clinical variables, identified CD38 expression [Hazard ratio (HR) = 4·26; P = 0·018], IGHV4‐39 usage (HR = 4·29; P = 0·018), and lymph node size ≥3 cm (HR = 9·07; P < 0·001) as independent RS prognosticators. A multivariate model simultaneously analysing biological and clinical variables identified lymph node size ≥3 cm (HR = 6·51; P = 0·001) and del13q14 absence (HR = 4·08; P = 0·031) as independent RS prognosticators. Risk factors of CLL transformation differed from risk factors of CLL progression. These results suggest that CD38 and del13q14 may identify biological subsets of CLL with different RS predisposition. Predominant nodal disease, CD38 expression, IGHV4‐39 usage, and absence of del13q14 may help in predicting RS at CLL diagnosis. Close monitoring and a careful biopsy policy are needed in patients carrying transformation risk factors.

The prognosis of clinical monoclonal B cell lymphocytosis differs from prognosis of Rai 0 chronic lymphocytic leukaemia and is recapitulated by biological risk factors According to the recent International Workshop on Chronic Lymphocytic Leukaemia (IWCLL) guidelines, diagnosis of chronic lymphocytic leukaemia (CLL) requires over 5AE0 · 10 9 /l circulating B-cells in the peripheral blood (Hallek et al, 2008). Based on IWCLL guidelines, asymptomatic monoclonal B-cells expansions characterized by a CLL-phenotype, but with less than 5AE0 · 10 9 /l circulating cells, enter the category of monoclonal B-cell lymphocytosis (MBL) (Marti et al, 2005;Hallek et al, 2008). The definition of MBL was initially prompted by the need to classify monoclonal B-cell expansions occasionally found in individuals from the general population whose probability to progress to symptomatic CLL would be uncertain (Rawstron et al, 2002a;Hoffbrand & Hamblin, 2007).MBL has been found in 3-7% of adults, in 9% of elderly individuals, and in over 10% of individuals with more than two first-degree relatives affected by CLL (Rawstron et al, 2002a,b;Marti et al, 2003;Ghia et al, 2004;Rachel et al, 2007;Shim et al, 2007;Dagklis et al, 2009). A fraction of MBL cases are diagnosed during the characterization of an otherwise asymptomatic lymphocytosis. Such cases represent clinical MBL (cMBL), and may be distinguished from low count MBL, that, in contrast, is accidentally found by screening individuals with a completely normal blood cell count (Dagklis et al, 2009).Based on published series, over 15% cMBL patients develop progressive CLL, 7% eventually require chemotherapy, and 2% cMBL had better humoral immune capacity and lower infection risk, lower prevalence of del11q22-q23/del17p13 and TP53 mutations, slower lymphocyte doubling time, and longer treatment-free survival. Also, cMBL diagnosis was a protective factor for treatment risk. Despite these favourable features, all cMBL were projected to progress, and lymphocytes <1AE2 · 10 9 /l and >3AE7 · 10 9 /l were the best thresholds predicting the lowest and highest risk of progression to CLL. Although IGHV status, CD38 and CD49d expression, and fluorescence in situ hybridization (FISH) karyotype individually predicted treatment-free survival, multivariate analysis identified the presence of +12 or del17p13 as the sole independent predictor of treatment requirement in cMBL (Hazard ratio: 5AE39, 95% confidence interval 1AE98-14AE44, P = 0AE001). Overall, these data showed that cMBL has a more favourable clinical course than Rai 0 CLL. Given that the biological profile can predict treatment requirement, stratification based on biological prognosticators may be helpful for cMBL management.

Purpose: Few biological prognosticators are useful for prediction of Richter syndrome (RS), representing the transformation of chronic lymphocytic leukemia (CLL) to aggressive lymphoma. Stereotyped B-cell receptors (BCR) may have prognostic effect in CLL progression. We tested the prognostic effect of stereotyped BCR for predicting RS transformation. Experimental Design: The prevalence of stereotyped BCR was compared in RS (n = 69) versus nontransformed CLL (n = 714) by a case-control analysis. Subsequently, the effect of stereotyped BCR at CLL diagnosis on risk of RS transformation was actuarially assessed in a consecutive CLL series (n = 753).Results: RS (n = 69) displayed a higher prevalence of stereotyped BCR (P < 0.001) compared with nontransformed CLL. The actuarial risk of RS transformation was significantly higher in CLL carrying stereotyped BCR (P < 0.001). Among BCR subsets most represented in CLL, subset 8 using IGHV4-39/IGHD6-13/IGHJ5 carried the highest risk of RS transformation [hazard ratio (HR), 24.50; P < 0.001]. Multivariate analysis selected stereotyped BCR (HR, 3.33; P = 0.001) and IGHV4-39 usage (HR, 4.03; P = 0.004) as independent predictors of RS transformation.The combination of IGHV4-39 usage and stereotyped BCR in the same patient identified CLL with a very high risk of RS transformation (5-year risk, 68.7%). The risk carried by stereotyped BCR and IGHV4-39 usage was specific for RS transformation and had no effect on CLL progression without transformation. Conclusions: Analysis of BCR features may help identify CLL patients at risk of RS. A close monitoring and a careful biopsy policy may help early recognition of RS in CLL patients using stereotyped BCR, particularly if combined with IGHV4-39.

283 The clinical course of chronic lymphocytic leukemia (CLL) ranges from very indolent, with a nearly normal life expectancy, to rapidly progressive leading to death and occasionally undergoing transformation to Richter syndrome (RS). TP53 disruption identifies a fraction of high risk CLL destined to experience a very short survival. High risk CLL, however, cannot be fully recapitulated by TP53 disruption and other lesions of cancer genes may be implicated in this aggressive phenotype. Analysis of the CLL coding genome has recently disclosed that the NOTCH1 proto-oncogene is recurrently mutated at CLL presentation. Here we assessed the prognostic role of NOTCH1 mutations in CLL. Two series of previously untreated CLL were utilized as training (n=309, median follow-up 6 years) and validation (n=230, median follow-up 7 years) cohorts. NOTCH1 mutations were analyzed by DNA Sanger sequencing in blind with respect to clinical data. In the training series, NOTCH1 mutations occurred in 34/309 (11.0%) patients, being mostly represented (26/34, 76.5%) by a recurrent two bp frameshift deletion (c.7544_7545delCT). The remaining NOTCH1 mutations (8/34, 23.5%) were frameshift deletions other than c.7544_7545delCT (n=7) and frameshift insertions (n=1). All mutations were predicted to disrupt the NOTCH1 PEST domain. CLL with NOTCH1 mutations preferentially carried unmutated IGHV genes (76.5%, p<.001). Other characteristics at presentation associated with NOTCH1 mutations were advanced Rai stage (26.5%, p=.006) and trisomy 12 (44.1%, p<.001). By univariate analysis, NOTCH1 mutations associated with an increase in the hazard of death (HR: 3.77; 95% CI: 2.14–6.66) and a significant overall survival OS shortening (p<.001) (Fig. 1A). Multivariate analysis selected NOTCH1 mutations as an independent risk factor of OS (HR: 4.22; 95% CI: 2.15–8.28; p<.001), after adjusting for age (p<.001), Rai stage (p=.005), IGHV mutation status (p=.465), 11q22-q23 deletion (p=.128), trisomy 12 (p=.183) and TP53 disruption (p<.001). The poor prognosis conferred by NOTCH1 mutations was attributable, at least in part, to a shorter time to progression requiring treatment (p<.001), and a higher cumulative probability of RS development (p=.026). Although NOTCH1 mutated patients were devoid of TP53 disruption in 31/34 (91.2%) cases, the OS predicted by NOTCH1 mutations was similar to that of TP53 mutated/deleted CLL (Fig. 1C). Analysis of the validation series confirmed: i) the prevalence of NOTCH1 mutations at CLL presentation (26/230, 11.3%); ii) the spectrum of NOTCH1 mutations at CLL presentation (c.7544_7545delCT: 21/26, 80.7%; other mutations: 5/26, 19.3%) iii) the adverse prognostic impact of NOTCH1 mutations in CLL both by univariate analysis (Fig. 1B) and by multivariate analysis (HR: 2.08; 95% CI: 1.10–3.93; p=.023); iv) the preferential mutually exclusive distribution of NOTCH1 mutations and TP53 disruption (25/26, 96.2%); v) that OS of NOTCH1 mutated CLL is similarly poor as that of TP53 disrupted CLL (Fig. 1D). The current study on 539 CLL documents that NOTCH1 mutations: i) represent one of the most frequent cancer gene mutations known to be involved at CLL presentation; ii) identify a subgroup of patients showing poor OS similar to that of TP53 disrupted cases; iii) exert a prognostic role independent of widely accepted clinical and genetic risk factors; iv) predict OS in series from different institutions, as documented by the training-validation approach chosen for the design of this study. Disclosures: No relevant conflicts of interest to declare.