The treatment of chronic lymphocytic leukemia (CLL) has been revolutionized by targeted therapies that either inhibit proliferation (ibrutinib) or reactivate apoptosis (venetoclax). Both ...significantly improve survival in CLL and replace chemoimmunotherapy for many patients. However, individually, they rarely lead to eradication of measurable residual disease (MRD) and usually are taken indefinitely or until progression. We present the CLARITY trial that combined ibrutinib with venetoclax to eradicate detectable CLL with the intention of stopping therapy.
CLARITY is a phase II trial that combined ibrutinib with venetoclax in patients with relapsed or refractory CLL. The primary end point was eradication of MRD after 12 months of combined therapy. Key secondary end points were response by International Workshop on CLL criteria, safety, and progression-free and overall survival.
In 53 patients after 12 months of ibrutinib plus venetoclax, MRD negativity (fewer than one CLL cell in 10,000 leukocytes) was achieved in the blood of 28 (53%) and the marrow of 19 (36%). Forty-seven patients (89%) responded, and 27 (51%) achieved a complete remission. After a median follow-up of 21.1 months, one patient progressed, and all patients were alive. A single case of biochemical tumor lysis syndrome was observed. Other adverse effects were mild and/or manageable and most commonly were neutropenia or GI events.
The combination of ibrutinib plus venetoclax was well tolerated in patients with relapsed or refractory CLL. There was a high rate of MRD eradication that led to the cessation of therapy in some patients. The progression-free and overall survival rates are encouraging for relapsed and refractory CLL.
The identification of new genetic lesions in chronic lymphocytic leukemia (CLL) prompts a comprehensive and dynamic prognostic algorithm including gene mutations and chromosomal abnormalities and ...their changes during clonal evolution. By integrating mutational and cytogenetic analysis in 1274 CLL samples and using both a training-validation and a time-dependent design, 4 CLL subgroups were hierarchically classified: (1) high-risk, harboring TP53 and/or BIRC3 abnormalities (10-year survival: 29%); (2) intermediate-risk, harboring NOTCH1 and/or SF3B1 mutations and/or del11q22-q23 (10-year survival: 37%); (3) low-risk, harboring +12 or a normal genetics (10-year survival: 57%); and (4) very low-risk, harboring del13q14 only, whose 10-year survival (69.3%) did not significantly differ from a matched general population. This integrated mutational and cytogenetic model independently predicted survival, improved CLL prognostication accuracy compared with FISH karyotype (P < .0001), and was externally validated in an independent CLL cohort. Clonal evolution from lower to higher risk implicated the emergence of NOTCH1, SF3B1, and BIRC3 abnormalities in addition to TP53 and 11q22-q23 lesions. By taking into account clonal evolution through time-dependent analysis, the genetic model maintained its prognostic relevance at any time from diagnosis. These findings may have relevant implications for the design of clinical trials aimed at assessing the use of mutational profiling to inform therapeutic decisions.
•The integration of mutations and cytogenetic lesions improves the accuracy of survival prediction in chronic lymphocytic leukemia.
The pathogenesis of chronic lymphocytic leukemia (CLL), the most common leukemia in adults, is still largely unknown. The full spectrum of genetic lesions that are present in the CLL genome, and ...therefore the number and identity of dysregulated cellular pathways, have not been identified. By combining next-generation sequencing and copy number analysis, we show here that the typical CLL coding genome contains <20 clonally represented gene alterations/case, including predominantly nonsilent mutations, and fewer copy number aberrations. These analyses led to the discovery of several genes not previously known to be altered in CLL. Although most of these genes were affected at low frequency in an expanded CLL screening cohort, mutational activation of NOTCH1, observed in 8.3% of CLL at diagnosis, was detected at significantly higher frequency during disease progression toward Richter transformation (31.0%), as well as in chemorefractory CLL (20.8%). Consistent with the association of NOTCH1 mutations with clinically aggressive forms of the disease, NOTCH1 activation at CLL diagnosis emerged as an independent predictor of poor survival. These results provide initial data on the complexity of the CLL coding genome and identify a dysregulated pathway of diagnostic and therapeutic relevance.
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.
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.
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.
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.
These data show that (a) TP53 mutations are an independent predictor of short survival and chemorefractoriness, and (b) that CLL presenting with TP53 mutations without del17p13 fare as poorly as CLL carrying del17p13. Because CLL harboring TP53 mutations without del17p13 are currently not recognized by conventional diagnostic strategies, these results may be relevant for a comprehensive prognostic characterization of CLL.
is a recurrently mutated gene in chronic lymphocytic leukemia (CLL) but the functional implications of
mutations are largely unexplored. Furthermore, little is known about the prognostic impact of
...mutations in CLL cohorts homogeneously treated with first-line fludarabine, cyclophosphamide, and rituximab (FCR). By immunoblotting analysis, we showed that the non-canonical nuclear factor-κB pathway is active in
-mutated cell lines and in primary CLL samples, as documented by the stabilization of MAP3K14 and by the nuclear localization of p52. In addition,
-mutated primary CLL cells are less sensitive to flu-darabine. In order to confirm in patients that
mutations confer resistance to fludarabine-based chemoimmunotherapy, a retrospective multicenter cohort of 287 untreated patients receiving first-line FCR was analyzed by targeted next-generation sequencing of 24 recurrently mutated genes in CLL. By univariate analysis adjusted for multiple comparisons
mutations identify a poor prognostic subgroup of patients in whom FCR treatment fails (median progression-free survival: 2.2 years,
<0.001) similar to cases harboring
mutations (median progression-free survival: 2.6 years,
<0.0001).
mutations maintained an independent association with an increased risk of progression with a hazard ratio of 2.8 (95% confidence interval 1.4-5.6,
=0.004) in multivariate analysis adjusted for
mutation, 17p deletion and
mutation status. If validated,
mutations may be used as a new molecular predictor to select high-risk patients for novel frontline therapeutic approaches.
Richter syndrome (RS) represents the development of diffuse large B-cell lymphoma in the context of chronic lymphocytic leukemia. The scarcity of biologic information about RS has hampered the ...identification of molecular predictors of RS outcome. We addressed this issue by performing a comprehensive molecular characterization of 86 pathologically proven RS. TP53 disruption (47.1%) and c-MYC abnormalities (26.2%) were the most frequent alterations, whereas common genetic lesions of de novo diffuse large B-cell lymphoma were rare or absent. By multivariate analysis, lack of TP53 disruption (hazard ratio, 0.43; P = .003) translated into significant survival advantage with 57% reduction in risk of death. An algorithm based on TP53 disruption, response to RS treatment, and Eastern Cooperative Oncology Group performance status had 80.9% probability of correctly discriminating RS survival (c-index = .809). RS that were clonally unrelated to the paired chronic lymphocytic leukemia phase were clinically and biologically different from clonally related RS because of significantly longer survival (median, 62.5 months vs 14.2 months; P = .017) and lower prevalence of TP53 disruption (23.1% vs 60.0%; P = .018) and B-cell receptor stereotypy (7.6% vs 50.0%; P = .009). The molecular dissection of RS into biologically distinct categories highlights the genetic heterogeneity of this disorder and provides clinically relevant information for refining the prognostic stratification of patients.
Biologists and clinicians agree that the B-cell receptor influences the behavior of chronic lymphocytic leukemia, and promising new drugs are aimed at receptor-associated kinases. Engagement of ...surface immunoglobulin by antigen is a key driver of malignant cells with outcome influenced by the nature of the cell, the level of stimulation and the microenvironment. Analysis of surface immunoglobulin-mediated signaling in the two major disease subsets defined by IGHV mutational status reveals bifurcation of responses toward proliferation or anergy. Mutated chronic lymphocytic leukemia, generally of relatively good prognosis, is mainly, but not exclusively, driven towards anergy in vivo. In contrast, unmutated chronic lymphocytic leukemia shows less evidence for anergy in vivo retaining more responsiveness to surface immunoglobulin M-mediated signaling, possibly explaining increased tumor progression. Expression and function of surface immunoglobulin M in unmutated chronic lymphocytic leukemia appear rather homogeneous, but mutated chronic lymphocytic leukemia exhibits a highly heterogeneous profile that may relate to further variable clinical behavior within this subset. Anergy should increase susceptibility to apoptosis but, in leukemic cells, this may be countered by overexpression of the B-cell lymphoma-2 survival protein. Maintained anergy spreads to chemokines and adhesion molecules, restraining homing and migration. However, anergy is not necessarily completely benign, being able to reverse and regenerate surface immunoglobulin M-mediated responses. A two-pronged attack on proliferative and anti-apoptotic pathways may succeed. Increased understanding of how chronic lymphocytic leukemia cells are driven to anergy or proliferation should reveal predictive biomarkers of progression and of likely response to kinase inhibitors, which could assist therapeutic decisions.
Richter syndrome (RS) occurs in up to 15% of patients with chronic lymphocytic leukemia (CLL). Although RS, usually represented by the histologic transformation to a diffuse large B-cell lymphoma ...(DLBCL), is associated with a very poor outcome, especially when clonally related to the preexisting CLL, the mechanisms leading to RS have not been clarified. To better understand the pathogenesis of RS, we analyzed a series of cases including 59 RS, 28 CLL phase of RS, 315 CLL, and 127 de novo DLBCL. RS demonstrated a genomic complexity intermediate between CLL and DLBCL. Cell-cycle deregulation via inactivation of TP53 and of CDKN2A was a main mechanism in the histologic transformation from CLL phase, being present in approximately one half of the cases, and affected the outcome of the RS patients. A second major subgroup was characterized by the presence of trisomy 12 and comprised one third of the cases. Although RS shared some of the lesions seen in de novo DLBCL, its genomic profile was clearly separate. The CLL phase preceding RS had not a generalized increase in genomic complexity compared with untransformed CLL, but it presented clear differences in the frequency of specific genetic lesions.
•Richter syndrome has genomic complexity intermediate between chronic lymphocytic leukemia and diffuse large B-cell lymphoma.•Inactivation of TP53 and of CDKN2A is a main mechanism in the transformation to Richter syndrome.
Signaling via the B-cell receptor (BCR) is a key driver and therapeutic target in chronic lymphocytic leukemia (CLL). BCR stimulation of CLL cells induces expression of eIF4A, an initiation factor ...important for translation of multiple oncoproteins, and reduces expression of PDCD4, a natural inhibitor of eIF4A, suggesting that eIF4A may be a critical nexus controlling protein expression downstream of the BCR in these cells. We, therefore, investigated the effect of eIF4A inhibitors (eIF4Ai) on BCR-induced responses. We demonstrated that eIF4Ai (silvestrol and rocaglamide A) reduced anti-IgM-induced global mRNA translation in CLL cells and also inhibited accumulation of MYC and MCL1, key drivers of proliferation and survival, respectively, without effects on upstream signaling responses (ERK1/2 and AKT phosphorylation). Analysis of normal naïve and non-switched memory B cells, likely counterparts of the two main subsets of CLL, demonstrated that basal RNA translation was higher in memory B cells, but was similarly increased and susceptible to eIF4Ai-mediated inhibition in both. We probed the fate of
MYC
mRNA in eIF4Ai-treated CLL cells and found that eIF4Ai caused a profound accumulation of
MYC
mRNA in anti-IgM treated cells. This was mediated by
MYC
mRNA stabilization and was not observed for
MCL1
mRNA. Following drug wash-out,
MYC
mRNA levels declined but without substantial MYC protein accumulation, indicating that stabilized
MYC
mRNA remained blocked from translation. In conclusion, BCR-induced regulation of eIF4A may be a critical signal-dependent nexus for therapeutic attack in CLL and other B-cell malignancies, especially those dependent on MYC and/or MCL1.
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