Prognostic and therapeutic role of targetable lesions in B-lineage acute lymphoblastic leukemia without recurrent fusion genes

To shed light into the molecular bases of B-lineage acute lymphoblastic leukemia lacking known fusion transcripts, i.e. BCR-ABL1, ETV6-RUNX1, E2A-PBX1, and MLL rearrangements (B-NEG ALL) and the differences between children, adolescents/young adults (AYA) and adults, we analyzed 168 B-NEG ALLs by genome-wide technologies. This approach showed that B-NEG cases carry 10.5 mutations and 9.1 copy-number aberrations/sample. The most frequently mutated druggable pathways were those pertaining to RAS/RTK (26.8%) and JAK/STAT (12.5%) signaling. In particular, FLT3 and JAK/STAT mutations were detected mainly in AYA and adults, while KRAS and NRAS mutations were more frequent in children. RAS/RTK mutations negatively affected the outcome of AYA and adults, but not that of children. Furthermore, adult B-NEG ALL carrying JAK/STAT mutations had a shorter survival. In vitro experiments showed that FLT3 inhibitors reduced significantly the proliferation of FLT3-mutated primary B-NEG ALL cells. Likewise, PI3K/mTOR inhibitors reduced the proliferation of primary cells harboring RAS and IL7R mutations. These results refine the genetic landscape of B-NEG ALL and suggest that the different distribution of lesions and their prognostic impact might sustain the diverse outcome between children, adults and partly AYA - whose genomic scenario is similar to adults - and open the way to targeted therapeutic strategies

Biallelic BIRC3 inactivation in chronic lymphocytic leukaemia patients with 11q deletion identifies a subgroup with very aggressive disease

Biallelic BIRC3 inactivation in chronic lymphocytic leukaemia patients with 11q deletion identifies a subgroup with very aggressive disease

Efficacy and Safety of a First Line Combined Therapeutic Approach for Young CLL Patients with Advanced or Progressive Disease Stratified According to the Biologic Features: First Analysis of the GIMEMA Multicenter Study LLC0405.

Eighty-one previously untreated CLL patients, ≤60 years, with advanced/progressive disease were included in the GIMEMA LLC0405 prospective multicenter study. Patients were stratified according to the biologic features. High risk (HR) patients were defined by the presence of: 1) 17p- (≥20% of analyzed cells), or 2) 11q- with ≥1 additional unfavorable factor (IGHV germline; Zap-70+ ≥10%; CD38+ ≥7%), or 3) germline IGHV or mutated VH3-21 and ≥2 unfavorable factors (Zap-70; CD38; 6q-; trisomy 12). Low risk (LR) patients were defined by the absence of the above features. HR patients received 4 monthly courses of fludarabine and campath-1H (FluCam; Flu 30 mg/m2 iv; Cam 30 mg iv, days 1-3). Responding patients underwent post-induction therapy: reduced intensity PBSC allogeneic transplant or, in the absence of a sibling donor, an autologous PBSC transplant or, in the absence of a sufficient harvest, Cam sc, 30 mg weekly for a maximum of 12 weeks. For LR patients, treatment included 6 monthly courses of fludarabine and cyclophosphamide (FC; fludarabine 30 mg/m2 iv and cyclophosphamide 250 mg/m2, days 1-3). All patients received bactrim prophylaxis. FluCam-treated patients underwent weekly CMV antigenemia monitoring and valacyclovir prophylaxis (2g/8h). In the presence of severe granulocytopenia, G-CSF was recommended and darbepoietin given in case of anemia (Hb <11g/dl). MRD was monitored in peripheral blood (PB) and marrow by four color-flow cytometry. The median age of patients was 55 years (range: 30-60), Rai stages III-IV were recorded in 23% of cases, 35% of patients showed “bulky” nodes (Ǿ ≥5 cm), 35% had 100 x 109/L or more PB lymphocytes and 51% increased β2 M values. A HR profile was found in 43 patients (53%) and a LR profile in 38 (47%). Within HR patients, 93% were IGHV unmutated, 69% CD38+, 80% Zap-70+, 40% 11q- and 21% 17p-. LR patients showed one or more unfavorable biologic factors in less than a third of cases (IgVH unmutated 21%, CD38+ 17%, Zap-70+ 29%); 13q- was recorded in 42% of cases, no detectable abnormalities in 39%, trisomy 12+ in 11% and 6q- in 8%. On an intention-to treat basis, a response was observed in 79% of HR cases (CR 26%, MRD- 19%) and in 87% of LR cases (CR 55%, MRD- 18%). In univariate analysis, age, IgG levels, β2 M, IgVH status, CD38 and Zap-70 played a significant role on CR achievement in HR patients, while CD38 was the only significant parameter for LR patients. As post-remission therapy, 2 HR patients received Cam , while 11 underwent a transplant procedure (allogeneic: 4, autologous: 7). The PFS probability at 36 months was 44% (95% CI: 36.9-51.8) for HR patients and 64% (95%CI: 53.6-76.7) for LR patients. In univariate analysis, β2 M and Zap-70 showed a significant effect on the PFS of HR patients, while a higher PB lymphocyte count (≥60x109/L) was associated with a lower PFS (p=0.07) in LR patients. The CR rate and PFS at 36 months after FluCam were 18% and 18% for 11q- patients, and 11% and 49% for 17p- patients. The OS probability at 36 months was 81% (95% CI: 71-93.3) for HR patients and 89% (95%CI:80.2-98.6) for LR patients. Cytogenetic abnormalities played a significant role (p=.02) on OS probability of HR patients. In particular, 17p- was associated with a lower survival probability (p=.04), while the OS of LR patients was influenced by the lymphocyte count (p=0.05). All transplanted patients are alive with a median follow-up of 31 months (range:16-42). Granulocytopenia was observed in 21% of cases treated with FluCam and in 32% of those treated with FC. Grade III-IV infections were recorded in 7% of FluCam-treated patients and in 13% of FC- treated patients. Asymptomatic CMV reactivation was detected in 3 FluCam-treated cases (7%). No FluCam-related deaths were observed, while 4 FC-related deaths were recorded (febrile granulocytopenia, 2 cases; cerebral hemorrhage, 1; cerebral abscesses of unknown origin, 1). In conclusion, an unfavorable biologic profile was observed in about half young CLL patients requiring first line treatment. Front-line FluCam was well tolerated and effective for most young CLL patients with an unfavorable biologic profile. However, our results suggest that FluCam is not the optimal treatment approach for 11q- patients. Front-line FC was associated with a high CR rate and prolonged PFS and OS probabilities in patients with a favorable biologic profile. Nevertheless, in young CLL patients FC-related severe granulocytopenia was a frequent reason of treatment failure

Analysis of the chronic lymphocytic leukemia coding genome: role of NOTCH1 mutational activation

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