INCB84344-201: Ponatinib and steroids in frontline therapy for unfit patients with Ph+ acute lymphoblastic leukemia

Tyrosine kinase inhibitors have improved survival for patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). However, prognosis for old or unfit patients remains poor. In the INCB84344-201 (formerly GIMEMA LAL 1811) prospective, multicenter, phase 2 trial, we tested the efficacy and safety of ponatinib plus prednisone in newly diagnosed patients with Ph+ ALL 6560 years, or unfit for intensive chemotherapy and stem cell transplantation. Forty-four patients received oral ponatinib 45 mg/d for 48 weeks (core phase), with prednisone tapered to 60 mg/m2/d from days-14-29. Prophylactic intrathecal chemotherapy was administered monthly. Median age was 66.5 years (range, 26-85). The primary endpoint (complete hematologic response [CHR] at 24 weeks) was reached in 38/44 patients (86.4%); complete molecular response (CMR) in 18/44 patients (40.9%) at 24 weeks. 61.4% of patients completed the core phase. As of 24 April 2020, median event-free survival was 14.31 months (95% CI 9.30-22.31). Median overall survival and duration of CHR were not reached; median duration of CMR was 11.6 months. Most common treatment-emergent adverse events (TEAEs) were rash (36.4%), asthenia (22.7%), alanine transaminase increase (15.9%), erythema (15.9%), and \u3b3-glutamyltransferase increase (15.9%). Cardiac and vascular TEAEs occurred in 29.5% (grade 653, 18.2%) and 27.3% (grade 653, 15.9%), respectively. Dose reductions, interruptions, and discontinuations due to TEAEs occurred in 43.2%, 43.2%, and 27.3% of patients, respectively; 5 patients had fatal TEAEs. Ponatinib and prednisone showed efficacy in unfit patients with Ph+ ALL; however, a lower ponatinib dose may be more appropriate in this population. This trial was registered at www.clinicaltrials.gov as #NCT01641107

Novel and Rare Fusion Transcripts Involving Transcription Factors and Tumor Suppressor Genes in Acute Myeloid Leukemia.

Approximately 18% of acute myeloid leukemia (AML) cases express a fusion transcript. However, few fusions are recurrent across AML and the identification of these rare chimeras is of interest to characterize AML patients. Here, we studied the transcriptome of 8 adult AML patients with poorly described chromosomal translocation(s), with the aim of identifying novel and rare fusion transcripts. We integrated RNA-sequencing data with multiple approaches including computational analysis, Sanger sequencing, fluorescence in situ hybridization and in vitro studies to assess the oncogenic potential of the ZEB2-BCL11B chimera. We detected 7 different fusions with partner genes involving transcription factors (OAZ-MAFK, ZEB2-BCL11B), tumor suppressors (SAV1-GYPB, PUF60-TYW1, CNOT2-WT1) and rearrangements associated with the loss of NF1 (CPD-PXT1, UTP6-CRLF3). Notably, ZEB2-BCL11B rearrangements co-occurred with FLT3 mutations and were associated with a poorly differentiated or mixed phenotype leukemia. Although the fusion alone did not transform murine c-Kit+ bone marrow cells, 45.4% of 14q32 non-rearranged AML cases were also BCL11B-positive, suggesting a more general and complex mechanism of leukemogenesis associated with BCL11B expression. Overall, by combining different approaches, we described rare fusion events contributing to the complexity of AML and we linked the expression of some chimeras to genomic alterations hitting known genes in AML

Molecular characterization of unresponsiveness to BiTE CD19-CD3 therapy in adult acute lymphoblastic leukemia

Acute lymphoblastic leukemia is a heterogeneous disease characterized by the sequential acquisition of genetic aberrations driving the leukemic clone’s onset and maintenance. The introduction of monoclonal antibodies has both increased over all survival rates and reduced the need of intensive and prolonged chemotherapy in relapsed/refractory (R/R) ALL. Blinatumomab is a BiTE (T-cell engaging bi-specific) antibody that redirects CD3-expressing T-cells to CD19-expressing leukemic cells. To identify predictive biomarkers of response/no-response and mechanisms underlying unresponsiveness to Blinatumomab, 26 B-ALL adult patients both responder and non-responder have been molecularly characterized by gene expression profiling. A bioinformatic analysis was performed employing the linear mixed model (LMM) in order to consider all the possible bias interfering with the results. The LMM output allows to classify training set patients (R or NR); the following LOPO (Leave One (Patient) Out) cross validation have been performed to avoid artifacts, determined by dataset structure. 649 genes pass the LOPO filter and the genes that contribute to less than the 1% to the total variance in the first PCA component have been discarded in order to obtain a small set of significant genes (MS4A1, CSRP2, MY05C, SEMA6A, CD200, CDR1, NEGR1, SCN3A, MME, DNTT, MIR1206). Moreover, the LMM capability of classify patients as responder or non-responder has been confirmed through its output blind application in validation set at baseline; only 1/8 patients is misclassified and additional data are needed to clarify if causes of only one patient misclassification are patient-related or structure dataset-related. Thus, the gene signature composed by 11 genes is capable of classify as responder or non-responder to Blinatumomab treatment adult B-ALL patients at baseline and easy to use for routine diagnostics. However, the dataset increase and deep molecular characterization (e.g. single-cell sequencing) are required to improve statistical significance and define strict associations between genomic characteristics and phenotypic features

The synergistic efficacy of Chk1/Chk2 inhibitors and doxorubicin in the treatment of acute lymphoblastic leukemia

none11nononeAndrea Ghelli Luserna di Rora, Ilaria Iacobucci, Enrica Imbrogno, Enrico Derenzini, Anna Ferrari, Valentina Robustelli, Viviana Guadagnuolo, Cristina Papayannidis, Maria Chiara Abbenante, Sandro Grilli, Giovanni MartinelliAndrea Ghelli Luserna di Rora, Ilaria Iacobucci, Enrica Imbrogno, Enrico Derenzini, Anna Ferrari, Valentina Robustelli, Viviana Guadagnuolo, Cristina Papayannidis, Maria Chiara Abbenante, Sandro Grilli, Giovanni Martinell

Prexasertib, a Chk1/Chk2 inhibitor, increases the effectiveness of conventional therapy in B-/T- cell progenitor acute lymphoblastic leukemia

During the last few years many Checkpoint kinase 1/2 (Chk1/Chk2) inhibitors have been developed for the treatment of different type of cancers. In this study we evaluated the efficacy of the Chk 1/2 inhibitor prexasertib mesylate monohydrate in B-/T- cell progenitor acute lymphoblastic leukemia (ALL) as single agent and in combination with other drugs. The prexasertib reduced the cell viability in a dose and time dependent manner in all the treated cell lines. The cytotoxic activity was confirmed by the increment of apoptotic cells (Annexin V/Propidium Iodide staining), by the increase of γH2A.X protein expression and by the activation of different apoptotic markers (Parp-1 and pro-Caspase3 cleavage). Furthermore, the inhibition of Chk1 changed the cell cycle profile. In order to evaluate the chemo-sensitizer activity of the compound, different cell lines were treated for 24 and 48 hours with prexasertib in combination with other drugs (imatinib, dasatinib and clofarabine). The results from cell line models were strengthened in primary leukemic blasts isolated from peripheral blood of adult acute lymphoblastic leukemia patients. In this study we highlighted the mechanism of action and the effectiveness of prexasertib as single agent or in combination with other conventional drugs like imatinib, dasatinib and clofarabine in the treatment of B-/T-ALL