CARD11 gain of function upregulates BCL2A1 expression and promotes resistance to targeted therapies combination in B-cell lymphoma.

A strategy combining targeted therapies is effective in B-cell lymphomas (BCL), such as mantle cell lymphoma (MCL), but acquired resistances remain a recurrent issue. In this study, we performed integrative longitudinal genomic and single-cell RNA-sequencing analyses of patients with MCL who were treated with targeted therapies against CD20, BCL2, and Bruton tyrosine kinase (OAsIs trial). We revealed the emergence of subclones with a selective advantage against OAsIs combination in vivo and showed that resistant cells were characterized by B-cell receptor (BCR)-independent overexpression of NF-κB1 target genes, especially owing to CARD11 mutations. Functional studies demonstrated that CARD11 gain of function not only resulted in BCR independence but also directly increased the transcription of the antiapoptotic BCL2A1, leading to resistance against venetoclax and OAsIs combination. Based on the transcriptional profile of OAsIs-resistant subclones, we designed a 16-gene resistance signature that was also predictive for patients with MCL who were treated with conventional chemotherapy, underlying a common escape mechanism. Among druggable strategies to inhibit CARD11-dependent NF-κB1 transduction, we evaluated the selective inhibition of its essential partner MALT1. We demonstrated that MALT1 protease inhibition led to a reduction in the expression of genes involved in OAsIs resistance, including BCL2A1. Consequently, MALT1 inhibition induced synergistic cell death in combination with BCL2 inhibition, irrespective of CARD11 mutational status, both in vitro and in vivo. Taken together, our study identified mechanisms of resistance to targeted therapies and provided a novel strategy to overcome resistance in aggressive BCL. The OAsIs trial was registered at www.clinicaltrials.gov #NCT02558816.

Diagnosis and prognosis are supported by integrated assessment of next-generation sequencing in chronic myeloid malignancies. A real-life study.

Next-generation sequencing (NGS) is used to investigate the presence of somatic mutations. The utility of incorporating routine sequencing to guide diagnosis and therapeutic decisions remains unclear. We report the findings of an observational, multicenter study that aimed to assess the impact of somatic mutation testing by NGS in a reallife setting of chronic myeloid malignancies. A total of 177 patients were enrolled, partitioned into two overlapping groups. In group A (n=94), the indication was to search for clonal hematopoiesis, in a context of suspected myelodysplastic syndrome or myeloproliferative neoplasia. In group B (n=95), the theranostic impact of somatic mutations was studied. A panel of 34 genes was used on DNA extracted from blood or bone marrow samples. Within group A, the detection of clonal hematopoiesis supported the diagnosis of chronic myeloid malignancies for 31 patients while the absence of clonal hematopoiesis ruled out the suspected diagnosis in 47 patients. Within group B, NGS identified prognostically relevant somatic mutations in 32 patients, which had a therapeutic impact in 18 cases. By determining the presence or absence of somatic mutations, the application of NGS in daily practice was found to be useful for an integrated final diagnosis in 83% of the patients. Moreover, the search for somatic mutations had a prognostic impact that led to treatment modification in 19% of the cases. This study outlines the fact that adequate implementation of new investigations may have a significant positive medico-economic impact by enabling appropriate management of patients.

Molecular characterization and follow-up of five CML patients with new BCR-ABL1 fusion transcripts.

We report five chronic myeloid leukaemia (CML) patients in whom we identified and characterized undescribed BCR-ABL1 fusion transcripts. We investigated the precise features of the molecular rearrangements and the minimal residual disease follow-up for these five patients. Three resulted from new rearrangements between the BCR and ABL1 sequences (the breakpoints being located within BCR exon 13 in two cases and within BCR exon 18 in one case). The other two cases revealed a complex e8-[ins]-a2 fusion transcript involving a third partner gene, PRDM12 and SPECC1L, respectively. Moreover, single nucleotide polymorphism-array analysis performed in the latter two cases showed copy number alterations shared by the two patients, thus identifying genes that were deleted during rearrangement and suggesting their potential role in CML pathogenesis. Interestingly, we highlight that the prognosis of alterations, such as the presence of an e8a2 transcript or the deletion of various genes, which have been controversial, may be definitively erased by the introduction of tyrosine kinase inhibitors (TKIs).

BCR-ABL1 molecular remission after 90Y-epratuzumab tetraxetan radioimmunotherapy in CD22+ Ph+ B-ALL: proof of principle.

Although targeted therapies are used increasingly in hematologic malignancies, we are unaware of any prior studies of radioimmunotherapy (RAIT) in B-acute lymphoblastic leukemia (ALL), even though this radiosensitive tumor expresses CD22, potentially a good target for this approach. Here, we report a patient with Philadelphia chromosome-positive B-ALL in third relapse who received RAIT with (90) yttrium ((90) Y)-labeled anti-CD22 epratuzumab tetraxetan. Seven weeks after initiating therapy, the patient achieved a BCR-ABL1 molecular remission documented by RT-qPCR, which is now continuing at 6 months while awaiting an allogeneic hematopoietic stem cell transplant. (90) Y-Epratuzumab tetraxetan may be a promising therapeutic option for CD22(+) B-ALL patients.

CPX-351 in higher risk myelodysplastic syndrome and chronic myelomonocytic leukaemia: a multicentre, single-arm, phase 2 study.

BACKGROUND: CPX-351, an encapsulated form of cytarabine and daunorubicin, has shown greater efficacy than the classic 3 + 7 treatment administration in secondary acute myeloid leukaemia. Given that higher-risk myelodysplastic syndrome and chronic myelomonocytic leukaemia share similarities with secondary acute myeloid leukaemia, we aimed to investigate the safety and efficacy of CPX-351 in this context. METHODS: This investigator-initiated two-cohort phase 2 trial was conducted by the Groupe Francophone des Myélodysplasies, with 12 participating centres in France. It comprised cohort A (reported here and completed), which included patients in first-line treatment, and cohort B, which was stopped for lack of inclusion (ie, not enough patients met the inclusion criteria), for patients with hypomethylating agent failure that is not reported here. Cohort A enrolled patients with newly diagnosed higher-risk myelodysplastic syndrome or chronic myelomonocytic leukaemia (aged 18-70 years old) with an Eastern Cooperative Oncology Group performance status of 0-1. Intravenous CPX-351 (100 mg/m2 cytarabine and 44 mg/m2 daunorubicin) was given on days 1, 3, and 5, with a second induction cycle given (same daily dose on days 1 and 3) if at least a partial response was not reached. Patients who responded could receive up to four monthly consolidation cycles (same daily dose on day 1) or allogeneic haematopoietic stem-cell transplantation (HSCT). Overall response rate after one or two induction courses according to European LeukemiaNet 2017 acute myeloid leukaemia was the primary endpoint after CPX-351 induction, whether patients received one or two induction cycles. Safety was assessed in all patients enrolled (in cohort A). This trial is registered with ClinicalTrials.gov, NCT04273802. FINDINGS: Between April 29, 2020, and Feb 10, 2021, 21 (68%) male and ten (32%) female patients were enrolled. 27 (87%) of 31 patients responded (95% CI 70-96). 16 (52%) of the 31 patients received at least one consolidation cycle. 30 (97%) of the 31 patients included were initially considered eligible for allogeneic HSCT and 29 (94%) of the 31 patients had the procedure. Median follow-up was 16·1 months (IQR 8·3-18·1). The most common grade 3-4 adverse events were pulmonary (eight [26%] of 31 patients) and cardiovascular (six [19%] of 31 patients). There were 14 serious adverse events (mainly hospitalisation for infection [n=5] and only one was treatment-related) and no treatment-related death. INTERPRETATION: CPX-351 appears to be active and safe in patients with higher-risk myelodysplastic syndrome and chronic myelomonocytic leukaemia, allowing bridging to allogenic HSCT in most patients. FUNDING: Jazz Pharmaceuticals.

Aggressive, early resistant and relapsed mantle cell lymphoma distinct extrinsic microenvironment highlighted by transcriptome analysis.

Immunotherapy strategies relying on innate or adaptive immune components are increasingly used in onco-haematology. However, little is known about the infiltrated lymph nodes (LN) or bone marrow (BM) landscape of mantle cell lymphoma (MCL). The original transcriptomic approach of reverse transcriptase multiplex ligation-dependent probe amplification (RT-MLPA) was applied here to explore the expression of 24 genes of interest in MCL at diagnosis (21 LN and 15 BM) or relapse (18 LN). This allowed us to identify that at baseline, samples from MCL patients with an aggressive morphology (i.e. blastoid or pleomorphic) or a high proliferative profile, displayed significantly higher monocyte/macrophage-associated transcripts (CD14 and CD163) in LN and BM. Regarding T-cells, aggressive MCL forms had significantly lower amounts of LN CD3E transcripts, yet an increased expression of cytotoxic markers in LN (CD8) and BM (CD94). A very high-risk group with early treatment resistance displayed, at diagnosis, high proliferation (KI67) and high macrophages and cytotoxic transcript levels. Post-immunochemotherapy relapsed samples revealed lower levels of T- and natural killer-cells markers, while monocyte/macrophage markers remained similar to diagnosis. This study suggests that rapid analysis of MCL microenvironment transcriptome signatures by RT-MLPA could allow for an early distinction of patient subgroups candidates for adapted treatment strategies.