CAR-modified Cellular Therapies in Chronic Lymphocytic Leukemia: Is the Uphill Road Getting Less Steep?

The clinical development of chimeric antigen receptor (CAR) T-cell therapy has been more challenging for chronic lymphocytic leukemia (CLL) compared to other settings. One of the main reasons is the CLL-associated state of immune dysfunction that specifically involves patient-derived T cells. Here, we provide an overview of the clinical results obtained with CAR T-cell therapy in CLL, describing the identified immunologic reasons for the inferior efficacy. Novel CAR T-cell formulations, such as lisocabtagene maraleucel, administered alone or in combination with the Bruton tyrosine kinase inhibitor ibrutinib, are currently under investigation. These approaches are based on the rationale that improving the quality of the T-cell source and of the CAR T-cell product may deliver a more functional therapeutic weapon. Further strategies to boost the efficacy of CAR T cells should rely not only on the production of CAR T cells with an improved cellular composition but also on additional changes. Such alterations could include (1) the coadministration of immunomodulatory agents capable of counteracting CLL-related immunological alterations, (2) the design of improved CAR constructs (such as third- and fourth-generation CARs), (3) the incorporation into the manufacturing process of immunomodulatory compounds overcoming the T-cell defects, and (4) the use of allogeneic CAR T cells or alternative CAR-modified cellular vectors. These strategies may allow to develop more effective CAR-modified cellular therapies capable of counteracting the more aggressive and still incurable forms of CLL

Immunotherapeutic strategies in chronic lymphocytic leukemia: advances and challenges

Immune-based therapeutic strategies have drastically changed the landscape of hematological disorders, as they have introduced the concept of boosting immune responses against tumor cells. Anti-CD20 monoclonal antibodies have been the first form of immunotherapy successfully applied in the treatment of CLL, in the context of chemoimmunotherapy regimens. Since then, several immunotherapeutic approaches have been studied in CLL settings, with the aim of exploiting or eliciting anti-tumor immune responses against leukemia cells. Unfortunately, despite initial promising data, results from pilot clinical studies have not shown optimal results in terms of disease control - especially when immunotherapy was used individually - largely due to CLL-related immune dysfunctions hampering the achievement of effective anti-tumor responses. The growing understanding of the complex interactions between immune cells and the tumor cells has paved the way for the development of new combined approaches that rely on the synergism between novel agents and immunotherapy. In this review, we provide an overview of the most successful and promising immunotherapeutic modalities in CLL, including both antibody-based therapy (i.e. monoclonal antibodies, bispecific antibodies, bi- or tri- specific killer engagers) and adoptive cellular therapy (i.e. CAR T cells and NK cells). We also provide examples of successful new combination strategies and some insights on future perspectives

Anti-tumor activity of selinexor in combination with antineoplastic agents in chronic lymphocytic leukemia

Despite recent relevant therapeutic progresses, chronic lymphocytic leukemia (CLL) remains an incurable disease. Selinexor, an oral inhibitor of the nuclear export protein XPO1, is active as single agent in different hematologic malignancies, including CLL. The purpose of this study was to evaluate the anti-tumor effects of selinexor, used in combination with chemotherapy drugs (i.e. fludarabine and bendamustine) or with the PI3K delta inhibitor idelalisib in CLL. Our results showed a significant decrease in CLL cell viability after treatment with selinexor-containing drug combinations compared to each single compound, with demonstration of synergistic cytotoxic effects. Interestingly, this drug synergism was exerted also in the presence of the protective effect of stromal cells. From the molecular standpoint, the synergistic cytotoxic activity of selinexor plus idelalisib was associated with increased regulatory effects of this drug combination on the tumor suppressors FOXO3A and IkB alpha compared to each single compound. Finally, selinexor was also effective in potentiating the in vivo anti-tumor effects of the PI3K delta inhibitor in mice treated with the drug combination compared to single agents. Our data provide preclinical evidence of the synergism and potential efficacy of a combination treatment targeting XPO1 and PI3K delta in CLL

A prospective, single-arm study on the use of the da Vinci® Table Motion with the Trumpf TS7000dV operating table

BACKGROUND: The da Vinci® Table Motion (dVTM) comprises a combination of a unique operating table (Trumpf Medical™ TruSystem® 7000dV) capable of isocenter motion connected wirelessly with the da Vinci Xi® robotic platform, thereby enabling patients to be repositioned without removal of instruments and or undocking the robot. MATERIALS AND METHODS: Between May 2015 to October 2015, the first human use of dVTM was carried out in this prospective, single-arm, post-market study in the EU, for which 40 patients from general surgery (GS), urology (U), or gynecology (G) were enrolled prospectively. Primary endpoints of the study were dVTM feasibility, efficacy, and safety. RESULTS:Surgeons from the three specialties obtained targeting success and the required table positioning in all cases. Table movement/repositioning was necessary to gain exposure of the operating field in 106/116 table moves (91.3%), change target in 2/116 table moves (1.7%), achieve hemodynamic relief in 4/116 table moves (3.5%), and improve external access for tumor removal in 4/116 table moves (3.5%). There was a significantly higher use of tilt and tilt plus Trendelenburg in GS group (GS vs. U p = 0.055 and GS vs. G p = 0.054). There were no dVTM safety-related or adverse events. CONCLUSIONS: The dVTM with TruSystem 7000dV operating table in wireless communication with the da Vinci Xi is a perfectly safe and effective synergistic combination, which allows repositioning of the patient whenever needed without imposing any delay in the execution of the operation. Moreover, it is helpful in avoiding extreme positions and enables the anesthesiologist to provide immediate and effective hemodynamic relief to the patient when needed

The Polycomb BMI1 Protein Is Co-expressed With CD26+ in Leukemic Stem Cells of Chronic Myeloid Leukemia

The Polycomb gene BMI1 expression exerts a negative predictive impact on several hematological malignancies, such as acute and chronic myeloid leukemia (CML), myelofibrosis, and follicular lymphoma. As already demonstrated in CML, BMI1 is responsible for the resistance to the tyrosine kinase inhibitors (TKIs) in a BCR-ABL1-independent way. Even if, it is unknown where BMI1 in CML is expressed (in progenitors or more mature cells). We decided, therefore, to evaluate if and where the BMI1 protein is located, focusing mainly on the CD34+/CD38-/CD26+ CML progenitors. To begin we measured, by flow cytometry, the proportion of CD34+/CD26+ cells in 31 bone marrow samples from 20 CML patients, at diagnosis and during treatment with imatinib. After that the bone marrow blood smears were stained with antibodies anti-CD26, BCR-ABL1, and BMI1. These smears were observed by a confocal laser microscope and a 3D reconstruction was then performed. At diagnosis, CD34+/CD26+ cells median value/μL was 0.48; this number increased from diagnosis to the third month of therapy and then reduced during treatment with imatinib. The number and behavior of the CD26+ progenitors were independent from the BCR-ABL1 expression, but they summed up what previously observed about the BMI1 expression modulation. In this work we demonstrate for the first time that in CML the BMI1 protein is co-expressed with BCR-ABL1 only in the cytoplasm of the CD26+ precursors; on the contrary, in other hematological malignancies where BMI1 is commonly expressed (follicular lymphoma, essential thrombocytemia, acute myeloid leukemia), it was not co-localized with CD26 or, obviously, with BCR-ABL1. Once translated into the clinical context, if BMI1 is a marker of stemness, our results would suggest the combination of the BMI1 inhibitors with TKIs as an interesting object of research, and, probably, as a promising way to overcome resistance in CML patients

Nuovi bersagli molecolari degli inibitori delle tirosin kinasi nella leucemia mieloide cronica: lo studio Athena

La leucemia mieloide cronica (CML) è un disordine mieloproliferativo derivante dalla trasformazione neoplastica della cellula staminale ematopoietica pluripotente CD34+/CD26+/CD38-/CD90+. Tale trasformazione è dovuta alla traslocazione reciproca t(9;22), da cui si genera l’oncoproteina BCR-ABL1, driver dell’evoluzione neoplastica. Oggi, grazie agli inibitori tirosin-chinasici (TKIs), i pazienti con CML hanno una sopravvivenza superiore al 90%, paragonabile ai soggetti sani; tuttavia, esistono ancora alcune problematiche aperte legate alla generazione di meccanismi di resistenza anche non dipendenti da BCR-ABL1. Lo studio ATHENA è uno studio condotto su 10 pazienti affetti da CML in prima linea di trattamento giunti alla osservazione presso l’ematologia di Pisa dal Gennaio 2016. Da questi pazienti sono stati raccolti sangue periferico, midollare e saliva alla diagnosi e dopo 6 mesi di trattamento con TKIs. Scopo dello studio ATHENA è quello di andare a valutare meccanismi di carattere biologico che rendono la cellula leucemica resistente ai TKIs, in modo da trovare nuovi elementi che possano guidarci verso una migliore definizione della prognosi ed essere al contempo utili nello scenario della target therapy. A tal fine, lo studio consta di diverse parti: 1) studio dell’espressione dei geni coinvolti nel pathway JAK-STAT, con particolare riferimento alle vie intracellulari attivate dall’interferone, allo scopo di valutare il rapporto tra immunità e malattia; 2) studio dell’espressione di geni espressi nella nicchia midollare, con lo scopo di individuare possibili meccanismi coinvolti nella resistenza ipossia-mediata; 3) studio dell’espressione di geni coinvolti nella regolazione epigenetica, con particolare riferimento ai geni del gruppo Polycomb; 4) identificazione di proteine CML-relate in compartimento differente dal sangue periferico o midollare (proteomica salivare). Dai risultati ottenuti, oltre 150 geni sono risultati differentemente espressi a 6 mesi di terapia rispetto ai loro valori alla diagnosi, suggerendo come l’utilizzo di TKIs vada ad agire su pathways intracellulari diversi da BCR-ABL1. Nonostante la casistica limitata, tali de-regolazioni si sono verificate per tutte le tipologie di TKIs utilizzate. Inoltre, la maggior parte dei geni de-regolati non era stata precedentemente descritta in tale patologia. Tra i vari geni, degni di nota sono quelli implicati nella via JAK/STAT e dell’interferone, altri implicati nel controllo del ciclo cellulare ed infine altri ancora coinvolti nella costituzione della nicchia ipossica. In particolare, la proteomica salivare ha identificato alcune proteine che si riteneva fossero localizzate specificamente nella nicchia midollare; tale dato potrebbe aprire la strada alla valutazione del compartimento salivare in alternativa a quelli già utilizzati per il consueto monitoraggio dei pazienti con CML

Beyond ibrutinib: novel BTK inhibitors for the treatment of chronic lymphocytic leukemia

Purpose of the reviewIbrutinib was the first Bruton tyrosine kinase inhibitor (BTKi) approved for clinical use, contributing to a dramatic change in the treatment landscape of chronic lymphocytic leukemia (CLL). This review provides an overview of next-generation BTKi that have been recently approved or are being investigated for the treatment of CLL, specifically highlighting differences and similarities compared to ibrutinib.Recent findingsAcalabrutinib presented comparable response rates to ibrutinib with lower rates of adverse events and is currently approved for the treatment of CLL. Zanubrutinib displayed excellent response rates with a lower incidence of BTKi-related adverse events, but major rates of neutropenia, and its approval is awaited. With the aim of overcoming drug resistance, noncovalent BTKi have been developed. Of all the explored agents to date, pirtobrutinib has shown promising results with manageable toxicities.SummaryFor the treatment of CLL, several effective therapeutic strategies to target BTK are or will soon be available: these drugs present different safety profiles, thus making it possible to tailor the treatment choice according to patient's characteristics. Importantly, noncovalent BTKi will provide a therapeutic chance also for those relapsed/refractory CLL patients who are BTKi-resistant and are considered an unmet clinical need