Treatment of adult acute lymphoblastic leukemia with inotuzumab ozogamicin

Transcriptome Profiling and Cytological Assessments for Identifying Regulatory Pathways Associated With Diorcinol N-Induced Autophagy in A3 Cells

Fungal secondary metabolites serve as a rich resource for exploring lead compounds with medicinal importance. Diorcinol N (DN), a fungal secondary metabolite isolated from an endophytic fungus, Arthrinium arundinis, exhibits robust anticancer activity. However, the anticancer mechanism of DN remains unclear. In this study, we examined the growth-inhibitory effect of DN on different human cancer cell lines. We found that DN decreased the viability of A3 T-cell leukemia cells in a time- and concentration-dependent manner. Transcriptome analysis indicated that DN modulated the transcriptome of A3 cells. In total, 9,340 differentially expressed genes were found, among which 4,378 downregulated genes and 4,962 upregulated genes were mainly involved in autophagy, cell cycle, and DNA replication. Furthermore, we demonstrated that DN induced autophagy, cell cycle arrest in the G1/S phase, and downregulated the expression of autophagy- and cell cycle-related genes in A3 cells. By labeling A3 cells with acridine orange/ethidium bromide, Hoechst 33,258, and monodansylcadaverine and via transmission electron microscopy, we found that DN increased plasma membrane permeability, structural disorganization, vacuolation, and autophagosome formation. Our study provides evidence for the mechanism of anticancer activity of DN in T-cell leukemia (A3) cells and demonstrates the promise of DN as a lead or even candidate molecule for the treatment of acute lymphoblastic leukemia.

Inotuzumab ozogamicin for the treatment of acute lymphoblastic leukemia

Therapy for adult acute lymphoblastic leukemia (ALL) with multiagent cytotoxic chemotherapy has not been as successful as that for pediatric patients. The advent of targeted monoclonal antibodies against common cell surface antigens (i.e. CD19, CD20, and CD22) has resulted in improved outcomes without additional toxicities. Inotuzumab ozogamicin is an anti-CD22 antibody-drug conjugate approved for the treatment of relapsed or refractory B-cell precursor ALL. It improved outcomes compared with standard salvage chemotherapy. Its combination with low-intensity chemotherapy in the relapse setting and in frontline elderly patients is promising.

Inotuzumab ozogamicin is effective in relapsed/refractory extramedullary B acute lymphoblastic leukemia

Background

Extramedullary involvement of B-cell Acute Lymphoblastic Leukemia (EM-ALL) is a rare occurrence, characterized by dismal outcome and the absence of a defined and shared therapeutic approach. In the landscape of innovative compounds, inotuzumab ozogamicin (IO) is a promising drug, whose mechanism of action relies on the killing of CD22 positive leukemic cells, through the delivery, after cell binding, of a molecule of calicheamicin.

Case presentation

We report two cases of CD22 positive relapsed EM-ALL treated with IO, obtained as compassionate use. Case 1, a 66 years old woman, affected by Philadelphia (Ph) negative B-ALL, relapsed with extramedullary involvement after 6 standard chemotherapy courses, who reached a complete metabolic response with IO treatment. Case 2, a 67 years old man with Ph positive B-ALL, initially treated with ponatinib, a third generation tyrosine-kinase inhibitor (TKI), obtaining a prolonged deep molecular remission. Nevertheless, for skin relapse during TKI treatment, the patient received local radiotherapy and, shortly after, standard chemotherapy, as multiple abdominal sites of relapse were detected too, with no response. The patient then received IO, obtained as compassionate use, with a good metabolic response.

Conclusions

These two cases suggest a possible key role of IO in the setting of advanced CD22 positive ALL, and underline its potential activity also in patients with EM involvement, relapsed after or refractory to conventional chemotherapy. Despite the well known hepatotoxic effect of the compound (Sinusoid Occlusive Syndrome), neither of them had such adverse event, moreover the second patient safely underwent allogeneic bone marrow transplantation.

Inotuzumab ozogamicin in the treatment of relapsed/refractory acute B cell lymphoblastic leukemia

The improvement in outcomes of adult patients with acute lymphoblastic leukemia (ALL) has been modest, with the exception of Philadelphia chromosome-positive disease, despite advances in supportive care and stem cell transplantation. The recent approvals of novel agents, including the bispecific T-cell engager blinatumomab, the antibody-drug conjugate inotuzumab ozogamicin, and chimeric antigen receptor T-cell products are changing the management of B-ALL, which traditionally relied on chemotherapy-based approaches. Inotuzumab ozogamicin is a humanized CD22 monoclonal antibody linked to the cytotoxic agent calicheamicin. CD22 is expressed on leukemic blasts in >90% of ALL patients, and inotuzumab ozogamicin has shown excellent clinical activity even among heavily pretreated relapsed/refractory (R/R) B-ALL patients and elderly B-ALL patients. Clinical trials have shown superior survival with the drug over chemotherapy-based approaches in the first- or second-line salvage therapy for relapsed B-ALL as monotherapy. Currently, new trials are evaluating inotuzumab ozogamicin in the frontline setting in combination-based approaches. In this review, we summarize the preclinical and clinical data of inotuzumab ozogamicin in R/R B-ALL and foresee the future use of this drug in the clinic.

Rituximab in the management of acute lymphoblastic leukemia

INTRODUCTION

The anti-CD20 chimeric monoclonal antibody rituximab has revolutionized the treatment of B-cell malignancies, significantly improving patient clinical outcome. Recently, some single-group studies have suggested that adding rituximab to chemotherapy can improve the outcome of CD20-positive B-cell acute lymphoblastic leukemia (ALL) patients. Areas covered: An overview of the current insights of rituximab in adult ALL patients is presented here. In particular, we focused on results of multicenter randomized phase III trial (GRAALL-2005 - Group for Research on Adult Acute Lymphoblastic Leukemia) that evaluated the benefit of associating rituximab to chemotherapy in Ph-negative, B-lineage ALL expressing the CD20 antigen. Expert opinion: Data from clinical trials confirm that rituximab enhances the efficacy of chemotherapy without additive toxicity in ALL. However, results of GRAAL 2005 study represent only a modest incremental improvement in the treatment of ALL. Other promising compounds as single agent or in combination with chemotherapy are currently in different stages of clinical development. The GRAALL 2005 study sets the stage for other prospective studies which will further elucidate the role of monoclonal antibodies in the management of ALL.