Nicola Gökbuget

Targeted Therapy With the T-Cell–Engaging Antibody Blinatumomab of Chemotherapy-Refractory Minimal Residual Disease in B-Lineage Acute Lymphoblastic Leukemia Patients Results in High Response Rate and Prolonged Leukemia-Free Survival

PURPOSE Blinatumomab, a bispecific single-chain antibody targeting the CD19 antigen, is a member of a novel class of antibodies that redirect T cells for selective lysis of tumor cells. In acute lymphoblastic leukemia (ALL), persistence or relapse of minimal residual disease (MRD) after chemotherapy indicates resistance to chemotherapy and results in hematologic relapse. A phase II clinical study was conducted to determine the efficacy of blinatumomab in MRD-positive B-lineage ALL. PATIENTS AND METHODS Patients with MRD persistence or relapse after induction and consolidation therapy were included. MRD was assessed by quantitative reverse transcriptase polymerase chain reaction for either rearrangements of immunoglobulin or T-cell receptor genes, or specific genetic aberrations. Blinatumomab was administered as a 4-week continuous intravenous infusion at a dose of 15 μg/m2/24 hours. RESULTS Twenty-one patients were treated, of whom 16 patients became MRD negative. One patient was not evaluable due to a grade 3 adverse event leading to treatment discontinuation. Among the 16 responders, 12 patients had been molecularly refractory to previous chemotherapy. Probability for relapse-free survival is 78% at a median follow-up of 405 days. The most frequent grade 3 and 4 adverse event was lymphopenia, which was completely reversible like most other adverse events. CONCLUSION Blinatumomab is an efficacious and well-tolerated treatment in patients with MRD-positive B-lineage ALL after intensive chemotherapy. T cells engaged by blinatumomab seem capable of eradicating chemotherapy-resistant tumor cells that otherwise cause clinical relapse.

Safety and activity of blinatumomab for adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia: a multicentre, single-arm, phase 2 study

BACKGROUND Adults with relapsed or refractory B-precursor acute lymphoblastic leukaemia have an unfavourable prognosis. Blinatumomab is a bispecific T-cell engager antibody construct targeting CD19, an antigen consistently expressed on B-lineage acute lymphoblastic leukaemia cells. We aimed to confirm the activity and safety profile of blinatumomab for acute lymphoblastic leukaemia. METHODS In a multicentre, single-arm, open-label phase 2 study, we enrolled adult patients with Philadelphia-chromosome-negative, primary refractory or relapsed (first relapse within 12 months of first remission, relapse within 12 months after allogeneic haemopoietic stem-cell transplantation [HSCT], or no response to or relapse after first salvage therapy or beyond) leukaemia. Patients received blinatumomab (9 μg/day for the first 7 days and 28 μg/day thereafter) by continuous intravenous infusion over 4 weeks every 6 weeks (up to five cycles), per protocol. The primary endpoint was complete remission (CR) or CR with partial haematological recovery of peripheral blood counts (CRh) within the first two cycles. Analysis was by intention to treat. This trial is registered at ClinicalTrials.gov, number NCT01466179. FINDINGS Between Jan 13, 2012, and Oct 10, 2013, 189 patients were enrolled and treated with blinatumomab. After two cycles, 81 (43%, 95% CI 36-50) patients had achieved a CR or CRh: 63 (33%) patients had a CR and 18 (10%) patients had a CRh. 32 (40%) of patients who achieved CR/CRh underwent subsequent allogeneic HSCT. The most frequent grade 3 or worse adverse events were febrile neutropenia (48 patients, 25%), neutropenia (30 patients, 16%), and anaemia (27 patients, 14%). Three (2%) patients had grade 3 cytokine release syndrome. Neurologic events of worst grade 3 or 4 occurred in 20 (11%) and four (2%) patients, respectively. Three deaths (due to sepsis, Escherichia coli sepsis, and Candida infection) were thought to be treatment-related by the investigators. INTERPRETATION Single-agent blinatumomab showed antileukaemia activity in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia characterised by negative prognostic factors. Further assessment of blinatumomab treatment earlier in the course of the disease and in combination with other treatment approaches is warranted. FUNDING Amgen.

Long-term follow-up of hematologic relapse-free survival in a phase 2 study of blinatumomab in patients with MRD in B-lineage ALL

Persistence or recurrence of minimal residual disease (MRD) after chemotherapy results in clinical relapse in patients with acute lymphoblastic leukemia (ALL). In a phase 2 trial of B-lineage ALL patients with persistent or relapsed MRD, a T cell-engaging bispecific Ab construct induced an 80% MRD response rate. In the present study, we show that after a median follow-up of 33 months, the hematologic relapse-free survival of the entire evaluable study cohort of 20 patients was 61% (Kaplan-Meier estimate). The hema-tologic relapse-free survival rate of a subgroup of 9 patients who received allogeneic hematopoietic stem cell transplantation after blinatumomab treatment was 65% (Kaplan-Meier estimate). Of the subgroup of 6 Philadelphia chromosome-negative MRD responders with no further therapy after blinatumomab, 4 are in ongoing hematologic and molecular remission. We conclude that blinatumomab can induce long-lasting complete remission in B-lineage ALL patients with persistent or recurrent MRD. The original study and this follow-up study are registered at www.clinicaltrials.gov as NCT00198991 and NCT00198978, respectively.

Phase II Trial of the Anti-CD19 Bispecific T Cell–Engager Blinatumomab Shows Hematologic and Molecular Remissions in Patients With Relapsed or Refractory B-Precursor Acute Lymphoblastic Leukemia

PURPOSE Patients with relapsed or refractory acute lymphoblastic leukemia (ALL) have a dismal prognosis. CD19 is homogenously expressed in B-precursor ALL and can be targeted by the investigational bispecific T cell-engager antibody blinatumomab. A phase II trial was performed to determine clinical activity in this patient cohort. PATIENTS AND METHODS Thirty-six patients with relapsed or refractory B-precursor ALL were treated with blinatumomab in cycles of 4-week continuous infusion followed by a 2-week treatment-free interval in a single-arm study with a dose-finding stage and an extension stage. The primary end point was complete remission (CR) or CR with partial hematologic recovery (CRh). Major secondary end points included minimal residual disease (MRD) response, rate of allogeneic hematopoietic stem-cell transplantation (HSCT) realization, relapse-free survival (RFS), overall survival (OS), and incidence of adverse events (AEs). RESULTS Median age was 32 years (range, 18 to 77 years). Twenty-five patients (69%) achieved a CR or CRh, with 88% of the responders achieving an MRD response. Median OS was 9.8 months (95% CI, 8.5 to 14.9), and median RFS was 7.6 months (95% CI, 4.5 to 9.5). Thirteen responders (52%) underwent HSCT after achieving a CR or CRh. The most frequent AE during treatment was pyrexia (grade 1 or 2, 75%; grade 3, 6%). In six patients with nervous system or psychiatric disorder AEs and in two patients with cytokine release syndrome, treatment had to be interrupted or discontinued. These medical events were resolved clinically. CONCLUSION The data support further investigation of blinatumomab for the treatment of adult patients with relapsed or refractory ALL in a larger confirmatory study.

Standardized MRD quantification in European ALL trials : Proceedings of the Second International Symposium on MRD assessment in Kiel, Germany, 18-20 September 2008

Assessment of minimal residual disease (MRD) has acquired a prominent position in European treatment protocols for patients with acute lymphoblastic leukemia (ALL), on the basis of its high prognostic value for predicting outcome and the possibilities for implementation of MRD diagnostics in treatment stratification. Therefore, there is an increasing need for standardization of methodologies and harmonization of terminology. For this purpose, a panel of representatives of all major European study groups on childhood and adult ALL and of international experts on PCR- and flow cytometry-based MRD assessment was built in the context of the Second International Symposium on MRD assessment in Kiel, Germany, 18–20 September 2008. The panel summarized the current state of MRD diagnostics in ALL and developed recommendations on the minimal technical requirements that should be fulfilled before implementation of MRD diagnostics into clinical trials. Finally, a common terminology for a standard description of MRD response and monitoring was established defining the terms ‘complete MRD response’, ‘MRD persistence’ and ‘MRD reappearance’. The proposed MRD terminology may allow a refined and standardized assessment of response to treatment in adult and childhood ALL, and provides a sound basis for the comparison of MRD results between different treatment protocols.

Immunopharmacologic response of patients with B-lineage acute lymphoblastic leukemia to continuous infusion of T cell–engaging CD19/CD3-bispecific BiTE antibody blinatumomab

T cell-engaging CD19/CD3-bispecific BiTE Ab blinatumomab has shown an 80% complete molecular response rate and prolonged leukemia-free survival in patients with minimal residual B-lineage acute lymphoblastic leukemia (MRD(+) B-ALL). Here, we report that lymphocytes in all patients of a phase 2 study responded to continuous infusion of blinatumomab in a strikingly similar fashion. After start of infusion, B-cell counts dropped to < 1 B cell/μL within an average of 2 days and remained essentially undetectable for the entire treatment period. By contrast, T-cell counts in all patients declined to a nadir within < 1 day and recovered to baseline within a few days. T cells then expanded and on average more than doubled over baseline within 2-3 weeks under continued infusion of blinatumomab. A significant percentage of reappearing CD8(+) and CD4(+) T cells newly expressed activation marker CD69. Shortly after start of infusion, a transient release of cytokines dominated by IL-10, IL-6, and IFN-γ was observed, which no longer occurred on start of a second treatment cycle. The response of lymphocytes in leukemic patients to continuous infusion of blinatumomab helps to better understand the mode of action of this and other globally T cell-engaging Abs. The trial is registered with www.clinicaltrials.gov identifier NCT00560794.

Inotuzumab ozogamicin versus standard therapy for acute lymphoblastic leukemia

BACKGROUND The prognosis for adults with relapsed acute lymphoblastic leukemia is poor. We sought to determine whether inotuzumab ozogamicin, an anti-CD22 antibody conjugated to calicheamicin, results in better outcomes in patients with relapsed or refractory acute lymphoblastic leukemia than does standard therapy. METHODS In this phase 3 trial, we randomly assigned adults with relapsed or refractory acute lymphoblastic leukemia to receive either inotuzumab ozogamicin (inotuzumab ozogamicin group) or standard intensive chemotherapy (standard-therapy group). The primary end points were complete remission (including complete remission with incomplete hematologic recovery) and overall survival. RESULTS Of the 326 patients who underwent randomization, the first 218 (109 in each group) were included in the primary intention-to-treat analysis of complete remission. The rate of complete remission was significantly higher in the inotuzumab ozogamicin group than in the standard-therapy group (80.7% [95% confidence interval {CI}, 72.1 to 87.7] vs. 29.4% [95% CI, 21.0 to 38.8], P<0.001). Among the patients who had complete remission, a higher percentage in the inotuzumab ozogamicin group had results below the threshold for minimal residual disease (0.01% marrow blasts) (78.4% vs. 28.1%, P<0.001); the duration of remission was longer in the inotuzumab ozogamicin group (median, 4.6 months [95% CI, 3.9 to 5.4] vs. 3.1 months [95% CI, 1.4 to 4.9]; hazard ratio, 0.55 [95% CI, 0.31 to 0.96]; P=0.03). In the survival analysis, which included all 326 patients, progression-free survival was significantly longer in the inotuzumab ozogamicin group (median, 5.0 months [95% CI, 3.7 to 5.6] vs. 1.8 months [95% CI, 1.5 to 2.2]; hazard ratio, 0.45 [97.5% CI, 0.34 to 0.61]; P<0.001); the median overall survival was 7.7 months (95% CI, 6.0 to 9.2) versus 6.7 months (95% CI, 4.9 to 8.3), and the hazard ratio was 0.77 (97.5% CI, 0.58 to 1.03) (P=0.04). In the safety population, the most frequent grade 3 or higher nonhematologic adverse events with inotuzumab ozogamicin were liver-related. Veno-occlusive liver disease of any grade occurred in 15 patients (11%) who received inotuzumab ozogamicin and in 1 patient (1%) who received standard therapy. CONCLUSIONS The rate of complete remission was higher with inotuzumab ozogamicin than with standard therapy, and a higher percentage of patients in the inotuzumab ozogamicin group had results below the threshold for minimal residual disease. Both progression-free and overall survival were longer with inotuzumab ozogamicin. Veno-occlusive liver disease was a major adverse event associated with inotuzumab ozogamicin. (Funded by Pfizer; INO-VATE ALL ClinicalTrials.gov number, NCT01564784.).

Treatment of Adult ALL According to Protocols of the German Multicenter Study Group for Adult ALL (GMALL)

The German Multicenter Study Group for Adult Acute Lymphoblastic leukemia (GMALL) has conducted 5 consecutive trials with more than 3000 patients since 1981. This article provides an overview on aims, treatment concepts, and results of these studies. It includes brief summaries on the development of prognostic models within the GMALL group and on approaches for prophylaxis of CNS relapse, and it summarizes specific treatment concepts for mature B-lineage acute lymphocytic leukemia.

Blinatumomab versus Chemotherapy for Advanced Acute Lymphoblastic Leukemia

Background Blinatumomab, a bispecific monoclonal antibody construct that enables CD3‐positive T cells to recognize and eliminate CD19‐positive acute lymphoblastic leukemia (ALL) blasts, was approved for use in patients with relapsed or refractory B‐cell precursor ALL on the basis of single‐group trials that showed efficacy and manageable toxic effects. Methods In this multi‐institutional phase 3 trial, we randomly assigned adults with heavily pretreated B‐cell precursor ALL, in a 2:1 ratio, to receive either blinatumomab or standard‐of‐care chemotherapy. The primary end point was overall survival. Results Of the 405 patients who were randomly assigned to receive blinatumomab (271 patients) or chemotherapy (134 patients), 376 patients received at least one dose. Overall survival was significantly longer in the blinatumomab group than in the chemotherapy group. The median overall survival was 7.7 months in the blinatumomab group and 4.0 months in the chemotherapy group (hazard ratio for death with blinatumomab vs. chemotherapy, 0.71; 95% confidence interval [CI], 0.55 to 0.93; P=0.01). Remission rates within 12 weeks after treatment initiation were significantly higher in the blinatumomab group than in the chemotherapy group, both with respect to complete remission with full hematologic recovery (34% vs. 16%, P<0.001) and with respect to complete remission with full, partial, or incomplete hematologic recovery (44% vs. 25%, P<0.001). Treatment with blinatumomab resulted in a higher rate of event‐free survival than that with chemotherapy (6‐month estimates, 31% vs. 12%; hazard ratio for an event of relapse after achieving a complete remission with full, partial, or incomplete hematologic recovery, or death, 0.55; 95% CI, 0.43 to 0.71; P<0.001), as well as a longer median duration of remission (7.3 vs. 4.6 months). A total of 24% of the patients in each treatment group underwent allogeneic stem‐cell transplantation. Adverse events of grade 3 or higher were reported in 87% of the patients in the blinatumomab group and in 92% of the patients in the chemotherapy group. Conclusions Treatment with blinatumomab resulted in significantly longer overall survival than chemotherapy among adult patients with relapsed or refractory B‐cell precursor ALL. (Funded by Amgen; TOWER ClinicalTrials.gov number, NCT02013167.)

Treatment of adult acute lymphoblastic leukemia.

Treatment results in adult acute lymphoblastic leukemia (ALL) have improved considerably in the past decade, with an increase of complete remission rates to 85% to 90% and overall survival rates to 40% to 50%. Superior chemotherapy and supportive care, the integration of stem cell transplantation (SCT) into frontline therapy, and optimized risk stratification were important developments. Even more impressive is the success of targeted therapies in subgroups of ALL. In the formerly most unfavorable subgroup, Philadelphia chromosome (Ph)/BCR-ABL-positive ALL, survival now ranges from 40% to 50% after incorporating imatinib in combination chemotherapy. In mature B-ALL, survival rates increased above 80% with the combination of short intensive chemotherapy and rituximab. The prerequisite for comprehensive therapy is standardized and rapid diagnosis and classification as the basis for treatment stratification. Historically, the major aim of original risk stratification was to identify patients with a poor prognosis who would benefit from treatment intensification with SCT; currently stratification has become more complex. Subgroup-specific approaches include age-adapted therapy, subgroup-adjusted therapy, targeted therapy, and individualized therapy based on the presence of minimal residual disease (MRD).