Response to blinatumomab or inotuzumab ozogamicin for isolated extramedullary relapse of adult acute lymphoblastic leukemia after allogeneic hematopoietic cell transplantation: a case study.

Isolated extramedullary relapse (EMR) without bone marrow relapse (BMR) after allogeneic hematopoietic cell transplantation (allo-HCT) is a rare condition in patients with acute lymphoblastic leukemia (ALL), and the role of immunotherapeutic agents for these patients remains unclear. We analyzed treatment outcomes of blinatumomab or inotuzumab ozogamicin (INO) as first- or second-line salvage therapy in nine patients with Philadelphia chromosome-negative B-cell precursor ALL presenting with isolated EMR after previous allo-HCT. In seven patients receiving blinatumomab as first-line salvage therapy, 4 (57.1%) achieved complete remission (CR). Among the three patients without remission after blinatumomab, two switched to INO and subsequently showed responses {one CR and one partial response [PR]}, and one switched to multiagent chemotherapy that led to CR. In the two patients receiving first-line salvage therapy with INO, one showed PR and the other achieved CR. Overall, 6 (66.7%) of nine patients achieved CR, and five of them proceeded to allo-HCT in CR. The median overall survival after relapse was 27.8 months. In conclusion, both blinatumomab and INO showed good response rates and a safe bridging role to second allo-HCT in patients with isolated EMR. However, clinical differences between isolated EMR and EMR with BMR remain to be elucidated.

Sequential Therapy of Inotuzumab Ozogamicin and Blinatumomab as a Bridge-to Hematopoietic Stem Cell Transplantation in a Pediatric Patient With Primary Refractory Acute Lymphoblastic Leukemia: A Case Report.

For relapsed/refractory (r/r) acute lymphocytic leukemia (ALL), there is a clinical question on how to combine blinatumomab and inotuzumab ozogamicin (InO), which are newly emerging immunotherapeutic agents, with conventional treatment. We report the case of an 11-year-old boy with B-cell ALL, who had a failed primary treatment and achieved molecular complete remission treated with a sequence therapy of InO and blinatumomab. Later, hematopoietic stem cell transplantation could be performed without major complications. Our case may suggest that the sequence therapy of InO and blinatumomab as a bridge-to hematopoietic stem cell transplantation could be effective in the treatment of pediatric r/r ALL.

Interventions and outcomes of adult patients with B-ALL progressing after CD19 chimeric antigen receptor T-cell therapy.

CD19-targeted chimeric antigen receptor (CAR) T-cell therapy has become a breakthrough treatment of patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). However, despite the high initial response rate, the majority of adult patients with B-ALL progress after CD19 CAR T-cell therapy. Data on the natural history, management, and outcome of adult B-ALL progressing after CD19 CAR T cells have not been described in detail. Herein, we report comprehensive data of 38 adult patients with B-ALL who progressed after CD19 CAR T therapy at our institution. The median time to progression after CAR T-cell therapy was 5.5 months. Median survival after post-CAR T progression was 7.5 months. A high disease burden at the time of CAR T-cell infusion was significantly associated with risk of post-CAR T progression. Thirty patients (79%) received salvage treatment of post-CAR T disease progression, and 13 patients (43%) achieved complete remission (CR), but remission duration was short. Notably, 7 (58.3%) of 12 patients achieved CR after blinatumomab and/or inotuzumab administered following post-CAR T failure. Multivariate analysis revealed that a longer remission duration from CAR T cells was associated with superior survival after progression following CAR T-cell therapy. In summary, overall prognosis of adult B-ALL patients progressing after CD19 CAR T cells was poor, although a subset of patients achieved sustained remissions to salvage treatments, including blinatumomab, inotuzumab, and reinfusion of CAR T cells. Novel therapeutic strategies are needed to reduce risk of progression after CAR T-cell therapy and improve outcomes of these patients.

Inotuzumab ozogamicin in infants and young children with relapsed or refractory acute lymphoblastic leukaemia: a case series.

No data on inotuzumab ozogamicin (InO) in infant acute lymphoblastic leukaemia (ALL) have been published to date. We collected data internationally on infants/young children (<3 years) with ALL treated with InO. Fifteen patients (median 4.4 months at diagnosis) received InO due to relapsed or refractory (R/R) disease. Median percentage of CD22+ blasts was 72% (range 40-100%, n = 9). The median dose in the first course was 1.74 mg/m2 (fractionated). Seven patients (47%) achieved complete remission; one additional minimal residual disease (MRD)-positive patient became MRD-negative. Six-month overall survival was 47% (95% confidence interval [CI] 27-80%). Two patients developed veno-occlusive disease after transplant. Further evaluation of InO in this subgroup of ALL is justified.

Inotuzumab Ozogamicin for Relapsed/Refractory Acute Lymphoblastic Leukemia in the INO-VATE Trial: CD22 Pharmacodynamics, Efficacy, and Safety by Baseline CD22.

PURPOSE: We assessed the relationship between cluster of differentiation-22 (CD22) expression and outcomes of inotuzumab ozogamicin versus standard of care (SC) in INO-VATE (NCT01564784). PATIENTS AND METHODS: Adults with relapsed/refractory B-cell precursor CD22-positive (by local or central laboratory) acute lymphoblastic leukemia were randomized to inotuzumab ozogamicin (n = 164) or SC (n = 162). Outcomes were analyzed by baseline CD22 positivity (percentage of leukemic blasts CD22 positive, ≥90% vs. <90%) and CD22 receptor density [molecules of equivalent soluble fluorochrome (MESF), quartile analysis]. RESULTS: Most patients had high (≥90%) CD22 positivity per central laboratory. The response rate was significantly higher with inotuzumab ozogamicin versus SC. Minimal/measurable residual disease negativity, duration of remission (DoR), progression-free survival, and overall survival (OS) were significantly better with inotuzumab ozogamicin versus SC in patients with CD22 positivity ≥90%. Fewer patients had CD22 positivity <90%; for whom, response rates were higher with inotuzumab ozogamicin versus SC, but DoR and OS appeared similar. Similar trends were evident in quartile analyses of CD22 MESF and CD22 positivity per local laboratory. Among inotuzumab ozogamicin-responding patients with subsequent relapse, decrease in CD22 positivity and receptor density was evident, but not the emergence of CD22 negativity. Rates of grade ≥3 hematologic adverse events (AEs) were similar and hepatobiliary AEs rate was higher for inotuzumab ozogamicin versus SC. No apparent relationship was observed between the rates of hematologic and hepatic AEs and CD22 expression. CONCLUSIONS: Inotuzumab ozogamicin demonstrated a favorable benefit-risk profile versus SC in patients with higher and lower CD22 expression. Patients with high CD22 expression and normal cytogenetics benefited the most from inotuzumab ozogamicin therapy.

Efficacy and Safety of Inotuzumab Ozogamicin (CMC-544) for the Treatment of Relapsed/Refractory Acute Lymphoblastic Leukemia and Non-Hodgkin Lymphoma: A Systematic Review and Meta-Analysis.

INTRODUCTION: The purpose of this systematic review and meta-analysis was to evaluate the efficacy and safety of inotuzumab ozogamicin (INO) in patients with relapsed/refractory acute lymphocytic leukemia (ALL) and non-Hodgkin lymphoma (NHL). MATERIALS AND METHODS: Databases (PubMed, EMBASE, and Cochrane databases) were searched through April 4, 2020. Outcome measures of efficacy covered complete remission (CR) rates and minimal residual disease response rates. Safety was evaluated by hepatic venous obstructive disease/sinus obstructive syndrome and grade ≥ 3 hematologic adverse events. We also evaluated the quality of enrolled studies by the Newcastle-Ottawa Quality Assessment Scale. RESULTS: A total of 12 studies involving 644 patients were included. The summary estimates of the CR and minimal residual disease response rates for patients with ALL were 67% (95% confidence interval [CI], 61%-73%) and 45% (95% CI, 37%-53%) of patients with NHL. The pooled CR rate was 28% (95% CI, 15%-47%). Thrombocytopenia and neutropenia were the most common adverse events. In patients receiving INO, venous obstructive disease/sinus obstructive syndrome, grade ≥ 3 thrombocytopenic events, grade ≥ 3 neutropenic events of the pooled estimated incidence were 8% (95% CI, 5%-14%), 29% (95% CI, 20%-39%), and 48% (95% CI, 38%-57%). CONCLUSIONS: According to our study, INO was effective in the treatment of relapsed/refractory ALL and NHL with limited adverse effects. High-quality randomized controlled trials and extensive follow-up are pending to confirm and update the results of this analysis in the future.

Venetoclax and dexamethasone synergize with inotuzumab ozogamicin-induced DNA damage signaling in B-lineage ALL.

Adult patients with relapsed B-cell precursor acute lymphoblastic leukemia (BCP-ALL) have a dismal prognosis. To improve pharmacotherapy, we analyzed induction of apoptosis by venetoclax and inotuzumab ozogamicin in terms of cytotoxicity and mode of action. Flow cytometry-based analyses of mitochondrial outer membrane permeabilization (MOMP) and ataxia telangiectasia mutated activation demonstrate rapid induction of MOMP by venetoclax and DNA damage signaling by inotuzumab ozogamicin, respectively. In primary ALL samples and patient-derived xenograft (PDX) models, venetoclax and inotuzumab ozogamicin cooperated and synergized in combination with dexamethasone in vitro in all tested samples of ALL. In murine PDX models, inotuzumab ozogamicin, but not venetoclax, induced complete remission in a dose-dependent manner but constantly failed to achieve relapse-free survival. In contrast, combination therapy with venetoclax, dexamethasone, and inotuzumab ozogamicin induced long-term leukemia-free survival and treatment-free survival in all 3 ALL-PDX models tested. These data demonstrate synergistic and highly efficient pharmacotherapy in preclinical models that qualify for evaluation in clinical trials.

Sequencing of novel agents in relapsed/refractory B-cell acute lymphoblastic leukemia: Blinatumomab and inotuzumab ozogamicin may have comparable efficacy as first or second novel agent therapy in relapsed/refractory acute lymphoblastic leukemia.

BACKGROUND: The availability of novel agents (NAs), including blinatumomab and inotuzumab ozogamicin (InO), has improved the outcomes of patients with relapsed/refractory (RR) B-cell acute lymphoblastic leukemia (ALL). Because of the relative effectiveness, it is often a challenge for clinicians to determine how to best sequence these NAs with respect to efficacy and toxicity. METHODS: In this multicenter, retrospective study of patients with RR ALL treated with blinatumomab, InO, or both, their efficacy as a first or second NA was compared. RESULTS: Among 276 patients, 221 and 55 received blinatumomab and InO, respectively, as a first NA therapy. The complete remission (CR)/complete remission with incomplete count recovery (CRi) rate was 65% and 67% for the blinatumomab and InO groups, respectively (P = .73). The rate of treatment discontinuation due to adverse events was 4% and 7% in the blinatumomab and InO groups, respectively. Ninety-two patients (43%) in the blinatumomab group and 13 patients (29%) in the InO group proceeded with allogeneic hematopoietic stem cell transplantation. The median overall survival (OS) was 15 and 11.6 months in the blinatumomab and InO groups, respectively. A subset analysis was performed for 61 patients who received both NAs (blinatumomab and then InO [n = 40] or InO and then blinatumomab [n = 21]). The CR/CRi rate was 58% for patients who received InO as the second NA and 52% for patients who received blinatumomab as the second NA. The median OS was 10.5 for patients who received InO as the second NA and 5.9 months for patients who received blinatumomab as the second NA (P = .09). CONCLUSIONS: Although the limited power of this study to detect a significant difference between subgroups is acknowledged, the data suggest that blinatumomab and InO may have comparable efficacy as a first or second NA therapy in RR ALL.

Clinical utilization of blinatumomab and inotuzumab immunotherapy in children with relapsed or refractory B-acute lymphoblastic leukemia.

BACKGROUND: The treatment paradigm for patients with relapsed/refractory B-cell acute lymphoblastic leukemia (rrALL) has been revolutionized given recent clinical trials demonstrating remarkable success of immunotherapies and leading to drug approvals by United States and European agencies. We report experience with commercial blinatumomab and inotuzumab use at two North American pediatric oncology centers in children and adolescents/young adults with B-ALL. PROCEDURE: Patients 0-25 years old treated with the CD19 × CD3 bispecific T cell-engaging antibody blinatumomab and/or the CD22 antibody-drug conjugate inotuzumab from January 1, 2010, to June 1, 2018, were eligible. Disease status included relapsed B-ALL in second or greater relapse, primary chemotherapy-refractory B-ALL, or B-ALL complicated by severe infection precluding delivery of conventional chemotherapy. RESULTS: We identified 27 patients who received blinatumomab and/or inotuzumab outside of clinical trials during the study period. Four of the 13 patients (31%) with relapsed disease achieved minimal residual disease (MRD)-negative remission, and five patients (39%) underwent hematopoietic stem cell transplant (HSCT). In the 12 patients with primary chemorefractory B-ALL treated with immunotherapy, 11 (92%) achieved MRD-negative remission as assessed by flow cytometry; 10 patients (83%) underwent subsequent HSCT. Two patients with B-ALL in MRD-negative remission received blinatumomab due to severe infection and remained in remission after chemotherapy continuation. CONCLUSIONS: Blinatumomab and inotuzumab can induce deep remissions in patients with rrALL and facilitate subsequent HSCT or other cellular therapies. Blinatumomab can also serve as an effective bridging therapy during severe infection. The optimal timing, choice of immunotherapeutic agent(s), and duration of responses require further investigation via larger-scale clinical trials.

Characterization of the Relationship of Inotuzumab Ozogamicin Exposure With Efficacy and Safety End Points in Adults With Relapsed or Refractory Acute Lymphoblastic Leukemia.

Inotuzumab ozogamicin (InO), an anti-CD22 monoclonal antibody conjugated to calicheamicin, is approved in Europe and the United States for treatment of adults with relapsed or refractory acute lymphoblastic leukemia (ALL). Population analyses were performed to evaluate the relationship between InO exposure and efficacy and safety end points in patients with ALL. The probability of achieving complete remission/complete remission with incomplete hematologic recovery (CR/CRi) and minimal residual disease (MRD)-negativity for InO relative to chemotherapy was also investigated. Data from study 1010 (NCT01363297) and INO-VATE (NCT01564784) were pooled for exposure-response (InO, n = 234) and treatment-response (InO, n = 234; chemotherapy, n = 143) analyses. The analyses demonstrated that InO exposure was significantly correlated with achieving CR/CRi and MRD-negativity, as well as with hepatic event adjudication board-reported veno-occlusive disease/sinusoidal obstruction. Patients with ALL treated with InO had significantly greater odds of achieving CR/CRi (7-times higher) and MRD-negativity (13-times higher) than those receiving chemotherapy.

Multifocal Necrotizing Leukoencephalopathy With Preferential Microglia Toxicity in a Patient Treated With Chimeric Antigen Receptor T-Cells and Review of the Literature.

Neurotoxic side effects of traditional systemic chemotherapy are abundantly described. The introduction of newly developed biologic therapeutics and cellular immune effector therapies has expanded the spectrum of neurotoxicity. Multifocal necrotizing leukoencephalopathy (MNL) is a pathologic condition of unknown etiology that has been observed in patients after prolonged critical illness. We observed a case of MNL in a patient treated with extensive multimodal therapy including chimeric antigen receptor T cells. A month before death, MRI demonstrated signs of inflammation and developing edema in brainstem structures. At autopsy the abnormal MRI regions showed a wave-like loss of microglia with hemorrhagic MNL in regions closest to the brain surface. These findings reiterate the susceptibility of white matter to antineoplastic therapy and suggest new mechanisms of neurotoxicity when traditional chemotherapy is combined with biologic or cellular effector therapy.

Blinatumomab and inotuzumab for B cell precursor acute lymphoblastic leukaemia in children: a retrospective study from the Leukemia Working Group of the Spanish Society of Pediatric Hematology and Oncology (SEHOP).

Blinatumomab and inotuzumab ozogamycin represent promising alternatives to conventional chemotherapy in acute lymphoblastic leukaemia (ALL). We analysed data from 29 children with ALL treated under compassionate use with blinatumomab, inotuzumab or both. The complete remission (CR) rate in a heavily pretreated population with overt relapse was 47·6%. At earlier stages (first/second CR), both antibodies represented a useful tool to reduce minimal residual disease, and/or avoid further toxic chemotherapy until stem cell transplantation. Six patients developed grade 3 reversible non-haematological toxicity. The 12-month overall survival and event-free survival rates were 50·8 ± 26·4% and 38·9 ± 25·3% with blinatumomab, 45·8 ± 26% and 27·5 ± 25% with inotuzumab.

Cost Effectiveness of Blinatumomab Versus Inotuzumab Ozogamicin in Adult Patients with Relapsed or Refractory B-Cell Precursor Acute Lymphoblastic Leukemia in the United States.

BACKGROUND AND OBJECTIVE: The TOWER and INO-VATE-ALL trials demonstrated the efficacy and safety of blinatumomab and inotuzumab ozogamicin (inotuzumab), respectively, versus standard-of-care (SOC) chemotherapy in adults with relapsed or refractory (R/R) B-cell precursor acute lymphoblastic leukemia (ALL). The cost effectiveness of blinatumomab versus inotuzumab has not previously been examined. METHODS: Cost effectiveness of blinatumomab versus inotuzumab in R/R B-cell precursor ALL patients with one or no prior salvage therapy from a United States (US) payer perspective was estimated using a partitioned survival model. Health outcomes were estimated based on published aggregate data from INO-VATE-ALL and individual patient data from TOWER weighted to match patients in INO-VATE-ALL using matching adjusted indirect comparison (MAIC). Analyses were conducted using five approaches relating to use of anchored versus unanchored comparisons of health outcomes and, for the anchored comparisons, the reference treatment to which treatment effects on health outcomes were applied. Estimates from TOWER including the probabilities of complete remission and allogeneic stem-cell transplant (allo-SCT), overall and event-free survival, utilities, duration of therapy, and use of subsequent therapies were MAIC adjusted to match INO-VATE-ALL. Costs of treatment, adverse events, allo-SCT, subsequent therapies, and terminal care were from published sources. A 50-year time horizon and 3% annual discount rate were used. RESULTS: Incremental costs for blinatumomab versus inotuzumab ranged from US$7023 to US$36,244, depending on the approach used for estimating relative effectiveness. Incremental quality-adjusted life-years (QALYs) ranged from 0.54 to 1.78. Cost effectiveness for blinatumomab versus inotuzumab ranged from US$4006 to US$20,737 per QALY gained. CONCLUSIONS: Blinatumomab is estimated to be cost effective versus inotuzumab in R/R B-cell precursor ALL adults who have received one or no prior salvage therapy from a US payer perspective.

Outcomes of Allogeneic Stem Cell Transplantation after Inotuzumab Ozogamicin Treatment for Relapsed or Refractory Acute Lymphoblastic Leukemia.

Attaining complete remission of acute lymphoblastic leukemia (ALL) before hematopoietic stem cell transplantation (HSCT) correlates with better post-transplant outcomes. Inotuzumab ozogamicin (InO), an anti-CD22 antibody conjugated to calicheamicin, has shown significantly higher rates of remission, minimal residual disease negativity, and HSCT versus standard chemotherapy in treating relapsed/refractory (R/R) ALL. We investigated the role of previous transplant and proceeding directly to HSCT after remission as factors in determining post-transplant survival in the setting of InO treatment for R/R ALL. The analyzed population comprised InO-treated patients who proceeded to allogeneic HSCT in 2 clinical trials (phase 1/2: NCT01363297 and phase 3: NCT01564784). Overall survival (OS) was defined as time from HSCT to death (any cause). Of 236 InO-treated patients, 101 (43%) proceeded to allogeneic HSCT and were included in this analysis. Most received InO as first salvage (62%); 85% had no previous HSCT. Median (95% confidence interval [CI]) post-transplant OS was 9.2 months (5.1, not evaluable) with 2-year survival probability (95% CI) of 41% (32% to 51%). In first-HSCT patients (n = 86), median (95% CI) post-transplant OS was 11.8 months (5.9, not evaluable) with 2-year survival probability (95% CI) of 46% (35% to 56%); some patients relapsed and needed additional treatment before HSCT (n = 28). Those who went directly to first HSCT upon remission with no additional salvage/induction treatment (n = 73) fared best: median post-transplant OS was not reached with a 2-year survival probability (95% CI) of 51% (39% to 62%). In patients with R/R ALL, InO followed by allogeneic HSCT provided an optimal long-term survival benefit among those with no previous HSCT who went directly to transplant after remission.

The Clinical and Cost Effectiveness of Inotuzumab Ozogamicin for the Treatment of Adult Relapsed or Refractory B-Cell Acute Lymphoblastic Leukaemia: An Evidence Review Group Evaluation of a NICE Single Technology Appraisal.

The National Institute for Health and Care Excellence (NICE) invited Pfizer, the manufacturer of inotuzumab ozogamicin (henceforth inotuzumab), to submit clinical- and cost-effectiveness evidence for inotuzumab as part of NICE's single technology appraisal process. The Centre for Reviews and Dissemination and the Centre for Health Economics, both at the University of York, were commissioned as the independent evidence review group (ERG). The clinical-effectiveness data were from a multicentre randomised controlled trial that compared inotuzumab with standard of care (SoC), where SoC was the investigator's choice of chemotherapy. Inotuzumab demonstrated statistically significant improvements in response rates or in the proportion of patients progressing to haematopoietic stem cell transplant (HSCT) but failed to meet the second primary objective of longer overall survival. Treatment-emergent adverse events were more frequent in the SoC arm, except veno-occlusive disease, which was more frequent in the inotuzumab arm. The company's economic model split patients into three post-hoc subgroups and used a partitioned survival approach within each group, with a cure assumption 3 years after receiving HSCT. In contrast with the trial results, the economic model estimated substantial improvement in survival with inotuzumab compared with SoC, providing an additional 5.2 life-years and 2.2 quality-adjusted life-years (QALYs) using a discount rate of 1.5% per annum. The ERG's critique highlighted a number of concerns, including the use of a post-hoc post-randomisation patient subset for extrapolation, the choice of a 1.5% discount rate, the complexity of the parametric modelling, the assumption of further treatment benefit post-HSCT, the nature of the cure assumption, and the length of inpatient stay while receiving treatment. The combination of the ERG's adjustments resulted in an incremental cost-effectiveness ratio (ICER) of £122,174 per QALY gained using Kaplan-Meier survival estimates and £114,078 per QALY gained with parametric survival models fit to the trial data. The final determination of the appraisal followed four NICE Appraisal Committee meetings, an appeal by the company and other stakeholders, two patient access schemes, and a company response to each appraisal consultation. The final ICER post-consultation was between £33,749 and £37,497 per QALY gained compared with SoC (excluding the confidential discount for blinatumomab received as subsequent therapy). The Appraisal Committee concluded that the ICER for inotuzumab was within the range usually considered cost effective for end-of-life care and recommended inotuzumab within its licensed indication.

Treatment of Recurrent Refractory Pediatric Pre-B Acute Lymphoblastic Leukemia Using Inotuzumab Ozogamicin Monotherapy Resulting in CD22 Antigen Expression Loss as a Mechanism of Therapy Resistance.

BACKGROUND: Inotuzumab ozogamicin is a novel antibody-drug conjugate that targets CD22, a common antigen on pre-B acute lymphoblastic leukemia cells. OBSERVATIONS: A 7-year-old boy with pre-B acute lymphoblastic leukemia in his second relapse was given 2 cycles of inotuzumab ozogamicin. He responded morphologically with a negative bone marrow evaluation. However, he relapsed in cycle 3 of therapy with a loss of CD22 expression on his lymphoblast population. CONCLUSION: To our knowledge, this is the first published case of CD22 expression loss as a mechanism of therapy resistance for inotuzumab ozogamicin.