Phase 2 study of inotuzumab ozogamicin for measurable residual disease in acute lymphoblastic leukemia in remission.

ABSTRACT: The detection of measurable residual disease (MRD) is the strongest predictor of relapse in acute lymphoblastic leukemia (ALL). Using inotuzumab ozogamicin in the setting of MRD may improve outcomes. Patients with ALL in first complete remission (CR1) or beyond (CR2+) with MRD ≥ 1 × 10-4 were enrolled in this phase 2 trial. Inotuzumab was administered at 0.6 mg/m2 on day 1 and 0.3 mg/m2 on day 8 of cycle 1, then at 0.3 mg/m2 on days 1 and 8 of cycles 2-6. Twenty-six consecutive patients with a median age of 46 years (range, 19-70 years) were treated. Nineteen (73%) were in CR1 and seven (27%) in CR2+; 16 (62%) had Philadelphia chromosome-positive ALL. Fifteen (58%) had baseline MRD ≥ 1 × 10-3. A median of 3 cycles (range, 1-6) were administered. Eighteen (69%) patients responded and achieved MRD negativity. After a median follow-up of 24 months (range, 9-43), the 2-year relapse-free survival rate was 54% and the 2-year overall survival rate was 60% in the entire cohort. Most adverse events were low grade; sinusoidal obstruction syndrome was noted in 2 patients (8%). In summary, inotuzumab ozogamicin resulted in favorable survival, MRD negativity rates, and safety profiles for patients with ALL and MRD-positive status. This study was registered at www.ClinicalTrials.gov as #NCT03441061.

Results of the compassionate program of inotuzumab ozogamicin for adult patients with relapsed or refractory acute lymphoblastic leukemia in Spain.

INTRODUCTION: The prognosis of relapsed B cell precursor acute lymphoblastic leukemia (B-ALL) is poor and few patients can be successfully rescued with conventional therapies. Inotuzumab ozogamicin (IO), an antibody against the CD22 antigen linked to calicheamicin, has been approved as a rescue treatment in relapsed/refractory (R/R) B-ALL. PATIENTS AND METHODS: This was an observational, retrospective, multicenter study of adult patients included in the Spanish program of compassionate use of IO in centers from the PETHEMA group (Programa Español de Tratamientos en Hematología). RESULTS: Thirty-four patients with a median age of 43 years (range, 19-73) were included. Twenty patients (59%) were refractory to the last treatment, IO treatment was given as ≥3rd salvage treatment in 25 patients (73%) and 20 patients (59%) received allogeneic hematopoietic stem cell transplantation before IO treatment. After a median of 2 cycles of IO, 64% of patients achieved complete response (CR)/complete response with incomplete recovery. The median response duration, progression-free survival and overall survival (OS) were 4.7 (95%CI, 2.4-7.0 months), 3.5 (95%CI, 1.0-5.0 months) and 4 months (95%CI, 1.9-6.1 months) respectively, with better OS for patients with relapsed B-ALL versus refractory disease (10.4 vs. 2.5 months, respectively) (p = .01). There was a trend for better OS for patients with first CR duration >12 months (7.2 months [95%CI, 3.2-11.2] vs. 3 months [95% CI, 1.8-4.2] respectively) (p = .054). There was no sinusoidal obstruction syndrome (SOS) event during IO treatment, but three patients (9%) developed grade 3-4 SOS during alloHSCT after IO treatment. CONCLUSIONS: Our study showed slightly inferior outcomes of the pivotal trial probably due to poorer risk factors and late onset of IO therapy of recruited patients. Our results support early use of IO in relapsed/refractory ALL patients.

Post-Transplantation Sinusoidal Obstruction Syndrome in Adult Patients with B Cell Acute Lymphoblastic Leukemia Treated with Pretransplantation Inotuzumab.

Sinusoidal obstruction syndrome (SOS) is a potentially life-threatening complication that can be observed after allogeneic hematopoietic cell transplantation (HCT). Inotuzumab ozogamicin is an anti-CD22 monoclonal antibody-drug conjugate that has demonstrated high efficacy in relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) but is associated with an increased risk of SOS in HCT recipients. Here we aimed to examine the incidence and outcomes of SOS in 47 adult patients with R/R ALL who received inotuzumab therapy and subsequently underwent HCT at our institution. All patients received prophylactic therapy with ursodiol, and continuous low-dose heparin also was administered to patients receiving myeloablative conditioning (MAC). SOS occurred in 12 patients (26%) post-HCT, at a median onset of 11 days (range, 3 to 41 days). SOS was graded as very severe in 50% (n = 6), severe in 25% (n = 3), and mild in 25% (n = 3). All patients diagnosed with SOS received treatment with defibrotide for a median of 21 days (range, 3 to 34 days), with resolution of SOS occurring in 8 patients (67%). Mortality from SOS was 33% (n = 4) and occurred at a median of 10 days from diagnosis (range, 3 to 31 days) in patients graded as very severe (n = 3) or severe (n = 1). There were no significant differences between patients who developed SOS and those who did not develop SOS in the median time from the last dose of inotuzumab to transplantation (46 days versus 53 days; P = .37), use of an MAC regimen (42% versus 49%; P = .75), number of lines of therapy prior to inotuzumab (P = .79), median number of administered cycles of inotuzumab (2 versus 2; P = .14), or receipt of inotuzumab as the last therapy prior to HCT (67% versus 66%; P = 1.0). Sirolimus-based graft-versus-host disease (GVHD) prophylaxis was used more frequently in the SOS group (75% versus 29%; P < .01), but there was no between-group difference in the peak sirolimus level (P = .81) or the median time to peak sirolimus level (7 days versus 3.5 days; P = .39). In univariable analysis, only the use of sirolimus-based GVHD prophylaxis was significantly associated with an increased risk of SOS (hazard ratio [HR], 7.50; 95% confidence interval [CI], 1.7 to 33.6; P < .01). In the SOS group, the 100-day mortality rate was 33% (n = 4), and median overall survival (OS) post-HCT was 4.3 months (range, 0.2 to 57.2 months). In the group without SOS, the 100-day mortality rate was 14% (n = 5) and the median OS post-HCT was 10.7 months (range, .52 to 39.6 months). In this study cohort, SOS was prevalent in HCT recipients who had been treated with inotuzumab prior to transplantation, and sirolimus-based GVHD prophylaxis was a risk factor for SOS in inotuzumab recipients.

Evaluation of the efficacy of ursodiol for prevention of hepatotoxicity in patients receiving gemtuzumab ozogamicin and inotuzumab ozogamicin.

Gemtuzumab ozogamicin (GO) and inotuzumab ozogamicin (InO) are indicated for newly diagnosed or relapsed/refractory CD33-positive acute myeloid leukemia and relapsed/refractory B-cell precursor acute lymphoblastic leukemia respectively. Patients undergoing therapy with these agents are at increased risk for hepatotoxicity. Forty-nine patients received either GO or InO with concomitant ursodiol (n=14) or no ursodiol (n=35) for hepatotoxicity prophylaxis. Hepatotoxicity occurred in 2 (14%) patients in the ursodiol group compared to 15 (43%) patients in the no ursodiol group (p=0.10). Median days (17 versus 11; p=0.66) and doses (4 versus 2; p=0.28) to development of hepatotoxicity were higher in the ursodiol versus no ursodiol group. After adjusting for concomitant hepatotoxic medications and prior chemotherapy, ursodiol did not significantly reduce the incidence of hepatotoxicity. Ursodiol prophylaxis was associated with a similar incidence of hepatotoxicity compared to no ursodiol, but may delay the time to occurrence.

[Allogeneic hematopoietic stem cell transplantations for relapsed and refractory acute lymphoblastic leukemia following inotuzumab ozogamicin treatment].

Inotuzumab ozogamicin (InO) was administered in three cases of relapsed/refractory adult acute lymphoblastic leukemia (ALL) before allogeneic hematopoietic stem cell transplantation (allo-SCT). One case developed extremely severe sinusoidal obstruction syndrome (SOS) but recovered after receiving defibrotide therapy. A gap of 63 days in the SOS case was noted from the last administration of InO to allo-SCT, the duration was 133 and 86 days for the other two cases, and the remaining risk factors for SOS were comparable in the three cases. In contrast to gemtuzumab ozogamicin (GO), the interval between InO exposure and allo-SCT has not been reported as a risk for SOS. Nevertheless, this case suggests that the intervals should be as long as possible.

Acute lymphoblastic leukemia in older adults: curtain call for conventional chemotherapy?

Unlike younger adults with acute lymphoblastic leukemia (ALL), older adults are rarely cured due to a combination of intrinsic disease resistance and treatment-related toxicities. Novel therapeutics such as inotuzumab ozogamicin, blinatumomab, venetoclax, and ABL kinase inhibitors have high activity in ALL and are well tolerated by older adults. Frontline treatment regimens for older adults using novel therapeutics with reduction or omission of conventional chemotherapy are being developed with early results demonstrating high remission rates and lower toxicity, but long-term efficacy and toxicity data are lacking. Collaboration between academic and pharmaceutical stakeholders is needed to develop clinical trials to define the optimal treatment regimens for older adults with ALL.

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.

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.

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.

A phase 1 study of inotuzumab ozogamicin in pediatric relapsed/refractory acute lymphoblastic leukemia (ITCC-059 study).

This phase 1 study investigated the recommended phase 2 dose (RP2D) of inotuzumab ozogamicin (InO), a CD22-directed antibody-drug conjugate, in pediatric patients with multiple relapsed/refractory (R/R) CD22+ acute lymphoblastic leukemia (ALL). Patients (age ≥1 year or <18 years) received 3 doses of InO (days 1, 8, and 15) per course. Dose escalation was based on dose-limiting toxicities (DLTs) during course 1. Dose level 1 (DL1) was 1.4 mg/m2 (0.6, 0.4, 0.4 mg/m2) and DL2 was 1.8 mg/m2 (0.8, 0.5, 0.5 mg/m2). Secondary end points included safety, antileukemic activity, and pharmacokinetics. Twenty-five patients (23 evaluable for DLTs) were enrolled. In course 1, the first cohort had 1 of 6 (DL1) and 2 of 5 (DL2) patients who experienced DLTs; subsequent review considered DL2 DLTs to be non-dose-limiting. Dose was de-escalated to DL1 while awaiting protocol amendment to re-evaluate DL2 in a second cohort, in which 0 of 6 (DL1) and 1 of 6 (DL2) patients had a DLT. Twenty-three patients experienced grade 3 to 4 adverse events; hepatic sinusoidal obstruction syndrome was reported in 2 patients after subsequent chemotherapy. Overall response rate after course 1 was 80% (95% confidence interval [CI], 59% to 93%) (20 of 25 patients; DL1: 75% [95% CI, 43% to 95%], DL2: 85% [95% CI, 55% to 98%]). Of the responders, 84% (95% CI, 60% to 97%) achieved minimal residual disease (MRD)-negative complete response, and 12-month overall survival was 40% (95% CI, 25% to 66%). Nine patients received hematopoietic stem cell transplantation or chimeric antigen receptor T cells after InO. InO median maximum concentrations were comparable to simulated adult concentrations. InO was well tolerated, demonstrating antileukemic activity in heavily pretreated children with CD22+ R/R ALL. RP2D was established as 1.8 mg/m2 per course, as in adults. This trial was registered at https://www.clinicaltrialsregister.eu as EUDRA-CT 2016-000227-71.

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.

Inotuzumab ozogamicin for relapsed/refractory acute lymphoblastic leukemia: outcomes by disease burden.

Adults with relapsed/refractory acute lymphoblastic leukemia (R/R ALL) have a poor prognosis, especially if disease burden is high. This post hoc analysis of the phase 3 INO-VATE trial examined the efficacy and safety of inotuzumab ozogamicin (InO) vs. standard of care chemotherapy (SC) among R/R ALL patients with low, moderate, or high disease burden, respectively, defined as bone marrow blasts (BMB) < 50% (n = 53 vs. 48), 50-90% (n = 79 vs. 83), and >90% (n = 30 vs. 30). Patients in the InO vs. SC arm with low, moderate, and high BMB%, respectively, had improved rates of complete remission/complete remission with incomplete hematologic recovery (74% vs. 46% [p = 0.0022], 75 vs. 27% [p < 0.0001], and 70 vs. 17% [p < 0.0001]), and improved overall survival (hazard ratio: 0.64 [p = 0.0260], 0.81 [p = 0.1109], and 0.60 [p = 0.0335]). Irrespective of BMB%, cytopenias were the most common treatment-emergent adverse events, and post-transplant veno-occlusive disease was more common with InO vs. SC. Patients with extramedullary disease or lymphoblastic lymphoma showed similar efficacy and safety outcomes. This favorable benefit-to-risk ratio of InO treatment irrespective of disease burden supports its use in challenging and high disease burden subpopulations. INO-VATE is registered at www.clinicaltrials.gov : #NCT01564784.

Cost-utility analysis of inotuzumab ozogamicin for relapsed or refractory B cell acute lymphoblastic leukemia from the perspective of Taiwan's health care system.

OBJECTIVES: We conduct a cost-utility analysis of inotuzumab ozogamicin (INO) versus chemotherapy as the standard of care (SOC) for adults with relapsed or refractory B cell acute lymphoblastic leukemia. METHODS: A Markov model incorporating transition probabilities between health states was applied to simulate disease progression. The model inputs, including overall survival, progression-free survival, and utility parameters, were obtained from the INO-VATE ALL trial and literatures. The Taiwan Cancer Registry Database and the Health and Welfare Database were utilized to identify the patient cohort and medical costs from the perspective of National Health Insurance Administration. The lifetime medical costs (in 2017 US dollars), quality-adjusted life years (QALYs) gained, and associated incremental cost-effectiveness ratio (ICER) were the main study outcomes. RESULTS: The lifetime medical costs for INO and SOC were $176,795 and $69,496, and the QALYs gained were 2.25 and 0.84, respectively. The ICER for INO versus SOC was $76,044 per QALY gained, which is slightly more than three times Taiwan's gross domestic product per capita (i.e., $73,224). Favorable economic results for INO versus SOC were found with an increased time horizon for model simulation, less discounting for the future benefit, and higher stem cell transplantation (SCT) rate after INO treatment; and among patients aged less than 55 years, with no SCT history, or in the first salvage treatment. CONCLUSIONS: INO versus SOC has higher costs but is more effective. The use of INO is favorable for patients in the early treatment course and when more future benefit associated with INO is considered.

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.

Inotuzumab ozogamicin versus standard of care in Asian patients with relapsed/refractory acute lymphoblastic leukemia.

Inotuzumab ozogamicin (InO) is a targeted treatment for adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). InO was previously studied in INO-VATE, an international, open-label, randomized phase 3 trial comparing InO against standard of care (SoC). In the present subgroup analysis, we evaluated outcomes in the 55 Asian patients who were randomized in INO-VATE (31 InO and 24 SoC). Complete remission (CR) or CR with incomplete hematologic recovery (CRi) was achieved in 22/31 patients treated with InO versus 5/24 treated with SoC. In the InO arm, more of the patients achieving CR/CRi were minimal residual disease (MRD)-negative (17/22 versus 1/5), and more patients proceeded directly to hematopoietic stem cell transplantation (15/31 versus 3/24). Median overall survival for the respective arms was 5.8 versus 3.9 months (hazard ratio 0.67; 97.5% CI 0.28, 1.62). In the safety analysis (n = 51), the most common adverse events were hematologic. Sinusoidal obstruction syndrome was reported in five InO patients and one SoC patient. In conclusion, Asian patients with relapsed or refractory B-cell ALL experienced improved efficacy with InO versus SoC, with an efficacy and safety profile consistent with results of the overall INO-VATE population.Clinical trial registration: ClinicalTrials.gov identifier: NCT01564784.

Inotuzumab ozogamicin versus standard of care in relapsed or refractory acute lymphoblastic leukemia: Final report and long-term survival follow-up from the randomized, phase 3 INO-VATE study.

BACKGROUND: Inotuzumab ozogamicin (InO) is an antibody-drug conjugate used for adults with relapsed/refractory B-cell precursor (BCP) acute lymphoblastic leukemia (ALL). The INotuzumab Ozogamicin trial to inVestigAte Tolerability and Efficacy (INO-VATE) previously reported improved outcomes with InO versus standard-of-care (SoC) chemotherapy. This article reports the final INO-VATE results (≥2 years of follow-up) and additional analyses of patient characteristics associated with improved outcomes. METHODS: Between August 27, 2012, and January 4, 2015, this multicenter, parallel, open-label, phase 3 trial randomized 326 adults with relapsed/refractory ALL to InO (n = 164) or SoC (n = 162); 307 received 1 or more doses of the study drug (164 in the InO arm and 143 in the SoC arm). RESULTS: The complete remission (CR)/complete remission with incomplete hematologic recovery (CRi) rate was higher with InO versus SoC (73.8% vs 30.9%; 1-sided P < .0001), with consistent CR/CRi rates across patient subgroups. The median overall survival (OS) was 7.7 months with InO and 6.2 months with SoC, with 2-year OS rates of 22.8% and 10.0%, respectively (overall hazard ratio, 0.75; 97.5% confidence interval [CI], 0.57-0.99; 1-sided P = .0105). The predictors of OS with InO were the best minimal residual disease status, baseline platelet count, duration of first remission, achievement of CR/CRi, and follow-up hematopoietic stem cell transplantation (HSCT; all 2-sided P values < .05). More InO arm patients proceeded directly to HSCT after achieving CR/CRi before any follow-up induction therapy (39.6% [95% CI, 32.1%-47.6%] vs 10.5% [6.2%-16.3%]; 1-sided P < .0001). The most frequent all-grade and grade 3 or higher adverse events in both arms were hematologic. Veno-occlusive disease (VOD)/sinusoidal obstruction syndrome (SOS) was more frequent with InO (23 of 164 [14.0%] vs 3 of 143 [2.1%]). CONCLUSIONS: In patients with relapsed/refractory BCP ALL in INO-VATE, InO was associated with a greater likelihood of CR/CRi across key patient subgroups, and it served as a bridge to HSCT. Potential VOD/SOS risk factors must be considered when InO treatment decisions are being made.

Matching-Adjusted Indirect Comparison of Blinatumomab vs. Inotuzumab Ozogamicin for Adults with Relapsed/Refractory Acute Lymphoblastic Leukemia.

INTRODUCTION: In the absence of head-to-head trials, this analysis aimed to provide a fair indirect comparison of the efficacy between blinatumomab and inotuzumab ozogamicin (InO), two treatments for adult patients with relapsed or refractory acute lymphoblastic leukemia (R/R ALL) who received no more than one prior salvage therapy, by adjusting for cross-trial differences. METHODS: Patient-level data from the Phase 3 blinatumomab trial TOWER and published aggregated data from the Phase 3 InO trial INO-VATE-ALL were used to conduct matching-adjusted indirect comparisons. Patients with 2+ prior salvage therapies from TOWER were excluded because such patients were not included in INO-VATE-ALL. To ensure balance in the remaining patients, baseline characteristics for the TOWER patients were weighted to match the average baseline characteristics in INO-VATE-ALL, including sex, age, race, performance status, bone marrow blast, previous salvage therapy, previous allogeneic transplantation, complete remission with complete hematologic recovery (CR) to most recent induction therapy, and duration of first remission. Overall survival (OS), including median and restricted mean survival time (RMST) at 12 and 20.7 months, and CR were estimated and compared. RESULTS: A total of 310 patients in TOWER were included (blinatumomab, n = 203; standard of care chemotherapy, n = 107). After matching the listed baseline characteristics, the median OS was 9.3 months for blinatumomab and 7.7 months for InO (weighted log-rank test p = 0.4). The relative RMST at 12 months was 1.6 months longer for blinatumomab than for InO [95% CI (0.1, 3.2); p = 0.04]; at 20.7 months the RMST was not significantly different. The CR rates were similar [anchor-based difference = - 2.8%, 95% CI (- 17.5%, 11.9%); p = 0.71]. CONCLUSIONS: After adjusting for cross-trial differences, blinatumomab demonstrated a similar CR rate and potential OS benefit versus InO among adult patients with R/R ALL who received no more than one prior salvage therapy. Further studies are suggested to confirm this finding. FUNDING: Amgen.