Indirect Treatment Comparison of Inotuzumab Ozogamicin Versus Blinatumomab for Relapsed or Refractory Acute Lymphoblastic Leukemia

Real-world use of inotuzumab ozogamicin is associated with lower health care costs than blinatumomab in patients with acute lymphoblastic leukemia in the first relapsed/refractory setting

Aim: To compare all-cause and acute lymphoblastic leukemia (ALL)-related healthcare resource utilization (HCRU) and costs among patients receiving inotuzumab ozogamicin (InO) and blinatumomab (Blina) for ALL in the first relapsed/refractory (R/R) setting. Patients & methods: We studied retrospective claims for adult commercial and Medicare Advantage enrollees with ALL receiving InO (n = 29) or Blina (n = 23) from 1 January 2015 to 16 February 2021. Mean per-patient-per-month (PPPM) HCRU and total costs were described and multivariable-adjusted PPPM total all-cause and ALL-related predicted costs were calculated. Results: Mean monthly ALL-related hospitalizations were the same for patients receiving InO and Blina (PPPM = 0.8 stays); however, the length of ALL-related hospital stay was almost twice as long among patients receiving Blina versus InO (ALL-related: InO = 7.6 days; Blina = 14.1 days; p = 0.346). In multivariable models, total ALL-related costs were 43% lower for InO compared with Blina (PPPM costs: InO = $93,767; Blina = $163,470; p = 0.021). Conclusion: In the first R/R setting, patients who used InO had significantly lower all-cause and ALL-related costs compared with patients who used Blina, in part driven by hospitalization patterns.

Matching-Adjusted Indirect Comparisons of Brexucabtagene Autoleucel with Alternative Standard Therapies for Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia in Adult Patients

INTRODUCTION

Brexucabtagene autoleucel (brexu-cel), a CD19-directed chimeric antigen receptor T-cell therapy, is approved for relapsed/refractory B-cell precursor acute lymphoblastic leukemia in adults aged 18+/26+ years in the US/European Union (EU), based on efficacy results from the single-arm ZUMA-3 trial. This study aimed to estimate the relative treatment effects of brexu-cel versus inotuzumab ozogamicin (InO), blinatumomab (blina), and chemotherapies using unanchored matching-adjusted indirect comparison (MAIC) methods.

METHODS

Individual patient data from ZUMA-3 and published aggregate level data from two randomized controlled trials, INO-VATE (InO versus chemotherapy) and TOWER (blina versus chemotherapy), were used. Patient-level data from ZUMA-3 were weighted to match the mean of the following prognostic variables at baseline, which were pre-specified based on clinical input, for each comparator population: primary refractory disease, duration of first remission < 12 months, prior stem-cell transplantation, age, performance status, salvage status, bone marrow blast, complex karyotype, and Philadelphia chromosome status. The base case analysis was conducted using the modified intention-to-treat population (i.e., received brexu-cel) from ZUMA-3. Relative treatment effects for overall survival (OS) and event-free survival (EFS) were expressed as hazard ratios (HR) and differences in restricted mean survival time (RMST) with 95% confidence intervals (CI).

RESULTS

The base case MAIC results suggested brexu-cel improved OS and EFS compared to blina (OS HR 0.46 [95% CI 0.28, 0.75]; EFS HR 0.37 [95% CI 0.25, 0.56]) and pooled INO-VATE/TOWER chemotherapy (OS HR 0.32 [95% CI 0.18, 0.56]; EFS HR 0.27 [0.18, 0.40]). Brexu-cel also improved OS compared to InO (HR 0.45 [95% CI 0.24, 0.85]). The point estimate for EFS favored brexu-cel over Ino but the difference was not statistically significant (HR 0.67 [95% CI 0.41, 1.10]). Findings were consistent between the HR and RMST analyses.

CONCLUSION

Despite limitations, these MAIC results suggest that brexu-cel may improve OS and EFS versus currently used therapies in this population.

A Comparison of Relative-Efficacy Estimate(S) Derived From Both Matching-Adjusted Indirect Comparisons and Standard Anchored Indirect Treatment Comparisons: A Review of Matching-Adjusted Indirect Comparisons

OBJECTIVES

We present an empirical comparison of relative-efficacy estimate(s) from matching-adjusted indirect comparisons (MAICs) with estimates from corresponding standard anchored indirect treatment comparisons.

METHODS

A total of 80 comparisons were identified from 17 publications through a systematic rapid review. A standardized metric that used reported relative treatment efficacy estimates and their associated uncertainty was used to compare the methods across different treatment indications and outcome measures.

RESULTS

On aggregate, MAICs presented for connected networks tended to report a more favorable relative-efficacy estimate for the treatment for which individual-level patient data were available relative to the reported indirect treatment comparison estimate.

CONCLUSIONS

Although we recognize the importance of MAIC and other population adjustment methods in certain situations, we recommend that results from these analyses are interpreted with caution. Researchers and analysts should carefully consider if MAICs are appropriate where presented and whether MAICs would have added value where omitted.

Matching-adjusted indirect comparison of the pelabresib-ruxolitinib combination vs JAKi monotherapy in myelofibrosis

Janus kinase inhibitors (JAKis) ruxolitinib, fedratinib, and pacritinib are the current standard of care in symptomatic myelofibrosis (MF). However, progressive disease and toxicities frequently lead to JAKi discontinuation. Preclinical data indicate that combining JAK and bromodomain and extraterminal (BET) domain inhibition leads to overlapping effects in MF. Pelabresib (CPI-0610), an oral, small-molecule BET1,2 inhibitor (BETi), in combination with ruxolitinib showed improvements in spleen volume reduction (SVR35) and total symptom score reduction (TSS50) from baseline in the phase 2 MANIFEST study (NCT02158858) in patients with MF. Given the absence of a head-to-head clinical comparison between JAKi monotherapy and JAKi with BETi combination therapy, we performed an unanchored matching-adjusted indirect comparison analysis to adjust for differences between studies and allow for the comparison of SVR35, TSS50, and TSS measured at several timepoints in arm 3 of MANIFEST (pelabresib with ruxolitinib in JAKi treatment-naive patients with MF), with data from the following JAKi monotherapy studies in JAKi treatment-naive patients: COMFORT-I and COMFORT-II (ruxolitinib), SIMPLIFY-1 (ruxolitinib and momelotinib), and JAKARTA (fedratinib). Response rate ratios >1 were observed for pelabresib with ruxolitinib vs all comparators for SVR35 and TSS50 at week 24. Improvements in TSS were observed as early as week 12 and were durable. These results indicate that pelabresib with ruxolitinib may have a potentially higher efficacy than JAKi monotherapy in JAKi treatment-naive MF.

A phase I study of inotuzumab ozogamicin as a single agent in pediatric patients in Japan with relapsed/refractory CD22-positive acute lymphoblastic leukemia (INO-Ped-ALL-1)

Inotuzumab ozogamicin (InO) is a CD22-directed antibody conjugated with calicheamicin approved for adult relapsed or refractory CD22-positive acute lymphoblastic leukemia (ALL). This phase 1 study primarily aimed to determine the pediatric recommended doses of InO through the standard 3 + 3 design, and to evaluate the safety, tolerability, pharmacokinetic (PK) profile, immunogenicity and efficacy of InO. Dose level 1 (DL1) was 1.8 mg/m² (days 1, 8, and 15: 0.8, 0.5, and 0.5 mg/m², respectively). Six of the seven registered patients were eligible [median age, 7.5 (2-17) years]. Although all six patients started DL1, only five completed the dose. No dose-limiting toxicity was observed. All patients experienced adverse events (AEs), including increased alanine aminotransferase and aspartate aminotransferase in four patients. Three patients experienced serious AEs, which were hepatic veno-occlusive disease (VOD), ALL, and fever. Five patients achieved complete remission (CR) or CR with incomplete blood cell recovery (CRi), among whom 3 (60%) were negative for minimal residual disease. PK findings were similar to those in adults. No patient had anti-drug antibodies to InO. In conclusion, InO was well tolerated in children and promoted similar antileukemic efficacy as in adults. Nonetheless, the risk for VOD requires attention.

Successful Salvage of Very Early Relapse in Pediatric Acute Lymphoblastic Leukemia With Inotuzumab Ozogamicin and HLA-haploidentical Peripheral Blood Stem Cell Transplantation With Posttransplant Cyclophosphamide

Herein, we describe a 14-year-old female patient with B-cell precursor acute lymphoblastic leukemia who relapsed in early consolidation. Minimal residual disease-negative complete remission was obtained after 1 cycle of inotuzumab ozogamicin therapy. She underwent HLA-haploidentical peripheral blood stem cell transplantation after a myeloablative conditioning regimen. Posttransplant cyclophosphamide, tacrolimus, and mycophenolate mofetil were administered for the prophylaxis of graft-versus-host disease. At 23 months, she was in complete remission. Although the administration of inotuzumab ozogamicin followed by haploidentical peripheral blood stem cell transplantation with posttransplant cyclophosphamide has been limited in children, this strategy may be an effective treatment for pediatric refractory acute lymphoblastic leukemia.

Cytogenetic guided therapy using blinatumomab and inotuzumab ozogamicin in a patient with relapse/refractory acute lymphoblastic leukemia

INTRODUCTION

Acute Lymphoblastic Leukemia (ALL) is an aggressive cancer that requires intense chemotherapy and has a high rate of recurrence. Treatments of Relapse/Refractory (R/R) B-cell ALL are limited. Blinatumomab, a bispecific T-cell engager (CD19/CD3) monocolonal antibody, and Inotuzumab Ozogamicin, an anti-CD22 antibody conjugate, are current recommended options.

CASE REPORT

To describe a R/R B-cell ALL patient who failed blinatumomab therapy. Subsequently she received inotuzumab ozogamicin achieving a complete response.

MANAGEMENT & OUTCOME

Our patient was initially treated with CALGB 10403 regimen but did not achieve a complete response. Blinatumomab was given for relapse/refractory disease however she had an incomplete response despite having 100% expression in CD19 markers. Consequently, she received inotuzumab ozogamicin attributable to 70% expression of CD22. She responded with a complete response and transitioned to a successful hematopoietic stem cell transplant.

DISCUSSION

There is limited clinical guidance on the preferred treatment of adult R/R B-Cell ALL. Currently, there are no randomized head-to-head trials comparing efficacy of blinatumomab and inotuzumab ozogamicin. Clinical patterns of blinatumomab resistance has been reported. Our case study remains unclear of why our patient had unsuccessful outcomes with blinatumomab regardless of having CD19 positivity of 100%. Future prospective analysis and comparative studies are needed to determine proper sequencing of these therapies.

Efficacy of Targeted Immunotherapy as Induction or Salvage Therapy in Acute Lymphoblastic Leukemia: A Systematic Review and Meta-Analysis

Background:

Monoclonal antibodies targeting cluster of differentiation (CD) proteins have been incorporated into standard treatments for multiple types of hematologic malignancies, including acute lymphoblastic leukemia (ALL). This systematic review and meta-analysis investigated the efficacy of using CD-targeted antibodies for ALL.

Materials and Methods:

The EMBASE and MEDLINE databases were searched for research papers using immunotherapy- and ALL-related terms from inception to July 2021. Eligible studies were randomized, controlled trials (RCTs) or cohort studies in which ALL patients received CD-targeted immunotherapy or conventional chemotherapy as the induction or salvage therapy. The reports had to report our primary outcomes of interest: overall survival (OS), relapse-free survival (RFS), or complete remission (CR), with the patient number for each outcome. The effect estimates with 95% confidence interval (CI) from each study were combined to calculate the pooled-effect estimate, using the Hantel-Maenszel method.

Results:

Five RCTs and 9 retrospective cohort studies were eligible for the meta-analysis. ALL patients given CD-targeted immunotherapy in the induction or salvage therapy had significantly higher OS and RFS rates than those administered conventional chemotherapy only, with pooled odds ratios (OR) of 2.11 (95% CI, 1.76-2.53; I², 0%) and 2.25 (95% CI, 1.62-3.14; I², 61%), respectively. The rates of achieving CR and minimal residual disease negativity were also higher for the immunotherapy group, with pooled ORs of 1.70 (95% CI, 1.07-2.69; I², 79%) and 2.98 (95% CI, 1.17-7.58; I², 90%), while developing less risk for febrile neutropenia (pooled OR, 0.22; 95% CI, 0.08-0.58; I², 84%). Subgroup analyses revealed that all antibody types yielded dramatically better OS rates than those for patients administered chemotherapy alone.

Conclusions:

The ALL patients receiving CD-targeted immunotherapy as induction or salvage therapy had significantly higher response rates and survival outcomes, as well as lower odds of acquiring febrile neutropenia, than the patients given conventional chemotherapy.

Comparative effectiveness of glasdegib versus venetoclax combined with low-dose cytarabine in acute myeloid leukemia

Background: Two combination therapies recently approved and recommended for use in combination with low-dose cytarabine (LDAC) in acute myeloid leukemia patients unfit for intensive chemotherapy are glasdegib+LDAC and venetoclax+LDAC. Materials & methods: An indirect treatment comparison used median overall survival, overall survival hazard ratios, complete remission (CR), CR+CR with incomplete blood count recovery and transfusion independence to assess comparative effectiveness, and a simulated treatment comparison accounted for differences in patient characteristics between trials. Results: Differences in efficacy between glasdegib+LDAC and venetoclax+LDAC were suggestive and not statistically significant. Conclusion: With no significant differences in comparative effectiveness, considerations such as safety profiles, burden of administration and patient preference are likely to guide treatment decisions.

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 Significance of Inotuzumab Ozogamicin in Non-transplant Patients with Relapsed Acute Lymphoblastic Leukemia: A Report of Four Cases

Relapsed acute lymphoblastic leukemia (ALL) has a poor prognosis. Inotuzumab Ozogamicin (InO) is a novel therapeutic drug for the treatment of relapsed ALL. InO has received attention as a bridging therapy before transplantation due to its high complete remission (CR) rate. However, the significance of InO in non-transplant patients remains unclear. We retrospectively evaluated four non-transplant patients treated with InO. All cases achieved CR after receiving at least two cycles of InO. Three of the four cases survived for more than 11 months without relapse. Moreover, all patients received InO as outpatients, because the adverse events were well-controlled. InO therefore appears to be a beneficial treatment even for non-transplant patients.

Blinatumomab or Inotuzumab Ozogamicin as Bridge to Allogeneic Stem Cell Transplantation for Relapsed or Refractory B-lineage Acute Lymphoblastic Leukemia: A Retrospective Single-Center Analysis

BACKGROUND

Blinatumomab and inotuzumab ozogamicin are now widely used to treat relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL).

PATIENTS AND METHODS

We have reported the clinical course of 34 adult patients with r/r B-ALL receiving blinatumomab or inotuzumab ozogamicin at our institution from 2009 to 2019.

RESULTS

Blinatumomab-based salvage therapy was applied for overt r/r B-ALL (n = 13) or minimal residual disease (MRD) positivity (n = 5). Of the 13 patients with r/r B-ALL, 9 (69%; 95% confidence interval [CI], 39%-91%) achieved complete remission (CR), with 78% of CR patients (95% CI, 40%-97%) reaching MRD negativity. MRD negativity was also achieved in all 5 patients treated for MRD positivity. The 1-year overall survival of patients receiving blinatumomab for r/r B-ALL and MRD positivity was 54% (n = 13; 95% CI, 26%-81%) and 80% (n = 5; 95% CI, 44-100), respectively. In the inotuzumab ozogamicin group, all 16 patients were treated for overt r/r B-ALL. The rate of CR was 94% (95% CI, 70%-100%), with 67% (95% CI, 38%-88%) of CR patients reaching MRD negativity. The 1-year OS after the first application of inotuzumab ozogamicin was 46% (95% CI, 18%-74%). Of those patients receiving blinatumomab and inotuzumab ozogamicin as a bridge-to-transplant strategy, 79% and 80%, respectively, proceeded to allogeneic stem cell transplantation. The most frequent drug-specific adverse events were similar to those previously reported, including cytokine release syndrome, capillary leak syndrome, and neurotoxicity for blinatumomab and transplant-associated veno-occlusive disease of the liver for inotuzumab ozogamicin.

CONCLUSION

Together with previous observations from phase III clinical trials, these data suggest that blinatumomab and inotuzumab ozogamicin are highly effective salvage regimens in r/r B-ALL.