Association of leukemic molecular profile with efficacy of inotuzumab ozogamicin in adults with relapsed/refractory ALL

The phase 3 INO-VATE trial demonstrated higher rates of remission, measurable residual disease negativity, and improved overall survival for patients with relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) who received inotuzumab ozogamicin (InO) vs standard of care chemotherapy (SC). Here we examined associations between genomic alterations and the efficacy of InO. Of 326 randomized patients, 91 (InO, n=43; SC, n=48) had samples evaluable for genomic analysis. The spectrum of gene fusions and other genomic alterations observed was comparable with prior studies of adult ALL. Responses to InO were observed in all leukemic subtypes, genomic alterations, and risk groups. Significantly higher rates of complete remission (CR)/CR with incomplete count recovery rates were observed with InO vs SC in patients with BCR::ABL1-like ALL (85.7% [6/7] vs 0% [0/5] P=0.0076), with TP53 alterations (100% [5/5] vs 12.5% [1/8], P=0.0047), and in the high-risk BCR::ABL1- (BCR::ABL1-like, low hypodiploid, KMT2A-rearranged) group (83.3% [10/12] vs 10.5% [2/19]; P<0.0001). This retrospective, exploratory analysis of the INO-VATE trial demonstrated potential for benefit with InO for patients with R/R ALL across leukemic subtypes, including BCR::ABL1-like ALL, and for those bearing diverse genomic alterations. Further confirmation of the efficacy of InO in patients with R/R ALL exhibiting the BCR::ABL1-like subtype or harboring TP53 alterations is warranted. This trial was registered at www.clinicaltrials.gov as no. NCT01564784.

A phase IV study evaluating QT interval, pharmacokinetics, and safety following fractionated dosing of gemtuzumab ozogamicin in patients with relapsed/refractory CD33-positive acute myeloid leukemia

PURPOSE

Gemtuzumab ozogamicin (GO) is indicated for treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML). The QT interval, pharmacokinetics (PK), and immunogenicity following the fractionated GO dosing regimen have not been previously assessed. This phase IV study was designed to obtain this information in patients with R/R AML.

METHODS

Patients aged ≥ 18 years with R/R AML received the fractionated dosing regimen of GO 3 mg/m² on Days 1, 4, and 7 of each cycle, up to 2 cycles. The primary endpoint was mean change from baseline in QT interval corrected for heart rate (QTc).

RESULTS

Fifty patients received ≥ 1 dose of GO during Cycle 1. The upper limit of the 2-sided 90% confidence interval for least squares mean differences in QTc using Fridericia's formula (QTcF) was < 10 ms for all time points during Cycle 1. No patients had a post-baseline QTcF > 480 ms or a change from baseline > 60 ms. Treatment-emergent adverse events (TEAEs) occurred in 98% of patients; 54% were grade 3-4. The most common grade 3-4 TEAEs were febrile neutropenia (36%) and thrombocytopenia (18%). The PK profiles of both conjugated and unconjugated calicheamicin mirror that of total hP67.6 antibody. The incidence of antidrug antibodies (ADAs) and neutralizing antibodies was 12% and 2%, respectively.

CONCLUSION

Fractionated GO dosing regimen (3 mg/m²/dose) is not predicted to pose a clinically significant safety risk for QT interval prolongation in patients with R/R AML. TEAEs are consistent with GO's known safety profile, and ADA presence appears unassociated with potential safety issues.

TRIAL REGISTRY

Clinicaltrials.gov ID: NCT03727750 (November 1, 2018).

Time to First Subsequent Salvage Therapy in Patients With Relapsed/Refractory Acute Lymphoblastic Leukemia Treated With Inotuzumab Ozogamicin in the Phase III INO-VATE Trial

BACKGROUND

In relapsed/refractory acute lymphoblastic leukemia (R/R ALL), successive salvage therapies may worsen outcomes and decrease quality of life. This post hoc analysis of the phase III INO-VATE trial investigates subsequent salvage therapies and compared the time from randomization to first subsequent salvage therapy (TST) in the inotuzumab ozogamicin (InO) and standard-of-care chemotherapy (SoC) arms.

PATIENTS AND METHODS

Adults (aged ≥18 years) with CD22+ R/R ALL were randomized to InO (n = 164) or SoC (n = 162) treatment. We determined TST and proportion of patients receiving subsequent salvage therapies by treatment arm and for subgroups based on transplantation status and baseline characteristics.

RESULTS

In the InO versus SoC arm, a smaller proportion of patients received subsequent salvage therapy (34.1% [n = 56] vs. 56.8% [n = 92]), and TST was longer (median 19 vs. 4 months, hazard ratio 0.339, P < .0001). Similar benefits were seen with InO versus SoC irrespective of transplantation status, age, salvage phase, first remission duration, Philadelphia chromosome status, or CD22 expression. Following receipt of subsequent salvage therapy, median overall survival was 4 months, irrespective of treatment arm.

CONCLUSION

Patients in the InO versus SoC arm were less likely to receive subsequent salvage therapy, and showed a clinically meaningful extension of TST irrespective of subgroup. This suggests InO treatment leads to improved outcomes by increasing the likelihood that subsequent salvage therapies and their associated adverse impacts can be delayed or avoided.

PLAIN LANGUAGE SUMMARY

Available in Supplementary Materials.

CLINICAL TRIAL REGISTRATION

NCT01564784.

Abstract CT027: Exploration of association of leukemic molecular profile with efficacy in patients (pts) with relapsed/refractory acute lymphoblastic leukemia (ALL) treated with inotuzumab ozogamicin (InO) in the phase 3 INO-VATE trial

Background: INO-VATE (NCT01564784) demonstrated higher rates of remission, MRD-negativity, and improved overall survival (hazard ratio 0.75, one-sided P=0.01) for pts with R/R ALL who received InO vs standard chemotherapy (SC). Here we explore the potential association between leukemic molecular profiles and efficacy of InO.

Methods: Pts with CD22+ ALL due to receive salvage treatment were randomized to InO or SC; clinical methods and results were published previously (Kantarjian HM, et al. N Engl J Med 2016; PMID: 27292104). Bone marrow samples collected at screening post protocol amendment 2 underwent RNA-sequencing with analysis of gene expression profile, fusions, and genomic alterations. Data cutoff: Jan 4, 2017.

Results: Of 326 pts in the INO-VATE intent-to-treat (ITT) population, 91 (InO, 43; SC, 48) had samples evaluable for molecular profiling. Baseline characteristics were similar in the evaluable pts vs the ITT population. Most common (≥5%) ALL subtypes were BCR-ABL1-positive (14%), low hypodiploidy (12%), Philadelphia chromosome (Ph)-like (11%), KMT2A-rearranged (9%), and DUX4-rearranged (6%); 29% (26/91) of pts could not be subtyped due to low blast counts. Most common (≥5%) non-BCR-ABL1 oncogenic fusions detected were IGH-CRLF2 (8%), and KMT2A-AFF1 (6%). Among non-fusion genomic alterations, those involving chromatin modifying genes featured prominently (e.g. KMT2D, 18%; CREBBP, 12%; KMT2C, 11%; ARID2, 9%; ARID1A, 8%; SET2D, 7%; EP300, 6%). Other commonly altered (≥9%) genes included TP53 (14%), NOTCH1 (11%), KRAS (9%), and PAX5 (9%).

Similar to the overall findings of INO-VATE, complete remission (CR)/CR with incomplete count recovery (CRi) rates were numerically higher with InO vs SC across ALL subtypes, including but not limited to, low hypodiploidy (67% [2/3] vs 13% [1/8], P=0.15), Ph-like (83% [5/6] vs 0% [0/4], P=0.02), and KMT2A (100% [2/2] vs 17% [1/6], P=0.11), although not in BCR-ABL1-positive (67% [4/6] vs 57% [4/7], P=0.59). Within pts bearing common non-BCR-ABL1 oncogenic fusions, CR/CRi was seen for InO including for IGH-CRLF2 (50% [1/2] vs 20% [1/5] for SC), KMT2A-AFF1 (100% [1/1] vs 25% [1/4] for SC), and IGH-DUX4 (100% [3/3] vs 0% [0/1] for SC). Consistent with a previous report (Yang X, et al. Blood 2019; 134 [Suppl 1]: 3888) CR/CRi rates were high for InO in pts with TP53 alterations (100% [5/5] vs 13% [1/8] for SC, P=0.0047).

Conclusions: This retrospective, exploratory analysis of INO-VATE demonstrated potential for benefit with InO for ALL pts across leukemic subtypes, including Ph-like, and for those bearing diverse fusions. Further exploration of Ph-like subtype or TP53 alterations as candidate predictive biomarkers for InO in pts with R/R ALL is warranted.

Citation Format: Yaqi Zhao, A Douglas Laird, Kathryn Roberts, Rolla Yafawi, Hagop Kantarjian, Daniel J. DeAngelo, Matthias Stelljes, Michaela Liedtke, Wendy Stock, Nicola Gökbuget, Susan O'Brien, Elias Jabbour, Ryan D. Cassaday, Melanie R. Loyd, Scott Olsen, Geoffrey Neale, Xueli Liu, Erik Vandendries, Charles G. Mullighan, Anjali Advani. Exploration of association of leukemic molecular profile with efficacy in patients (pts) with relapsed/refractory acute lymphoblastic leukemia (ALL) treated with inotuzumab ozogamicin (InO) in the phase 3 INO-VATE trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT027.

MagnetisMM-9: An open-label, multicenter, non-randomized phase 1/2 study of elranatamab in patients with relapsed/refractory multiple myeloma

TPS8068

Background: Elranatamab (PF-06863135) is a humanized bispecific antibody that targets both B cell maturation antigen (BCMA) on multiple myeloma (MM) cells and CD3 on T cells resulting in T cell- mediated cytotoxicity. In preclinical studies, elranatamab has demonstrated anti-myeloma activity and delayed disease progression. In the ongoing phase 1 MagnetisMM-1 study, elranatamab has demonstrated clinical efficacy and a manageable safety profile in patients with relapsed/refractory MM (Bahlis et al, J Clin Oncol 2021). Elranatamab maximum tolerated dose has not yet been reached. Subcutaneous (SC) elranatamab at the recommended dose of 76 mg QW on a 28-d cycle with a 2 step-up priming dose regimen administered during the first week is currently being evaluated in a phase 2 study, MagnetisMM-3 (Lesokhin et al, Blood, 2021). Methods: MagnetisMM-9 (start date: Oct 2021; estimated completion date: Apr 2025) is an open-label, multicenter, non-randomized phase 1/2 study evaluating an alternative priming regimen to further mitigate cytokine release syndrome (CRS) incidence and severity and to evaluate SC elranatamab Q2W and Q4W dosing regimens in patients with relapsed/refractory MM. In part 1 of the study, patients will receive premedications and 2 step-up priming doses on cycle 1 D1 (4 mg) and D4 (20 mg), followed by elranatamab 76 mg QW for 6 cycles, and a dose Q2W thereafter if partial response or better is achieved and maintained. In part 2, higher doses of elranatamab ( > 76 mg) at increased intervals between doses will be evaluated. The primary endpoint is grade ≥2 CRS rate during cycle 1. Secondary endpoints include dose-limiting toxicities (part 2 only), objective response rate, duration of response, progression-free survival, overall survival, minimal residual disease negativity rate, safety, and pharmacokinetics. Eligible patients should be ≥18 years of age with a MM diagnosis and measurable disease according to IMWG criteria, refractory to at least one proteasome inhibitor, one immunomodulatory drug, and one anti-CD38 antibody, relapsed/refractory to their last treatment regimen, and have an ECOG performance status ≤1. Key exclusion criteria are smoldering MM, active plasma cell leukemia, amyloidosis, POEMS syndrome, stem cell transplant within 12 weeks of enrollment, active, uncontrolled bacterial, fungal, or viral infections, or any other active malignancy within 3 years prior to enrollment (except for adequately treated basal cell or squamous cell skin cancer, or carcinoma in situ), or previous treatment with an anti-BCMA bispecific antibody. The study is open at centers in the USA, UK, Japan, and Taiwan. Clinical trial information: NCT05014412.

A registry-based, observational safety study of inotuzumab ozogamicin (InO) treatment in patients (pts) with B-cell precursor acute lymphoblastic leukemia (ALL) who proceeded to hematopoietic stem cell transplant (HSCT)

7017

Background: InO is a CD22-directed antibody-drug conjugate indicated for treatment of relapsed/refractory (R/R) ALL. InO has been associated with hepatotoxicity and hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS), particularly post-HSCT. Registry data (Center for International Blood and Marrow Transplant Research [CIBMTR]) was analyzed to assess toxicity in pts with ALL who received InO prior to HSCT. Methods: CIBMTR patient data are being collected for a 5-year period after US approval of InO (Aug 2017 – Aug 2022). Data from US pts age ≥18 y treated with InO who proceeded to allogeneic HSCT were included. Using interim data at 3 y, we evaluated post-HSCT outcomes, including clinical status, overall survival, transplant-related (non-relapse) mortality (NRM), relapse, death after relapse (time from HSCT to death after the first 28 d from any cause with prior relapse/progression post-HSCT), and investigator-defined adverse events, including hepatic VOD/SOS. All statistical analyses are descriptive. Results: Data accrued from 18 Aug 2017 to 17 Aug 2020 for 131 adult pts (median age 40 y) who proceeded to first allogeneic HSCT: 31% in first complete remission (CR1), 46% in CR2, 13% in ≥CR3, 5% in 1st relapse, 2% in ≥3rd relapse, and 3% in primary induction failure. A majority (70%) had transplants from peripheral blood stem cells, and 47% involved an HLA-identical sibling or other related donor. Nearly half received myeloablative conditioning regimens. Before HSCT, 36% of pts received 1 cycle of InO, 46% had 2 cycles, and 17% had ≥3 cycles. Half (48%) received InO as a single agent. Median time from last dose of InO to HSCT was 2.0 mo (range: 0.4–26.2). At time of data-lock (11 Nov 2020), post-transplant data were available for 131 pts. Outcomes for these pts are shown in the Table. Among a subgroup of adults with active R/R ALL (n = 91) at time of HSCT (median of 4 lines prior therapy), VOD/SOS incidence within 100 d of HSCT was 18%. Conclusions: Incidence of VOD/SOS after first HSCT in InO-treated pts with R/R ALL in this study was similar to the 18–19% reported in pooled analyses of 2 clinical trials among InO-treated pts with R/R ALL (Marks et al, Biol Blood Marrow Transplant 2019) and in the INOVATE study (Kantarjian et al, Lancet Haematol 2017). The NRM at 1 y of 21% (23% R/R ALL) is lower than the NRM at 1 y of 38% reported in the pooled analyses of R/R ALL InO recipients.[Table: see text]

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.

Outcomes following hematopoietic stem cell transplantation in patients treated with standard chemotherapy with or without gemtuzumab ozogamicin for acute myeloid leukemia

The phase 3 ALFA-0701 trial demonstrated improved outcomes with fractionated-dose gemtuzumab ozogamicin (GO) combined with standard chemotherapy vs. standard chemotherapy alone in adults with de novo acute myeloid leukemia (AML). We examined post-transplant outcomes and occurrence of hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) in patients who received hematopoietic stem cell transplantation (HSCT) as follow-up therapy in ALFA-0701. Patients aged 50-70 years were randomized to standard chemotherapy with or without GO (3 mg/m2 on days 1, 4, and 7 of induction and day 1 on each of two consolidation courses). Allogeneic HSCT was recommended for patients in first complete remission with matched (related or unrelated) donor, except those with core-binding factor AML or normal karyotype and either NPM1+/FLT3-ITDwt or CEBPA+ AML. Eighty-five patients (GO: n = 32; control: n = 53) received HSCT in first complete remission or after relapse/primary induction failure. Three patients (GO: n = 2; control: n = 1 [received GO as follow-up therapy]) developed VOD/SOS after HSCT or conditioning. Post-transplant survival, non-relapse mortality, and relapse were not different between arms. Results indicate fractionated-dose GO as part of induction and consolidation chemotherapy for AML does not induce excess post-transplant VOD/SOS or mortality and thus does not preclude the use of HSCT as consolidation treatment.

Efficacy of inotuzumab ozogamicin in patients with Philadelphia chromosome-positive relapsed/refractory acute lymphoblastic leukemia

BACKGROUND

Patients with relapsed/refractory (R/R) Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) have a poor prognosis and limited treatment options.

METHODS

The efficacy of inotuzumab ozogamicin (InO), a humanized anti-CD22 monoclonal antibody conjugated to the cytotoxic antibiotic calicheamicin, was evaluated in R/R ALL patients in the phase 1/2 study 1010 (NCT01363297) and open-label, randomized, phase 3 study 1022 (INO-VATE; NCT01564784). This analysis focused specifically on Ph+ R/R ALL patients. In study 1022, Ph+ patients were randomly assigned 1:1 to InO (n = 22) or standard intensive chemotherapy (SC) (n = 27) and 16 Ph+ patients in study 1010 received InO.

RESULTS

In study 1022, rates of complete remission/complete remission with incomplete hematologic recovery (CR/CRi) and minimal residual disease (MRD) negativity (patients achieving CR/CRi) were higher with InO (CR/CRi = 73%; MRD = 81%) versus SC (CR/CRi = 56%; MRD = 33%). The corresponding rates in study 1010 were 56% (CR/CRi) and 100% (MRD). The hematopoietic stem cell transplantation (HSCT) rate in study 1022 was 41% versus 19% for InO versus SC; however, there was no benefit in overall survival (median OS: 8.7 vs 8.4 months; hazard ratio, 1.17 [95% CI, 0.64-2.14]). The probability of being event-free (progression-free survival) at 12 months was greater with InO versus SC (20.1% vs 4.8%).

CONCLUSION

Given the substantial improvement in responses and rates of HSCT, InO is an important treatment option for patients with R/R Ph+ ALL. Future studies need to consider better characterization of disease characteristics, more sensitive MRD measurements, MRD-directed therapy before HSCT, and potentially combination therapies, including tyrosine kinase inhibitors.

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.

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.

Burden of hospitalization in acute lymphoblastic leukemia patients treated with Inotuzumab Ozogamicin versus standard chemotherapy treatment

Background

Inotuzumab Ozogamicin (INO), has demonstrated an improvement in overall survival, high rate of complete remission, favorable patient‐reported outcomes, and manageable safety profile vs standard of care (SoC; intensive chemotherapy) for relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) in the phase 3 INO‐VATE trial. With a one‐hour weekly dosing schedule, INO might be associated with lower healthcare system burden. This study analyses hospitalizations for INO vs SoC.

Methods

All patients receiving study treatment in the INO‐VATE trial were included. The days hospitalized during study treatment was calculated. Due to different treatment durations for INO and SoC (median of 3 vs 1 cycles), number of hospital days was mainly reported per observed patient month. Hospital days per patient month were analyzed for different treatment cycles, subgroups, and main reasons for hospitalization. Differences between treatments were analyzed by the incidence rate ratio (IRR).

Results

Overall, 82.9% and 94.4% INO and SoC patients experienced at least one hospitalization. The mean hospitalization days per patient month was 7.6 and 18.4 days for INO and SoC (IRR = 0.413, P < .001), which corresponds to patients spending 25.0% and 60.5% of their treatment time in a hospital. Main hospitalization reasons were R/R ALL treatment (5.2 (INO) vs 14.0 (SoC) days, IRR = 0.368, P < .001), treatment toxicities (1.4 vs 2.8 days, IRR = 0.516, P < .001) or other reasons (1.0 vs 1.6 days, IRR 0.629, P < .001).

Conclusions

Inotuzumab Ozogamicin treatment in R/R ALL is associated with a lower hospitalization burden compared with SoC. It is likely this lower burden has a favorable impact on healthcare budgets and cost‐effectiveness considerations.

Pharmacokinetic/Pharmacodynamic Modeling to Support the Re-approval of Gemtuzumab Ozogamicin

Gemtuzumab ozogamicin (Mylotarg; Pfizer, New York, NY) was the first antibody-drug conjugate to be approved for CD33-positive acute myeloid leukemia (AML). However, it was voluntarily withdrawn from the US market due to lack of clinical benefit in the confirmatory phase III trial. In 2012, several investigator cooperative studies using a different dosing regimen showed efficacy, but pharmacokinetic (PK) data were not collected in these trials. Through simulation of expected concentrations for new dosing regimens, PK/pharmacodynamic modeling was able to support the safety and efficacy of these regimens. Significant exposure-response relationships were found for the attainment of complete remission with and without platelet recovery, attainment of blast-free status, the time course of myelosuppression, several grade ≥ 3 hepatic adverse events, and veno-occlusive disease. Gemtuzumab ozogamicin received full approval by the US Food and Drug Administration (FDA) in September 2017 for newly diagnosed and relapsed AML in adult patients and relapsed AML in pediatric patients aged 2-17 years.

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

Introduction

No head-to-head studies have compared inotuzumab ozogamicin (InO) and blinatumomab (Blina) for the treatment of adults with relapsed or refractory B cell precursor acute lymphoblastic leukemia (ALL). Indirect treatment comparisons (ITCs), namely network meta-analysis (NMA), anchored matching-adjusted indirect comparison (MAIC), and simulated treatment comparison (STC), were conducted to compare the relative efficacy of these therapies.

Methods

Patient-level data from a study that evaluated InO with standard of care (SoC) chemotherapy (INO-VATE-ALL) and published data from a study that evaluated Blina with SoC chemotherapy (TOWER) were used in the analyses. Endpoints evaluated included remission rate defined as complete remission or complete remission with incomplete hematologic recovery (CR/CRi), hematopoietic stem cell transplantation (HSCT), overall survival (OS), and event-free survival (EFS). For each outcome, treatment-effect modifiers were adjusted for in the anchored MAIC and STC analyses.

Results

Analyses showed statistically significant higher rates of remission and HSCT with InO compared to Blina irrespective of the ITC method used or measure of the effect (i.e., odds ratio [OR] or rate difference). The treatment effects derived from the MAIC and STC analyses were consistent and stronger than those estimated from the NMA. A trend favoring InO was detected for EFS. The ITC results for OS suggest no difference between InO and Blina.

Conclusion

Results from these ITCs indicated a statistically significant advantage for InO over Blina for rates of remission and HSCT in adults with relapsed or refractory B cell precursor ALL. It was not possible to fully adjust for all treatment-effect modifiers, and the similarity in chemotherapy regimens used in the SoC comparator arms of the INO-VATE-ALL and TOWER studies is worthy of further exploration. Both studies, however, used chemotherapy regimens that have a low response rate; therefore, no significant differences in efficacy outcomes are expected between SoC arms.

Funding

Pfizer Inc, New York, NY.

Plain Language Summary

Plain language summary available for this article.

Electronic supplementary material

The online version of this article (10.1007/s12325-019-00991-w) contains supplementary material, which is available to authorized users.

Inotuzumab ozogamicin (InO) treatment in patients with relapsed/refractory acute lymphoblastic leukemia (R/R ALL): Outcomes of patients treated in salvage one with a long duration of first remission

7029

Background: In R/R ALL, data are limited supporting targeted therapies like InO as first salvage in patients (pts) who had a long first complete remission (CR1). InO, a calicheamicin-conjugated antibody, targets CD22 on ALL blasts. Here we report outcomes in pts with ALL in first salvage (S1) who had a long CR1 before receiving InO vs standard of care chemotherapy (SC). Methods: Adults with CD22+ R/R ALL, stratified by salvage and length of remission (CR1 ≥ or < 12 mos), were randomized to receive InO (n = 164) or SC (n = 162). Methods were previously described (Kantarjian et al, NEJM 2016), with data shown up to the last patient last visit (January 4, 2017). Outcomes including complete remission (CR)/CR with incomplete hematologic recovery (CRi) and overall survival (OS) were determined for S1 pts who achieved CR1 ≥ 12 mos and CR1 ≥ 18 mos. Results: For S1 pts with CR1 ≥ 12 mos or CR1 ≥ 18 mos, InO and SC arms had generally comparable baseline characteristics. For S1 pts with CR1 ≥ 12 mos and CR1 ≥ 18 mos, fewer pts had received a prior stem cell transplant in the InO vs SC arm (10.4% vs 25.0% and 9.7% vs 21.4%). For S1 pts with CR1 ≥ 12 mos and CR1 ≥ 18 mos respectively, InO vs SC treatment led to a higher CR/CRi rate (85.4% vs 27.5% [ P< 0.0001] and 83.9% vs 32.1% [ P< 0.0001]) and improved OS (HR = 0.547 [ P= 0.0086] and 0.504 [ P= 0.0163]), with veno-occlusive liver disease reported in 12.5% and 12.9% of InO pts Clinical trial information: NCT01564784. Conclusions: Improved outcomes were seen with InO vs SC among S1 pts who had a long first complete remission (CR1 ≥ 12 mos or CR1 ≥ 18 mos), supporting the benefit of InO vs SC in this population.[Table: see text]

Time from randomization to first subsequent induction/salvage therapy (ST) in patients with relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) treated with inotuzumab ozogamicin (InO) in the phase 3 INO-VATE trial

7025

Background: Additional salvage regimens are burdensome for R/R ALL patients (pts) due to therapy-associated toxicities, which may affect quality of life with poor efficacy. In INO-VATE (Kantarjian et al, NEJM 2016), pts receiving InO vs standard chemotherapy (SC) had significantly greater remission rates and longer overall survival; after study treatment discontinuation, overall fewer STs (mainly burdensome chemotherapies) were used in the InO group vs SC. Methods: Study design was published. Adults with CD22+ ALL who were due to receive 1st or 2nd salvage treatment were randomized 1:1 to InO (n = 164) or SC (n = 162). Time to the first ST (TST) was time from randomization to the start of the first ST. Pts who did not receive any ST were censored. Data cutoff: Jan 4, 2017. Results: Fewer InO pts had ST vs SC pts (Table). Among the censored pts, 83/108 (76.9%) in the InO vs 54/69 (78.3%) in the SC group died, 23/108 (21.3%) vs 5/69 (7.2%) were alive at the end of the study, and 2/108 (1.9%) vs 10/69 (14.5%) were no longer being followed for survival. TST was longer in pts receiving InO vs SC. Overall median (95% CI) TST was 18.8 (14.7–NA) vs 3.9 (2.4–5.1) months; hazard ratio (HR) = 0.34, 97.5% CI: 0.23–0.49, 1-sided P< 0.0001. For pts (InO: 85, SC: 126) who never received hematopoietic stem cell transplantation (HSCT) on study, fewer InO pts had ST vs SC pts; TST was significantly longer in InO vs SC. For pts (InO: 70, SC: 18) who had HSCT directly after salvage, TST was extended in InO vs SC. Conclusions: In this study, treatment with InO provided the benefit of extended TST, effectively allowing patients a longer time period until an ST was needed in both patients who proceeded to as well as those who did not proceed to HSCT. Clinical trial information: NCT01564784. [Table: see text]

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.

Prognostic implications of cytogenetics in adults with acute lymphoblastic leukemia treated with inotuzumab ozogamicin

Karyotype is frequently used to predict response and outcome in leukemia. This post hoc exploratory analysis evaluated the relationship between baseline cytogenetics and outcome in patients with relapsed/refractory acute lymphoblastic leukemia (R/R ALL) treated with inotuzumab ozogamicin (InO), a humanized CD22 antibody conjugated to calicheamicin, in the phase 3, open-label, randomized INO-VATE trial. Data as of March 8, 2016, are presented in this analysis. Of the 326 patients randomized, 284 had screening karyotyping data (144 in the InO arm and 140 in the standard care [SC] arm). With InO, complete remission or complete remission with incomplete hematologic recovery (CR/CRi), minimal residual disease negativity rates, and overall survival (OS) were not significantly different between cytogenetic subgroups. CR/CRi rates favored InO over SC in the diploid with ≥20 metaphases, complex, and "other" cytogenetic subgroups. The OS hazard ratio favored InO over SC in the diploid with ≥20 metaphases, complex, and other cytogenetic subgroups. Generally, InO is effective and provides substantial clinical benefit in patients with R/R ALL who have specific baseline karyotypes.

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.

Efficacy and safety analysis by age cohort of inotuzumab ozogamicin in patients with relapsed or refractory acute lymphoblastic leukemia enrolled in INO-VATE

BACKGROUND

Inotuzumab ozogamicin (InO) has demonstrated efficacy and tolerability in patients aged 18 to 78 years with relapsed/refractory acute lymphoblastic leukemia (ALL) in the INO-VATE trial. This subset analysis compared the efficacy and safety of InO in younger and older patients.

METHODS

Intent-to-treat analyses of morphologic responses and overall survival (OS) included 326 randomized patients, and safety assessments included 307 patients receiving 1 or more doses of the study treatment. Of the 326 patients, 164 received InO at a starting dose of 1.8 mg/m² /cycle (0.8 mg/m² on day 1 and 0.5 mg/m² on days 8 and 15 of a 21- to 28-day cycle [≤6 cycles]); 60 patients were aged ≥55 years, and 104 were aged <55 years.

RESULTS

For older and younger patients, the median duration of InO therapy and the types and frequencies of adverse events of any grade were generally similar. Although the remission rates, median duration of remission (DOR), and progression-free survival were similar with InO for those aged <55 years and those aged ≥55 years, OS was longer for younger patients (median, 8.6 vs 5.6 months; hazard ratio, 0.610). Among patients proceeding to hematopoietic stem cell transplantation after InO treatment (28% of older patients and 58% of younger patients), the incidence of veno-occlusive disease was greater in older patients (41% vs 17%). The study database was not locked at the time of this analysis.

CONCLUSIONS

InO was tolerable in older patients with relapsed/refractory ALL. Although OS was longer for younger patients versus older patients, InO demonstrated high response rates with similar DOR in the 2 age groups. Cancer 2018;124:1722-32. © 2018 American Cancer Society.

Phase 1 study of inotuzumab ozogamicin combined with R-GDP for the treatment of patients with relapsed/refractory CD22+ B-cell non-Hodgkin lymphoma

Objective: To evaluate safety, tolerability, and preliminary activity of inotuzumab ozogamicin (InO) plus rituximab, gemcitabine, dexamethasone, and cisplatin (R-GDP) in patients with relapsed/refractory CD22+ B-cell non-Hodgkin lymphoma (NHL). Methods: Patients received InO plus R-GDP (21-day cycle; six-cycle maximum) using up-and-down dose-escalation schema for gemcitabine and cisplatin to define the highest dosage regimen(s) with acceptable toxicity (Part 1; n = 27). Part 2 (n = 10) confirmed safety and tolerability; Part 3 (n = 18) evaluated preliminary efficacy. Results: Among 55 patients enrolled, 42% were refractory at baseline (median 2 [range, 1-6] prior therapies); 38% had diffuse large B-cell lymphoma (DLBCL). The highest dosage regimen with acceptable toxicity was InO 0.8 mg/m², rituximab 375 mg/m², cisplatin 50 mg/m², gemcitabine 500 mg/m² (day 1 only) and dexamethasone 40 mg (days 1-4); this was confirmed in Part 2, in which three patients had dose-limiting toxicities (grade 4 thrombocytopenia [n = 2], febrile neutropenia [n = 2]). Most frequent treatment-related adverse events were thrombocytopenia (any grade, 85%; grade ≥3, 75%) and neutropenia (69%; 62%). Overall (objective) response rate (ORR) was 53% (11 complete, 18 partial responses); ORR was 71%, 33%, and 62% in patients with follicular lymphoma (n = 14), DLBCL (n = 21), and mantle cell lymphoma (n = 13), respectively. Conclusions: InO 0.8 mg/m² plus R-GDP was associated with manageable toxicity, although gemcitabine and cisplatin doses were lower than in the standard R-GDP regimen due to hematologic toxicity. Evidence of antitumor activity was observed; however, these exploratory data should be interpreted with caution due to the small sample size and short follow-up duration (Clinicaltrials.gov number: NCT01055496).

Hospitalization for patients in the United States (US) and European Union (EU) treated with inotuzumab ozogamicin (InO) vs standard of care (SOC) for relapsed/refractory acute lymphoblastic leukemia (R/R ALL) in a global phase 3 trial

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Background: InO, an anti-CD22 antibody-calicheamicin conjugate, with its once a week, 1-hour infusion schedule, has demonstrated lower hospital utilization in association with superior clinical activity, favorable patient-reported outcomes (PROs), and a generally manageable safety profile versus SOC (intensive chemotherapy) for R/R ALL in the phase 3 INO-VATE trial. Here, regional-specific hospitalizations in the trial are presented. Methods: Patients receiving study treatment and recruited from the US and the EU were included in the analyses. The total number of days hospitalized for each patient was calculated. Hospital days prior to randomization and those after the end of study treatment were excluded. Due to different treatment durations for InO and SOC (median 1 vs 3 cycles), calculations were reported for cycle 1 treatment period (randomization to end of cycle 1) and for the entire treatment period (all cycles - randomization to end of treatment). Results: A total of 281 patients were available for the analyses. 154 were from the US and 127 from 11 of the EU countries. The median and mean hospitalization days were shorter for patients in the InO arm compared to the SOC arm across both regions (Table). The difference between the two treatment arms appear to be greater in the US compared to the EU. Hospitalizations in the US appear to be shorter than in the EU, particularly for patients receiving InO. Conclusions: InO treatment in R/R ALL is associated with less hospitalization across both the US and EU compared to SOC, consistent with InO’s better efficacy, tolerability, PRO and dosing schedule. The finding that US has lower hospitalization than the EU might be explained by different patient care practices in the two regions. Given that hospitalization is the biggest cost driver in cancer care, the discrepancy may lead to greater cost-savings in healthcare systems where hospitalizations are strictly managed. Clinical trial information: NCT01564784. [Table: see text]

Factors associated with allogeneic hematopoietic stem cell transplantation (HSCT) outcomes in patients (pts) with relapsed/refractory acute lymphoblastic leukemia (R/R ALL) treated with inotuzumab ozogamicin (InO) versus (v) conventional chemotherapy (C)

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Background: InO therapy in R/R ALL resulted in superior complete remission (CR)/CR with incomplete hematologic recovery (CRi) rates v C in the Phase 3 INO-VATE trial (NCT01564784; Kantarjian NEJM 2016). More InO v C pts proceeded to HSCT (41% [45/109] v 11% [12/109]; P<0.001). Factors associated with outcomes after HSCT are described. Methods: Full details have been published. Multivariate analyses (MVA) using Cox regression modeling were conducted to determine predictors of non-relapse mortality (NRM) and overall survival (OS). Results: As of 3/8/16, 108/326 pts underwent allogeneic HSCT (InO n=77; C n=31). Baseline characteristics were generally similar, except baseline platelet values were lower in InO v C pts. More InO v C pts achieved minimal residual disease negativity (MRDneg [best status]; 71% v 26%; P<0.0001). Less InO v C pts received additional therapy before HSCT (14% v 55%, P<0.0001). NRM rates were higher in InO v C pts at 1 year (yr; 36% [95% CI 26–47] v 20% [8–36]) and 2 yrs (39% [27–51] v 31% [13–51]), but relapse rates were lower (1 yr, 23% [15–33] v 29% [13–48]; 2 yrs, 33% [22–44] v 46% [24–65]). No significant difference in post-HSCT survival was detected in InO v C pts; however, visual inspection of the curve suggested the survival probability varied before and after 15 months post-HSCT (1 yr, 44% [95% CI 33–55] v 65% [44–79]; 2 yr, 39% [28–50] v 34% [15–54]). Fatal veno-occlusive disease (VOD) was observed in 5 InO pts (all during the first 100 days from the date of HSCT) and no C pts. MVA showed that conditioning regimens without dual alkylators and thiotepa were associated (2-sided; P<0.05) with lower risk of NRM and post-HSCT survival, respectively. Conclusions: Compared with C, InO permitted more pts with R/R ALL to proceed to HSCT in CR/CRi with MRDneg (best status). Despite increased NRM and fatal VOD, long-term survival was attainable in InO pts. In pts previously treated with InO, interventions to reduce NRM and improve OS after HSCT include avoiding dual alkylator conditioning regimens, especially those containing thiotepa. Funding: Pfizer Clinical trial information: NCT01564784.

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.).

Phase I study of inotuzumab ozogamicin (INO) combined with R-GDP for relapsed CD22+ B-cell non-Hodgkin lymphoma (B-NHL)

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Background: CD22 is expressed on most B-NHL. INO, an anti-CD22 antibody linked to calicheamicin, has activity in refractory B-NHL. This study hypothesized that INO plus rituximab, gemcitabine, dexamethasone, and cisplatin (R-GDP) for relapsed CD22+ B-NHL was safe and tolerable. Methods: Patients (pts) with relapsed CD22+ B-NHL treated with ≥1 prior R-chemo regimen were enrolled using an up-and-down independent dose-escalation schema for G and P. INO (0.8 mg/m2 day 2) was combined with R-GDP (R 375 mg/m2, G, and P day 1; oral D 40 mg days 1-4) on a 21-d cycle for up to 6 cycles. Dose-limiting toxicity (DLT) included febrile neutropenia, grade (Gr) 4 ANC lasting ≥7 d, Gr 4 platelets ≥7 d, Gr ≥3 platelets with bleeding and transfusion support, Gr ≥3 QTc prolongation, Gr 4 AST/ALT, Gr 2 bilirubin ≥7 d, G-CSF during cycle 1, Gr ≥3 clinically significant or drug-related nonhematologic toxicity ≥7 d, and Gr ≥2 drug-related nonhematologic toxicity causing dose delay of ≥7 d. Results: Thirty-seven pts were treated: 15 DLBCL, 11 FL, 7 MCL, 1 MZL, 1 SLL, and 2 indolent B-NHL. Characteristics: aged 33 to 81 y (median 65 y); 34 with ECOG PS £1; median of 2 prior chemo regimens (range 1-6); 5 refractory to prior therapy. No DLTs were observed at the starting dose of G 500 mg/m2, P 37.5 mg/m2 (n = 6); 2 DLTs (febrile neutropenia, Gr 2 platelets) at G 1000 mg/m2, P 37.5 mg/m2 (n = 3); no DLTs at G 1000 mg/m2, P 0 mg/m2 (n = 6); 2 DLTs (febrile neutropenia; Gr 4 ANC ≥7 d) at G 500 mg/m2, P 50 mg/m2 (n = 8); and 2 DLTs (Gr 3 hypokalemia, Gr 4 neutropenic sepsis) at G 500 mg/m2, P 75 mg/m2 (n = 4). In a maximum tolerated dose (MTD) confirmation cohort of 10 additional pts, 3 pts had DLTs (2 with Gr 4 platelets, 1 with febrile neutropenia); thus MTD was determined to be INO 0.8 mg/m2, R 375mg/m2, G 500 mg/m2, D 40 mg, P 50 mg/m2. Gr ≥3 adverse events included thrombocytopenia (68%), neutropenia (54%), lymphopenia (32%), anemia (27%), leukopenia (24%), hypokalemia (22%), fatigue (11%), and febrile neutropenia (11%). Median treatment cycle was 4 (range 1-6). There were 8 complete and 9 partial responses. Conclusions: INO 0.8 mg/m2 with R-GDP is tolerable at reduced doses of G (500 mg/m2) and P (50 mg/m2). Preliminary efficacy is being explored in the ongoing MTD expansion cohort. Clinical trial information: NCT01055496.

Safety and clinical activity of a combination therapy comprising two antibody-based targeting agents for the treatment of non-Hodgkin lymphoma: results of a phase I/II study evaluating the immunoconjugate inotuzumab ozogamicin with rituximab

PURPOSE

Inotuzumab ozogamicin (INO) is an antibody-targeted chemotherapy agent composed of a humanized anti-CD22 antibody conjugated to calicheamicin, a potent cytotoxic agent. We performed a phase I/II study to determine the maximum-tolerated dose (MTD), safety, efficacy, and pharmacokinetics of INO plus rituximab (R-INO) for treatment of relapsed/refractory CD20(+)/CD22(+) B-cell non-Hodgkin lymphoma (NHL).

PATIENTS AND METHODS

A dose-escalation phase to determine the MTD of R-INO was followed by an expanded cohort to further evaluate the efficacy and safety at the MTD. Patients with relapsed follicular lymphoma (FL), relapsed diffuse large B-cell lymphoma (DLBCL), or refractory aggressive NHL received R-INO every 4 weeks for up to eight cycles.

RESULTS

In all, 118 patients received one or more cycles of R-INO (median, four cycles). Most common grade 3 to 4 adverse events were thrombocytopenia (31%) and neutropenia (22%). Common low-grade toxicities included hyperbilirubinemia (25%) and increased AST (36%). The MTD of INO in combination with rituximab (375 mg/m(2)) was confirmed to be the same as that for single-agent INO (1.8 mg/m(2)). Treatment at the MTD yielded objective response rates of 87%, 74%, and 20% for relapsed FL (n = 39), relapsed DLBCL (n = 42), and refractory aggressive NHL (n = 30), respectively. The 2-year progression-free survival (PFS) rate was 68% (median, not reached) for FL and 42% (median, 17.1 months) for relapsed DLBCL.

CONCLUSION

R-INO demonstrated high response rates and long PFS in patients with relapsed FL or DLBCL. This and the manageable toxicity profile suggest that R-INO may be a promising option for CD20(+)/CD22(+) B-cell NHL.

Abstract 3767: Use of pharmacokinetic-pharmacodynamic modeling to characterize platelet response following inotuzumab ozogamicin treatment in patients with follicular or diffuse large B-cell non-Hodgkin's lymphoma

Background: Inotuzumab ozogamicin (CMC-544) is an immunoconjugate chemotherapy agent composed of a CD22-directed IgG4 antibody linked to calicheamicin, a potent cytotoxic anti-tumor antibiotic. Thrombocytopenia was the most frequent adverse event observed in phase 1/2 studies. This integrated population pharmacokinetic-pharmacodynamic (PK/PD) analysis was undertaken to a) elucidate the relationship between exposure of inotuzumab or total calicheamicin (tCali) and the decrease in platelet count; b) identify the covariates that influence the PK of inotuzumab and platelet response; and c) optimize the dosing schedule. Methods: Serum concentrations of inotuzumab, tCali (sum of conjugated and unconjugated forms), and platelet count were available from 5 phase 1/2 studies with follicular or diffuse large B-cell non-Hodgkin's lymphoma (NHL) who received inotuzumab alone or in combination with rituximab. Most patients received 1.8 mg/m2 of inotuzumab infused over 1 hour every 3 to 4 weeks (dose range, 0.4-2.4 mg/m2). The sequential PK/PD analysis was performed by nonlinear regression using NONMEM, version 7, level 1.2 (Icon Development Solutions, Hanover, MD). Covariates (factors for demography, hematology measures, renal and hepatic function, and baseline tumor size) were evaluated using graphical analysis, a general additive model (GAM), and a stepwise covariate model by forward addition and backward elimination process (SCM). Results and Conclusion: A 2-compartment model with linear elimination adequately described the PK of inotuzumab and tCali. The time course of platelet response was modeled using a semi-mechanistic transit compartment model model with drug effect as a sigmoidal Emax function. Significant covariate effects identified for PK estimates of inotuzumab included baseline body surface area (BSA) on clearance (CL) and central volume (V1), and baseline creatinine clearance on inter-compartment clearance (Q). For tCali, significant covariate effects included baseline BSA on CL and V1, treatment occasion (cycle) on CL and V1, and gender on peripheral volume (V2). The CL of tCali decreased from 0.73 L/h in Cycle 1 to 0.3 L/h in Cycles 2 and 3, suggesting a nonlinear disposition process. For the platelet model, the EC50 estimates for effect of inotuzumab and tCali on production of platelets were 219 and 50.2 ng/mL, respectively. Baseline platelet count was identified as a significant covariate. Integrated modeling of drug concentration and platelet count provides a means to quantify the magnitude of platelet suppression and to identify dosing schedules that mitigate the incidence of thrombocytopenia.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3767. doi:1538-7445.AM2012-3767

Phase I study of anti-CD22 immunoconjugate inotuzumab ozogamicin plus rituximab in relapsed/refractory B-cell non-Hodgkin lymphoma

Inotuzumab ozogamicin (CMC-544), a humanized anti-CD22 antibody conjugated to the potent cytotoxic antibiotic calicheamicin, targets the CD22 antigen expressed on the majority of B-cell non-Hodgkin lymphomas. This phase I study assessed the tolerability, safety, pharmacokinetics, and preliminary efficacy of inotuzumab ozogamicin administered intravenously in combination with rituximab in Japanese patients with relapsed or refractory B-cell non-Hodgkin lymphoma. Ten patients were administered rituximab 375 mg/m(2) followed by inotuzumab ozogamicin at the maximum tolerated dose (1.8 mg/m(2)). Treatment was repeated every 28 days up to eight cycles, or until occurrence of disease progression or intolerable toxicity. The safety profile was similar to that of inotuzumab ozogamicin monotherapy, with hematologic adverse events occurring most frequently. The most common grade three or higher adverse events were thrombocytopenia (70%), neutropenia (50%), leukopenia (30%), and lymphopenia (30%). The overall response rate was 80% (8/10; 95% CI, 44-98%). Drug exposure increased with successive doses, similar to the pharmacokinetic profiles observed in previous phase I monotherapy studies. Efficacy results suggested promising antitumor activity, and the overall findings support the continued clinical development of this therapeutic regimen in patients with relapsed or refractory B-cell non-Hodgkin lymphoma. This trial was registered at www.ClinicalTrials.gov as NCT00724971.

Safety, pharmacokinetics, and preliminary clinical activity of inotuzumab ozogamicin, a novel immunoconjugate for the treatment of B-cell non-Hodgkin's lymphoma: results of a phase I study

PURPOSE Inotuzumab ozogamicin (CMC-544) is an antibody-targeted chemotherapy agent composed of a humanized anti-CD22 antibody conjugated to calicheamicin, a potent cytotoxic agent. This was a phase I study to determine the maximum-tolerated dose (MTD), safety, and preliminary efficacy of inotuzumab ozogamicin in an expanded MTD cohort of patients with relapsed or refractory CD22(+) B-cell non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS Inotuzumab ozogamicin was administered intravenously as a single agent once every 3 or 4 weeks at doses ranging from 0.4 to 2.4 mg/m(2). Outcomes included MTD, safety, pharmacokinetics, response, progression-free survival (PFS), and overall survival. Results Seventy-nine patients were enrolled. The MTD was determined to be 1.8 mg/m(2). Common adverse events at the MTD were thrombocytopenia (90%), asthenia (67%), and nausea and neutropenia (51% each). The objective response rate at the end of treatment was 39% for the 79 enrolled patients, 68% for all patients with follicular NHL treated at the MTD, and 15% for all patients with diffuse large B-cell lymphoma treated at the MTD. Median PFS was 317 days (approximately 10.4 months) and 49 days for patients with follicular NHL and diffuse large B-cell lymphoma, respectively. CONCLUSION Inotuzumab ozogamicin has demonstrated efficacy against CD22(+) B-cell NHL, with reversible thrombocytopenia as the main toxicity.

Phase I clinical and pharmacokinetic (PK) trial of the kinesin spindle protein (KSP) inhibitor MK-0731 in patients with solid tumors

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Background: KSP is essential for the separation of spindle poles during mitosis and inhibition results in mitotic arrest. MK- 0731 is a potent inhibitor of KSP, with an IC50 of 2.2 nM, and >20,000 fold selectivity against other kinesins. MK-0731 causes mitotic arrest with an EC50 in several tumor cell lines of 3–5 nM. Methods: Phase I study to determine the safety and tolerability, MTD, and PK of MK-0731 administered IV over 24 hrs every 21 days. In part 1, dosing started at 6 mg/m2/24 hr and was escalated until the MTD was reached. In part 2, pts with measurable taxane-resistant cancer were treated at the MTD established in Part 1 (target accrual =22 pts in part 2). Interim Results: 35 pts with solid tumors (M/F 23/12), median age 63 yrs (23 - 79), were treated at doses of 6 to 48 mg/ m2/24hrs (median cycles 3, range 1–10, total cycles=128). Frequent tumor types included prostate (8), ovarian (4), colon (3), bladder (2), neuroendocrine (2), lung (2), breast (2). Prolonged (>5 days) grade 4 neutropenia was observed in 2 pts at 48 mg/m2/24hrs (11 days duration) and 2 pts at 24 mg/m2/24hrs (7 days duration) leading to expansion of cohorts at lower dose levels. At the MTD of 17 mg/ m2/24, there were no DLTs. 14 patients have been enrolled at the MTD in part 2 of the study. Drug related grade 3/4 toxicities were anemia (1), AST (1), hyperglycemia (1), nausea/vomiting (1), neutropenia (7), syncope (1). PK results from the first 20 patients suggest that MK- 0731 concentrations appear to decline monoexponentially or biexponentially following the infusion with terminal t1/2 from ∼4 to 22 hrs. In some patients, steady-state concentrations may not be achieved by the end of the 24 hr infusion. Mean values at the 17 mg/m2/24hrs dose level were Cmax=599 nM, AUC8=14.56 μM·hr, and CL=119 mL/min. AUC, exposures, and end of infusion concentrations appear to increase proportionally with dose. Stable disease for = 4 cycles (range 4- 10) was seen in 16 patients. Conclusion: Treatment with MK-0731 at the MTD of 17 mg/m2/day every 21 days in patients with advanced solid tumors was well tolerated with consistent dose limiting toxicity of myelosuppression.

No significant financial relationships to disclose.

Accumulation of tissue factor into developing thrombi in vivo is dependent upon microparticle P-selectin glycoprotein ligand 1 and platelet P-selectin

Using a laser-induced endothelial injury model, we examined thrombus formation in the microcirculation of wild-type and genetically altered mice by real-time in vivo microscopy to analyze this complex physiologic process in a system that includes the vessel wall, the presence of flowing blood, and the absence of anticoagulants. We observe P-selectin expression, tissue factor accumulation, and fibrin generation after platelet localization in the developing thrombus in arterioles of wild-type mice. However, mice lacking P-selectin glycoprotein ligand 1 (PSGL-1) or P-selectin, or wild-type mice infused with blocking P-selectin antibodies, developed platelet thrombi containing minimal tissue factor and fibrin. To explore the delivery of tissue factor into a developing thrombus, we identified monocyte-derived microparticles in human platelet-poor plasma that express tissue factor, PSGL-1, and CD14. Fluorescently labeled mouse microparticles infused into a recipient mouse localized within the developing thrombus, indicating that one pathway for the initiation of blood coagulation in vivo involves the accumulation of tissue factor- and PSGL-1-containing microparticles in the platelet thrombus expressing P-selectin. These monocyte-derived microparticles bind to activated platelets in an interaction mediated by platelet P-selectin and microparticle PSGL-1. We propose that PSGL-1 plays a role in blood coagulation in addition to its known role in leukocyte trafficking.

Development and testing of invasion-associated DNA probes for detection of Shigella spp. and enteroinvasive Escherichia coli

Genetic determinants of the invasive phenotype of Shigella spp. and enteroinvasive Escherichia coli (EIEC), two common agents of bacillary dysentery, are encoded on large (180- to 210 kilobase), nonconjugative plasmids. Several plasmid-encoded antigens have been implicated as important bacterial ligands that mediate the attachment and invasion of colonic epithelial cells by the bacteria. Selected invasion plasmid antigen (ipa) genes have recently been cloned from Shigella flexneri serotype 5 into the lambda gt11 expression vector. Portions of three ipa genes (ipaB, ipaC, and ipaD) were tested as DNA probes for diagnostic detection of bacillary dysentery. Under stringent DNA hybridization conditions, all three DNA sequences hybridized to a single 4.6-kilobase HindIII fragment of the invasion plasmids of representative virulent Shigella spp. and EIEC strains. No hybridization was detected in isogenic, noninvasive Shigella mutants which had lost the invasion plasmid or had deleted the ipa gene region. Furthermore, these probes did not react with over 300 other enteric and nonenteric gram-negative bacteria tested, including Salmonella, Yersinia, Edwardsiella, Campylobacter, Vibrio, Klebsiella, Aeromonas, Enterobacter, Rickettsia, and Citrobacter spp. and various pathogenic E. coli strains. The use of unique invasion-essential gene segments as probes for the specific detection of invasive dysentery organisms should benefit both epidemiologic and diagnostic analyses of Shigella spp. and EIEC.