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308 Addition of Inotuzumab to a Pediatric Inspired Chemotherapy Regimen in Young Adult Patients with B-Cell Acute Lymphoblastic Leukemia: Findings from the Alliance A041501 Phase 3 Randomized Trial

Program: Oral and Poster Abstracts
Type: Oral
Session: 613. Acute Lymphoblastic Leukemias: Therapies Excluding Allogeneic Transplantation: Clinical Trials in Pediatric and Young Adult Patients
Hematology Disease Topics & Pathways:
Clinical trials, Research, Clinical Research
Saturday, December 7, 2024: 4:15 PM

Daniel J. DeAngelo, MD, PhD1, Jun Yin2*, Anjali S. Advani, MD3, Selina Luger, MD, FRCPC4, Jill Fulcher, MD, PhD, FRCPath5, Michaela Liedtke, MD6, Geoffrey L. Uy, MD7, Shira N. Dinner, MD8, Lindsay Wilde, MD9, Marlise R. Luskin, MD1, Caner Saygin, MD10, Ella Postich10*, Noreen Fulton10*, Richard C. Harvey, PhD11*, Gaby E Perez Burbano, MS12*, Rebecca Teske12*, Harry P. Erba, MD, PhD13, Mark R. Litzow, MD14, Richard M. Stone, MD1 and Wendy Stock, MD10

1Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
2Department of Biostatistics and Bioinformatics, HL Moffitt Cancer Center, Tampa, FL
3Department of Hematology and Medical Oncology, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH
4Abramson Cancer Center, Hospital of the University of Pennsylvania, Philadelphia, PA
5Department of Medicine, University of Ottawa at The Ottawa Hospital and the Ottawa Hospital Research Institute, Ottawa, ON, CAN
6Stanford University Cancer Center, Stanford, CA
7Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO
8Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL
9Sidney Kimmel Comprehensive Cancer Center, Thomas Jefferson University, Philadelphia, PA
10Department of Medicine, Section of Hematology/Oncology, University of Chicago, Chicago, IL
11University of New Mexico School of Medicine, Albuquerque, NM
12Division of Clinical Trials and Biostatistics, Mayo Clinic, Rochester, MN
13Duke University Cancer Institute, Durham, NC
14Division of Hematology, Mayo Clinic, Rochester, MN

Introduction: Inotuzumab ozogamicin (INO) is an antibody targeting CD22 conjugated with a cytotoxic antitumor antibiotic (calicheamicin) approved for treatment of relapsed/refractory CD22 positive B-cell acute lymphoblastic leukemia (ALL) (Kantarjian et al. NEJM 2017). CD22 is expressed on the surface of lymphoblasts in ALL (~95%). Young adult patients (pts) 18-39 years (yrs) treated on the pediatric regimen CALGB 10403 resulted in a 3-yr event-free survival (EFS) of 59% (95% CI: 52-67%) and an estimated 3-yr overall survival (OS) of 73% (95% CI: 68-78%) (Stock et al. Blood 2019). Alliance A041501(NCT03150693), a phase 3 NCTN sponsored cooperative group trial was conducted to determine if the addition of INO to the CALGB 10403 pediatric regimen would significantly improve EFS.

Methods: Eligibility included pts 18-39 years with newly diagnosed CD22 positive ALL, defined as baseline expression in > 20% of lymphoblasts by local institution. Pts with Burkitt-type ALL, BCR::ABL1 positive ALL, or Down syndrome were excluded. Eligible pts received the CALGB 10403 regimen modified to omit extended induction, include dexamethasone as opposed to prednisone as steroid backbone, cap the pegaspargase dose to 3750 units, and adding rituximab for pts with CD20 expression (> 20%). An amendment added blinatumomab for minimal residual disease (MRD) positivity. Pts achieving a complete remission (CR/CRi) or partial remission (PR) were eligible for randomization. Following a 6 pt safety run-in with INO, pts were randomized 1:1 to receive INO or continue CALGB 10403 backbone. Two cycles of INO (1.5 mg/m2/cycle) were administered following induction in the experimental arm. Pts were stratified by age, disease status post induction (M0/M1 vs M2), CD20 status, and LDA Card, which tests for the Ph-like status. The primary endpoint was to determine if the addition of INO would improve the EFS of the pediatric regimen CALGB 10403 without censoring for stem cell transplant (SCT). Key secondary endpoints included the impact of INO on disease-free survival (DFS), OS, and MRD. The Alliance Data and Safety Monitoring Board halted enrollment after 273 out of a planned 341 pts were registered because of increased grade (gr) 5 events in the INO arm compared with the control arm.

Results: 273 pts were enrolled between 6/15/2018, and 5/24/2022. Median age was 27.0 yrs, 65.2% were White, 30.4% were Hispanic, and 63.4% were male. Baseline CSF analysis revealed 14% with CNS-2/3 disease. The overall CR rate was 86.8% (82.8-90.8%). 46 pts were not randomized due to death (5), withdrawal (6), ineligibility (3), toxicity (5), receipt of non-protocol therapy (8), progression (5), and other (14). 227 eligible pts were randomized 1:1 to receive INO (N=111) or not (N=116)). For randomized pts, 92.5% achieved M0/M1 marrow status, 48.9% had a positive LDA Card defining Ph-like ALL, 50.7% were CD20 positive. Only 36 pts (13%) received a SCT.

With a median follow up of 28.3 months for randomized pts, 3-yr EFS was 69.0% (59.1-80.5%) for the INO arm and 66.7% (57.1-78.1%) for the control (HR=0.97; 0.58-1.63). Similarly, the 3-yr OS was 79.4% (71.0-88.7%) for the INO arm and 80.3% (71.9-89.6%) for the control (HR=1.05; 0.55-2.01). The MRD undetectable rate at Course II Day 56 was 80.6% in the INO arm and 74.2% in the control arm. Univariate analysis suggests improved EFS with INO in pts with a positive LDA card (Ph-like ALL) and of Hispanic ethnicity. There were 22 gr 5 events, 7 occurred prior to randomization. Of the 15 gr 5 events on the randomized cohort, 12 were reported in the INO arm and 3 in the control arm. Of the 12 gr 5 events in the INO arm, all occurred during intensive consolidation courses complicated by prolonged pancytopenia infection/sepsis (8), hepato-biliary in setting of infection (2), multi-organ failure (1), or post-surgical complication (1). These events occurred after INO during Course II (3), Course III (5), or Course IV (4).

Conclusions: Although this trial did not meet the primary EFS endpoint for the addition of INO to the pediatric regimen CALGB 10403, these data provide compelling evidence for continued use of pediatric regimens in young adults with ALL as the EFS and OS compares favorably with prior published results. INO may still be efficacious if late toxicity can be mitigated. A pilot study is planned that will decrease INO dose, add 2 cycles of blinatumomab and strict infectious prophylaxis guidelines.

Support: U10CA180821, U10CA180882

Disclosures: DeAngelo: Gilead: Consultancy; Amgen: Consultancy, Honoraria; AbbVie: Research Funding; Blueprint: Consultancy, Research Funding; Curis: Consultancy; Daiichi-Sankyo: Other: DSMB; Fibrogen: Other: DSMB; Glycomimetics: Research Funding; Bristol-Meyers Squibb: Honoraria; Servier: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy; Jazz: Consultancy; Kite: Consultancy; Novartis: Consultancy, Research Funding; Incyte: Consultancy; Autolos: Consultancy; MT Sinai MPN Consortium: Other: DSMB; Takeda: Consultancy. Advani: Seattle Genetics: Research Funding; Glycomimetics: Research Funding; Amgen: Research Funding; Springer: Honoraria; Macrogenics: Research Funding; Pfizer: Other: Manuscript help, Research Funding; Kite: Consultancy, Research Funding; BEAM: Other: Research support, Research Funding; Emmes: Honoraria; PER: Honoraria; Incyte: Research Funding; OBI: Research Funding; MJH Life: Honoraria; Immunogen: Research Funding; Web MD: Honoraria; Wiley: Honoraria; Wolters Kluwer: Honoraria; MD Education: Honoraria; American Society of Hematology: Honoraria; Servier: Research Funding; Kura: Research Funding; Novartis: Consultancy. Luger: AbbVie: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Marker Therapeutics: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy. Fulcher: Pfizer: Honoraria; Amgen: Honoraria; AbbVie: Honoraria; Gilead: Honoraria; Jazz Pharmaceuticals: Honoraria; Novartis: Honoraria. Liedtke: Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Allogene: Research Funding; Biomea: Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Caelum/Alexion: Research Funding; Gilead: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite: Membership on an entity's Board of Directors or advisory committees; Nexcella: Membership on an entity's Board of Directors or advisory committees; Seagen: Research Funding. Dinner: Kite: Consultancy; Rigel: Consultancy; Pfizer: Consultancy. Wilde: Protagonist: Research Funding; Gilead: Research Funding; Karyopharm: Research Funding; Servier: Research Funding. Luskin: AbbVie: Research Funding; Jazz: Honoraria; KITE: Honoraria; Pfizer: Honoraria; Novartis: Honoraria, Research Funding. Erba: Daiichi Sankyo: Honoraria. Litzow: Abbvie: Research Funding; Amgen: Research Funding, Speakers Bureau; Actinium: Research Funding; Astellas: Research Funding; Pluristem: Research Funding; Sanofi: Research Funding; Beigene: Speakers Bureau; Biosight: Other: Data Safety Monitoring Committee. Stone: AbbVie: Consultancy, Other: Research funding to my institution; AvenCell: Consultancy; Ligand Pharma: Consultancy; Epizyme: Consultancy, Other: DSMB; ENSEM: Consultancy; Jazz: Consultancy; Novartis: Other: Research funding to my institution; Janssen: Other: Research funding to my institution; CTI Biopharma: Consultancy; Curis Oncology: Consultancy; BerGenBio: Consultancy; Aptevo: Consultancy; Kura Oncology: Consultancy; AMGEN: Consultancy; Syntrix: Other: DSMB; Rigel: Consultancy; Glycomimetrics: Consultancy; Glaxosmithkline: Consultancy; Bristol Meyers Squibb: Consultancy; Cellarity: Consultancy; Daiichi Sankyo: Consultancy; Lava Therapeutics: Consultancy; Redona therapeutics: Consultancy; Hermavant: Consultancy; Syndax: Other: Research funding to my institution; Takeda: Other: DSMB. Stock: Kura: Research Funding; Adaptive: Consultancy, Honoraria; Kura, Servier, Newave, Adaptive, Jazz, Asofarma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

OffLabel Disclosure: Inotuzumab in upfront ALL

*signifies non-member of ASH