Session: 614. Acute Lymphoblastic Leukemias: Therapies, Excluding Transplantation and Cellular Immunotherapies: Poster I
Hematology Disease Topics & Pathways:
Lymphoid Leukemias, Clinical Trials, ALL, Biological therapies, Adults, Bispecific Antibody Therapy, Workforce, Diseases, Therapies, Lymphoid Malignancies, Study Population
Methods: From October 2018 to December 2020, 95 patients with high-risk Ph-negative BCP-ALL without central nervous system involvement at diagnosis and in continuous complete remission after induction and consolidation 1, were prospectively included to start blinatumomab at week 12. One patient was excluded because of T-ALL phenotype (with CD19 aberrant expression). Patients with alloSCT indication and a stem cell source received blinatumomab 28 microg/d administered by continuous intravenous infusion (cIV) until transplant. A minimum of 4 weeks blinatumomab was recommended before proceeding to transplantation. All other patients received 5 cycles of blinatumomab 28 microg/day cIV (for 28 days), during consolidation 2 and 3 and at months 1/3/5 of the maintenance phase respectively. The primary objective was disease-free survival (DFS). Secondary objectives included post-blinatumomab MRD response at TP3 (after consolidation 2 or before alloSCT), overall survival (OS), and safety. Early results are reported here.
Results: Median age was 35 years old (range, 18-60). Median white blood cell count (WBC) at diagnosis was 12 G/L (range, 1-449). Oncogenetic analyses allowed classifying ALL as Ph-like (18%), KMT2A-r (17%), DUX4/ERGdel (13%), ZNF384-r (11%), low hypodiploidy/near triploidy (7%), B-other (26%) or unknown (9%). An IKZF1del was found in 37/93 (40%). A TP1-MRD ≥ 0.01% was found in 46/94 patients (49%). Final risk group was HR for 45 patients and VHR for 49 patients. Last pre-blinatumomab MRD was <0.01% in 49/88 (56%) of evaluable patients. A total of 40 patients (42%) received an alloSCT. The median number of blinatumomab cycles received in patients not proceeding to alloSCT was 4 cycles (range, 1-5). Thirty-nine severe adverse events (SAEs) were reported: 1 CRS (grade 2), 8 neurotoxicities (1 grade 2, 3 grade 3, 3 grade 4, 1 grade 5), 19 infections, and 11 others. The only grade 5 SAE occurred after alloSCT (seizures). After blinatumomab, a complete MRD response (with at least 0.01% sensitivity) was achieved in 61/82 (74%) evaluable patients and in evaluable patients with pre-blinatumomab detectable MRD. MRD response to blinatumomab was lower in patients with high pre-blinatumomab MRD level, while not impacted by age, WBC, or oncogenic subgroup. With a median follow-up of 20 months, 18-month DFS and OS was 78.8% (95% CI [66.9-86.8]) and 92.1% (95% CI [83.2-96.4]) respectively (Figure 1). Patients with VHR diseases had a worse DFS (68.8%, 95% CI [51.1-81.2]) as compared to other patients (90.6%, 95% CI [72.1-97.1]); p=0.018). This difference of DFS was abrogated by censoring patients at transplant (VHR 88.1%, 95% CI [65.5-96.3] versus others 90.6%, 95% CI [72.1-97.1%], p=0.10). Other factors significantly associated with better DFS were DUX4/ERGdel subgroup, low pre-blinatumomab MRD, and complete MRD response after blinatumomab.
Conclusion. In patients wih high-risk BCP-ALL, blinatumomab added to consolidation is safe and gives promising results. A comparison to similar patients treated in the same GRAALL-2014 study before October 2018 is planned with a longer follow-up.
Disclosures: Boissel: Novartis: Consultancy, Honoraria, Research Funding; Incyte: Honoraria; Amgen: Consultancy, Honoraria, Research Funding; SANOFI: Honoraria; Servier: Consultancy, Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; CELGENE: Honoraria; JAZZ Pharma: Honoraria, Research Funding; PFIZER: Consultancy, Honoraria. Huguet: Novartis: Other: Advisor; Jazz Pharmaceuticals: Other: Advisor; Celgene: Other: Advisor; BMS: Other: Advisor; Amgen: Other: Advisor; Pfizer: Other: Advisor. Rousselot: Incyte, Pfizer: Consultancy, Research Funding. Chalandon: Incyte, BMS, Pfizer, Abbie, MSD, Roche, Novartis, Amgen: Other: Advisory Board; Incyte: Speakers Bureau; Incyte, BMS, Pfizer, Abbie, MSD, Roche, Novartis, Gilead, Amgen, Jazz, Astra Zenec: Other: Travel EXpenses, Accomodation. Delabesse: Astellas: Consultancy; Novartis: Consultancy. Dombret: Abbvie: Honoraria; Amgen: Honoraria, Research Funding; Incyte: Honoraria, Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; NOVARTIS: Research Funding; pfizer: Honoraria, Research Funding; servier: Research Funding; BMS-Celgene: Honoraria; Daiichi Sankyo: Honoraria.
OffLabel Disclosure: Blinatumomab in frontline high-risk acute lymphoblastic leukemia