A phase II study of hyper-CVAD with sequential blinatumomab (Blina), with or without inotuzumab ozogamicin (INO), in adults with newly diagnosed B-cell acute lymphoblastic leukemia (ALL).

7034 Background: Blina and INO are highly effective in relapsed/refractory B-cell ALL and are associated with high rates of measurable residual disease (MRD) clearance. Use of these agents in the frontline setting may improve outcomes. Methods: Patients (pts) 14-59 years of age with newly diagnosed Philadelphia chromosome (Ph)-negative B-cell ALL, including pts who had received no more than 1 prior cycle of chemotherapy, were eligible. Pts received hyper-CVAD alternating with high-dose MTX/Ara-C for up to 4 cycles, followed by 4 cycles of Blina. Pts with CD20+ disease received 8 doses of an anti-CD20 antibody. Eight doses of IT chemotherapy were given. Maintenance was with alternating blocks of POMP (maintenance cycles 1-3, 5-7, 9-11, and 13-15) and Blina (maintenance cycles 4, 8, and 12). Beginning with pt #39, INO at a dose of 0.3 mg/m2 on day 1 and 8 was added to the 2 cycles of MTX/Ara-C and to 2 cycles of Blina (4 total cycles with INO). Results: Characteristics of the 58 treated pts (38 without INO and 20 with INO) are summarized in Table. Among 45 pts with active disease at study entry, 100% achieved CR. Overall, 76% achieved MRD negativity by flow cytometry after induction and 95% at any time over the course of therapy. The median follow-up of the entire cohort is 26 months (range, 3-61+ months). Overall, 5 pts (9%) relapsed, 18 (31%) underwent transplant in first remission (including an additional 2 pts who relapsed post-transplant), 2 (3%) died in CR, and 33 (57%) remain in continuous remission without transplant. All relapses occurred in pts with established poor-risk features and no relapses have occurred beyond 2 years. For the entire cohort, the estimated 3-year OS is 85% and the 3-year continuous remission duration is 84%. No relapses or deaths have occurred in the INO group, and the estimated 1-year OS is 100%. Treatment was overall well-tolerated. One patient discontinued Blina due to recurrent grade 2 neurotoxicity. No pts have discontinued INO due to toxicity and no cases of veno-occlusive disease have been observed. Conclusions: Hyper-CVAD with sequential Blina is highly effective as frontline treatment of Ph-negative B-cell ALL. The addition of INO to this regimen was safe and early results are encouraging, with no relapses observed to date. Clinical trial information: NCT01371630. [Table: see text]