Updated results from a phase II study of mini-hyper-CVD (mini-HCVD) plus inotuzumab ozogamicin (INO), with or without blinatumomab (Blina), in older adults with newly diagnosed Philadelphia chromosome (Ph)-negative B-cell acute lymphoblastic leukemia (ALL).

Abstract

7011 Background: INO and Blina improve overall survival (OS) in patients (pts) with relapsed/refractory B-ALL. The use of these agents in older adults in the frontline setting may allow for use of less chemotherapy and improve remission duration and OS compared to standard therapies. Methods: Pts ≥60 years with newly diagnosed Ph-negative B-cell ALL received mini-HCVD for up to 8 cycles. Initially, INO was given at 1.3-1.8mg/m2 on day 3 of cycle 1 and 0.8-1.3mg/m2 on day 3 of cycles 2-4. Rituximab (if CD20+) and prophylactic IT chemotherapy were given for the first 4 cycles. Responding pts received POMP maintenance for up to 3 years. Beginning with pt #50, INO was given in fractionated doses each cycle (0.6 mg/m2 on day 2 and 0.3 mg/m2 on day 8 of cycle 1; 0.3 mg/m2 on day 2 and 8 of cycles 2-4) and 4 cycles of Blina were given following 4 cycles of mini-HCVD plus INO. Maintenance was with 12 cycles of POMP and 4 cycles of Blina (1 cycle of Blina after 3 cycles of POMP). Results: Characteristics of the 80 pts are shown in Table. 6 pts were in complete remission (CR) at enrollment. Among 74 evaluable pts, 73 (99%) responded (CR in 89%). MRD negativity by flow was achieved in 80% of pts after 1 cycle and in 94% overall. The 30-day mortality rate was 0%. Among 79 responders, 11 (14%) relapsed, 4 (5%) underwent SCT, 33 (42%) remain in ongoing continuous remission, and 31 (39%) died in remission. Notably, 6 pts (8%) developed veno-occlusive disease, 1 after subsequent SCT. With a median follow-up of 55 months, the 5-year continuous remission and OS rates were 76% and 47%, respectively. Age ≥70 and poor-risk cytogenetics were associated with worse outcomes. The inferior outcomes in pts ≥70 years was primarily due to higher rates of death in CR. The 5-year OS for pts age 60-69 years without poor-risk cytogenetics (n=37), age 60-69 with poor-risk cytogenetics (n=13), age ≥70 without poor-risk cytogenetics (n=24) and age ≥70 with poor-risk cytogenetics (n=6) were 69%, 39%, 36% and 0%, respectively. Conclusions: The combination of mini-HCVD plus INO, with or without Blina, in older adults with newly diagnosed Ph-negative ALL resulted in an overall response rate of 99% and a 5-year OS rate of 47%. Particularly favorable outcomes were seen in pts age 60-69 years without poor-risk cytogenetics (5-year OS: 69%). Chemotherapy-free regimens may improve outcomes in pts age ≥70 years, and novel agents/regimens are still needed for those with poor-risk cytogenetics. Clinical trial information: NCT01371630. [Table: see text]