ORLANDO, FL—Inotuzumab ozogamicin combined with low-intensity mini-hyper-CVD chemotherapy is safe and shows encouraging results in older patients with acute lymphoblastic leukemia (ALL), according to results from an ongoing study reported at the 57th American Society of Hematology (ASH) Annual Meeting.1
The 2-year overall survival for patients treated with the mini-hyper-CVD regimen was 64%, compared with 38% for historical HCVAD with and without rituximab in a similar patient population (P = .09).
The objective response rate was 97%, the cytogenetic complete response rate was 100%, and the negative minimal residual disease rate was 100%.
“These early results appear to be better than those achieved with a chemotherapy alone only approach and may become the new standard of care for frontline treatment of older patients with ALL,” said Elias Jabbour, MD, of the University of Texas MD Anderson Cancer Center in Houston, TX.
Previously, inotuzumab ozogamicin, a CD22 monoclonal antibody bound to a toxin, calicheamicin, has shown single-agent activity in patients with relapsed/refractory ALL. Dr Jabbour and colleagues hypothesized that among the elderly with ALL, who poorly tolerate intensive chemotherapy, might benefit from treatment with inotuzumab ozogamicin when combined with mini-hyper-CVD (cyclophosphamide and dexamethasone at 50% dose reduction, no anthracycline, methotrexate at 75% dose reduction, cytarabine at 0.5 g/m2 x 4 doses).
The study treated patients 60 or older newly diagnosed with Ph-negative pre-B-cell ALL with the combination on day 3 of each of the first 4 courses. Rituximab and intrathecal chemotherapy were given for the first 4 courses. The first 6 patients received inotuzumab ozogamicin 1.3 mg/m2 for cycle 1 followed by 0.8 mg/m2 for subsequent cycles; patients 7 to 34 received 1.8 mg/m2 for Cycle 1 followed by 1.3 mg/m2 for subsequent cycles; and patient 35 and beyond received 1.3 mg/m2 for Cycle 1 followed by 1.0 mg/m2 for subsequent cycles.
To date, 38 patients have been treated; 61% were male and median age is 69 (range, 60-79).
Response in 35 patients showed 29 (80%) had a complete remission (3 patients enrolled with a complete remission) and 6 (17%) attained a CR with incomplete platelet recovery, for an objective response rate of 97%. One patient had no response and none of the patients experienced an early death.
Veno-occlusive disease was observed in 4 patients; mild in 2 and severe in 2.
At a median follow-up of 23 months (range, 1-45 months), 24 patients were alive, Dr Jabbour reported.
Nine patients in remission died; causes were sepsis (3 patients), gunshot wound (1 patient), veno-occlusive disease (2 patients), dementia (1 patient), end-stage renal disease (1 patient), and unknown (1 patient). Two patients (6%) had received allogeneic stem cell transplantation, and 1 remained alive.
Of the responders, 4 patients (12%) were receiving consolidation chemotherapy with a median of 5 cycles (range, 1-8 cycles) and 16 patients (47%) were receiving 6-mercaptopurine, vincristine, methotrexate, and prednisone (POMP) maintenance chemotherapy. Two had completed treatment.
1. Jabbour E, O’Brien S, Sasaki K, et al. Frontline inotuzumab ozogamicin in combination with low-intensity chemotherapy (mini-hyper-CVD) for older patients with acute lymphoblastic leukemia (ALL). Oral presentation at: 57th American Society of Hematology (ASH) Annual Meeting; December 5, 2015, Orlando, FL.