The following is a summary of “Inotuzumab Ozogamicin as Induction Therapy for Patients Older Than 55 Years With Philadelphia Chromosome–Negative B-Precursor ALL,” published in the October 2023 issue of Oncology by Stelljes, et al.

For a study, researchers sought to evaluate the efficacy and safety of inotuzumab ozogamicin and dexamethasone as induction therapy in older patients with newly diagnosed CD22-positive BCR::ABL-negative B-precursor acute lymphoblastic leukemia (B-ALL).

In the phase II multicenter INITIAL-1 trial conducted by the German Multicenter Study Group for Adult ALL (GMALL), 45 patients aged over 55 years with B-ALL were enrolled. Patients underwent up to three cycles of inotuzumab ozogamicin/Dex induction therapy, followed by age-adapted GMALL consolidation and maintenance therapy for up to six cycles.

In the study, 43 evaluable patients diagnosed with common/pre-B (n = 38) and pro-B acute lymphoblastic leukemia (ALL) (n = 5), with a median age of 64 years (range, 56-80), underwent at least two cycles of inotuzumab ozogamicin induction therapy. All patients achieved complete remission (CR/CR with incomplete hematologic recovery). Molecular assessment revealed that 53% and 71% of patients had no measurable residual disease (MRD) after the second and third inductions, respectively, using a minimum threshold of 10e−4. Over a median follow-up of 2.7 years, the event-free survival rates at one and three years were 88% (95% CI, 79 to 98) and 55% (95% CI, 40 to 71), respectively. The overall survival (OS) rates at the same time points were 91% (95% CI, 82 to 99) and 73% (95% CI, 59 to 87), respectively. No deaths occurred within the first 6 months after the start of induction. The most common adverse events during induction with a grade ≥3, according to common toxicity criteria, included leukocytopenia, neutropenia, thrombocytopenia, anemia, and elevated liver enzymes. Only one patient developed nonfatal veno-occlusive disease after the second induction.

Inotuzumab ozogamicin–based induction followed by age-adapted chemotherapy demonstrated high remission rates and overall survival. The findings supported the integration of inotuzumab ozogamicin into first-line regimens for older patients with B-ALL.

Source: ascopubs.org/doi/10.1200/JCO.23.00546