First-line monotherapy with low-dose gemtuzumab ozogamicin significantly improved overall survival compared with best supportive care in older patients with newly diagnosed acute myeloid leukemia (AML) ineligible to undergo intensive chemotherapy, a study published online ahead of print in the Journal of Clinical Oncology has shown.1
For the phase 3 trial, researchers sought to compare single-agent gemtuzumab ozogamicin with best supportive care, including hydroxyurea, as frontline therapy in older patients with AML unsuitable for intensive chemotherapy.
Researchers enrolled a total of 237 patients at least 61 years old and randomly assigned them to receive a single induction course of gemtuzumab ozogamicin 6 mg/m2 on day 1 and 3 mg/m2 on day 8 or best supportive care. Participants that did not progress after induction could receive up to 8 monthly infusions at 2 mg/m2 per dose.
Results showed that median overall survival was 4.9 months (95% CI: 4.2-6.8) with the immunoconjugate and 3.6 months (95% CI: 2.6-4.2) with best supportive care (HR, 0.69; 95% CI: 0.53-0.90; P=.005). The 1-year overall survival rate was 24.3% and 9.7%, respectively.
Subgroup analyses demonstrated an overall survival benefit with gemtuzumab ozogamicin across most subgroups, particularly in patients with high CD33 expression, those with a favorable/intermediate cytogenetic risk profile, and in women.
With respect to safety, the incidence of serious adverse events was similar between the 2 arms. Researchers observed no unexpected treatment-related adverse reactions and toxicity was manageable.
1. Amadori S, Suciu S, Selleslag D, et al. Gemtuzumab ozogamicin versus best supportive care in older patients with newly diagnosed acute myeloid leukemia unsuitable for intensive chemotherapy: Results of the randomized phase III EORTC-GIMEMA AML-19 trial [published online ahead of print January 25, 2016]. J Clin Oncol. doi:10.1200/JCO.2015.64.0060.