Clinical impact of post-remission therapy after MIDAM regimen in patients with acute myeloid leukemia

In a Letter to the Editor of the American Journal of Hematology, Salem Bahashwan and colleagues from Clermont Auvergne University, Clermont-Ferrand, France, reported data from their study which evaluated the efficacy and tolerance of gemtuzumab ozogamicin, intermediate-dose cytarabine, and mitoxantrone (MIDAM) as salvage therapy in patients with relapsed or refractory (R/R) acute myeloid leukemia (AML). The impact of post-remission therapy after MIDAM therapy was also evaluated.

Eighty-six patients (median age = 60 years; range: 17–75) with relapsed (n = 62) or refractory (n = 24) AML who were treated with MIDAM regimen between 2008 and 2013 at Clermont Auvergne University Hospital were included in this study. Patients received a MIDAM regimen consisting of gemtuzumab ozogamicin (9 mg/m² on day 4), cytarabine (1 g/m² every 12 hours on day 1–5), and mitoxantrone (12 mg/m²/d on day 1–3) as salvage therapy after one (n = 73) or more (n = 13) prior therapy lines. 

Key findings

• Overall response rate: 63% (54/86)
• Complete response (CR) rate: 36% (31/86)
• CR with incomplete platelet count (CRp): 27% (23/86)
• Eight (9.3%) patients had veno-occlusive disease (VOD) associated with MIDAM regimen
• Grade 3–4 hyperbilirubinemia and febrile neutropenia occurred in 11 (12.8%) and all patients, respectively
• Forty-six (53.5%) patients had persistent thrombocytopenia at day 45
• 30-day mortality rate: 10% (9/86)

Of the 54 patients with CR or CRp, post-remission therapy consisted of chemo-based approaches (chemotherapy only, n = 10; chemotherapy plus autologous transplantation, n = 3) and allogeneic hematopoietic stem cell transplantation (allo-HSCT, n = 29). Seven patients who underwent allo-HSCT received consolidation therapy prior to allo-HSCT.

• Median follow-up time: 6 years
• 2-year relapse-free survival (RFS): 28%
  • Allo-HSCT as post-remission therapy led to a significantly better RFS compared to chemo-based and consolidation therapy: 51% vs 33% vs 9%, respectively, P = 0.001
• 2-year overall survival (OS): 20%
  • Allo-HSCT as post-remission therapy led to a significantly better OS compared to chemo-based approaches: 43% vs 15%, respectively, P = 0.005
• None of the patients who underwent allo-HSCT had VOD

This study represents the largest cohort of patients treated with MIDAM who have been analyzed. The findings of this study demonstrate that MIDAM regimen is a valid therapeutic option as salvage chemotherapy in patients with R/R AML and it is associated with an “acceptable toxicity profile.”

In addition, allo-HSCT was found to be the consolidation strategy of choice after MIDAM regimen and it is associated with no increased risk of VOD.