The comparison of outcomes of two salvage therapies in patients with relapsed or unresponsive acute myeloid leukemia

The study evaluated the effectiveness of two salvage therapies – mitoxantrone (Novantrone), etoposide (Etopophos), and cytarabine (Cytosar-U) also known as MEC and cladribine (Leustatin), cytarabine, filgrastim (Neupogen), and mitoxantrone also known as CLAG-M, for treating relapsed/refractory acute myeloid leukemia (RR-AML). The main finding was that both therapies had similar outcomes in these patients, with a better survival for patients treated with MEC who proceeded to a stem cell transplant (SCT).

Patients with AML often face relapse or leukemia’s return after treatment. Survival is poor among relapsed patients whose AML is also refractory, meaning that leukemia is unresponsive to any standard treatment. Such patients can be treated with stem-cell transplantation which is risky.

Salvage treatments are meant to treat relapsed or refractory cancer. Current salvage therapies for AML contain the combinations of either CLAG-M or MEC. However, studies comparing the outcomes of two therapies are lacking in patients with RR-AML.

This study analyzed the medical records of 150 adult patients with RR-AML. 34 of them received CLAG-M and 116 received MEC. Relapse occurred early in 31% of patients within 6 months of initial therapy. 17% of patients experienced late relapse after 6 months. The rest 52% had refractory AML. All patients were followed-up for 23.5 months on average.

Complete remission (CR) or disappearance of leukemic signs or symptoms was achieved in 35.5% of patients in the CLAG-M group and 32.4% of patients in the MEC group. CR with incomplete hematologic recovery (CRi) is achieved when patients experience CR without full recovery of blood cell count. CRi rate for CLAG-M was 25.8% and for MEC was 23.1%.

On average, patients survived for 9.5 months under CLAG-M and 10 months under MEC therapy. Average survival without relapse was 5 months for CLAG-M and 8 months for MEC recipients.

76 patients received a SCT after salvage therapy. The average survival after SCT was 13 months for CLAG-M and 31 months for MEC. On average, transplanted patients with late relapse survived for 9 months in the CLAG-M group and 48 months in the MEC group.

The authors concluded that treatment outcomes were not different in patients treated with CLAG-M or MEC. However, MEC improved survival among patients who faced late relapses and opted for SCT.

The study was retrospective meaning that it looked back in time to analyze data. Similar comparative studies can also be performed in clinical trial settings.