Metronomic therapy with oral 6-mercaptopurine in elderly acute myeloid leukemia: A prospective pilot study

Acute myeloid leukemia (AML) in elderly patients differs biologically from that in younger patients and is known to have unfavorable chromosomal rearrangements, higher resistance, and lower tolerance to chemotherapy. In such circumstances, instead of giving full-blown chemotherapy, palliative metronomic chemotherapy (MCT) could be a treatment option.

We performed a prospective pilot study of old AML patients (age >60 years) not amenable to curative treatment. Thirty-two patients were enrolled into the study and were treated with daily oral 6-mercaptopurine 75 mg/m(2). The following inclusion criteria were used: age >60 years, nonpromyelocytic AML, the absence of uncontrolled comorbidities, and patient not amenable to curative treatment. Overall survival (OS) was calculated using Kaplan-Meier method and Cox regression analysis were used to calculate the hazards ratio of significant factors.

The median age of the patients was 69 years (range: 61-86 years) with male: female ratio of 2.5:1. About 59.4% of patients had Eastern Cooperative Oncology Group performance status of 2 while rest had the status of 3. The median OS was 6 months (95% confidence interval [CI]: 4.4-7.6). Males had median OS of 7 months (95% CI: 5.4-8.6) versus females with OS of 3 months (95% CI: 1.5-4.4; P = 0.008). There was no survival difference on the basis of baseline hemoglobin or French-American-British class. There were no Grade 4 toxicities and no episode of febrile neutropenia.

MCT with oral 6-mercaptopurine is an attractive treatment option in elderly AML patients who are not amenable to curative therapy with minimal toxicities.