A partial response in patients with acute myeloid leukaemia after initial induction chemotherapy has prognostic value and can guide the next steps in treatment, Australian haematologists have concluded.
Writing in a letter in the British Journal of Haematology Dr Shaun Fleming from the Alfred Hospital in Melbourne and colleagues said failure to achieve a partial response (PR) with the first cycle of intensive chemotherapy identified a population of patient with poor risk that could potentially be considered candidates for allogeneic stem cell transplantation.
The research team reviewed 104 patients with acute myeloid leukaemia who were treated with one cycle of intensive chemotherapy and had not achieved either a complete response (CR) or a complete response with an incomplete blood count recovery.
However 24% of these patients achieved a PR by conventional criteria, and 38% achieved a PR using a modified definition.
Failure to achieve a complete response is thought to confer a poor outcome. However those with a partial response have a low chance of a subsequent response to conventional chemotherapy, the study authors said.
These patients could be defined as having ‘refractory’ AML and are suitable candidates for investigational therapy.
“Our findings suggest that patients achieving PR after the first cycle of standard or higher-dose cytarabine have a reasonable outcome using standard treatment approaches and are therefore not ideal candidates for ‘refractory’ AML studies,” they said.
“In contrast, lack of a PR to initial induction chemotherapy portends a dismal prognosis and delineates an AML population clearly in need of investigational approaches directed at improving clinical outcome.”
Future studies should examine the clinical relevance of PR and mPR after the first induction cycle when using other induction regimens, and also the benefit of haematopoietic stem cell transplantation in this poor-risk group, they said.
“However, the lack of a standard definition for ‘refractory’ AML has ramifications for how patients are managed in clinical practice and eligibility of patients with resistant disease for clinical trials.”