Acute leukaemia: The benefit of certain types of stem cell transplantation is currently not proven
IQWiG criticises the lack of verified data comparing stem cell transplantation and chemotherapy
In the past few decades, stem cell transplantation has become a commonly used alternative to chemotherapy in patients with acute leukaemia. However, in some groups of patients, the scientific evaluation of this high-risk therapy has not kept pace with its application. According to research conducted by the Institute for Quality and Efficiency in Health Care (IQWiG), for certain indications there are insufficient reliable data available to prove the benefit of stem cell transplantation. These gaps in knowledge should be closed as quickly as possible. This is the result of the final report published by IQWiG on 4 June 2007.
However, no general conclusions against the use of stem cell transplantation in acute leukaemia can be inferred from the report, as the assessment of this therapy depends on individual disease features, patient characteristics, as well as on the exact circumstances of therapy. In its current report, IQWiG (commissioned by the German Federal Joint Committee), only evaluated certain types of stem cell transplantation for the treatment of adult patients with acute lymphoblastic leukaemia (ALL) or acute myeloid leukaemia (AML). One question concerned patients with AML or ALL, for whom no suitable related donor is available, and who therefore undergo stem cell transplantation with an unrelated donor. The benefit of unrelated-donor stem cell transplantation cannot currently be assessed because of the lack of meaningful comparative studies with chemotherapy as a potential treatment alternative.
A second question concerned a type of stem cell transplantation in which the pre-treatment of patients is less aggressive. Indications were found that such dose-reduced transplantation may show advantages in 2 groups of patients. The first group is patients with AML or ALL in whom chemotherapy is no longer effective enough (therapy-refractory course). Indications are available that dose-reduced transplantation may extend the survival of affected patients. The other group is patients with AML for whom a suitable related stem cell donor is available. In these patients, dose-reduced transplantation may be superior to chemotherapy. However, here too, no definitive statements can yet be made, as only one study including these patients was identified, which furthermore showed various deficiencies.
For reasons of patient safety, these gaps in knowledge should therefore be closed as quickly as possible. This would be possible if these types of stem cell transplantation were used within the framework of suitable clinical studies. This also includes non-randomised studies, in which all meaningful treatment options are available, but which, in order to enable the comparison of treatment results, also document relevant data on patient history and disease progression.
Changes to the preliminary report
In July 2006, IQWiG published the preliminary report, which was in part heavily criticised. The final report now published is the usual revision of the preliminary report, which also includes a debate in the discussion section referring to the criticism received, as well as an analysis of newly submitted data and publications. All in all, after reviewing the criticism, IQWiG concluded that there was no reason to revise the conclusions of the preliminary report. The report explains in detail in which cases the Institute regarded criticism as being either justified or inappropriate (discussion section, pp. 182 to 211).