Clinical trials: two arms are better than one, says IQWiG

Germany’s Institute for Quality and Efficiency in Health Care (IQWiG) has responded critically to a reflection paper by the European Medicines Agency (EMA) on the approval of new drugs based on single-arm studies.

The EMA correctly points out that studies without a control arm are subject to bias and that, in general, it is hardly possible to estimate causal effects from them. However, it does not provide clear criteria for limiting drug approval based on such studies to extremely rare exceptional cases.

Furthermore, the IQWiG points out, there is no recommendation on external controls - in contrast to guidance published in February by the US Food and Drug Administration (FDA).