Researchers investigate conflicting regulatory judgements for flu treatment

Why do some US labels for certain flu treatments say that the medicines have not been proven to reduce complications, whereas EU labels claim the opposite?

The study focused on the first neuraminidase inhibitor (NI), Relenza (zanamivir), a class of drugs which also includes Tamiflu (oseltamivir). A qualitative analysis of United States (US) and European Union (EU) regulatory appraisals for Relenza was conducted to discover the reasons for the conflicting regulatory judgements relating to Relenza’s ability to alleviate symptoms and reduce frequency of complications of influenza.

The study states that “a key unsettled question is why the United States Food and Drug Administration (FDA) has approved more cautious efficacy statements in labelling than European regulators for both drugs”.

Mulinari and Davis discovered that part of the reason was because of differences in evaluation of Relenza in the US and EU. Due to the FDA’s “more probing and meticulous evaluative methodology” they had a greater understanding and knowledge of the Relenza clinical evidence. It was shown that unlike the EMA, the FDA “rejected the manufacturer’s insistence on pooling efficacy data, remained wary of subgroup analyses and insisted on stringent statistical analyses. These differences meant that the FDA was less likely to depart from prevailing regulatory and scientific standards in interpreting trial results”.

The differences could be explained due to the contrasting review methodologies of each institution, for example, the FDA examines original data and documentation from trials, whereas the European regulators rely on manufacturer-compiled summaries.

The findings of the study “challenge the current emphasis on evaluating regulatory performance mainly in terms of speed of review.” The study proposed that “persistent uncertainty and knowledge deficits regarding NIs could have been ameliorated had regulators engaged in the public debates over the drugs’ efficacy and explained their contrasting methodologies and judgments.”

In the conclusion of the study, the authors stated that “regulators use major resources to evaluate new medicines, but if regulators’ assessments are not effectively disseminated and used, resources are used inefficiently.”

To read the full study, please click here.