New research published last week digs into cross-national regulatory divergences, with a focus on why some US labels for certain flu treatments say the medicines have not been proven to reduce complications while EU labels claim the opposite.
Shai Mulinari of Sweden’s Lund University and Courtney Davis of Kings College London, the authors of the research published in Health Research Policy and Systems, focus their work on Relenza (zanamivir), which represents the first neuraminidase inhibitor (NI), a class of drugs also including the controversial Tamiflu (oseltamivir).
"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," the study says.
Part of the reason, Mulinari and Davis found, was that the evaluation of Relenza differed in the EU and US, and FDA’s "probing and meticulous review practices" resulted in a better understanding of the Relenza clinical evidence.
FDA reviewers "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 researchers wrote.
"Our findings challenge the current emphasis on evaluating regulatory performance mainly in terms of speed of review. Furthermore, had regulators explained their contrasting assessments, this could have improved the broader medical community’s critical appraisal of the evidence base for anti-influenza drugs. Regulators use major resources to evaluate new medicines, but if regulators’ assessments are not effectively disseminated and used, resources are wasted."
However, the researchers also noted that neither FDA, Sweden’s Medical Products Agency, nor the EMA made their positions sufficiently clear.
"Indeed, as debates in the medical literature raged on, a peculiarity of these disagreements was that protagonists on both sides referred to the FDA’s judgment to substantiate conflicting positions," the researchers found.
In its conclusion, the authors added: "Regulators use major resources to evaluate new medicines, but if regulators’ assessments are not effectively disseminated and used, resources are wasted."