Researchers working on the latest Cochrane Collaboration meta-analysis of the evidence on oseltamivir (Tamiflu) have claimed that the drug’s manufacturer is still denying them access to full trial data. This is despite Roche, the Swiss company behind oseltamivir, pledging in the BMJ two years ago that it would make “full study reports” available.1 As a consequence, confusion still surrounds the evidence on oseltamivir and guidance on how doctors should prescribe it.

The latest Cochrane review on oseltamivir, a drug on which governments around the world have spent billions of pounds, is published today (18 January). But the Cochrane reviewers have received only part of the clinical study reports—the summary of the study methods and the results. The company says this is enough for the Cochrane group to conduct their review, but Cochrane denies this.

Meanwhile, GlaxoSmithKline—the makers of the less popular antiviral drug zanamivir (Relenza)—have offered individual patient data. When the BMJ asked Roche why it was refusing to make its data available, despite GSK’s promises, it said it refused to answer until it had had the chance to see the full Cochrane review.

Clinicians can be forgiven for being confused about what the evidence on oseltamivir says. Last September, the UK Department of Health announced that in the event …