Lancet: Thumbs up on Tamiflu

Addressing a controversy that arose in the UK, the Lancet published a study that concludes oseltamivir (Tamiflu/Roche) does show efficacy in treating influenza.

Joanna Dobson, MSc and Stuart Pocock, PhD, statisticians at the London School of Hygiene & Tropical Medicine, and colleagues in the United States examined data from 9 trials including 4,328 patients. Those included all trials sponsored by Roche and any others they could find on sites like Medline and ClinicalTrials.gov.

“Our findings show that oseltamivir in adults with influenza accelerates time to clinical symptom alleviation, reduces risk of lower respiratory tract complications, and admittance to hospital, but increases the occurrence of nausea and vomiting.”

That refutes the findings of a 2014 British Medical Journal study that charged the drug had no antiviral effect, the authors said. The earlier study also alleged that the drug’s adverse effects outweighed any benefits.

Roche provided the data for the Lancet study, but did not participate beyond that, the authors wrote. Roche also provided the funding through the Multiparty Groups for Advice on Science. But the Roche grant to that group was unrestricted and stipulated that the pharma company would not be involved in the analysis.

The primary outcome of trials was to measure how long the drug vs. placebo took to alleviate flu symptoms. Those included congestion, sore throat, chills, aches, pains and cough—all scored as to how severe they were. The conclusion was that oseltamivir shortened the flu by one day.

One shortcoming of the study was that PCR analysis to confirm flu strains was not available during the time many of the earlier trials were done—though laboratory-confirmed flu was a criterion for subjects to be included in the key trials submitted for licensure.

Most of the participants in those trials were ill with Type A H3N2 strains.

The team found that there were significantly higher adverse events related to nausea (an increase of 3.7%) and an increase of 4.7% in vomiting in those who got oseltamivir bur no difference vs. placebo when it came to serious adverse events. The drug also had a lower rate of lower respiratory complications than placebo.

The study confirmed oseltamivir's efficacy as an anti-viral for flu, but the authors point out that if a patient who took it turned out not to have flu, the risk-benefit analysis would be different. “Treatment strategies need to avoid this through availability of rapid diagnostic testing,” the authors wrote. Though they did not address the issue of the significant number of false negatives these rapid tests have been shown to have, they called for physician judgment on whether to prescribe the drug.

“Whether the magnitude of these benefits outweigh the harms attributed to nausea and vomiting needs to be carefully considered, they wrote.