Oseltamivir reduces viral shedding in low-risk influenza patients
Treatment with oseltamivir shows virologic efficacy in patients at low risk of complications of influenza, with the drug reducing viral shedding as compared with placebo, a study has found.
Researchers randomized 556 patients (median age, 36 years; 62 percent female; 69 percent Asian) to receive either oseltamivir 75 mg (n=277) or placebo (n=279) orally twice a day for 5 days. All patients presented with at least one respiratory symptom (cough, sore throat and nasal symptoms) that started no more than 48 hours before screening and were screened for influenza by rapid antigen or polymerase chain reaction (PCR).
Of the randomized patients, 501 were confirmed to have influenza. A total of 449 patients contributed data for the analysis of the primary endpoint, which was the percentage of participants with virus detectable by PCR in nasopharyngeal swab at day 3.
Results for the primary endpoint were significantly more favourable in the oseltamivir arm (99 of 220 [45.0 percent] vs 131 of 229 [57.2 percent] patients; absolute difference, –12.2 percent; p=0.010). Symptoms in patients with confirmed influenza infection improved within a median of 79.0 hours with the active drug and 84.0 hours with placebo (p=0.34).
According to the researchers, the findings should not be used to raise a question about the utility of oseltamivir in most populations. They believe that there are sufficient data from several previous studies, including many nonmanufacturer sponsored observational studies, to support the conclusion that neuraminidase inhibitors such as oseltamivir have clinical benefit, and that current recommendations advocating its use for treating influenza patients requiring hospitalization, those who are very sick, and those who are at high risk of severe influenza complications are justified.
However, caution should be exercised when extending those recommendations to include treatment of a low-risk population, given the minimal virologic benefit and the nonsignificant clinical differences demonstrated in the present study, the researchers added.