(Reuters) - Diversified healthcare company Johnson & Johnson (>> Johnson & Johnson) said on Wednesday its experimental flu drug significantly reduced the presence of the virus in patients with a type of influenza in a mid-stage study.

With its antiviral drug, pimodivir, J&J aims to help treat influenza patients who have developed resistance to existing antiviral drugs as well as address the lack of approved medications for people hospitalized with the virus, the company said.

More than one billion people suffer from influenza worldwide each year, resulting in about five million cases of severe illness and up to half a million deaths.

J&J's trial tested pimodivir as a mono-therapy or in combination with a widely used flu drug, oseltamivir, for the treatment of acute uncomplicated seasonal influenza.

Influenza viruses can evolve from one flu season to the next, and even change within the course of the same season. As a flu virus replicates, its genetic makeup may change in a way that results in the virus becoming resistant to treatment.

There are three antiviral drugs recommended by the U.S. Centers for Disease Control & Prevention for this season: oseltamivir (which is available as a generic or under the trade name Tamiflu), zanamivir and peramivir.

Pimodivir targets another part of the viral replication process when compared to oseltamivir, and if successful, could treat influenza A patients who have developed resistance to existing treatments.

J&J said trial data showed that treatment with pimodivir alone resulted in a statistically significant reduction in viral load in patients over seven days from the start of dosing, when compared with a placebo.

Adding pimodivir to oseltamivir also resulted in a significantly lower viral load compared to those who received pimodivir alone, the company added.

Pimodivir was granted the U.S. Food and Drug Administration's "fast-track" status in March due to its potential to address medication for patients who develop the influenza A infection and are hospitalized, or are at high risk of related complications.

The Band-aid maker bought the worldwide rights to pimodivir from Vertex Pharmaceuticals Inc (>> Vertex Pharmaceuticals) in 2014, and its development is being funded in part by the U.S. Department of Health and Human Services.

J&J said it expects to begin a late-stage trial for the drug in the second half of the year.

The company's shares were up 0.8 percent at $133.06 in early trading on Wednesday.

(Reporting by Divya Grover in Bengaluru; Editing by Sai Sachin Ravikumar)

By Divya Grover

Stocks treated in this article : Johnson & Johnson, Vertex Pharmaceuticals