Xofluza, Roche's bid to replace sales from the now generic Tamiflu, has not yet caught in the US and new reports of viral resistance in Japan will not help the case.
Some doctors in the country have delayed the Xofluza prescription in light of new evidence that mutant viral influenza strains may stop the drug from acting as intended for some patients, The Wall Street Journal reported. Tokyo's National Institute of Infectious Diseases had identified six resistant strains on February 6.
As the institute noted, resistance problems were cut into clinical trials for developer Shionogi; Almost 25% of the children in the last trials had resistant strains, meaning the problem is not new.
But that doesn't sound good to Roche, who is trying to drive Xofluza growth in the face of copycats to pursue Tamiflu. The new drug, which runs $ 150 for patients without insurance, has hitherto limited its use thanks in part to the price; It generated just $ 13 million in the fourth quarter after beating its FDA OK in October.
"Xofluza is very expensive and was only approved, so many people do not take it." Susan Wilder, MD, an Arizona-based family doctor, told the WSJ.
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Of course, Tamiflu is not without its own resistance problems. Xofluza is "extremely promising, especially in the treatment of influenza strains resistant to Tamiflu," says Wilder, adding that "Xofluza has a wider range of efficacy than other available influenza drugs."
But some doctors worry that Xofluza will lose its edge if it gets too much to play this year.
"There is the possibility that Xofluza will not be effective in the next influenza season if it is used very much now, as this will cause drug-resistant viruses to spread rapidly," Naoto Hosokawa, head of the infectious disease department at Kameda Medical Center near Tokyo , WSJ told.
Meanwhile, Roche pointed out that Xofluza still has some utility in mutant strains. While showing "reduced susceptibility" to Xofluza, the fabric still had some effect on them – meaning they are not resistant to US government standards. Further study is needed to determine the extent of the problem and the transferability of the respective strains, and a global study of how Xofluza affects influenza spreading begins this year, Journal says.