Shionogi seeks approval for injectable peramivir (Rapiacta) to treat severe flu in children

Japanese drug maker Shionogi is planning to seek approval for the use of intravenous antiviral drug peramivir to treat influenza infection in children.

Peramivir, which is sold in the brand name Rapiacta  has been available in Japan for use in adults since Jan. 27.

Peramivir is neuraminidase inhibitor for intravenous infusion being developed by Shionogi in Japan. Peramivir’s has shown high potent activity against influenza A and B viruses. Peramivir has also shown that it is active against highly pathogenic H5N1 (avian flu) viruses.

Permivir has strong binding to neuraminidase and it is not easily dissociated. Shionogi licensed peramivir from US-based BioCryst Pharmaceuticals, Inc in March 2007. Shionogi agreed to pay $35 million to Birmingham, Alabama-based BioCryst Pharmaceuticals Inc for rights to develop and sell peramivir in Japan.

Peramivir, Shionogi & Co believes, will earn annual sales of about 5 billion yen ($54 million) in Japan, if approved.

Shionogi plans to file data on peramivir to Japan’s health ministry in November for approval.

Peramvir is expected to reach markets as early as October next year, Shionogi sources said.

Currently, Roche Holding AG’s Tamiflu (oseltamivir) and GlaxoSmithKline Plc’s Relenza (zanamivir) are only available antivirals to  treat the pandemic H1N1 swine infection.

Paramivir also has an advantage over oseltamivir and zanamivir as it is administered directly as intravenous injection into the blood stream, allowing it to be effective more rapidly. Relenza is usually inhaled, while Tamiflu comes in pill form.

Two Phase3 clinical studies of peramivir conducted during the 2008-2009 influenza season have achieved the primary objectives Shionogi & Co announced in July.

Shionogi conducted a three-armed, multi-center,randomized, double-blind, multi-national Asian study that compared the efficacy and safety of a single dose treatment of i.v. peramivir (either 300 mg or 600 mg) and or al treatment with oseltamivir phosphate (Tamiflu) twice a day for 5 days.

A total of 1,099 uncomplicated patients infected with seasonal influenza virus were enrolled at 146 centers – Japan:100; Korea:25; Taiwan:21.

Both the 300 mg and 600 mg single dose peramivir groups positive outcomes compared to that the oseltamivir group.

In addition, Shionogi conducted a double-blind, multi-center Phase3 study of i.v. peramivir with dosing over multiple days. The study enrolled 42 influenza patients at high-risk of serious complications due to one or more qualifying conditions: diagnosis with poorly controlled diabetes mellitus, a chronic respiratory disease requiring pharmacotherapy, or current treatment with any immunosuppressive drug.

The results indicated that the symptoms of influenza of patients with high risk, which is
believed to be prolonged were also improved in shorter period.

Peramivir 300 mg or 600 mg i.v. single and multiple doses were generally safe and well tolerated in these trials.

Permavir is a good drug for severely ill flu patients as there is demand for intravenously administered drugs for such patients, experts said.

Shionogi, the maker of the Crestor cholesterol pill, is the first among three Japanese drugmakers to seek approval in Japan for flu treatments under development. Laninamivir from Daiichi Sankyo Co. and favipiravir from Fujifilm Holdings Corp.’s Toyama Chemical Co are the two ather antivirals currenly in development.

Biocryst the original developer of the drug, has been selling it in the United States for severely ill flu patients since October 2009.

The Osaka, Japan-based Shionogi bought the rights to develop and sell peramivir in Japan and Taiwan from BioCryst in 2007 for $35 million.