Japan’s New Drug: One Pill May Stop The Flu in Just One Day (Forbes, 24-02-2018)
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One day, you may be able to stop flu viruses in your body in just one day with just one pill. Based on an announcement yesterday, that day may be someday very soon in May in Japan.
On Friday, Japanese pharmaceutical company Shionogi announced that the flu medication that they have developed, Xofluza, otherwise known as baloxavir marboxil (which sounds a bit like a Klingon General), has been approved to be manufactured and sold in Japan. Beginning in October 2015, the medication underwent priority review by Japan’s Ministry of Health, Labor, and Welfare. Shionogi filed for approval in the autumn of 2017. Compared to Tamiflu, which requires two doses each day for five days, apparently only a single dose of Xofluza will be needed to treat the flu. Even though Xofluza has received approval, people will have to wait until the Japanese national insurance sets a price for the medication, which according to Preetika Rana writing for the Wall Street Journal, may not occur until May.
Xofluza works via a different mechanism from neuroaminidase inhibitors like Tamiflu (oseltamivir) and Relenza (zanamivir). Flu viruses are like squatters in your home that then use the furniture and equipment in your home to reproduce. Yes, I know, that makes for a lovely picture. A flu infection begins when flu viruses reach your lungs. Each flu virus will enter a cell in your lungs and then use your cell’s genetic material and protein production machinery to make many, many copies of itself. In order to do this, the flu virus uses “cap-snatching”, which has nothing to do with bottle caps or Snapchat. The virus employs an endonuclease enzyme to clip off and steal the caps or ends of your messenger RNA and then re-purposes these caps to reproduce its own genetic material. After the virus has made multiple copies of itself, the resulting viruses implement another enzyme called a neuroaminidase to separate themselves from parts of the host cell and subsequently spread throughout the rest of your body to cause havoc. While Tamiflu, Relenza, and other neuroaminidase inhibitors try to prevent the neuroaminidase enzyme from working, Xofluza acts at an earlier step, stopping the “cap-snatching” by blocking the endonuclease enzyme.
By acting at an earlier step before the virus has managed to replicate, Xofluza could stop a flu virus infection sooner than neuroaminidase inhibitors. The results from Shionogi’s Phase III CAPSTONE-1 clinical trial compared Xofluza (then called Cap-dependent Endonuclease Inhibitor S-033188, which doesn’t quite roll off the tongue) with oseltamivir and placebo, with results being published in Open Forum Infectious Diseases. The study found that baloxavir marboxil (or Xofluza) stopped an infected person from shedding flu virus earlier (median 24 hours) than oseltamivir (median 72 hours). Those taking baloxavir marboxil also had lower measured amounts of viruses than those taking oseltamivir throughout the first 3 days of the infection. Baloxavir marboxil also seemed to shorten the duration of flu symptoms (median 53.7 hours compared to a median of 80.2 hours for those taking placebo). Since symptoms are largely your body’s reaction to the flu virus, you can begin shedding virus before you develop symptoms, and symptoms can persist even when you are no longer shedding the virus.
The key with any of these flu medications is early treatment, especially within the first 24 to 48 hours of infection, which may be before you notice any symptoms. Once the virus has replicated and is all over your body, your options are limited. The vaccine still remains the best way to prevent an infection.
Link to the Forbes article