Can oral medicine be "the trump card" for COVID-19 countermeasure? US pharmaceutical giants emphasize the effect, while some experts are skeptical.

2021年11月17日 06時30分
The Japanese government summarized the measures for the "sixth wave" of the COVID-19 on 12th. The oral medicine would be one of the pillars, and government promised to secure the medicine for 1.6 million people. US pharmaceutical giants Merck and Pfizer have announced that their newly developed drug has been highly effective in clinical trials. It is said that taking it in the early stages of infection can reduce the severity of the disease, and some doctors say, "If we can take effective medicine, the day may come when we can think of COVID-19 as influenza." On the other hand, there are voices that warn of excessive expectations.

◆ Interfere with virus growth

The drugs taken by both companies have the function of suppressing the growth of viruses and are called antiviral drugs. The coronavirus invades cells, copies the RNA of the genetic material, and proliferates.
Molnupiravir, developed by Merck, interferes with RNA copying. The company announced the results of clinical trials that the risk of hospitalization and death was halved. The UK approved it on the 4th. Pfizer's Paxrovid prevents the production of proteins to be part of the virus. In clinical trials, the severity was reduced by 89%.
In each case, when the positive result is confirmed, the patient can be given it to take it by himself / herself. Antiviral drugs are less effective unless administered in the early stages of infection. Dr. Takeda of Kawaguchi Cardiology and Respiratory Hospital (Kawaguchi City, Saitama Prefecture), who continues to treat critically ill patients, pointed out that "it is important to create a system that can hand over medicine to patients as soon as confirmed positive." He also mentions, "Taking advantage of immediate antigen testing is one of the good ways, too."

Molnupiravir of Merck & Co., Inc. Copyright © 2009-2021 Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, N.J., U.S.A. All rights reserved.)

◆ The government accelerates procurement

The COVID-19 remedy has lacked a decisive factor. Regarding the approved antiviral drug Remdesivir, Dr. Takeda confesses, "I'm not sure if it works." The steroid dexamethasone is also a drug that suppresses inflammation and has an aspect of symptomatic treatment for moderate to severely ill patients.
This year, a therapeutic drug using human antibody (antibody drug) was approved. This drug works if it can be given early in the infection, but it requires an IV drip. Dr. Takeda said, "It is difficult to use a bed when the number of patients increases due to intravenous drip," and emphasizes that oral medicine is easier to use.
Therefore, the government's expectations for oral medicine are high. Prime Minister Kishida Fumio calls oral medicine as "the trump card for the people to live with peace of mind," and the Japanese government agreed with Merck to raise medicine for 1.6 million people, even before the regulatory approval in Japan. It also decided to support 2 billion yen for the development of domestically produced medicine.
In Japan, Shionogi will develop a oral medicine, that prevents the virus from making proteins. The final stage of clinical trials began at the end of September, but Japan's vaccine development has been far behind foreign countries. Shionogi is rushing to develop oral medicines, otherwise major US companies may take over the market.

◆ Expert "Currently, vaccines are the main countermeasures"

However, there are also voices that warn of relying too much on medicine. Professor Miyasaka of Osaka University points out that "there are few infectious diseases that can be completely cured by antiviral drugs; Only hepatitis C and herpes." The background is that it is difficult to deliver a sufficient amount of drug into cells and that resistant viruses are likely to develop.
As for influenza, there are cases in which a resistant virus emerged immediately to the expected new drug, and it was not used much the following year. Professor Miyasaka emphasizes, "Of course, it would be great if it were proved as a good drug, but vaccines and antibody drugs are already highly effective. At the present time, this is the main countermeasure."

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