FDA approves drug to treat smallpox

Disease considered eradicated in 1980 but drug development for smallpox is an important component for medical countermeasure response

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[6/4/2021] The U.S. Food and Drug Administration today approved Tembexa (brincidofovir) to treat smallpox. Although the World Health Organization declared smallpox, a contagious and sometimes fatal infectious disease, eradicated in 1980, there have been longstanding concerns that the virus that causes smallpox, the variola virus, could be used as a bioweapon.

Before its eradication in 1980, the variola virus mainly spread by direct contact among people. Symptoms typically began 10 to 14 days after infection and included fever, exhaustion, headache, and backache. A rash consisting of small, pink bumps progressed to pus-filled sores before it crusted over and scarred. Complications of smallpox included encephalitis (inflammation of the brain), corneal ulcerations (an open sore on the clear, front surface of the eye), and blindness.

Although naturally occurring smallpox no longer exists, concerns about potential uses of variola virus as a bioweapon has made smallpox drug development an important component of the U.S. medical countermeasures response.

Because smallpox is eradicated, the effectiveness of Tembexa was studied in animals infected with viruses that are closely related to the variola virus. Effectiveness was determined by measuring animals’ survival at the end of the studies. More animals treated with Tembexa survived compared to the animals treated with placebo. FDA approved Tembexa under the agency’s Animal Rule, which allows findings from adequate and well-controlled animal efficacy studies to serve as the basis of an approval when it is not feasible or ethical to conduct efficacy trials in humans.

Safety information to support approval of Tembexa was derived from clinical trials of the drug for a non-smallpox indication, primarily from patients who received hematopoietic stem cell transplants.  An increased risk of death was seen in another disease (Cytomegalovirus disease – a viral infection) when Tembexa was used for a longer-than-recommended duration (longer than once a week for two weeks on days 1 and 8). Tembexa is only approved for the treatment of smallpox.  

The most common side effects when using Tembexa are diarrhea, nausea, vomiting, and abdominal pain.

Tembexa received priority review, fast track and orphan drug designations. Priority review directs overall attention and resources to the evaluation of applications for drugs that, if approved, would be significant improvements in the safety or effectiveness of the treatment, diagnosis or prevention of serious conditions when compared to standard applications. Fast track is designed to facilitate the development and expedite the review of drugs to treat serious conditions and fill an unmet medical need. Orphan drug designation provides incentives to assist and encourage the development of drugs for rare diseases.  

Tembexa was developed in conjunction with the U.S. Department of Health and Human Services’ Biomedical Advanced Research and Development Authority (BARDA). FDA granted approval of Tembexa to Chimerix Inc.

Related Information

• Smallpox Preparedness and Response Updates from FDA
• Smallpox (Variola Virus) Infection: Developing Drugs for Treatment or Prevention Guidance for Industry
• CDC: Smallpox

　日本語はこちら　https://gigazine.net/news/20210611-drug-treat-smallpox-tembexa/

　このニュースが、次にアウトブレイクするウイルスはこれだよという予告記事なら嫌だなと思った訳である。まあ、現状では陰謀論未満の妄想ですが、アングロサクソンミッションみたいな例がありましたので。因にsmallpox、日本語でいえば天然痘です。

　こんなバカな話は早く止めて、TCA回路についての議論を続けたいのだが、とにかくコロナゲート事件の進展が早過ぎて落ち着く暇がない。正直な所、中国政府を頭から信じてはいない。どの程度信じているかって？WHOあるいは日本政府と同じくらいかな。新型コロナウイルスのアウトブレイクが武漢で起こったとして、同時に他の場所で多発的に起こっていた可能性がないとは言い切れない。中国を非難している国々の研究者たちが、武漢の研究所での機能獲得実験に大きく係わったり、資金提供をしている。これをどう解釈するかで筋書きは大きく変わるだろう。それにしても小松左京は先見の明があったということかな。

　田植え直前で忙しい。明日は肥料撒きである。爺の米作、なかなか世話が届かないので反当たり7俵程度しか取れない。肥料をうまく使えばもう少し増えるかもしれないが、味が落ちる。湧き水を主な水源とする田んぼで味の良さだけが取り柄だから、収量は無視して貧栄養で作っている。梅雨に入ったというのに雨が降らない。移植したナスとトウガラシ、ニガウリリも水不足で青息吐息の状況。明日も晴れるようなら、夕方には水やりが必要になりそうだ。3日ほど前からジャンボニンニクの収穫を始めた。収穫物を干しているため家の周囲がニンニク臭い。悪魔払いになるだろうか。

　作物は水不足で生育不良なのだが、雑草（失礼、野草と言おうか）の生育は旺盛である。空き時間を草刈りに充てているが、とても間に合わない。実はスチル社のクリアリングソーを買った。FS311と言う機種である。アタッチメントを含め10万円をかなり超えたのだが、今日、本格的に使ってみた。重い、8Kg近くある、つまり体格の良いゲルマン民族用の機械のようだ。ハンドルの幅も私には広過ぎる。但し、切れ味はすばらしい。傾斜地で使おうと思って買ったのだが、足腰が重さに耐えきれない。ナイロンワイヤーをつけて平坦地で使うには問題はなさそうだ。https://www.stihl.co.jp/STIHL-製品カタログ/刈払機＆クリアリングソー/クリアリングソー/275067-220/FS-311.aspx