2013年5月1日水曜日

HIV Vaccine Fails

HIVワクチンは失敗だった。
 米保健当局は、後天性免疫不全症候群(AIDS)を引き起こすヒト免疫不全
ウイルス(HIV)の感染を防ぐために開発した試験ワクチンが、感染を止めら
れないことが判明したとして、臨床試験の中止を発表した。

HVTN 505
・2009年から研究が開始されたHIVワクチン。

米国立アレルギー感染症研究所(National Institute of Allergy and
Infectious Diseases、NIAID)
・臨床試験
 全米の19都市で同性愛者の男性、またはトランスジェンダーで男性と
 性交渉をもっている人たちから被験ボランティアを募り、2500人が参加。
  試験ワクチン 1250人
  偽薬     1244人。
  ワクチン投与グループ 41人が感染
  偽薬グループ 30人が感染
 試験の中止を勧告。

タイで実験されたRV144は、一部効果があり。
米国で実験されたHVTN505は、効果がない。

薬剤で赤ちゃんのHIV感染反応が消えた報道があったが、ワクチンについて
はまだ先のようだ。
2014年から、RV144のワクチン実験を実施し、効果を確認とのこと。

HIVワクチンボランティア参加者は、危険な環境に身を置き、HIVへの予防
処置を行わないのだろうか。生活が成り立たないために、環境を変えるこ
とは難しいと思うが、非感染者がHIVワクチンを接種し、危険を冒せば、
自殺志願者のようにも見える。HIVワクチン接種実験の契約は、どうなって
いるのだろうか。

HIVワクチン実証
インフルワクチン HIV感染者に免疫効果
A Baby With HIV Is Deemed Cured


STUDIES ARE BEEN HALT ON THE LATEST HIV VACCINE!


---抗HIVワクチンの臨床試験、失敗判明で中止に 米国---
2013年04月26日 17:21 発信地:ワシントンD.C./米国
http://www.afpbb.com/article/life-culture/health/2940939/10645238

 【4月26日 AFP】米保健当局は25日、後天性免疫不全症候群(AIDS、エイズ)を引き起こすヒト免疫不全ウイルス(HIV)の感染を防ぐために開発した試験ワクチンが、感染を止められないことが判明したとして、臨床試験の中止を発表した。
 問題のワクチンは2009年から研究が開始された「HVTN 505」。米国立アレルギー感染症研究所(National Institute of Allergy and Infectious Diseases、NIAID)によると、臨床試験では全米の19都市で同性愛者の男性、またはトランスジェンダーで男性と性交渉をもっている人たちから被験ボランティアを募り、1250人に試験ワクチンが、1244人には偽薬が投与された。
 ところが、研究チームが22日に試験結果を分析したところ、ワクチン投与グループでは41人、偽薬グループでは30人の感染が示唆されたため、NIAIDは25日、試験の中止を勧告した。研究結果をさらに分析するため、今後も被験者の調査は継続するという。
 NIAIDは米国立衛生研究所(US National Institutes of Health、NIH)傘下の機関で、今回の臨床試験もNIHが資金提供している。


---Another HIV vaccine fails as agency halts study---
2:19 p.m. EDT April 25, 2013
http://www.usatoday.com/story/news/nation/2013/04/25/hiv-vaccine-study/2113065/

WASHINGTON (AP) - Bad news in the fight against the AIDS virus: The government is halting a large U.S. study of a possible HIV vaccine because the experimental shots are not preventing infection.

The study had enrolled about 2,500 people, mostly gay men, in 19 cities. Half received an experimental vaccine developed by the National Institutes of Health, and half received dummy shots.

A safety review this week found that slightly more volunteers who had received the vaccine later became infected with HIV. It is not clear why.

The NIH said Thursday that it is stopping vaccinations, but will continue to study the volunteers' health.

Multiple attempts at creating an AIDS vaccine have failed over the years. But researchers continue to try, pointing to modest success in a 2009 study in Thailand.


---HIV Vaccine Trial Of 2,500 Participants Stopped---
Hilda Scott
First Posted: Apr 26, 2013 11:53 AM EDT
http://www.itechpost.com/articles/8373/20130426/hiv-vaccine-trial-2-500-participants-stopped.htm

National Institute of Allergy and Infectious Diseases (NIAID) announced Thursday that a large-scale HIV vaccine trial was stopped, due to its failure. The AIDS Vaccine Advocacy Coalition (AVAC) said that the trial's end is a reminder of how difficult it is to develop an effective HIV vaccine.

An independent Data Safety and Monitoring Board for the trial, HVTN 505, found that the vaccine wouldn't be able to show effective results, according to the data. Participants in the trial included 2,500 homosexual men and transgender women, all from the U.S. The trial was testing a two-part HIV vaccine before the immunizations were stopped. 

"This trial has provided a clear, swift answer about a specific vaccine strategy. It's not the answer we hoped for, but the search doesn't end here. There are other approaches that must be pursued without delay, and this result will help to focus and guide research efforts," AVAC Executive Director Mitchell Warren said in a press release.

Although the trial was stopped and showed no benefit, the data will be analyzed to help refine the next approach to HIV vaccine research.

"Researchers need to unpack the data from this trial to understand more about why this strategy didn't prevent infection," Warren said.

The HIV vaccine from the HVTN 505 was a two-part strategy, a series of DNA "prime" shots with a vaccine "boost." The vector was based on a common cold virus known as adenovirus type 5 (Ad5).  The adenovirus-based vaccine is just one the HIV approaches that researchers are studying in the hope of finding a way to prevent the virus that causes AIDS.

Warren added that reductions in new HIV infections can be achieved with proven prevention and treatment strategies. Male and female condoms, HIV treatment, voluntary medical male circumcision, oral pre-exposure prophylaxis (PrEP) are all preventive measures.

"AVAC also recognizes the enormous contributions of the more than 2,500 volunteers in this trial. Their altruistic involvement makes HIV vaccine research possible. While today's result is disappointing, we need to look at the bigger picture of AIDS vaccine science," Warren said. Follow-up among the participants of the stopped HIV trial will continue.


---HIV vaccine trial shut down---
April 25, 2013|By Melissa Healy, Los Angeles Times
http://articles.latimes.com/2013/apr/25/science/la-sci-hiv-vaccine-trial-halted-20130426

Federal researchers shut down a clinical trial of an HIV vaccine involving about 2,500 subjects after it is found to be ineffective at preventing healthy subjects from contracting the virus.

In another major setback for efforts to develop an HIV vaccine, federal researchers have shut down a key clinical trial after an independent panel of safety experts determined that volunteers who got an experimental vaccine appeared to be slightly more likely to contract the human immunodeficiency virus than those who got a placebo.

Investigators involved in recruiting volunteers and running the trial at 21 sites across the country were ordered Tuesday morning to stop immunizing volunteers with the genetically engineered HVTN 505 vaccine and to inform the nearly 2,500 people who participated in the study whether they got the vaccine or the placebo. All of the volunteers were men or transgender people who have sex with men.

The announcement came Thursday from the National Institute of Allergy and Infectious Diseases, known as NIAID, which developed the HVTN 505 vaccine and launched the advanced clinical trial in 2009. The vaccine was designed to prime the immune system to mount a robust defense against all three subtypes of the HIV virus.

Although earlier trials that tested the vaccine on fewer people suggested it was able to produce an immune response to HIV and had a good safety record, the larger trial revealed a "non-statistically significant increase in HIV acquisition among volunteers in the investigational vaccine group compared to those in the placebo group," NIAID said in a statement.

The difference in infection risk between the vaccine group and the placebo group could have been a matter of chance. Even so, the data failed to indicate that the vaccine was having - or would ever achieve - its intended effects of reducing one's risk of infection with HIV, the virus that causes AIDS.

Also discouraging was the fact that the three-shot vaccine regimen did not help suppress the replication of HIV in people once they were infected, NIAID noted.

"This is quite a substantial disappointment," said Dr. Scott Hammer, a Columbia University virologist who is one of the trial's principal investigators. But, Hammer added, "we've learned from every clinical efficacy trial we've done. We've had good and bad news, but each one takes us a little closer in terms of what to pursue and not to pursue."

Altogether, there were 41 HIV infections among the 1,250 study volunteers who got the experimental vaccine and 30 infections among the 1,244 who received the placebo.

Of the 23 volunteers who became infected with HIV in the first 28 weeks of the study, 14 had received the vaccine and nine had received the placebo.

The experimental vaccine was also a disappointment for another reason: It failed to reduce the viral load of volunteers who became infected after they enrolled in the trial.

In its statement, NIAID said that it "remains committed to the pursuit of a highly effective, preventive HIV vaccine as part of a multifaceted HIV prevention research program." Meanwhile, it said that study volunteers who became infected during the trial would be referred to local services "for appropriate care and treatment." The study's investigators would continue to follow those volunteers for five years from the time they enrolled, NIAID said.

This is not the first large HIV vaccine trial to end abruptly after initial results proved disappointing. In 2003, early trials testing a Genentech Inc. vaccine known as Aidsvax found that some who got it developed HIV - prompting government regulators to block further testing in the United States. In 2007, a trial in South Africa that tested a vaccine made by Merck & Co. was ended prematurely because participants who got the active vaccine were found to have higher rates of infection than those who did not.

The HVTN 505 vaccine regimen was an outgrowth of one of those disappointments. Researchers improved upon the Aidsvax vaccine and tested the new formulation, called RV-144, in heterosexuals in Thailand. In 2009, they found that it reduced infection rates by 30%.

The HVTN 505 vaccine incorporated many of the lessons learned from the RV-144 trial about constructing a vaccine that would train the immune system to recognize and fight the genetic guts of the virus as well as its "envelope," or outer cell wall.

That those lessons failed to yield a successful vaccine in the NIAID trial was a bitter disappointment to researchers. In the coming weeks and months, researchers will be poring over two years' worth of blood samples from volunteers, said Dr. Stephen J. Brown, medical director of the AIDS Research Alliance, the Los Angeles site participating in the HVTN 505 trial.

As they do so, Brown said, researchers are likely to glean new insights into which parts of the current vaccine might form the basis for new HIV-prevention regimens. The next HIV vaccine trials are to start next year in southern Africa.

The World Health Organization estimates that 34 million people worldwide are living with HIV, including 2.5 million who became infected in 2011 - a statistic that underscores the need for a vaccine. More than 25 million people have died since the HIV/AIDS epidemic began, according to the WHO.

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