ZARD坂井泉水死去/子宮頚癌とHPVウイルス(15) ワクチン開発の革新、伝説の再来

画像 先日、肥満ウイルスの発見とワクチンの可能性の話題があった。HPVウイルスワクチン Gardasil は莫大な利益をもたらしている。

 1950年代にはワクチン開発者は、アップルのSteve Jobs や Google の創立者のようにアメリカ革新のスターだった。Maurice Hilleman がインフルエンザ、麻疹、ムンプス、風疹などのワクチンを開発し医学史上かってないほどの多くの人々の救命を保証した。しかし、1990年代半ばにはこの動きは止まり、25あった新ワクチン開発企業は数社にまで減少してしまった。しかし、うってかわって今や、ワクチンが巨額の利益をもたらすものとして、Astra Zeneca, Novartis, Pfizerといったメジャーな製薬企業を含めて多くの企業が、多数のワクチン開発にしのぎをけずる状況となっている。GlaxoSmithKlineと Merckが最近、発展途上国で多数の子どもの死者がでているロタウイルスのワクチンを開発した。
 現在最も成功したのはMerk社である。2005年には11億$でその前3年は増加がなかったワクチン売上が、昨年子宮頚癌ワクチンを発売し、2007年上半期だけでワクチンのみで20億$と昨年以上の売上となった(このうち子宮頚癌ワクチンGardasil が7億2300万$)。開発当初は周囲から冷たい扱いを受けたという。
 種々の癌やマラリアなどの感染症にたいしてのワクチン開発研究に巨費が投入されている。Mayo Clinicのワクチン専門家Gregory A. Poland によれば「ワクチン学の黄金時代に突入している」という。科学技術革新により、個人の遺伝子特性に合わせた、その人に最も危険なウイルスに対するワクチンといった、より効果的な個人的なワクチン(personalized vaccines)の開発も進められることだろう。


Vaccines and Their Promise Are Roaring Back
Published: August 26, 2007

THE prospect of profit drives innovators, perhaps as much as solving the technical problems that make innovation possible.

This truism is gaining new currency among innovators in the once-legendary field of vaccines. In the 1950s, vaccine inventors were the stars of American innovation, celebrated the way Steve Jobs of Apple and the pair who founded Google are today. In 1955, Jonas Salk virtually wiped out polio with a vaccine, becoming the most celebrated scientist in America. In a phenomenal run starting in the late 1950s, Maurice Hilleman created vaccines for flu, measles, mumps, rubella and other illnesses, getting credit for saving more lives than any medical innovator in history.
By the mid-1990s, however, innovation in vaccines had virtually come to a halt. Only a handful of companies even tried to develop new ones, compared with 25 in 1955.
But in a stunning reversal, innovators today are chasing dozens of vaccines, stimulated by some recent high-profile successes. “People see vaccines as money makers,” says Paul A. Offit, chief of the infectious diseases section at the Children’s Hospital of Philadelphia and the author of “Vaccinated,” a new book on Hilleman’s career.
As wealthy countries spend much more on health care, and as poorer countries put new emphasis on disease prevention, many companies are jumping into vaccine innovation, including major pharmaceutical makers like Astra Zeneca, Novartis and Pfizer. Two separate teams, one involving Dr. Offit at GlaxoSmithKline, and the other at Merck, created in recent years rotavirus vaccines for childhood diarrhea, a big killer in less developed countries.
“Vaccine makers are tackling major public-health problems again,” says Adel Mahmoud, a vaccine expert and a professor in the department of molecular biology at Princeton. “The size of the market is incredible, both in America and around the world.” Dr. Mahmoud was previously president of Merck’s vaccines unit.
To date, the biggest winner in the revival is Merck, which in the first six months of 2007 posted revenue of nearly $2 billion from vaccines alone, more than the company’s vaccine sales for all of 2006. As recently as 2005, Merck’s vaccine sales totaled barely $1.1 billion and were essentially flat over the prior three years. But last year, Merck received permission to sell three new vaccines, including a breakthrough preventive treatment for cervical cancer, and another for shingles.
“We’re realizing in recent years that if you have strong vaccines, customers are willing to pay for the value delivered,” says Margaret McGlynn, president of Merck’s vaccine business.
Across the industry, the research pipeline is bulging. Companies are spending billions trying to develop vaccines for various cancers, staph infections and malaria. “We are entering a new golden era of vaccinology,” says Gregory A. Poland, a vaccine expert at the Mayo Clinic in Rochester, Minn.
In addition to traditional one-size-fits-all vaccines, Dr. Poland foresees a new class of personalized vaccines tuned toward the particular genetics and biology of the individual. Personalized vaccines will be more cost-effective; today everyone gets the same series of three hepatitis B shots over six months, for instance, though researchers know that one in five people, on average, could get the same protection with fewer.
“Technology will eventually allow us to do immuno-genetic profiles to tell me which viruses pose the most risks to a person,” says Dr. Poland, who works in this nascent field.
Personalized vaccines are likely many years away. So are vaccines for such vexing diseases as AIDS, a big killer whose variety and rapid mutations pose hard problems for vaccine makers.
Even so, potential markets look strong. Governments are more interested in funding vaccination programs after years of neglect, and public fears that vaccines cause harmful side effects are subsiding. Those fears are now largely discounted by medical experts. The specter of bioterrorism has also heightened interest in new vaccines, spawning new funding sources.
“There are a lot of targets that have not been tackled,” says Dr. Mahmoud at Princeton.
The willingness to try makes a big difference. The history of vaccine development is uneven, says Louis Galambos, a historian at Johns Hopkins University who wrote a book on the subject, “Networks of Innovation,” with Jane Eliot Sewell.
“There are waves of optimism in medical science that encourage investment,” Mr. Galambos says, “We’re in one of those waves now.”
THE story of Merck’s Gardasil vaccine to prevent cervical cancer ― a $360 series with sales of $723 million in the first half of this year ― shows why optimism is important. The basic engineering on the vaccine occurred in the late 1990s, and extensive field trials consumed years more and hundreds of millions of dollars.
Merck started Gardasil development when “the climate was really sour, negative,” recalls Eliav Barr, one of the leaders of the company’s Gardasil program. “Many people said it’s not worth creating vaccines.” Regulatory approval is not guaranteed, and production is difficult. Vaccines are grown in living organisms, and “there is an art to making them,” Dr. Barr says.
The allure of the silver bullet ― of wiping out an entire class of related diseases with a single injection ― remains a powerful symbol of technological advance. Fifty years ago, vaccine creators captivated the world’s imagination. With the return of vaccine-making to the center of the pharmaceutical business, new sources of profits are emerging, and new heroes of innovation.
G. Pascal Zachary teaches journalism at Stanford and writes about technology and economic development. E-mail: