Sunday, May 31, 2009

Wyeth's vaccine RandD head talks about vaccines past and future

Vaccine Viewpoint: Emilio A. Emini

Emilio A. Emini, Ph.D., joined Wyeth as executive vice president for Vaccine R&D in November 2005, following a stint at the International AIDS Vaccine Initiative and a 20-year career at Merck, where he last served as senior vice president of vaccine and biologics research. We spoke recently about Wyeth's commitment to vaccines and the expanding role of vaccines among major pharma companies.

Emilio Emini: Wyeth has had a very long history in vaccines. If you go back to our previous incarnation as American Home Products, it was an accumulation of a number of companies. So if you trace back the history of the predecessor companies that make up what we now call Wyeth Vaccines, you'll find a number of pathways that led us to where we are.

One of those pathways was a company called Praxis Biologicals, which was incorporated into Lederle Vaccines, which became part of American Cyanamid, which was then purchased by American Home Products, and then became Wyeth. In the 1980s, Praxis Biologicals invented conjugation technology, which permitted development of vaccines that could engender immune responses -- especially in infants -- against bacterial polysaccharide. This ultimately led to the development of Prevnar, the current pneumococcal vaccine.

The most important products historically were the oral polio virus vaccine, which was the main one used to eradicate polio in North America, and the smallpox vaccine that was used in the campaigns during the 1970s. Wyeth Vaccines has also produced vaccines against diphtheria, pertussis and tetanus.

So we have a pretty rich history, when it comes to vaccines.

CP: That's a long pedigree, considering the ebb-and-flow of vaccine makers in North America.

EE: That's true. And many products that Wyeth Vaccines once produced are no longer made by Wyeth. For example, the need to make oral live attenuated polio virus vaccine went away with the virus' elimination in North America. The need for a smallpox vaccine went away for the same reason. So, in the end, I suppose if one is very successful with a vaccine (eliminating the virus over a long period of time), the need for the vaccine would ultimately disappear.

CP: We're seeing a surge of interest in vaccines from major drug companies. What do you think has prompted it?

EE: I think it comes from a recognition of what vaccines can do. No other intervention in human history -- besides clean water -- has had such a profound effect on the quality of human life. What we're seeing in the past decade or two is a recognition of that role.

A significant driver changing the perception of the value of vaccines -- both from a medical and commercial perspective -- was the success of Prevnar, Wyeth's premier vaccine product. It was introduced in the U.S. in 2000, and is now in 80 countries worldwide, and it's been a success medically and commercially. In the countries where it's been introduced, it's largely eliminated the seven different serotypes of penumococcal organisms and the infections they cause.

The value of a vaccine like Prevnar caught everyone's attention. The commercial value follows the medical value.

CP: What role will vaccines play at Wyeth in future?

EE: Oh, they'll have a very important role. The company's dedicated itself to expanding vaccine development.

I joined Wyeth after having spent more than 20 years at Merck. More than half my time there was in vaccines and, at the time I left, I was head of Merck's vaccine research effort. I came here because of Wyeth's desire to expand and focus itself in a very large way on vaccine R&D.

We have a significant portfolio of potential vaccines in our pipeline. The one that we've talked about most is our second-generation Prevnar, which we call Prevnar-13. It goes after six more serotypes of pneumococcal organisms and will also be very useful in targeting the disease in the developing world.

This is a non-trivial effort on our part, as you can imagine. A 13-valent vaccine will be the most complex biological product ever produced.

CP: You mention Prevnar-13 in terms of its status as a biological. How do you differentiate between vaccines and large-molecule therapeutics?

EE: In terms of family relationship, vaccine development is more closely related to how one develops biologics than it is to small-molecule development. But it's still different enough to consider it a distinct entity. If you take a look at the overall Wyeth portfolio, we classify projects among small molecules, biologicals, and vaccines.

While the pathways are different, vaccines still fall into the same developmental timeline: between 10 and 15 years.

CP: Is there a significant difference between prophylactic and therapeutic vaccines?

EE: Not as such. A vaccine elicits an active immune response. So one elicits a response to prevent a disease, and the other elicits one to treat a disease. Historically, most vaccines were intended to treat infectious diseases, so they were prophylactic in nature. But there's been increasing interest in therapeutic vaccines. At Wyeth, we have a very large program aimed at therapeutic agents for Alzheimer's disease. One aspect of that effort is a passive immunization strategy, a monoclonal antibody aimed at a particular molecule that appears to be important in the progression of the disease: the beta-amyloid molecule. This is in collaboration with Elan.

Another aspect of that program is to develop an active vaccine, one that will elicit an antibody that will delay progression of Alzheimer's disease. So the former is a biologic, and the latter is a therapeutic vaccine.

CP: After Prevnar and Prevnar-13, what's on the horizon for Wyeth Vaccines?

EE: The only other one we've talked about publicly is an early-stage program for a vaccine against meningococcal type B. Again, this is a bacterial organism that can cause severe meningococcal disease in infants and adolescents.

As you can see, there's a certain pattern here. If you look at the infectious diseases that require vaccines, a lot of them are bacterial in nature. In many cases, these diseases are very rapidly progressive when they occur, oftentimes before we can intervene with a suitable antibiotic. In addition, for a lot of these bacterial diseases, they're increasingly antibiotic-resistant. So the best way to deal with these infections is not to wait for them to occur, and then begin treatment. The best way to deal with them is to not get them in the first place. And the best way to do that is with a successful vaccine.

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