Entrevista con Jenifer Allen de Merck

Semana: ¿Which is the technology or approach used by Merck with the AIDS vaccine?

We continue to focus our efforts on two forms of Merck's investigational HIV vaccine for our ongoing research -- an HIV-1 gag vaccine using plasmid or "naked DNA" technology, and a replication-defective adenovirus HIV-1 gag vaccine. [By gag, we are referring to a gene or tiny fragment of HIV, which is stitched into the vector in an effort to stimulate cellular immunity, eliminating those cells HIV has infected.] The vaccines do not contain either killed or attenuated HIV, and the use of an HIV gene gag cannot cause HIV infection.

Both of these investigational vaccines are designed to produce certain HIV-1 proteins and stimulate anti-HIV-1 cellular immune responses in recipients. It is likely that both forms of the vaccine would ultimately be used in a combination known as a "prime-boost" approach, something Merck scientists discussed briefly at the AIDS Vaccine 2001 meeting.

- DNA vaccine: This approach uses a plasmid DNA vector (known as 'naked DNA') and utilizes technology we have licensed from Vical, Inc., but which has been modified by Merck. It has been tested extensively in preclinical studies, including those reported in the journal Science in October 2000.

- Replication-defective adenoviral vaccine: This approach utilizes a form of adenovirus as a vector. The AdV is replication-defective, meaning that it has been modified so that it cannot reproduce in the recipient.

Results to date indicate that of the two vaccines, the adenoviral vector vaccine elicited relatively greater and persistent CD8+ and CD4+ T-cell responses.

Semana: ¿In what stage of develpment is the Merck Vaccine ?

A total of 10 Phase I protocols are currently underway involving Merck's two vaccine candidates ? an HIV-1 gag DNA vaccine and an HIV-1 gag replication-defective adenovirus vaccine. The Phase I studies, which represent the earliest stage of human testing, are expected to continue into 2003.

Of the 10 protocols, five are taking place in uninfected volunteers and five are taking place in HIV-infected volunteers.

Semana: ¿How do you see Vaxgen´s results?

VaxGen has been dedicated in its efforts to complete their North American Phase III HIV vaccine trial and for that they should be congratulated.

As we all know, there is a great need for an HIV/AIDS vaccine. While the results from the VaxGen trial are not encouraging, there are many dedicated scientists working every day to discover an effective vaccine. Like anyone who understands the devastating effects of HIV/AIDS on global health, you hope that the answer will be found quickly. That hasn't happened yet and there is much work to be done.

Merck has been involved in HIV/AIDS research for more than 15 years and our efforts in HIV vaccine research reflect our long-standing commitment to the development of life-saving medicines and vaccines. We have a long tradition of addressing major public health needs through vaccine development (including but not limited to measles, mumps, rubella, hepatitis A and B, pneumococcal infection and varicella).