Starpharma optimistic new microbicide will beat odds

VivaGel uses condom coating dosing

Jackie Fairley, BVSc, BSc, MBA, chief executive officer of Starpharma of Victoria, Australia, recently fielded some questions from AIDS Alert about the company's investigational microbicide, VivaGel.®

AIDS Alert: Where is the investigational microbicide VivaGel in the clinical research pipeline?

Fairley: The stand-alone VivaGel product is undergoing clinical studies in increasing numbers of sexually active women in order to expand on the safety profile of the product prior to phase 3 efficacy trials. This phase of testing is equivalent to typical phase 2 for a more traditional pharmaceutical product.

AIDS Alert: Why are you confident that VivaGel will not turn into a disappointment for the HIV/AIDS community, as have other vaginal microbicides to date?

Fairley: Starpharma has established a large body of data on the product. These data so far indicate that VivaGel has excellent activity against a wide range of HIV strains in cell-based assays and in very demanding animal studies. Nonclinical and clinical data also demonstrate a favorable safety profile of the product in the studies conducted.

AIDS Alert: Using VivaGel as a condom coating is an interesting dosing strategy. But how will that help women in developing nations gain more power over their own HIV protection?

Fairley: Successful development of a VivaGel coated condom would be good news for women, as it would confirm what we already believe, i.e. that microbicides make sense from a commercial point of view and provide benefits to the community. We believe this success would in turn generate further interest in the microbicide field from commercial parties. Starpharma's own development program for the stand-alone VivaGel product, which more directly gives women control of their own protection, would be significantly boosted and advanced by the successful development of the condom coating product.

AIDS Alert: Would you please describe how your short study will serve as an adequate surrogate for antiviral efficacy of VivaGel in humans? And if there are problems with the microbicide, will this trial adequately highlight the problems before phase III trials begin?

Fairley: As announced recently, the clinical study referred to will measure the level of antiviral (HIV and HSV-2) activity retained by VivaGel® after vaginal administration. This assessment of antiviral activity, which will be by laboratory assay of vaginal samples collected up to 24 hours after VivaGel application, is important as it takes into account the effect of direct exposure of drug to the vaginal environment.

There are no validated surrogates for antiviral activity (or lack thereof) of microbicides in humans. However, until a product is proved effective, Starpharma's trial provides a potential surrogate for antiviral efficacy of VivaGel in humans ahead of Phase 3 studies, as it will determine if SPL7013 is active against virus after contact of the drug with the vaginal mucosa and vaginal secretions.

AIDS Alert: Why are you and others in the HIV/AIDS research world working so intently on finding a vaginal microbicide despite the problems this area of study has had so far?

Fairley: It is important to note that there may never be a vaccine for HIV, although researchers continue to renew efforts towards this goal. Microbicides such as VivaGel are the only other key technology under research and development for prevention. With thousands of people being infected with HIV or dying from AIDS each day, it is self-evident why this is such an incredibly important pursuit. Commercially, a microbicide market in the developed world has been estimated at $1-3.5 billion. Research problems and the resolution or understanding of these problems serve to inform and improve research methods over time. Starpharma is continually applying gold-standard and newly evolved research and development practices in the development of VivaGel in an attempt t ensure a successful outcome.

AIDS Alert: Is there anything else about VivaGel that you'd like to say?

Fairley: VivaGel is being developed as a vaginal microbicide for the prevention of HIV and HSV-2. Other applications of VivaGel are also under assessment, including prevention of human papillomavirus (HPV), and treatment of bacterial vaginosis (BV). All these conditions can lead to increased risk of HIV transmission and acquisition, so are important targets for VivaGel and present excellent commercial opportunities for Starpharma.