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On the way to developing a vaccine for HIV

FIT Biotech has used its proprietary Gene Transport Unit (GTU®) vector delivery platform to develop an advanced HIV vaccine candidate. Preliminary results from a Phase II therapeutic clinical trial with the candidate in South Africa have been promising.

HIV is proving a major problem for many countries in Africa in particular, and in the case of South Africa more than 5.5 million people are infected with the disease. Women are particularly severely affected, with 29.1% of those presenting at public antenatal clinics infected.

Most HIV vaccine efforts to date have been aimed at developing a preventive HIV vaccine to protect non-infected individuals against possible future exposure. Therapeutic vaccination of individuals already infected, in contrast – employing an HIV vaccine that can modify the course of the infection and its progression towards the disease by maintaining a low viral load and high or constant CD4 cell counts – offers the best hope for chronically infected individuals not eligible for antiretroviral therapy.

This is especially important in South Africa, since access to antiretroviral therapy through public-sector health care is limited to individuals with a CD4 cell count of < 200 cells/mm3, which is relatively late in the progression of the disease to full-blown AIDS.

FIT Biotech’s HIV vaccine candidate is currently on trial in Soweto in South Africa.

Dealing with antigenic variability

Developing an HIV vaccine is complicated by the ability of the virus to mutate rapidly, resulting in a high variation between different HIV subtypes (Clades A-K). FIT Biotech has addressed this challenge by designing an antigenic artificial protein, known as MultiHIV, composed of sequences from six HIV genes and incorporating antigens from the A, B, C, and FGH HIV clades.

MultiHIV has been estimated to cover more than 95% of the theoretical antigenic variability within HIV strains – and lies at the heart of FIT Biotech’s lead HIV vaccine candidate, which is a DNA plasmid inserted within the company’s proprietary GTU® vector technology.

The University of Witwatersrand’s Perinatal HIV Research Unit is currently evaluating the vaccine in a Phase II therapeutic clinical trial in Soweto. The trial commenced in 2006 with 60 treatment-naïve HIV-infected individuals and will be completed in early 2009.

Preliminary results showing a significant reduction in viral load and an increase in CD4 counts in vaccinated individuals have led a number of major vaccine companies to take a growing interest in what can be achieved using FIT Biotech’s GTU® technology.

A versatile technology

FIT Biotech’s GTU® technology platform is based around a special DNA plasmid capable of delivering selected genes to human cells. In addition to providing up to 100 times stronger and more persistent gene expression than standard plasmids – thanks to enhanced transcription and nuclear anchoring – it also offers versatility, cost-efficient production opportunities, and freedom from the safety risks associated with viral vectors. In addition to HIV, the company is also working on vaccines against melanoma, diabetes, and Hepatitis C based on the use of GTU® technology.

> Kalevi Reijonen
(Published in HighTech Finland 2009)