SEEK, a privately owned biopharmaceutical company specializing in immunology, announces today that it has completed a Phase Ib/II clinical trial of its HIV-v vaccine which demonstrates a one log (approx 90 percent) difference in viral count in HIV-infected people compared with the placebo group, after just a single vaccine injection.

Gregory Stoloff, CEO of SEEK, commented: "This is the first time ever that an HIV vaccine has shown such a meaningful result in a human clinical trial. The next step will be to progress this to final human trials and determine the optimum dose and dosing regime to further enhance the vaccine's efficacy."

The development of an effective vaccine against HIV has been extremely difficult because the HIV virus constantly mutates. However, SEEK's HIV-v vaccine targets only the conserved regions in the internal proteins of the HIV virus which remain constant across all HIV strains. It is the first vaccine to generate both strong T-cell and antibody responses to eliminate HIV-infected cells and thus neutralise the HIV virus. These unique features mean that the vaccine, while initially tested in an early stage of the disease as a therapeutic, could also be effective as a prophylactic, pending confirmation in a future trial.

Commenting on the results, Marta Boffito, MD, PhD, from the St. Stephen's Aids Trust and the principal investigator in the trial, said: "These are remarkable results which demonstrate HIV-v's safety and immunogenicity and, for the first time, a clinically relevant result, as seen in the one log reduction in viral titres. HIV has long reached pandemic status and, despite growing numbers on anti-retrovirals, we are in desperate need of both a prophylactic and therapeutic vaccine. This HIV-v vaccine definitely warrants further investigation in both these areas."

About the Phase Ib/II trial

The Phase Ib/II trial involved 55 HIV-positive volunteers across the UK, assessing safety and tolerability, as well as the effectiveness of the vaccine by monitoring blood viral load and CD4+ T-cell count, an immune cell which is specifically infected with HIV. The involvement of T and B cells of the immune system in response to the vaccine was assessed by measuring Interferon Gamma and IgG levels.

It was conducted at six centres in the UK:

1) North Manchester General Hospital;
2) Grahame Hayton Unit of the Royal London Hospital;
3) Elton John Centre at the Royal Sussex County Hospital;
4) Royal Hallamshire Hospital;
5) St. Stephen's Centre at the Chelsea and Westminster Hospital, London; and
6) St. Thomas' Hospital, London.

There were five patient groups in the trial: four vaccinated with HIV-v vaccine and one placebo. The four vaccinated groups were divided into low-dose with and without adjuvant and then a higher-dose with and without adjuvant.

Wilson Caparros Wanderley, Chief Scientific Officer of SEEK, added: "The results demonstrate that after a single immunizationthe HIV-v vaccine produces a very strong response from both the antibody and T cell immune systems to the conserved regions only. This is the first time that an antibody response was made to a conserved internal protein that appears on the cell surface during the life-cycle of the HIV virus."

Since the vaccine is synthetically manufactured, it will be inexpensive to produce and can be quickly manufactured in large quantities, making it viable for cost-effective widespread distribution in low-income countries.

SEEK will evaluate partnerships to undertake final human trials during 2012/13. It is expected that these will be therapeutic Phase III trials, which will recruit HIV-infected patients whose viral-load levels will be monitored to determine the optimal dose and dosing regime. All patients will then be switched to that dose and dosing regime and will be followed for the remainder of the trials. Due to the defined and easily-measurable end-points (such as viral-load levels) the trials are expected to be short in duration. If approved, the vaccine could be available to patients in 3-5 years time.

These data are being released to coincide with the 6th IAS Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2011), the world's largest open scientific conference on HIV/AIDS, being held in Rome from 17-20 July 2011. Held every two years, the IAS conference attracts about 5,000 delegates from all over the world. It is a unique opportunity for the world's leading scientists, clinicians, public health experts and community leaders to examine the latest developments in HIV-related research, and to explore how scientific advances can inform the global response to HIV/AIDS.

Notes

Background

The development of an effective vaccine against HIV has been extremely difficult because the HIV virus constantly mutates, changing the peptide sequences ("epitopes") of the viral structural proteins that it presents to the human immune system. This means that conventional approaches to the development of vaccines cannot be employed.

SEEK's HIV-v vaccine has been designed to specifically target only certain conserved regions of the viral proteins that are not subject to regular mutation. The advantage of this approach is that HIV-v only delivers those specific epitopes that are important in the host's immune response, whereas other vaccines employ whole proteins that have multiple internal and external epitopes and therefore can cause the immune system to direct its response against the wrong targets. With HIV-v, the immune system is primed to recognise and target only those regions within HIV proteins that are highly conserved and hence present in all recorded strains of this highly variable virus.

HIV-v Vaccine

SEEK's HIV-v vaccine can be quickly, easily and cost-effectively manufactured. The vaccine consists of a number of peptide sequences from viral proteins. These peptides are made synthetically, thus allowing for increased purity and more controlled dosing of the vaccine compared with conventional vaccines obtained from or delivered by genetically-modified organisms.

HIV Background/Economics

Human Immunodeficiency virus (HIV) is the causative agent for AIDS. Infection with this retrovirus causes a progressive failure of the immune system making the host susceptible to opportunistic infections and cancers.

Currently, there are more than 33 million people living with HIV/AIDS worldwide, according to the World Health Organization, the majority of them in sub-Saharan Africa. Since 1980 over 25 million people have died as a result of HIV/AIDS. Only 6.5 million out of an estimated 17million are eligible for anti-retroviral (ARV) treatment. UNAIDS estimates that $22bn a year will be required by 2015 to ensure universal access to treatment care and support by people living with HIV/AIDS.

If the therapeutic efficacy of this vaccine is confirmed in further human studies, newly-diagnosed people infected with HIV may benefit from immediate treatment rather than waiting until their health deteriorates to the status required to qualify for expensive anti-retroviral (ARV) treatment programmes. This would also reduce the risk of transmission and. provide a cost-effective means of achieving UNAIDS' declared objective in their Treatment 2.0 policy for AIDS, by making HIV treatment affordable for low-income countries, especially those hardest hit in sub-Saharan Africa.

SEEK is working with the Rush Foundation to incorporate an access agreement for low-income countries, particularly sub-Saharan Africa, within any partnership arrangement.

Source:
SEEK