Results From Phase IIB Placebo Controlled Study of Bionor Pharma's Vacc-4x Show Excellent Safety Profile, Statistically Significant Viral Load Reduction in Patients With HIV Who Suspend Antiretroviral Therapy
BANGKOK, THAILAND--(Marketwire - September 14, 2011) -
Results from the furthest advanced study of a therapeutic vaccine candidate to treat people living with HIV/AIDS were announced at a news conference held by the Global HIV Vaccine Enterprise, hosts of AIDS Vaccine 2011 today in Bangkok.
The vaccine, developed by Bionor Pharma (OSLO: BIONOR), is designed to target immune responses to conserved domains of p24 since sustained immune responses to p24 have been proven to be associated with delayed disease progression.
The results were announced by Professor Jan van Lunzen, Medical Director of the Infectious Diseases Unit at the University Medical Centre Hamburg-Eppendorf, Germany and an investigator on the placebo controlled, multi-national, multi-center Vacc-4x trial.
Among the key findings reported at the news conference:
- Significant viral load reduction compared to pre-treatment levels. Patients on Vacc-4x experienced viral reduction of 70% (more than half a log) compared to their viral load levels before initiating ART. This reduction was not seen in the patients receiving placebo.
- Confirmation that HIV can be targeted at its "Achilles heel," the known conserved domain p24. The viral load of immune response (ELISPOT) positive Vacc-4x subjects was significantly lower than that of ELISPOT positive subjects in the placebo group (p=0.023) indicating that Vacc-4x immunization may improve immune responses to p24 leading to a lower viral load levels, or set point. From this researchers conclude that Vacc-4x appears to refine a patient's immune system to create a better response to p24.
- Improved viral load "set point." A statistically significant treatment difference in plasma viral load set point between the Vacc-4x and placebo groups in subjects after 28 weeks of ART.
- Vacc-4x extended the time period patients could stay off ART. Subjects receiving the vaccine were almost twice as likely to remain off ART for more than one year compared to the placebo group (30% versus 18%). This is in agreement with the follow-up data from the phase IIa study from Ullevål University Hospital between 2003 and 2006 that showed patients vaccinated with Vacc-4x could stay off ART for on average 31 months.
- Vacc-4x potential to prevent transmission of HIV. Because Vacc-4x can significantly lower viral load, and because researchers know that communities with lower viral load transmit the disease less successfully, the vaccine may be a candidate to slow the spread of HIV transmission -- a finding that could have major implications for the developing world where a vaccine would be easier to administer and less expensive than current options.
The p24 Conserved Domain: The Holy Grail of HIV Cure Research
Conserved domains are shared between diverse strains and are immunologically vulnerable. A recent cover article from the Proceedings of the National Academy of Sciences (USA) has highlighted a number of conserved sectors on p24 as immunologically vulnerable and where immune escape results in defective virus. Vacc-4x is derived from two of these sectors.
"Because we know that p24 cannot be changed without affecting viral fitness and that Vacc-4x is also derived from such conserved regions on p24, we can see why this vaccine has the potential to significantly inhibit HIV," said Professor Richard Pollard, Chief, Infectious Diseases, University of California-Davis Medical Center.
"These results prove that Vacc-4x acts like a flashlight, lighting the way for the immune system to address the virus at its Achilles heel -- a proven conserved domain of HIV," said Dr. van Lunzen. "We have far too few strategies that could lead us to a cure for HIV. Vacc-4x may be a bridge to lead researchers toward a way to 'plug the leak' or permanently stop the virus from mutating, which is not addressed by any current treatment."
The Need for a Therapeutic Vaccine
Although combination antiretroviral drug therapies are the standard treatment used to treat people living with HIV, they do not fully prevent HIV infection and fail to eradicate the virus once HIV infection is established. Patients who stop taking ART experience HIV replication and infection rebounds, and compliance is a significant problem due to cost and availability.
In the USA alone, thousands of people living with the virus are on a "wait list" to obtain these treatments. ART may cause unwanted side-effects, and lifelong treatment with ARTs can significantly affect a patient's quality of life. Additionally, HIV can become resistant to virtually all forms of traditional ART if good adherence is lacking, leaving a patient with limited treatment options. Studies show most patients on HIV at some point have adherence issues.
On this basis alternative treatments are required, and a therapeutic vaccine that fights HIV by mobilizing the patient's own immune system without any serious side effects, is strongly wanted.
The number of HIV-infected globally is approximately 35 million. Today, HIV-medicines constitute a market of at least US $12 billon, and every year approximately 3 million new people are infected by HIV.
Vacc-4x is a therapeutic HIV-vaccine based on four synthetic slightly modified peptide sequences from conserved parts of the P24 capsid protein of the HIV-virus. The chosen peptides are from conserved (low-mutating) parts of the virus, and the modification has been made to increase immunogenicity of the vaccine.
Bionor recently announced that the manufacturer of Revlimid (lenalidomide) has agreed to jointly fund a phase I/II trial in HIV patients with stable ART. All patients will remain on ART and all patients will receive Vacc-4x. Half of the patients in the double blind randomized trial will also receive Revlimid to see if it improves the efficacy of Vacc-4x.
About Bionor Pharma
Bionor Pharma (OSLO: BIONOR) is a Norwegian biotech company developing therapeutic and preventive peptide vaccines for chronic viral infections. The company has patented synthetic peptides from low-mutating parts of the virus, modified to improve immunogenicity and efficacy. No serious side-effects have been observed by the use of the company's vaccines.
HIV is the first disease targeted, with cell-mediated and humoral peptides in clinical development.
Bionor's patented technology platform is broadly applicable. In addition to the most advanced HIV-vaccine candidate, Vacc-4x, the company has a humoral HIV-vaccine candidate, Vacc-C5, which is planned to be tested clinically in Q1 2012. In addition, the company has vaccine candidates in pre-clinical development for other chronic infections, such as Hepatitis C, Influenza and cancer induced by human papilloma virus. For more information, see www.bionorpharma.com.