Two-Thirds Respond to "Re-vaccination"
Two-Thirds of Study Volunteers Respond to First-Ever "Re-vaccination " of Vacc-4x, Bionor Pharma's Peptide-based Therapeutic HIV-Vaccine
Study Highlights: 25 volunteers from previously conducted Phase 2a trial were "re-vaccinated" with the vaccine after 7 years as part of a Phase 2 trial. Two thirds of the study volunteers responded to re-vaccination with Vacc-4x, resulting in enhanced immune response to their HIV-virus. Vacc-4x was also found to trigger 'killer T-cells' that function to seek out and kill HIV-infected cells in the body, which is in line with the objective of a successful T-cell vaccine. Researchers believe these findings demonstrate the ability to safely and effectively "re-vaccinate" patients that previously have had an extended break in their daily HIV-medication (ART).
Bionor Pharma (OSLO: BIONOR) today reported preliminary findings of its Phase 2 trial that served to re-immunize, or "re-vaccinate" twenty five study volunteers from its original Phase 2a study conducted in 2002/2003. Previously, at the XVIII International AIDS Conference in Vienna in July 2010, the Company reported that about half of the study volunteers retained memory to Vacc-4x seven years after their initial immunization. Bionor Pharma researchers now report that this memory can be safely reactivated following re-immunization/re-vaccination resulting in improved anti-viral responses.
Two thirds of study volunteers responded to Vacc-4x, and these responses were found to be cross-reactive with the virus itself. The study also showed that Vacc-4x is capable of triggering the specific T-cells of the immune system that function to seek out and kill infected cells (CD8+ killer T-cells) which is the objective of a successful T-cell vaccine. The complete study results are being prepared for publication in an international peer reviewed journal.
'It is promising that Vacc-4x has been able to induce such durable memory in patients and that this can be re-boosted many years later even after long periods of treatment interruption,' says Prof. Dag Kvale from Oslo University Hospital, Norway, who has led the study. 'This therapeutic vaccination technique demonstrates clearly a potential to achieve sustained immune responses which can be boosted while on antiretroviral therapy.'
Vacc-4x is composed of four modified peptides corresponding to conserved regions of the HIV core protein (p24) that are injected intradermally beneath the skin. This method of immunization is relatively simple and suited to a regime involving periodic boosting. A phase IIa study carried out in 2002/2003 showed that Vacc-4x could support prolonged periods free of antiretroviral therapy (average 31 months). Twenty five of the study volunteers who participated in the original phase IIa study have now been successfully given a voluntary 're-vaccination' with Vacc-4x and followed while on antiretroviral therapy.