InnaVirVax, a biopharmaceutical company specialized in research and development of therapeutic and diagnostic solutions for major infectious and chronic diseases, today announced the overall results of its Phase I/IIa clinical study (IVVAC-3S/P1) of its VAC-3S immunotherapy, which is currently in development. These results were presented last weekend at the "2015 Towards an HIV Cure" symposium, organised by the International AIDS Society in Vancouver.
The primary goal of the IVVAC-3S/P1 study was achieved. VAC-3S immunotherapy was very well tolerated and an immune response was demonstrated, the intensity of which was clearly linked to the dose administered.
Above all, the administration of VAC-3S revealed immunovirological effects on four important markers:
- A reduction was observed in proviral DNA (one of the most widely studied marker of the viral reservoir); this reduction significantly correlated with the immune response to VAC-3S.
- 24 weeks after the first dose, patients responding to the VAC-3S vaccine showed significant results regarding the following immunological effects:
- a significant rise in the percentage of CD4+ T-lymphocytes, a key marker for reconstitution of the pool of CD4+ T lymphocytes that are destroyed by HIV;
- a significant fall in the percentage of CD8+ T lymphocytes, a marker of immune activation that reflects deregulation of the immune system related to the infection;
- Finally, a significant rise in the CD4/CD8 ratio was observed, this being a marker of immune reconstitution in patients living with HIV.
The positive course of all these immune measurements means that a functional cure could be envisioned through the administration of VAC-3S as part of cure strategy. Furthermore, these findings, and notably those concerning the fall in levels of a viral reservoir marker, are very promising. They need to be confirmed in future studies on a larger number of patients. That said, the modulation of virological and immunological markers of HIV infection clearly position the development of VAC-3S as part of a "functional cure" strategy designed to allow individuals living with HIV to discontinue their antiretroviral therapy while still controlling their viral load.
IVVAC-3S/P1 was a randomised, double-blind, placebo-controlled dose escalation study of VAC-3S, performed in 33 people living with HIV and receiving antiretroval therapy. Their viral loads were undetectable, and their CD4+ T lymphocyte levels higher than 200 cells/mm3.
This study was carried out in two reference centres at Hôpital de la Pitié-Salpêtrière (Professor Christine Katlama, coordinating investigator) and Hôpital Cochin (Professor Odile Launay) in Paris. VAC-3S was administered three times, at four week intervals. Some patients also received a fourth dose, six months after the third.
Professor Christine Katlama, Coordinating Investigator at Hôpital Pitié Salpêtrière stated:
The results of this study are very encouraging. The significant effects of VAC-3S on four immunovirological markers constitute a crucial step forwards in the clinical development of this immunotherapy. We can't wait to confirm these findings in a larger number of patients.
Raphaël Ho Tsong Fang, Director responsible for clinical development at InnaVirVax added:
These results, generated during a clinical study on tolerance and in a relatively small number of patients, are very positive. InnaVirVax is particularly grateful to all its partners, and to the patients living with HIV and their families, for their commitment to this study.
Joël Crouzet, Chairman and CEO of InnaVirVax concluded:
These promising results encourage us to pursue the clinical development of VAC-3S with the hope of a functional cure, the new frontier in this therapeutic area. We are eager to see the findings of the phase IIa study, called IPROTECT1, which was initiated in December 2013. As well as the patients who took part in this study, all the investigators and their teams, I would also like to thank INSERM, ANRS, AP-HP and UMPC who supported this project during its different research and development stages.