11 NAPWA Symposium 6 th IAS Meeting An HIV-based Lentiviral Vector Vaccine Achieves Functional Cure Post-challenge in a Subset of Vaccinated Macaques Dr. Lawrence Michaelis Chairman and CEO Rome, July 19 th 2011 “Delivering the Promise of Genetic Medicine and Vaccines”

VRX496 Autologous CD4 T Cell Therapy 65 patients in several Phase 1 and 2 trials of VRX496 ­Infusions found to be safe ­Induces significant CD4 cell increases in a sub-set of HIV-infected patients. Decreased viral load set point in STI setting. ­Produces mutations in HIV, making the virus less fit to replicate (see IAS WEPDA0205 Poster Discussion) Decision made to secure funding to advance program to Phase 2b ­ACTG agreed to support next trial ­Search for corporate co-development partner VRX496 platform provided important insights into next generation product - HIV vaccine candidate, VRX1273 ­Safety ­Design ­Manufacturing 2

General Benefits of Therapeutic HIV Vaccine Lower viral load Lower forward transmission Preserves the CD4 compartments Extends survival No toxicities Low frequency of treatment Preserve ARV alternatives Significantly reduce cost 3

Benefits of Therapeutic HIV Vaccine General Benefits Lower viral load Lower forward transmission Preserves the CD4 compartments Extends survival No toxicities Low frequency of treatment Preserve ARV alternatives Significantly reduce cost 4 VIRxSYS’ VRX1273 Viral load reduction achieved CD4 compartments maintained Survival advantage demonstrated No toxicities and reinfusion-safe Single set of infusions effective No drug-resistance of HIV expected Anticipated to be cost effective Clade-agnostic. Designed for global application

Benefits of Therapeutic HIV Vaccine General Benefits Lower viral load Lower forward transmission Preserves the CD4 compartments Extends survival No toxicities Low frequency of treatment Preserve ARV alternatives Significantly reduce cost 5 VIRxSYS’ VRX1273 Viral load reduction achieved CD4 compartments maintained Survival advantage demonstrated No toxicities and reinfusion-safe Single set of infusions effective No drug-resistance of HIV expected Anticipated to be cost effective Clade-agnostic. Designed for global application VRX1273 HIV Vaccine – Targeted as a Functional Cure

Reduce viral load Preserve the CD4 compartments Extend survival Objectives for VIRxSYS’ VRX1273 HIV Vaccine * T.C. Friedrich and D.I. Watkins,

Outstanding Results from the NHP SIV Model Vaccine extremely immunogenic –Unique, high-magnitude CD8 responses to SIV Strong protection from extremely high and pathogenic challenge; 40% of vaccinated monkeys responded favorably: –Long-term control of viral load, over a 18-months period, down to undetectable levels –Complete preservation of the immune compartment: vaccinees are not immuno-deficient and develop no symptoms of AIDS –SIV control extends to the immune sanctuaries, with dramatic decrease of virus in all reservoirs tested –Improved survival in all vaccinees, even in those that did not truly “respond” according to the above parameters 7 * Please refer to Late-Breaker abstract MOLBPE042: Franck Lemiale et al. “A lentiviral vector HIV vaccine candidate protects macaques from high dose SIV intrarectal challenge: vaccine responders achieve functional cure”.

1.E+01 1.E+02 1.E+03 1.E+04 SIV RNA copies/ml Plasma viral load Proviral DNA in PBMC Proviral DNA in lymph nodes Proviral DNA in jejunum SIV DNA copies/million cells LV-vaccinated Unvaccinated EC SIV-infected, deceased LV-vaccinated Unvaccinated EC SIV-infected, deceased LV-vaccinated Unvaccinated EC SIV-infected, deceased LV-vaccinated Unvaccinated EC SIV-infected, deceased Reduced SIV Provirus in Reservoirs of Vaccinees LV-only vaccine responders Mamu B*08+/B*17+ Elite Controller (EC) Averages of 13 NHP deceased of SIVmac251 infection

Next Steps HIV Vaccine Program was presented to the FDA Pre-IND meeting successfully completed No challenge to the strategy of using integrating HIV-based lentiviral vector as vaccine Finalized clinical design with help of Medical Advisory Board Preparing for IND-enabling studies (Tox/Biodistribution), analytical assays development and manufacturing scale-up 9

Why so Little for Therapeutic Vaccines? As for today, no preventive vaccine approach succeeded Despites over 20 years of efforts and massive investments Furthermore, preventive vaccine does not address the growing needs of alternative treatments for HIV infected individuals Thus one may question why there are insufficient funds available to develop therapeutic vaccine aimed at functional cure Small companies cannot do everything themselves Focusing on product development is their mandate Advocacy groups are better suited pushing a change in priorities We need your support for developing a Functional Cure for HIV 10

11 Thank You “Delivering the Promise of Genetic Medicine and Vaccines”

First ; Advantages of a TV Second: Overview of the monkey study. Emphasize toxicity and all animals severely infected, no prime, etc. Third: Results at 6, 12, and 18 months : VL, Survival, immune System, Proviral DNA, and lymphactics Fourth: Review our interpretation. “Not aware of other primate studies with such results, comments from MAB, what we would have with 40%, lentiviral vector and safety, PV in a therapeutic setting. Five: Next steps, FDA, Plan on TI in Phase I, More attention for funding of Functional cures,