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High Efficacy Vaccine and Microbicide Combination For Use Against HIV

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The development of a vaccine against human immunodeficiency virus (HIV) would be expected to provide long-lasting protection. Researchers at the National Cancer Institute (NCI) developed a high efficacy vaccine and microbicide combination for use in an improved HIV vaccine regimen.
NIH Reference Number
Product Type
  • Human Immunodeficiency Virus, HIV, Acquired Immuno-Deficiency Syndrome, AIDS, Vaccine, Microbicide, SAMT-247, Envelope Variable Region, V1, Envelope Glycoprotein 120, gp120, Antibody-dependent Cellular Cytotoxicity, ADCC, Efferocytosis, Franchini
Collaboration Opportunity
This invention is available for licensing and co-development.
Description of Technology

Human immunodeficiency virus (HIV) remains a major global health challenge despite the advancement made in development of effective antiretrovirals (ARVs). ARVs are effective at limiting replication and spread of the virus, and progression to acquired immuno-deficiency syndrome (AIDS). However, ARVs often lead to emergence of drug-resistant virus strains insensitive to treatment and with toxic effects following long-term usage. In addition, access to ARVs is limited in certain regions, particularly in sub-Saharan Africa – where the HIV epidemic continues unabated and disproportionately affects women and adolescent girls. There is a global health need for development of alternative approaches providing long-term protection from the virus, such as vaccines.

Researchers at the National Cancer Institute (NCI) previously demonstrated the efficacy of envelope glycoprotein 120 (gp120) variable region 1 (V1)-deleted simian immunodeficiency virus (SIV) vaccines against the highly pathogenic SIVmac251, which recapitulates human AIDS in animals. These SIV envelope V1-deleted vaccines increased the antigenicity of the envelope glycoprotein variable region 2 (V2) and were 65% effective in preventing vaginal SIVmac251 infection in the macaque animal model. However, the vaccine regimen was ineffective in about one third of animals. Therefore, the inventors added the SAMT-247 microbicide that disrupts the folded structure of the viral nucleocapsid protein NCp7 by interfering with zinc coordination in the protein. This resulted in the production of immature viral particles. Following 14 weekly exposures to SIVmac251, 80% of macaques vaccinated and treated with SAMT-247 remained uninfected – reducing infection risk >90%. SAMT-247 was administered 4 hours before each challenge exposure and dramatically augmented vaccine-induced protection via increased NK cytotoxicity, increased monocyte efferocytosis, and decreased T-cell activation (figure below).

NCI is seeking research co-development partners and/or licensees to evaluate, further develop or commercialize this high efficacy vaccine and microbicide combination for use against HIV. 

Potential Commercial Applications
  • Development of next generation HIV vaccines
  • Prevention of HIV infection and AIDS


Competitive Advantages

Increased vaccine efficacy of up to 80% 
Combination treatment – vaccine and SAMT-247 microbicide – significantly reducing risk of SIV infection
SAMT-247 microbicide is not toxic to human cervical tissue
SAMT-247 microbicide remains effective in cervical mucus


Marjorie Robert-Guroff Ph.D. (NCI), Daniel H Apella Ph.D (NIDDK), Ettore Appella Ph.D (NCI), Genoveffa Franchini (NCI)

Development Stage

Halt SH et al. An SAMT-247 microbicide provides potent protection against intravaginal Simian Immunodeficiency virus infection of Rhesus Macaques, whereas an added vaccine component elicits mixed outcomes.  [32393514]

Silva de Castro I et al. Anti-V2 antibodies virus vulnerability revealed by envelope V1 deletion in HIV vaccine candidates.  [33554060]

Patent Status
  • U.S. Provisional: U.S. Provisional Patent Application Number 63/228,707 , Filed 03 Aug 2021
  • PCT: PCT Application Number US2022/074432 , Filed 02 Aug 2022
Therapeutic Area
Friday, October 21, 2022