The renewed threat of smallpox as a bioweapon and the emerging zoonotic threat of monkeypox highlight the need for effective poxvirus countermeasures. Use of the smallpox vaccine poses a serious health risk, especially for the immunocompromised, or those with eczema/atopic dermatitis. It is our long-term goal to establish a safe and effective vaccine regimen that includes the use of the currently approved, efficacious smallpox vaccine and an antiviral drug to prevent or treat adverse events particularly in the aforementioned high-risk populations. We hypothesize that co-administration of the smallpox vaccine and ST-246, an antiviral drug, to inhibit viral dissemination from the original site of inoculation, will significantly reduce vaccine-related pathologies in immunodeficient and eczematous hosts without compromising protective immunity elicited by the vaccine. Our hypothesis extends from previous observations: First, lethal poxvirus infections in humans and in animal models results from dissemination from the original site of inoculation and wide-spread systemic infection. Second, treatment of a normally lethal poxvirus infection, with ST-246, a drug that specifically blocks viral dissemination, is fully protective in numerous animal models. Third, we have completed pilot studies performed in immunocompetent mice, demonstrating that protective immunity elicited by the Dryvax(r) smallpox vaccine is in no way compromised by ST-246 and may in fact be enhanced. It remains to be seen whether ST-246 actually reduces the occurrence of vaccine-related adverse events. To evaluate whether ST-246 may improve the safety of the smallpox vaccine without compromising protective immunity, we propose to utilize murine models for immunodeficiency and eczema/atopic dermatitis as hosts for poxvirus challenge and ST-246 treatment. Toward this end, the following specific aims are proposed: ? 1. Evaluate the prophylactic and therapeutic efficacy of ST-246 in vaccinia-challenged murine models of B and T cell immunodeficiency. ? 2. Evaluate the prophylactic and therapeutic efficacy of ST-246 in vaccinia-challenged murine models of eczema/atopic dermatitis. ? 3. Analyze protective immune responses elicited by vaccination in combination with ST- 246 in immunodeficient and eczematous mice. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Small Business Innovation Research Grants (SBIR) - Phase I (R43)
Project #
1R43AI075747-01
Application #
7325912
Study Section
Special Emphasis Panel (ZRG1-IMM-G (10))
Program Officer
Challberg, Mark D
Project Start
2007-08-01
Project End
2009-07-31
Budget Start
2007-08-01
Budget End
2008-07-31
Support Year
1
Fiscal Year
2007
Total Cost
$293,399
Indirect Cost
Name
Siga Technologies, Inc.
Department
Type
DUNS #
932651516
City
Corvallis
State
OR
Country
United States
Zip Code
97333
Grosenbach, Douglas W; Berhanu, Aklile; King, David S et al. (2010) Efficacy of ST-246 versus lethal poxvirus challenge in immunodeficient mice. Proc Natl Acad Sci U S A 107:838-43
Berhanu, Aklile; King, David S; Mosier, Stacie et al. (2010) Impact of ST-246® on ACAM2000™ smallpox vaccine reactogenicity, immunogenicity, and protective efficacy in immunodeficient mice. Vaccine 29:289-303
Berhanu, Aklile; King, David S; Mosier, Stacie et al. (2009) ST-246 inhibits in vivo poxvirus dissemination, virus shedding, and systemic disease manifestation. Antimicrob Agents Chemother 53:4999-5009
Grosenbach, Douglas W; Jordan, Robert; King, David S et al. (2008) Immune responses to the smallpox vaccine given in combination with ST-246, a small-molecule inhibitor of poxvirus dissemination. Vaccine 26:933-46