Aspergillus fumigatus is an opportunistic pathogenic fungus that predominantly infects immunocompromised patients. It is the most common cause of infectious pneumonic mortality in HIV patients, organ transplant recipients, and cancer patients. A. fumigatus infection in HIV-infected patients is most pertinent due to the exceptionally high mortality rate (>75% die within the first year of infection). Treatment is complicated by the fact that patients are often too fragile for invasive or toxic therapies. A first-line treatment for aspergillosis is amphotericin B (AMB) but it is both highly nephrotoxic and insoluble. Its nephrotoxicity can be a significant contributing factor to mortality and is dose limiting. Thus, AMB presents an array of challenges to its therapeutic application. In response to this problem, Lypro- Biosciences, Inc. has developed NanoDisks"""""""" (ND), a novel preparation of lipid and protein for the solubilization and delivery of hydrophobic drugs. NDs are 8 - 15 nm diameter disc-shaped structures composed of a lipid bilayer circumscribed by a stabilizing apolipoprotein or peptide mimetic. When AMB is incorporated into NDs (ND-AMB), there is a dramatic increase in AMB solubility and reduction in its toxicity. Furthermore, ND-AMB can be safely dosed to levels at least 10-fold greater than that of AMB deoxycholate (Fungizone - the conventional form of the drug). In comparison to a leading commercial liposomal formulation of AMB (AmBisome), the minimal inhibitory concentration of ND-AMB against A. fumigatus is 25-fold lower in vitro and in an animal model of systemically disseminated candidiasis, ND- AMB is effective at a 6-fold lower dose. Moreover, ND-AMB has a rapid onset of therapeutic effect in comparison to AmBisome, a critical parameter in the clinical treatment of aspergillosis, as patients are normally not diagnosed at an early stage of infection. The combination of enhanced potency, reduced toxicity, and rapid onset of therapy make ND-AMB an ideal therapeutic for the treatment of aspergillosis. In the proposed project we will test the hypothesis that ND-AMB is a fast acting, potent and safe therapy for treating and preventing disseminated aspergillosis in mice. Because patients with pulmonary aspergillosis are less capable of taking in inhaled therapies, the efficacy of intravenously (i.v.) administered ND-AMB will be examined against established Aspergillus infection. Parameters of antifungal potency, safety, and distribution will be determined, yielding a clinically relevant dataset for assessment of ND-AMB effectiveness. Because the normal route of Aspergillus infection is through inhalation of conidia, prophylactic measures directed to the lung may be most effective. We will test the hypothesis that inhaled ND-AMB can serve as an effective prophylactic for the prevention of aspergillosis. Through this proposal we will extend previous SBIR studies into clinically relevant scenarios, testing the ability of ND-AMB to remediate and prevent aspergillosis, a significant threat to the health and lives of HIV-infected patients.
Aspergillus fumigatus infection in HIV-infected patients has an exceptionally high mortality rate (>75% die within the first year of infection). Patients are often too fragile for invasive or toxic therapies. A first-line treatment for aspergillosis is amphotericin B (AMB) but it is both highly nephrotoxic and insoluble. Its nephrotoxicity can be a significant contributing factor to mortality and is dose limiting. We believe our efforts to reformulate AMB into AMB-containing NanoDisks (ND) have transformed it from a marginally effective treatment to a potent cure. Results from this study are essential for the development of ND- AMB into an improved i.v. and inhaled AMB-based therapy for the treatment and prevention of aspergillosis;a serious health issue for HIV infected patients, wherein median survival is 3 months. Intravenous and inhalable ND-AMB will bring to bear an effective cure and preventative to a deadly disease.
| Burgess, Braydon L; He, Yumin; Baker, Mandie M et al. (2013) NanoDisk containing super aggregated amphotericin B: a high therapeutic index antifungal formulation with enhanced potency. Int J Nanomedicine 8:4733-43 |
