FDA Grants Orphan Drug Designation for the Active Ingredient in MVD Vaccine

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The FDA has announced that the active ingredient in the vaccine MarVax (Soligenix, Inc.)—Marburg marburgvirus (MARV) glycoprotein—has received an orphan drug designation (ODD) for the prevention and post-exposure prophylaxis against Marburg virus disease (MVD). In addition to providing a 7-year term of market exclusivity when receiving a final FDA approval, the vaccine will also be able to be further tested in clinical trials and potentially receive a biologics license application if submitted by the company.¹

MarVax is a subunit protein vaccine of recombinantly-expressed MARV glycoprotein and stimulates an appropriate immune response without a risk of infection in the patient. Further, the vaccine also has a novel adjuvant that initiates both humoral- and cell-mediated immune responses as well as excipients generally regarded as safe that allow lyophilization—freeze-drying—of the vaccine. The product is created as a heat stable powder in a vial that is rebuilt with generically available water for injection immediately prior to use.¹

Prior research has shown the vaccine is heat stable for at least 2 years when stored at a temperature of 104 degrees Fahrenheit or higher, and it demonstrated complete protection of non-human primates that were exposed to fatal MARV injections. Similarly, the adjuvant therapy was also developed and tested in other subunit vaccines that had been examined during phase 1 and 2 clinical studies.^1,2

"MARV causes MVD, a highly related disease to the more commonly known Ebola Virus Disease. Although MARV has caused fewer outbreaks, they remain highly fatal and a significant risk in continental Africa, with the most recent outbreak occurring in 2023. There is no approved vaccine for MARV, and the only approved vaccines for filovirus type disease is specific to Zaire ebolavirus,” said Christopher J. Schaber, PhD, president and CEO of Soligenix, in a press release.¹

MVD is caused by MARV, which is part of the Filoviridae family that also includes Sudan ebolavirus (SUDV; Sudan virus disease) and Zaire ebolavirus (Ebola virus disease). Filoviruses, such as MVD, is believed to carried by animal specific in Africa (eg, bats), however, the specific host for these viruses is still not known. Transmission of filoviruses requires direct contact with bodily fluids from an infected person or animals. Mortality rates are very high and dependent on quality of supportive care and early treatment initiation.¹

“Subunit vaccines are a gold standard technology for safety and are also broadly applicable across the population, especially when combined with an effective adjuvant. Elements of this subunit vaccine platform have been utilized in [other] vaccine candidates, indicating its broad applicability. We have also demonstrated the ability to package more than 1 vaccine antigen in a single vaccine, particularly against MARV and SUDV, where there are currently no available vaccines,” said Schaber in the press release.¹

In the previous study that examined the vaccine in non-human primates, subjects were injected with a lethal dose of both human MARV and SUDV. To treat the viruses, subjects were given a single-vial, thermostabilized monovalent of the SUDV vaccine as well as both a bivalent MARV protein and SUDV protein vaccine that consisted of recombinant glycoproteins that were formulated with a clinical-grade adjuvant. Further, lyophilized formulations of the vaccines were reconstituted with water for injection.²

The findings demonstrated that the subjects were completely protected against severe and lethal filovirus diseases after SUDV and MARV infection. Sera collected after each of the 3 administered immunizations showed almost maximal glycoprotein-binding immunoglobulin G concentrations that were present as early as the second dose, and both the monovalent and bivalent vaccines had the same effect on the subjects. The researchers noted that, although it was mild, subclinical infection was observed in a small population.²

“The FDA's decision to grant an ODD to both the MARV and SUDV vaccine candidates signifies an important step for Soligenix as we continue to advance the program and adds significantly to the existing patent estate surrounding this novel technology and the filovirus program," said Schaber in the press release.¹

References

PR Newswire. FDA Grants Soligenix Orphan Drug Designation for the Prevention and Post-Exposure Prophylaxis Against Marburg Marburgvirus Infection. News release. April 15, 2024. Accessed April 15, 2024. https://prnmedia.prnewswire.com/news-releases/fda-grants-soligenix-orphan-drug-designation-for-the-prevention-and-post-exposure-prophylaxis-against-marburg-marburgvirus-infection-302115205.html

To A, Wong TAS, Ball AH, et al. Thermostable bivalent filovirus vaccine protects against severe and lethal Sudan ebolavirus and marburgvirus infection. Vaccine. 2024;42(3):598-607. doi:10.1016/j.vaccine.2023.12.053