Stability studies for the identification of critical process parameters for a pharmaceutical production of the Orf virus

A promising new vaccine platform is based on the Orf virus, a viral vector of the genus Parapoxvirus, which is currently being tested in phase I clinical trials. The application as a vaccine platform mandates a well-characterised, robust, and efficient production process. To identify critical process parameters in the production process affecting the virus' infectivity, the Orf virus was subjected to forced degradation studies, including thermal, pH, chemical, and mechanical stress conditions. The tests indicated a robust virus infectivity within a pH range of 5-7.4 and in the presence of the tested buffering substances (TRIS, HEPES, PBS). The ionic strength up to 0.5 M had no influence on the Orf virus' infectivity stability for NaCl and MgCl2, while NH4Cl destabilized significantly. Furthermore, short-term thermal stress of 2 d up to 37 & DEG;C and repeated freeze-thaw cycles (20 cycles) did not affect the virus' infectivity. The addition of recombinant human serum albumin was found to reduce virus inactivation. Last, the Orf virus showed a low shear sensitivity induced by peristaltic pumps and mixing, but was sensitive to ultrasonication. The isoelectric point of the applied Orf virus genotype D1707-V was determined at pH 3.5. The broad picture of the Orf virus' infectivity stability against environmental parameters is an important contribution for the identification of critical process parameters for the production process, and supports the development of a stable pharmaceutical formulation. The work is specifically relevant for enveloped (large DNA) viruses, like the Orf virus and like most vectored vaccine approaches. 2023 Elsevier Ltd. All rights reserved.

Automated summary

This study is based on the Orf virus as a vaccine platform and evaluates its stability in various environmental conditions. It was found that the virus remained highly infectious within a pH range of 5-7.4 and in the presence of certain buffering substances. The study also revealed the virus' low shear sensitivity induced by peristaltic pumps and mixing, as well as its sensitivity to ultrasonication.