Algorithm-Based Liquid Formulation Development Including a DoE Concept Predicts Long-Term Viral Vector Stability

Abstract

Specifically tailored amino acidebased formulations were previously shown to have a high potential to avoid stress-mediated degradation of complex molecules such as monoclonal antibodies and viral vectors. By using adenovirus 5 (Ad5) as a model, we studied whether such formulations may also efficiently protect viral vectors in thermal stress experiments and during long-term liquid storage. Algorithm-based amino acid preselection using an excipient database and subsequent application of design of experiments (DoE) in combination with a 37 C challenging model enabled the prediction of long-term storage stability of Ad5. By statistical analysis of the Ad5 infectivity, amino acids with significant influence on Ad5 stability were detected after 2 and 3 weeks of liquid storage at 37 C. Ad5 formulations comprising positively selected amino acids did not reveal any loss of infectivity after 24 months in liquid storage at 5 C. By contrast, a 2 log reduction after 3 months and complete loss of infectivity after 18 months was observed with a standard viral vector formulation. By an optimization round, we designed a simple and well-balanced formulation avoiding MgCl 2 , previously considered essential in Ad5 formulations. This work demonstrates the efficacy of an algorithm-based development approach in the formulation development for viral vectors.

Manufacturing Challenges and Rational Formulation Development for AAV Viral Vectors

“…138 Isomerization is prevalent in AAV viral vectors and has been reported in AAV5 under various stress conditions. 139…”

“…98 are susceptible to oxidation. Capsid proteins can oxidize upon exposure to light and due to metal ion impurities in the raw materials and excipients, 139 leading to a loss in functionality. 136 Oxidation can be prevented with the use of free amino acids such as methionine and histidine and metal ion scavengers such as ethanol, EDTA and DTPA.…”

“…The AAV5 was sensitive to methionine oxidation, data also showed significant reduction in the infectively loss when stored at 37°C. 139…”

Vaccine formulations in clinical development for the prevention of severe acute respiratory syndrome coronavirus 2 infection

“…They have recently published and extensively patented methods using algorithmic methods to identify mixtures of excipients which can stabilize diverse types of biopharmaceuticals. With this method they used Design of Experiments principles combined with accelerated stability testing to determine mixtures of excipients which most effectively preserved the stability of adenoviral vectors [ 186 , 187 ]. It remains to be seen what degree of stability this method may be able to impart to a vector-based vaccine against SARS-CoV-2.…”

The Science is There: Key Considerations for Stabilizing Viral Vector-Based Covid-19 Vaccines

“…30 Reinauer et al (2020) used a DoE approach with iterative optimization rounds and they reported significant enhancement of the stability of liquid, adenoviral vector vaccine formulations following such an algorithm. 31…”