AZD1222 (ChAdOx1 nCov-19): A Single-Dose biodistribution study in mice

Area of Science:

• Vaccinology
• Viral Vector Technology
• Immunology

Background:

• Adenovirus-based vaccines require biodistribution studies to assess in vivo spread and persistence for clinical development.
• AZD1222 (ChAdox1 nCov-19) is a non-human adenovirus-vectored vaccine designed for preventing coronavirus disease 2019.

Purpose of the Study:

• To evaluate the biodistribution and persistence of AZD1222 following intramuscular administration in a preclinical mouse model.
• To assess the safety and tolerability of AZD1222 in vivo.

Main Methods:

• Intramuscular injection of AZD1222 in mice.
• Biodistribution assessment over a 29-day period post-administration.
• Monitoring for systemic spread, including to blood, brain, spinal cord, and reproductive tissues.

Main Results:

• AZD1222 was found to be safe and well tolerated in mice.
• Vaccine spread was primarily localized to administration sites and the proximal sciatic nerve.
• Low levels were detected in organs involved in rapid clearance, with decreasing levels from Day 2 to Day 29, indicating clearance.
• No quantifiable levels of AZD1222 were found in blood, brain, spinal cord, or reproductive tissues.

Conclusions:

• AZD1222 demonstrates limited systemic spread and is effectively cleared from the body following intramuscular administration.
• The biodistribution profile suggests a lack of widespread or long-term distribution of the AZD1222 vector DNA.
• These findings support the continued clinical development of AZD1222 as a coronavirus disease 2019 vaccine.