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AZD1222 (ChAdOx1 nCov-19): A Single-Dose biodistribution study in mice
Richard Stebbings1, Gillian Armour1, Vivian Pettis2
1AstraZeneca, Clinical Pharmacology & Safety Sciences, Melbourn Science Park, Melbourn SG8 6HB, United Kingdom.
Abstract:
Biodistribution studies of adenovirus-based vaccines support their clinical development by evaluating their spread and persistence following in vivo administration. AZD1222 (ChAdox1 nCov-19) is a replication-deficient non-human adenovirus-vectored vaccine for coronavirus disease 2019. In this nonclinical study, the biodistribution of AZD1222 was assessed in mice for 29 days following intramuscular injection. Results show that AZD1222 was safe and well tolerated, with a spread that was largely confined to administration sites and the proximal sciatic nerve, with low levels observed in sites that are involved in rapid clearance of particulates by the reticuloendothelial system. Accordingly, levels of AZD1222 decreased from Day 2 to Day 29, indicating clearance. There were no quantifiable levels of AZD1222 in the blood, brain, spinal cord, and reproductive tissue, suggesting a lack of widespread or long-term distribution of AZD1222 vector DNA throughout the body following its administration.
Insights
Biodistribution studies show the adenovirus vector vaccine AZD1222 (ChAdox1 nCov-19) is safe. The vaccine spread was mostly local, with low levels in organs and rapid clearance, indicating no widespread distribution.
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.
