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A Single-center, Open-label, Dose-escalating Phase I Clinical Trial to Evaluate Recombinant Novel Coronavirus Vaccine (Adenovirus Type 5 Vector) in Healthy Adults Aged 18-60 Years Old

Our take —

This trial will provide insight into the safety and reactivity of an Ad5-nCoV vaccine for COVID-19. The study has three treatment arms receiving different doses of the experimental vaccine, as well as subjects receiving placebo, so it is well designed. Though this is a relatively small trial (n = 108), it is one of the first of its kind. The study also plans to assess the persistence of the immune response elicited by the vaccine, which will be helpful in assessing its long-term efficacy, which is one of the ultimate goals of creating a vaccine against the novel coronavirus.

Study design

Non-Randomized Trial

Study population and setting

This is a Phase I, interventional trial run by CanSino Biologics Inc., taking place at Tongji Hospital in China. It began on March 16th, 2020 and is no longer recruiting. This trial has an enrollment of 108 participants who meet the following criteria: negative for COVID-19, between 18 and 60 years of age, negative for HIV, and able to complete the study process in seclusion over the 6-month duration of the trial. Most other underlying health conditions are criteria for exclusion from this trial.

Subjects are divided into three study arms: a low-dose group, middle-dose, and high-dose group. The subjects in each group receive either experimental vaccine or placebo via intramuscular (IM) injection to the deltoid muscle. The low-dose group received one dose of 5e10 viral particles (vp) of recombinant novel coronavirus vaccine (Ad5-nCoV). The middle-dose group received one dose of 1e11 vp, and the high-dose group received one dose of 1.5e11 vp.

The primary outcome measure of this trial is to evaluate the safety indices of adverse reactions in the first 7 days post-vaccination, with secondary outcome measures including additional safety indices for longer term timepoints. The vaccine is comprised of an adenovirus type 5 vector engineered to express the S gene, which is a part of the novel coronavirus’s genome. Other objectives of this trial are to analyze the production of S protein-specific antibodies against the novel coronavirus in the serum via various laboratory techniques, as well as anti-Ad5 vector neutralizing antibody responses, at 14 days, 28 days, 3 months, and 6 months post-vaccination. This trial also aims to investigate various aspects of humoral and cellular immunity with regards to the vaccine. For humoral immunity, the study plans to analyze the relationship between the amount of S protein-specific antibodies against virus and the vaccine dose given, the persistence of these antibodies in the serum of subjects of the different groups, and the relationship between dose and how long it takes for S protein specific antibodies to appear in the plasma. In terms of cellular immunity, the trial will probe these same questions, but for adaptive immune cells such as T cells.

Summary of Main Findings

N/A, study is incomplete

Study Strengths

N/A, study is incomplete

Limitations

N/A, study is incomplete

Value added

This is one of the first studies to test an adenoviral vector vaccine to attempt to elicit an antibody response against the novel coronavirus S-protein.