AstraZeneca said on Tuesday a late-stage trial failed to provide evidence that its COVID-19 antibody therapy protected people who had contact with an infected person from the disease, a small setback in its efforts to find alternatives to vaccines. The study assessed whether the therapy, a cocktail of two types of antibodies, could prevent adults who had been exposed to the virus in the past eight days from developing COVID-19 symptoms. The therapy, AZD7442, was 33 percent effective in reducing the risk of people developing symptoms compared with a placebo, but that result was not statistically significant—meaning it might have...