Hydroxychloroquine, the 65-year-old malaria drug that President Donald Trump has praised, appeared not to help patients get rid of the pathogen in a small study.

The pill didn’t help patients clear the virus better than standard care and was much more likely to cause side effects, according to a study of 150 hospitalized patients by doctors at 16 centers in China. The research, which hasn’t been peer-reviewed, was released Tuesday.

The drug did help alleviate some clinical symptoms of Covid-19, however, and the patients who took it showed a greater drop in C-reactive protein, a measure of inflammation.