Healthcare workers in Britain and Thailand started taking part in a trial to determine whether two anti-malarial drugs can prevent COVID-19, including one that U.S. President Donald Trump says he has been taking.

Patients given the malaria drug touted by President Donald Trump as a potential treatment for COVID-19 did not improve significantly over those who did not, according to two new studies published in the medical journal BMJ .

At least 10 different drug compounds ranging from cancer therapies to antipsychotics and antihistamines may be effective at preventing the new coronavirus from multiplying in the body, according to a multidisciplinary study conducted by a team of scientists in the United States and France.

India shipped 50 million tablets of hydroxychloroquine to the United States, an Indian source with direct knowledge of the exports said, although U.S. regulators warned the anti-malarial drug may have harmful side effects in the treatment of COVID-19.

More drugs are being assessed as potential treatments against the pandemic as the battle against COVID-19 continues. Researchers in New York are seeking to determine if the active ingredient in an over-the-counter heartburn medication will have any impact on the disease.

Swiss pharma giant Novartis will launch a Phase III trial assessing hydroxychloroquine for the treatment of hospitalized patients with COVID-19 disease.

Novartis won the go-ahead from the U.S. Food and Drug Administration to conduct a randomized trial of the malaria drug hydroxychloroquine against COVID-19 disease to see if the medicine helps patients.

The American Medical Association (AMA) doubled down on the organization’s stance against using off-label medicines such as hydroxychloroquine and chloroquine to treat COVID-19 patients.

The National Institutes of Health is testing the anti-malaria drug hydroxychloroquine for treating COVID-19, days after several U.S. doctors said they were using the medicine on infected patients without evidence that the product worked.

Pinpoint Therapeutics believes that the company’s approach to treat therapy-resistant cancers also may be effective against COVID-19.