US President Donald Trump is being given an unapproved, experimental treatment for Covid-19 , according to a White House doctor. The antibody cocktail, developed by US company Regeneron Pharmaceuticals, was administered to the president “as a precautionary measure”, his doctor Sean Conley said on Friday. Trump, who along with his wife Melania tested positive for the coronavirus on Thursday, was moved to Walter Reed National Military Medical Centre in Bethesda, Maryland after experiencing mild symptoms on Friday, the White House said. “I think I’m doing very well, but we’re going to make sure that things work out,” he said in a video message posted to Twitter. Vaccine developers seek to help group hit hardest by Covid-19: the elderly At age 74, Trump falls into a higher risk category for severe disease. According to the US Centres for Disease Control and Prevention, eight out of 10 Covid-19-related deaths reported in the United States have been among adults aged 65 and over. Regeneron released the first data on the experimental treatment on Tuesday, sharing safety and efficacy results from 275 Covid-19 patients included in their ongoing clinical trials. The data, yet to be published in a medical journal, showed that the antibody cocktail, known as REGN-COV2, reduced the time to alleviate symptoms in a group of non-hospitalised patients with Covid-19 and indicated an “emerging well-tolerated safety profile”, the company said. “The greatest treatment benefit was in patients who had not mounted their own effective immune response,” said George Yancopoulos, Regeneron’s president and chief scientific officer. When given to patients in this category, the treatment rapidly reduced viral load, as measured over seven days, and reduced the median time for their symptoms to become mild or go away, the company said. The treatment is part of a class known as monoclonal antibodies that have generated significant buzz in the scientific community for their potential to treat Covid-19. US company Eli Lilly & Co has also announced encouraging early data from a trial of its coronavirus antibody treatment last month. Trump’s coronavirus test stirs conspiracy theories, action from social media giants The product administered to Trump is a combination of two synthetic versions of neutralising antibodies, thought to be a key element of the body’s natural immune response to Covid-19. They work by binding to the part of the coronavirus’s spike protein that enables it to attach to human cells. “It’s a short cut to immunity basically,” said immunologist Kylie Quinn, a vice-chancellor’s research fellow at RMIT in Melbourne. “Instead of having to wait for our body to make those neutralising antibodies, we can produce them … and then infuse them directly into your circulation … it’s an immediate form of protection,” she said. Given the available data and high cost of these kinds of treatments, they could be well suited to patients who were not mounting their own effective response to the virus, she said. More than 2,000 people have been enrolled in trials of Regeneron’s treatment, which has received federal funding, with no unexpected safety findings yet reported, the company said. The treatment is in the final, phase three, stage of testing on patients in hospital. Quinn said that while the treatment was still in trials, it was “not too out of the box” that it was administered to the president, given his higher risk of complications as an over-70 adult. She said that while there was always the “potential for things to not work out the way we think they will” many in the scientific community anticipated this kind of treatment should be relatively safe. Covid-19 fed off ‘panic and neglect’, says WHO-backed body that warned of possible pandemic The news of Trump being infected with the coronavirus prompted Chinese social media to offer their opinions on another experimental treatment he might consider using – traditional Chinese medicine. “For Trump’s treatment, we can consult the Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia (Trial Version 7), especially the role of traditional Chinese medicine,” a blogger wrote, referring to a manual released by China’s National Health Commission and the State Administration of Traditional Chinese Medicine in March. The treatments have been backed by some of China’s top physicians, including Zhong Nanshan , who earlier this year announced that a herbal capsule created by Lianhua Qingwen had shown promise in small-scale clinical trials. But the monoclonal antibodies treatment is not the first experimental remedy for Covid-19 the president has tried this year. In May he said he was taking a malaria drug known as hydroxychloroquine, which was later shown in clinical trials to have no benefit in reducing coronavirus infection. Additional reporting from Reuters