By Robert Hickson 04/10/2020


News reports indicate that a range of therapies are being tried on the President of the United States to treat his SARS-CoV-2 infection. Two of these involve treatments that have not yet completed clinical trials. One was a cocktail of two neutralising antibodies. The second is an anti-viral drug.

 

Monoclonal antibodies

The president was initially given a single treatment of a novel “antibody cocktail” developed by Regeneron. This consists of two neutralising antibodies that bind to the virus spike protein and inhibit it from infecting cells. They are called monoclonal antibodies because each antibody is derived from the same source, rather than being a mixture of different types.

The company only earlier this week released results from a small trial, but it has not yet published the results in a scientific journal. The trial on non-hospitalised patients demonstrated, according to the company, that the antibodies reduced viral load and alleviated symptoms. But only in people who hadn’t already developed their own antibodies against the virus and had very high levels of the virus.

The antibodies were derived from people who recovered from infections. The genes that produced these antibodies were isolated and the antibodies produced in large quantities by expressing them in Chinese hamster ovary cells. (Yes, Chinese Mr President).

Monoclonal antibody treatments have mixed evidence of effectiveness according to the New York Times’ Coronavirus Drug and Treatment Tracker.

Such antibody treatments are difficult to make and expensive. The drug company Lilly is also developing a monoclonal antibody treatment but haven’t shared their results yet.

A review of trials involving neutralising antibodies used to treat Covid-19 published recently in Trends in Pharmacological Sciences found that some show promise. However, there are risks that viral mutations can lead to resistance to them, so a cocktail of two or more are preferred. Antibody treatments can also lead to immune enhancement, where the patient’s immune system becomes overstimulated and results in more damage. So they need to be well tested before being used.

 

Remdesivir

The president is now on a five-day course of the anti-viral drug Remdesivir. This has an emergency use authorisation from the Food & Drug Administration, meaning that it has not completed clinical trials but shows some positive effects. It was initially developed to treat Ebola and Hepatitis C, but wasn’t very effective.

The Coronavirus Drugs and Treatment Tracker notes that Remdesivir is only one of two treatments that show “promising evidence”. That is there is  evidence from patient studies suggesting effectiveness, but more research is needed.

A metareview of a range of Covid-19 treatments published in July in the British Medical Journal concluded that Remdesivir can reduce the symptom duration by about 2.6 days in patients that do not have serious Covid-19 symptoms.

An earlier trial in macaques infected with SARS-CoV-2 found that it prevented development of pneumonia but did not reduce viral load.

 

Wait and see

So, the president is being treated with drugs that may or may not be effective. As with other patients it will be a waiting game. But there is the additional complication that there are already concerns about the lack of transparency from, and trust in, the White House.

Many have also pointed out that he is an elderly overweight man, and these tend to be more greatly affected by the virus. But he’ll be getting the best medical attention in the world.

A recent opinion in Journal of the American Medical Association highlights that elderly people (over 55) are usually under-represented in clinical trials. So treatments that show promise in clinical trials may not help the elderly as much.

 

Update 5 Oct: The president is now being treated with the steroid dexamethasone. This is typically given to patients with more severe respiratory problems. A metareview, published in September, of seven trials of this type of steroid found that they reduced deaths.

So, the president has in quick succession been given a suite of drugs not yet approved for general use. These cover the range for treating early stage infections through to severe disease.

 

Disclaimer: I’m monitoring coronavirus research for the Science Media Centre

Featured photo by Martin Sanchez on Unsplash