Coronavirus treatments: the potential ‘gamechangers’ in development
The first clinical trial results showing a positive effect for a pill that can be taken at home has been hailed as a potential gamechanger that could provide a new way to protect the most vulnerable people from the worst effects of Covid-19. Molnupiravir joins a growing list of medicines that have shown promise. Here are some of the main developments in treatments so far.
Favipiravir
This is an antiviral drug designed to block virus replication at the early stage of illness. It has been licensed to treat flu in Japan since 2014 and was the first antiviral drug to be included in the UK’s Principle trial in people’s homes or residential homes, with phase 3 results expected to be reported in the coming weeks.
Pfizer’s antiviral PF-07321332
Pfizer is testing a competitor antiviral pill in up to 2,660 healthy adult participants, including a cohort of people who live in the same household as an individual with a confirmed Covid-19 infection and a second group of non-hospitalised, symptomatic adult patients, to look at both treatment and preventing infection. The medicine works by blocking the activity of the Covid protease, an enzyme the virus needs to multiply inside the body. Trial results are expected before the end of the year.
Synairgen’s antiviral inhaler
The company Synairgen has reported encouraging early results for a drug initially developed to treat the lung condition chronic obstructive pulmonary disease (COPD). The drug, administered through a hand-held, battery-operated nebuliser, is based on interferon beta, a naturally occurring molecule that stimulates the lungs’ immune defences. Studies suggest the drug has “broad-spectrum antiviral activity” and it is in phase 3 trials.
Budesonide inhaler
Budesonide is a common corticosteroid used to treat asthma and COPD and has also been tested in the Principle trial. Recent results found that the drug can shorten recovery time for people not admitted to hospital by three days. At the moment, budesonide is not recommended as standard treatment, but can be used off-label for patients with additional risk factors, including those over 65 years and with comorbidities.
In Europe, Swiss pharma company Roche is working with Atea Pharmaceuticals on an oral antiviral it believes has dual potential: to treat people with Covid-19 and prevent illness in people who have been exposed to the virus. Initial results in hospitalised patients with moderate Covid-19 and at high risk of poor outcomes “indicated a rapid and sustained antiviral activity against
Sars-CoV-2, with no new or unexpected safety results,” the company said.
Dexamethasone
This cheap steroid, which is about 60 years old, became an early success story in the pandemic, when the Oxford-led Recovery trial found that the drug saved the lives of one in eight people seriously ill with Covid, on ventilators in hospital. A low dose of the drug is now the standard treatment for seriously ill patients in hospital. It is an anti-inflammatory, which can dampen down the overreaction of the immune system in severe cases in response to coronavirus.
Remdesivir
This antiviral, made by the US company Gilead Sciences, has been authorised for emergency use in the US, India and Singapore and approved in the EU, Japan and Australia for use on people with severe symptoms. It is expensive and is given intravenously. Its benefits to patients have been contested, with a large World Health Organization trial reporting little effect on mortality or the need for ventilation.
Convalescent blood plasma
It was hoped that blood containing antibodies collected from people who have recovered from Covid-19 would have a protective effect as convalescent plasma has been successfully used to treat other diseases. The US gave it emergency authorisation, but this week the largest trial to date involving 500,000 Americans hospitalised with Covid-19 showed no overall benefit, with patients who received convalescent plasma experiencing more adverse events than those who received standard care.