Pfizer’s anti-Covid pill may be ready this YEAR as first human trials are set to end in May – as expert studying another antiviral says effective drugs could end lockdowns forever

  • Pfizer’s first-phase trial of PF-07321332 is scheduled to finish on May 25
  • Anti-viral pill showed ‘potent antiviral activity’ in lab and is now in safety tests 
  • UK Government is committed to finding antiviral drugs for Covid by autumn
  • Glasgow University’s Kevin Blyth said success ‘would be a huge step forward’

Pfizer’s Covid-preventing pill could be available by the end of the year if human trials in the US and Belgium are successful.

There are currently no drugs other than vaccines that can stop people developing Covid-19 – but if one is discovered it could spell the end of lockdowns forever, one expert has said.

Pfizer, the company that made one of the most-used jabs in Europe and North America, is already testing its experimental pill on people.

The antiviral drug, named PF-07321332, could be given to stop the illness getting severe in people who have started showing signs of coronavirus infection.

Although most people will get vaccinated against Covid, jabs aren’t 100 per cent effective and some people can’t have them or don’t benefit as much, meaning coronavirus will still spread and still be dangerous for unprotected people. 

Pills could help to prevent severe illness in people for whom jabs don’t work as well, or be a second line of defence in case an immune-resistant new variant emerges.

Around 60 people are currently involved in the first phase of Pfizer’s PF-07321332 trial, which is expected to come to an end on May 25. 

After this, if the pill turns out to be safe, larger trials with more people will be done to prove that it definitely does stop Covid, as lab tests suggested it will.

Boris Johnson announced last week that the Government was setting up an antivirals taskforce to find and buy up antiviral drugs that could make Covid treatable at home by the autumn.

Professor Kevin Blyth, a University of Glasgow scientist running a trial of the antiviral drug favipiravir which could be given after someone has caught the virus, said: ‘It would be a huge step forward if antiviral drugs work… Normal services can function and you don’t have to have lockdown’.

Pfizer, the company that made one of the most-used vaccines in Europe and North America, is already testing its experimental pill on people. The antiviral drug, named PF-07321332, could be given to people who have started showing signs of coronavirus infection in order to stop the illness getting severe

Drug-makers often take years to get a new product studied, tested and produced for market, but science has been accelerated in the rush to stop Covid.

It took less than a year for Pfizer to get its vaccine from a lab into people’s arms and PF-07321332 could be ready by the end of 2021, The Telegraph reports.

Professor Penny Ward, a pharmaceutical medicine expert at King’s College London, told the newspaper: ‘If they have moved to this stage, they will be quietly optimistic.

‘The question will be about how the drug is tolerated… They will be going like the clappers.’

The trial being done now is to test the safety of the drug after it was found to have ‘potent antiviral activity’ in lab experiments.

It works by sticking to specific enzymes that the virus uses to reproduce and therefore forces it to stop multiplying, preventing it from spreading.

The drug belongs to a type called a protease inhibitor – similar meds are already used to stop viruses including HIV and hepatitis C. 

Pfizer hasn’t found any evidence of side effects in animal trials and will now be looking at how it affects humans, in a small test on healthy people. If they tolerate it well the trial will be widened to a bigger range of citizens.

When the company announced it was starting the trial it ‘could be prescribed at the first sign of infection, without requiring that patients are hospitalized or in critical care’.

The UK Government will be keeping a close eye on Pfizer’s trial as it looks to buy up pills that could stop Covid in its tracks.

The Prime Minister announced last week that a new antivirals taskforce would be set up to find these drugs and try to get them available in Britain by the autumn.

Mr Johnson said in a Downing Street briefing: ‘This means, for example, that if you test positive there might be a tablet you could take at home to stop the virus in its tracks and significantly reduce the chance of infection turning into more severe disease. 

‘Or if you’re living with someone who has tested positive, there might be a pill you could take for a few days to stop you getting the disease yourself.’

Boris Johnson announced last week that the Government was setting up an antivirals taskforce to find and buy up antiviral drugs that could make Covid treatable at home by the autumn

Remdesivir is the only antiviral drug routinely being used in hospitals in the UK and US, but it has to be injected and studies have struggled to prove that it works. It was not designed for Covid specifically.

Covid-specific therapies being developed include molnupiravir, by Merck and Ridgeback Biotherapeutics; Tollovir, by Todos Medical; and NT-300 by Romark.

A flu drug – favipiravir – and HIV antivirals – ritonavir and lopinavir – are also being trialled to see if they could be repurposed for people with coronavirus. 

Glasgow University’s Professor Kevin Blyth is running a trial of favipravir, which is already used to treat flu in Japan – marketed as Tamiflu – but was deemed too expensive for the NHS.

He said successfully finding an at-home treatment for Covid could spell the end of lockdowns for god.

Professor Blyth told The Mirror: ‘It would be a huge step forward if antiviral drugs work.

‘You don’t have any hospital services being put under enormous pressure because patients never come to the hospital.

‘Normal services can function and you don’t have to have lockdown or other draconian control measures.’

He added that, ideally, a pill could be given to someone soon after they got exposed to the virus and before they got sick.

‘You may be able to reduce spread and the risk of outbreaks happening,’ he said.  


Remdesivir is one antiviral that hit headlines earlier in the pandemic and was used to treat Covid patients for some time. It still is used in the NHS and in the US but studies have failed to prove it gives any substantial benefit to recovery.

Remdesivir has to be injected and currently doesn’t come in pill form, however, making it unsuitable for the Government’s plans.

There aren’t other antivirals routinely used to treat Covid, but clinical trials are ongoing.

One already in trials is molnupiravir, which was originally designed to tackle flu but worked against Covid in trials on hamsters and is now being studied in humans.

Molnupiravir, made by the pharmaceutical firm Merck, ‘continues to show promise as a potential treatment for non-hospitalised patients,’ the company said after their second phase study. They decided it was not effective for seriously ill people.

Another, called Tollovir, is being trialled on people by the company Todos Medical in Israel.

Todos Medical said past research had shown the drug could work against coronaviruses in general and that it had potential to ‘significantly reduce’ the severity of Covid. 

Favipiravir is a Japanese-made antiviral drug that is being trialled in the UK in the PRINCIPLE trial.

It is not a novel drug and Japanese health officials have already approved it for flu patients, but it could be added to the UK’s arsenal if trials show it works against Covid, too.

Ritonavir and lopinavir, drugs developed to treat HIV, are also being trialled on coronavirus patients. They have been in studies throughout the pandemic and results have been conflicting, but trials are still recruiting patients.

US company Romark is trying to get US approval for its antiviral drug NT-300, made using a chemical called nitazoxanide, which it said trials showed could cut the risk of severe disease by up to 85 per cent. Romark is still doing late-scale human trials of the drug and already uses a slightly different version of it treat parasitic illnesses. 

Although it’s not an antiviral, a study of the asthma steroid budesonide found that it appeared to have some ability to stop the virus from reproducing in the airways, while simultaneously reducing swelling the lungs and making it easier for patients to breathe.

The Oxford University-led study found that budesonide could reduce recovery time by three days, on average, by the country’s chief medics said there wasn’t enough evidence to make it part of the NHS’s standard care.

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