HHS Secretary Alex Azar said the US could get up to 'hundreds of thousands' of doses of Regeneron's experimental antibody treatment for COVID-19 this fall.
Regeneron submitted its application for FDA emergency use authorization of its cocktail of two lab-made antibodies to treat coronavirus on Thursday.
In the a Wednesday night Twitter video, Trump said that he thinks the antibody cocktail he received to treat coronavirus is a 'cure'.
There is no data to suggest the drug is a cure, and only early data to suggest it shortens recovery times and lowers viral load.
President Trump said he would try to make the drug free to all Americans.
He also said emergency use authorization for the drug was 'all set' but the EUA request was only confirmed later Wednesday night by Regeneron.
The company said it has enough doses to treat 50,000 patients ready and expects to make enough for 300,000 'in the next few months.
Already, doctors running clinical trials of Regeneron's antibody cocktail say`12345 they're seeing an influx of patient hoping to get the experimental treatment.
The US could have up to 300,000 doses of Regeneron's antibody treatment for coronavirus this fall, White House officials and the company said Thursday.
'We've applied the same methods to supporting therapeutics [as the government has to vaccine development] too,' Department of Health and Human Services (HHS) secretary Alex Azar said during a Thursday Goldman Sachs virtual event attended by CNN.
'That includes, for instance, support for both development and manufacturing of Regeneron's antibody cocktail, of which we could have tens or hundreds of thousands of doses this fall, pending FDA authorization.'
Coinciding with President Trump's passionate, though unproven, endorsement of the antibody cocktail as a 'cure' for coronavirus, Regeneron applied for emergency use authorization (EUA) from the FDA on Thursday.
In a statement, the company said it already has enough doses to treat 50,000 patients, and expects to ramp up manufacturing enough to make 300,000 doses of the experimental treatment 'in the next few months.'
Regeneron reiterated Trump's plans for the US government to make the drug free of cost to any American that needs it - but it remains entirely unclear how many figures its price tag might be.
Secretary Azar said that manufacturing for the drug would be scaled up under Operation Warp Speed (OWS), the initiative launched by the White House to speed the development and production of vaccines.
'OWS supported clinical trials continue for remdesivir in combination with other drugs. In addition to anticoagulants and other options,' Azar said at the Thursday virtual event.
'We're also supporting several randomized controlled clinical trials to produce more data on convalescent plasma, to which Americans have enjoyed broader access than anywhere on Earth.'
Already, clinical trials for Regeneron's injectable duo of lab-made antibodies, are seeing a surge interested patients hoping to enroll.
Dr Gary Kleiner, a pediatric immunologist at the University of Miami Miller School of Medicine and investigator in a trial designed to see if Regeneron's antibodies can prevent coronavirus infection, told Reuters he has been approached by patients seeking the drug since last week.
Dr Dirk Sostman, head of the research network at Houston Methodist Hospital, a trial site for Regeneron and Eli Lilly antibody programs, said more patients are asking to participate in an antibody trial.
He was cautious about broader use without more data.
'All we have seen are very brief press releases...so there is not much to go on,' he said.
'The politics of the situation would suggest to me that the story could be Trump gets COVID...then American technology fostered by the Trump Administration cures COVID,' Dr Sostman added.
'I would think there would be pressure on regulators.'
Regeneron's drug 'cocktail,' REGN-COV2, contains an antibody made by the company from mice and another isolated from a recovered COVID-19 patient, each of which may help to neutralize coronavirus.
The firm's latest data from the ongoing trials, show the drug drove down the viral loads of patients who were not hospitalized and cut their recovery times by nearly half.
But it's very much an experimental treatment, and the data announced earlier this week are the first published from the trial.
Two patients treated with the antibody cocktail had 'adverse events' - undesirable side effects. One of those was a 'serious' adverse event, but Regeneron did not reveal details of what happened to the patient, who received a low dose of the drug.
REGN-COV2 is comprised of a duo of therapeutics in a class of drugs known as monoclonal antibodies (hence REGN-COV2's distinction as a 'polyclonal antibody'), which are clones of antibody that attacks a specific antigen.
Top US infectious disease expert D. Anthony Fauci, speaking on Monday on CNN, said he was 'strongly suspicious' that Regeneron's drug has contributed to Trump's progress.
'Obviously you can't prove that until you do a number of studies to show that it actually works,' he said.
Doctors emphasized that the timeline for Trump's illness was not entirely clear. 'If he is responding at a pace where he is truly much better, it is going to be due to the antibodies,' Dr Edward Jones-Lopez, infectious disease specialist at the University of Southern California Keck School of Medicine in Los Angeles, told Reuters.
Giving the treatment to the president seems 'a tacit endorsement by the federal medical bureaucracy for Regeneron's medicine, and we expect an EUA for the treatment of COVID in a matter of days,' Leerink analyst Geoffrey Porges said in a research note.
'Patients most likely to benefit from this treatment have a similar profile to President Trump, in that they had undetectable antibodies at baseline and were early in the course of disease,' Regeneron spokeswoman Alexandra Bowie said in an emailed statement.
Regeneron has received $450 million from the U.S. government for up to 300,000 doses of the dual-antibody cocktail, and the company has said those supplies would be distributed free of charge.
President Donald Trump has admitted that Operation Warp Speed's former focus, a vaccine, will likely not be available until after the November 3 election and called the antibody cocktail drug he received as treatment for the coronavirus a 'cure'.
In a video shared on Twitter, Trump addressed the American people's concerns for a vaccine to combat the virus that has killed more than 210,000 people and infected more than 7 million others in the US alone. The president has repeatedly expressed his wish for a vaccine to be available prior to the election.
'We're going to have a great vaccine very, very shortly. I think we should have it before the election, but frankly the politics gets involved and that's OK,' Trump said in the video that was recorded outside the White House.
A maskless Trump continued: 'They want to play their games. It's going to be right after the election.
'The FDA has acted as quickly as they've ever acted in history,' Trump said. 'No president has ever pushed them like I've pushed them either, to be honest with you.'
Scroll down for video
In the same video, Trump falsely called the experimental Regeneron drug a 'cure'. Trump received the drug while being treated for the virus at Walter Reed over the weekend.
Trump said that hundreds of thousands of doses are 'just about ready to go, I have emergency use authorization all set'.
Regeneron, which makes the experimental drug given to President Trump, had not announced the submission of its application for emergency use authorization with the Food and Drug Administration (FDA) at the time of Trump's Twitter video.
Later Wednesday night, the company confirmed it had submitted its application in a press release dated the same day.
Eli Lilly, which makes a similar competing antibody drug, announced it had asked the FDA for emergency approval of its own combination antibody treatment on Wednesday.
'I think it was a blessing from God that I caught this, it was a blessing in disguise I caught it, because I heard about this drug and it was my suggestion that we try it and it was incredible the way it worked....and I want you to get what I got,' Trump said.
The president offered no details on how he planned to make Regeneron's antibody cocktail free and there is no data to suggest that the drug is a cure.
Presidents also do not hold the power to give regulatory approval to drugs.
Earlier this week, the White House approved FDA rules that make it nearly impossible for the agency to give emergency approval to a shot ahead of Election Day.
Conflating the Regeneron treatment that he received and its competitor's antibody treatment, Trump said: 'We have these drugs from Eli Lilly and others that are so good that they are, in my opinion - remember, they're going to say that they are therapeutic, some people don't know how to define therapeutic - but I view it different, for me, it's a cure.'
Regeron applied for emergency use authorization (EUA) on Tuesday after publishing its first data from trials of its antibody cocktail, REGN-COV2, last week.
REGN-COV2 is a 'cocktail' of two lab-made versions of immune proteins the body naturally develops to fight off COVID-19 once exposed.
Coronavirus patients who were not sick enough to be hospitalized and treated with the drug saw their viral loads decline twice as far as did patients who got placebo.
By Natalie Rahhal, US Health Editor
'HIS PHYSICAL EXAM AND VITAL SIGNS, INCLUDING OXYGEN SATURATION AND RESPIRATORY RATE, ALL REMAIN STABLE AND IN THE NORMAL RANGE'
As measured by a pulse oximeter, normal oxygen saturation levels are between 95 and 100 percent.
Trump had to be given oxygen twice after it fell below 95 percent, including one dip beneath 94 percent.
A normal, healthy adult takes about 12 to 16 breaths a minute.
But it's not clear what Trump's normal, resting vitals were before he tested positive for COVID-19, nor has he given White House physician Dr Sean Conley permission to share a readout of his stats since his diagnosis.
'HE'S NOW BEEN FEVER-FREE FOR MORE THAN 4 DAYS, SYMPTOM FREE FOR OVER 24 HOURS AND HAS NOT NEEDED OR RECEIVED ANY SUPPLEMENTAL OXYGEN SINCE INITIAL HOSPITALIZATION'
Dr Conley said late Friday morning that President Trump had spiked a 'high fever.' We do not know how high his fever climbed, what his normal resting body temperature is (they typically range anywhere from 97 to 99F) or when exactly Dr Conley ceased to consider it 'high.'
During a Tuesday press conference, Dr Conley made a point of telling reporters that Trump had been on no fever reducing medications for over 72 hours.
Conspicuously absent from Wednesday's statement was any mention of such medications, which might artificially keep the president's temperature below 100.4F (the CDC's definition of a fever).
Dr Conley's statement puts Trump's condition in terms that mirror the CDC's criteria for when a COVID-19 patient can safely be around others again - but does not meet them:
According to official White House statements, it has been only six days since Trump's first symptoms appeared. Fever or none, the CDC still considers him at-risk for infecting countless others in the White House.
Dr Conley had previously acknowledged that Trump's oxygen levels dropped suddenly twice - making his statement that he had not needed oxygen since initial hospitalization confusing.
'THE PRESIDENT'S LABS DEMONSTRATED DETECTABLE LEVELS OF SARS-CoV-2 IgG ANTIBODIES FROM LABS DRAWN MONDAY; INITIAL IgG ANTIBODIES...WERE UNDETECTABLE'
The body generates two categories of antibodies in response to pathogens, including the virus that causes COVID-19: IgM and IgG antibodies.
IgM antibodies arise more quickly and fade more quickly and, broadly speaking, offer very limited protection against re-infection.
IgG antibodies in general confer more lasting protection, although we don't know how long or how effective their protection is.
The vast majority of patients will develop antibodies of both types. It's normal for a patient to start developing both IgM and IgG antibodies with the first week of infection.
IgG antibodies are usually generate about a week after infection, peak within about three weeks, and appear to last around three months - although studies are ongoing.
However, Trump also received Regeneron's antibody cocktail drug on Thursday, artificially introducing antibodies to his body.
'Most standard assays for IgG would not distinguish [between] endogenous (self-made) antibodies and the ones delivered by our therapy,' Regeneron told it in a statement.
'However, given the volume of IgG antibodies delivered in our therapy and the timing of these tests, it is likely the second test is detecting REGN-COV2 antibodies.'
In other words, it's very possible that the antibodies detected in Trump have nothing to do with his own immune response, but are man made immune cells from the experimental drug he received.
Equally, there is no way to know for sure if the drug is working and responsible for the infection-fighting antibodies, which would be detectable in most patients any way by this point in the course of their illness - regardless of their prognosis.
People who got the antibody treatment recovered and had fewer or no symptoms in about half the time it took people who received the sham treatment to reach that level of improvement.
None of the patients in the study - regardless of whether they got the antibody cocktail or a placebo - died, so there is no way to know if it reduces the risk that someone will die of COVID-19.
Regeneron has not revealed the results of tests for its drug in hospitalized patients.
Eli Lilly asked the FDA to allow emergency use of its experimental antibody therapy for coronavirus, the firm announced Wednesday.
Its application is based on early results from a study that suggested the drug reduced symptoms, the amount of virus, hospitalizations and ER visits for patients with mild or moderate COVID-19.
Trump was not treated with Lilly's drug.
In addition to Regeneron's antibody cocktail, the president received Gilead's antiviral remdesivir and the steroid dexamethasone.
Remdesivir and dexamethasone have both been shown to reduce mortality from COVID-19 in clinical trials.
The FDA has issued an EUA for remdesivir to treat COVID-19 patients. Dexamethasone has not been given that distinction, though it is approved for other uses. The steroid is also only indicated for treating severely ill patients, and may actually harm people with milder cases.
Moreover, 'the president has just received probably the best medical care that anyone could see and that is accessible to almost nobody else in the US,' Dr Craig Bryan, a psychiatrist at Ohio State University told it in a recent interview.
President Trump's free-wheeling promises came shortly after his executive order for the Departments of Defense and of Veteran Affairs to launch an investigation into the links between the pandemic and suicides.
'If I get sick, I'm going to not get treatment or go into debt getting treatment that could save my life and potentially the lives of my loved ones,' said Dr Bryan.
'All of these things I think would be astronomically more more impactful for suicide prevention,' than the plan to reduce the potential mental health fallout of the pandemic that the president has demanded be drawn up in the next 45 days.
Now, Trump claims he will make his bespoke treatment course available to anyone in the US, for free.
'If you're in the hospital and you're feeling really bad, I think we're going to work it so you get them and you get them free, especially if you're a senior, we're going to get you in there quick,' he said.
'I want everybody to get the same treatment as your president got, because I feel great, I feel perfect.'
A five-day treatment course of remdesivir is estimated to cost $3,120.
About 20 per cent of people who catch coronavirus seek some form of treatment, according to the World Health Organization (WHO).
On Tuesday, 43,562 new US cases of COVID-19 were reported in the US, according to figures from Johns Hopkins University.
Treating 20 percent of them with remdesivir would cost the US government about $27.2million - and that rough estimate is for just one day.
Dexamethasone costs just $6, but is only used in severely ill patients.
Neither Eli Lilly nor Regeneron have given possible price points for their experimental drugs, but while experts have anticipated the development of antibody drugs as potentially the most effective, they've warned that they could be prohibitively expensive.
And this is all assuming the drugs are approved.
Trump alternated between praising and criticizing the FDA, the agency that will have to issue the approvals he is now promising.
'The FDA has acted as quickly as they've ever acted in history and there's never been a time [like this] and no president has ever pushed them like I've pushed them, to be honest with you,' he said.
His insinuations of a 'cure' have also been blamed for pushing the FDA to give emergency approval to the malaria drug hydroxychloroquine, which Trump also took.
That approval had to be retracted, after data showed the drug did not offer any preventive or therapeutic benefit to patients, and may have raised mortality risks in some by triggering heart problems.
Trump's rush to approve vaccines has also fueled distrust in vaccines developed under Operation Warp Speed, with half of Americans saying they are unsure if they will get the first shot developed to prevent COVID-19.
FDA regulators got stricter approval guidelines for coronavirus vaccines approved by the White House Tuesday, in an effort to rebuild that trust, and effectively putting an end to Trump's hopes to get a vaccine approved by the November 3 election.
'They call them therapeutic,' Trump said of treatments like Regeneron's antibody cocktail, 'but I call them a cure.
'So we have to get them done and get them to the hospital where people are feeling badly, that's much more important than the vaccine but on vaccines, we have many companies that are in the final stages for vaccines - Johnson & Johnson, Moderna, Pfizer -all great companies, and many of them are going to have a great vaccine very shortly.
'I think we should have it before the election, but frankly the politics gets involved that's okay, they want to play their games, it's going to be right after the election, but we did it, nobody else, nobody else would have ever been able to.'
The US has approved no vaccines to prevent coronavirus. No shot-makers have compiled enough data to submit for emergency use authorization from the FDA.
Only two treatments have been given EUAs: remdesivir, which offers moderate reduction in death risks, and convalescent plasma, which may offer no benefit.
More than 7.5 million Americans have tested positive for COVID-19. That's assumed to be an underestimate.
Yesterday, 705 Americans lost their lives to the virus. To-date, at least 211,513 people have died of COVID-19, and the toll is expected to surpass 363,00 before Inauguration Day.
President Trump has been given at least three potent drugs since announcing he tested positive for COVID-19 on Thursday night: Regeneron's cocktail of lab-made antibodies, the antiviral remdesivir, and the steroid dexamethasone.
Two of those medications are still experimental for treating COVID-19, and have given emergency use authorization by the Food and Drug Administration (FDA).
And White House physician Dr Sean Conley admitted on Monday that he would not disclose every single medication that the president is currently receiving (citing HIPAA patient privacy laws, which suggests that Trump himself gave Dr Conley permission to disclose some of his medications, but not all of them).
Remdesivir, dexamethasone and the antibody cocktail are all in ongoing trials - but it's unclear if anyone besides the US Commander-in-Chief has ever been treated with all three.
Those three drugs are 'as much as we know [about the president's treatment regimen] - but I found it all really confusing, based on the reports,' Dr Mark Poznansky, an infectious disease specialist at Massachusetts General Hospital told it.
When asked if there was any precedent for treating a COVID-19 patient with all three drugs, Dr Poznansky replied, 'no.'
'But the individual decisions are based on the individual patient, and all bets are off when you're dealing with the president, the commander-in chief,' he added.
'The implication is that the doctors believe that the risk of using these is outweighed by the potential benefit.'
And while we have some clarity on the potential side effects of each of the drugs, how they might interact is a mystery, 'because they just haven't been used frequently enough...we don't know about the combination,' Dr Poznansky said.
But even on their own, the side effects of these drugs could be particularly concerning for the president, considering that the steroid can cause mood swings, confusion and aggression.
The drugs he was treated with and their potential side effects are:
REGENERON'S EXPERIMENTAL ANTIBODY COCKTAIL DRUG
WHEN HE GOT IT: Trump received a single 8 gram dose of Regeneron's cocktail of lab-made antibodies on Friday.
WHAT IT DOES: REGN-COV2 is a combination of two lab-made versions of antibodies that help block the coronavirus from entering cells.
One of the antibodies in the 'cocktail' is based on an antibody that mice produce in response to coronavirus, while the other is based on an antibody isolated from the one of the first US COVID-19 patients.
The hope is that the treatment drives down viral load, keeping it from overrunning the body and sending the immune system haywire, and preventing the infection from becoming severe.
WHAT THE DATA SAYS: REGN-COV2 is still in early trial phases, but the first data from its clinical trial found that it dramatically lowered viral load within a week and cut recovery time in half in patients that weren't sick enough to be hospitalized.
Regeneron has not yet studied the drug in severely ill patients.
THE POSSIBLE SIDE EFFECTS: The main concern is these types of treatment occasionally trigger 'antibody-dependent enhancement,' which means the intended therapeutic actually helps the virus invade cells.
So far, the trials don't suggest that REGN-COV2 is causing this phenomenon.
Antibody treatments can also cause allergic reactions including anaphylaxis, as well as fever, chills, nausea, diarrhea, weakness, headache and low blood pressure.
REMDESIVIR, GILEAD'S ANTIVIRAL DRUG
WHEN HE GOT IT: President Trump was given his first dose of a five-day treatment course on Friday evening, after he was transferred from the White House to Walter Reed National Medical Center.
He has since received his second and third dose of the drug.
WHAT IT DOES: Remdesivir is an antiviral therapy originally designed to treat Ebola.
Scientists are not entirely sure why, but it helps to prevent coronavirus from making more copies of itself.
WHAT THE DATA SAYS: Late-stage clinical trials of remdesivir found that patients treated with the drug were more likely to recover within 11 days than those who did not get the drug.
Their survival odds were about 40 percent better. In May, the drug became the first to get emergency use authorization from the FDA for treating severely ill patients. That approval has since been expanded to any hospitalized patients.
THE POSSIBLE SIDE EFFECTS: It can cause nausea, vomiting, chils, sweating or light-headedness. The drug also may harm liver function, meaning that patients have to be closely monitored.
There was some suggestion the Trump's liver and kidney function were suboptimal last night, but Dr Conley said Monday the president was just 'dehydrated.'
DEXAMETHASONE, THE $6 STEROID WITH COMMON PSYCHIATRIC SIDE EFFECTS
WHEN HE GOT IT: The president got a dose of dexamethasone on Saturday after he developed a high fever and his blood oxygen levels dropped below 94 percent on two occasions.
WHAT IT DOES: Dexamethasone is a cheap steroid known to tamp down inflammation. It's already approved for use in other conditions in the US.
WHAT THE DATA SAYS: Although it hasn't yet been given emergency approval in the US, dexamethasone is the most promising treatment yet for coronavirus.
In a major UK study, the steroid cut the risk of death by 36 percent for patients sick enough to need breathing machines and by 18 percent for patients needing just supplemental oxygen.
However, it seemed harmful at earlier stages or milder cases of illness: 18 percent of those on the drug died versus 14 percent of those given usual care.
For that reason, many doctors were alarmed to see President Trump treated with the drug because using it suggested either that he was very sick, or that doctors were taking a risk in giving it to him early.
THE POSSIBLE SIDE EFFECTS: The steroid is potent, and can cause swelling, headaches, stomach pain, nausea, weakness, dizziness sleep problems, vision changes, skin problems, severe allergic reactions including mood changes.
These mood changes include aggression, agitation and confusion.
'Steroids are always very dangerous medications to use,' Dr Edward Jones-Lopez, an infectious disease specialist at the University of Southern California in Los Angeles, told Reuters.
'That is why it (dexamethasone) is used in severe to critical patients... There can be neuropsychiatric side effects. These are medications that we use very, very carefully.'