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Pfizer's oral Covid-19 antiviral cuts hospitalization, death by 85%

872 points| jeremylevy | 4 years ago |fiercebiotech.com

1128 comments

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[+] pezzana|4 years ago|reply
> Pfizer’s phase 2/3 trial randomized non-hospitalized adult COVID-19 patients who were at high risk of progressing to severe illness to receive placebo or Paxlovid, a combination of the protease inhibitors PF-07321332 and ritonavir. The efficacy analysis is based on 1,219 patients.

One noteworthy feature is the newness of this drug:

> PF-07321332 was developed from scratch during the current pandemic. It’s a reversible covalent inhibitor that reacts with one of the main protease’s cysteine residues. Owen [director of medicinal chemistry at Pfizer] also discussed the chemistry involved in scaling up the compound. The first 7 mg of the compound were synthesized in late July 2020. Encouraged by the early biological data, the Pfizer team aimed to scale up the synthesis. By late October, they’d made 100 g of the compound. Just two weeks later, the chemists had scaled up the synthesis to more than 1 kg. Owen said 210 researchers had worked on the project.

https://cen.acs.org/acs-news/acs-meeting-news/Pfizer-unveils...

Less than two years from lab to clinic is highly unusual. If approved, I believe this would be the fastest lab-to-approval for a small molecule drug in the history of the FDA.

[+] HWR_14|4 years ago|reply
>Less than two years from lab to clinic is highly unusual.

I assume like most other COVID vaccines/treatments, the timeline is shrunk by going straight to more expensive phases of the trial instead of having preliminary ones of escalating cost and confidence. Or at least prepping for them.

For instance, all the vaccines started setting up commercial production around the same time they started trials, because it's not worth the months delay of setting up a production line to determine if it worked first.

[+] osrec|4 years ago|reply
It's not uncommon for human tragedies to serve as a backdrop for significant scientific progress.

Wars and pandemics seem to be the testbeds for medicine, where people are desperate enough to try anything, and legislation is relaxed accordingly. The biotech companies know this all too well, and take advantage when the opportunity arises.

[+] UncleOxidant|4 years ago|reply
Development tools help accelerate software development. Better tools help you go faster. This is happening in biotech as well - they're getting some very good development tools.
[+] ricardobayes|4 years ago|reply
Is anyone familiar how this scaling up process works? To what point can it be scaled up using lab methods, and at which point does it make sense to start making it large-scale?
[+] snarf21|4 years ago|reply
Is the similiarity of COVID-19 to other coronaviruses also a speed up? We are not starting from complete scratch in that case.
[+] catlikesshrimp|4 years ago|reply
This is something I haven't encountered before in biochemistry

"reversible covalent"

A chemical covalent bond. Maybe it means something else in this article?

[+] shusaku|4 years ago|reply
I think it’s hard to overstate what a big deal this is for science. This is a completely novel molecule that appears effective as an antiviral. This would a huge achievement for the field of drug design, and will hopefully lead to all kinds of great medicine.
[+] orra|4 years ago|reply
I am thinking: if and when this is approved, we have to think about distribution.

This drug is fantastically effective at preventing hospitalisation and death, if administered within three days of symptom onset.

That gives quite a long time! But we still need to make it easy to take. Do pharmacies give it out? ER rooms? We don't want to wait until people are hospitalised; we are trying to avoid that.

So when you test positive, does the government send you out a pill with the "sorry, you have to isolate" SMS?

[+] fredliu|4 years ago|reply
> As a protease inhibitor, Paxlovid is free from the theoretical DNA-alteration risk tied to the mechanism of action of Merck’s molnupiravir.

This is the line I was looking for. Not that I know how protease inhibitor works, but looks more like a traditional anti-viral approach v.s. the potentially DNA altering molnupiravir.

[+] tzs|4 years ago|reply
> [...] patients who received Paxlovid within five days of symptom onset [...]

I wonder how well it will do on people who are farther along in their COVID infection?

There are a lot of people who don't get vaccinated, don't take precautions to avoid COVID, dismiss their early symptoms either because they believe COVID isn't worse than a typical cold or flu or because they think that is probably what they have, just treat it at home with vitamins and ivermectin if they do anything at all about it, and don't end up going to a doctor or hospital until they are having so much trouble breathing they have to go to the emergency room.

[+] jaywalk|4 years ago|reply
I wonder if having an effective oral antiviral readily available will result in someone who would have acted in the manner you suggest seeking this treatment instead.
[+] grey413|4 years ago|reply
My understanding is that other antivirals are much less effective after the first week or so of infection.
[+] swader999|4 years ago|reply
Why not just treat it at home with ivermectin if it works? It did for me for long covid.
[+] TacticalCoder|4 years ago|reply
So no we have the Pfizer vaccine (which I got) who cuts the risk of both catching the virus and the risk of severe complication by a lot (forgot the number but it's big) and in addition to that we now have Pfizer oral medication that can be given to positive cases and which reduces both hospitalization and death risk by 85%.

When can life go back to normal?

[+] phh|4 years ago|reply
> Pfizer used data on patients who were treated within three days of symptom onset as the headline finding in its press release

> There were six hospitalizations and no deaths among the 607 patients who received Paxlovid within five days of symptom onset, compared to 41 hospitalizations and 10 deaths in the placebo cohort.

> Like Merck, Pfizer excluded people vaccinated against COVID-19 from its late-phase study.

No pricing information. I'm worried that "3 days after symptoms onset" is too short to be usable in real-life, but I could be wrong.

[+] adventured|4 years ago|reply
From the NY Times:

"The U.S. government has been in negotiations with Pfizer for enough pills for 1.7 million courses of treatment, with an additional option for 3.3 million, according to a senior administration official. That is about the same quantity that the United States has ordered from Merck. The government expects to pay about $700 per treatment course for both drugs, the official said."

https://www.nytimes.com/2021/11/05/health/pfizer-covid-pill....

[+] nradov|4 years ago|reply
Monoclonal antibody treatments are also commonly administered about 3 days after symptoms onset. They have proven to be somewhat effective in real life, although they still aren't being given to some patients who could potentially benefit.
[+] prepend|4 years ago|reply
If the cost is low enough and the side effects are mild enough it could work. People would take it before a test is positive so would end up taking it when they didn’t really need it.

It’s similar to the antivirals for flu where you need to take it early on so it becomes habit to test early and start early.

Home labs will help with this too. Where someone could take a test, get a prescription and pickup within a few hours.

[+] ganzuul|4 years ago|reply
10 deaths with placebo...

Medical ethics are confusing. Maybe this field needs more oversight. Especially on the corporate level.

[+] loceng|4 years ago|reply
Did they also check and exclude if they had natural immunity - COVID recovered, having antibodies?
[+] neltnerb|4 years ago|reply
If you take an antiviral like this, do you still develop a good immune response to reinfection?

I wonder because almost everyone who might end up needing this isn't vaccinated (based on hospitalization rates) so I hope that at the end they also end up having some immunity to catching it again at least.

In the moment of course it is better to use than not.

[+] rsynnott|4 years ago|reply
While this looks like potentially great news, Pfizer really needs a new Head of Making Up Drug Names. Paxlovid! Between this and ‘Comirnaty’ (the vaccine) it is clearly not their strong point.
[+] dekhn|4 years ago|reply
Damn, the structure has 3 fluorines. This particular structure is stable, but in general, fluorine chemistry is tricky.

Obligatory classic: https://www.science.org/content/blog-post/things-i-won-t-wor...

[+] gpcr1949|4 years ago|reply
trifluoroacetyl is a pretty stable substituent, as far as the fluorines go. trifluoromethyl as a substituent is a classic "medicinal chemist's favorite" and will not be labile. for example: efavirenz, fluoxetine, celecoxib all have a TFM. It's true fluorine chemistry is generally tricky, including some organofluorine chemistry, on the other hand in this case trifluoroacetic acid, trifluoroacetyl chloride etc are commercially available, affordable and common so no issue to make the trifluoroacetyl amide at some point. anyway for me this is a really nice "medchem" friendly compound.. i like the little oddball bicyclo[3.1.0]hexane ringsystem in there (the part that looks like a pentagon fused with a triangle).
[+] comicjk|4 years ago|reply
C-F bonds are very stable, not like O-F bonds. They're found in common drugs like Prozac, and common materials like Teflon.
[+] whymauri|4 years ago|reply
Exactly what I was thinking, especially for an entirely novel molecule. I wonder how novel the scaffold is. Whichever med chemist led this initiative is an artist -- amazing job.
[+] cblconfederate|4 years ago|reply
I hope this proves to be real going forward. The vaccination route seems to be hitting a deadend as a way to end the pandemic. The pill will have to be cheap and available over the counter, it makes no sense not to subsidize this.
[+] jdlyga|4 years ago|reply
This is excellent news. Vaccines and an easy to get prescription treatment like tamiflu are how this stops being a pandemic.
[+] charles_f|4 years ago|reply
> compared to 41 hospitalizations and 10 deaths in the placebo cohort

This makes me weirdly sad. Can you imagine entering the trial for a long sought drug against a deadly disease that turn out to be working, and end up in the control group? I know that there's more to it (it's necessary, they knew, it could have not worked, plainly be nocive, etc.) but it's like being unlucky twice in a row and die out of that while having received the real thing would have saved you

[+] hungryforcodes|4 years ago|reply
Who cares about the skeptics. Give me the drug if I'm sick. End of story.
[+] shoto_io|4 years ago|reply
This is Pfizer’s antiviral drug. Merck’s drug might be effective as well, but if seems like to be also a drug with many side affects interfering with your genome.

Getting vaccinated looks like a better option to me. Anyone know if the Pfizer one works similarly?

https://www.forbes.com/sites/williamhaseltine/2021/11/02/har...

[+] blackbear_|4 years ago|reply
Note that to make the overall risk of adverse effects from covid19 lower, any treatment that is taken after the onset of symptoms must be much more effective at preventing adverse effects in symptomatic patients compared to a vaccine. This is because the vaccine greatly reduces the probabilty of symptomatic infections, while the other treatments do not.
[+] charbull|4 years ago|reply
The data sample is a bit low? 1200 people
[+] DavidPeiffer|4 years ago|reply
To mention it, not necessarily directed at you. Larger test groups are required when trying to distinguish between less effective treatments.

If rabies has a 99% death rate and you try your rabies treatment on 10 people, 9 of whom live, that's much stronger evidence than a situation where 50% of people died without treatment versus 48% with treatment (sample size 100). To be confident it's not just random chance, you'll need a really large sample size for the 2nd situation.

[+] tpxl|4 years ago|reply
Depending on the effect severity you can get a representative sample from as low as 40 people (not necessarily in this case).
[+] spywaregorilla|4 years ago|reply
That's not low for the effect size they're observing. Note that this is a phase 2/3 trial. The safety trials have already occurred.
[+] nonfamous|4 years ago|reply
This is a randomized clinical trial; participants are recruited into the study using methods that eliminate the biases associated with self-selected participation, like internet or TV polls. You can get statistically valid results from small samples, that apply to very broad populations, using this methodology.
[+] dragontamer|4 years ago|reply
Gotta prove it with 1200 before you get the funding for 10,000.
[+] anonuser123456|4 years ago|reply
Does this molecule inhibit replication of related coronaviruses or is it highly specific to SARS-CoV-2?