Gut bacteria from amphibians and reptiles achieve tumor elimination in mice • Hacker News Board

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#121

Post by estearum » Thu, Dec 18, 2025, 2:58 PM UTC

kevincox wrote: post #114

estearum wrote: post #41

Earlier quoted context omitted.

Good reasons: * Most drug candidates just don't work * Even among the drug candidates that do, figuring how to safely deliver them to their target is very hard (looks similar to "just doesn't work") Bad reasons: * It's too expensive to prove that a drug works * It's too difficult to differentiate the patients for whom a drug works and the patients for whom it does not * It is very hard to predict recruitment and to a…

> It's too expensive to prove that a drug works I'm not sure that is necessary a bad reason. You need to factor in a lot of concerns to determine what "too expensive" means. But if you are going to spend billions of dollars to develop a drug that only treats about 2 people a year it is likely too expensive even if it is 100% effective. That money would be better spent on treatments that have wider applicability. Of c…

Agreed it isn't necessarily a bad reason. In some cases it's a good reason for failure (like the one you describe).

In other cases it's a bad reason for failure: it's also incredibly expensive to prove your drug works even if it does work for a lot of people.

That's bad! It'd be better if it were cheaper.

Actually counterintuitively, due to a weird drug approval and payor reimbursement policy arbitrage, pharma companies are highly incentivized to produce drugs for tiny populations.

One of my hobby horses is railing against this specific dynamic.

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#122

Post by estearum » Thu, Dec 18, 2025, 3:01 PM UTC

d--b wrote: post #112

estearum wrote: post #104

Earlier quoted context omitted.

Yes there are few that claim 100% efficacy and no side effect at this stage, but there are far, far, far fewer who make it to human availability. I wouldn't describe it working in humans as "a stretch" per se. I'm not identifying a specific reason it shouldn't work in humans. I'm just saying that's true of thousands and thousands of really great looking treatments (per year!) that, nonetheless, end up not working in…

If it is the case that there are such treatments (easy to produce, 100% efficacy, no side effect) that cure fairly common deadly disease such as colorectal cancer in mice, and that never make it to human trial, there is something seriously broken about medical research...

No, the issue is that mice are very different from humans.

The only thing such a state of affairs clearly indicates is broken is using mice as proto-human test subjects.

Which of course, when you state it like that, is obviously suboptimal. But no one knows what to do about it.

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#123

Post by citrate05 » Thu, Dec 18, 2025, 3:41 PM UTC

torben-friis wrote: post #9

100% response, zero side effects? This sounds like world changing news. Can anyone with domain expertise explain the catch, if any?

It looks like they screened 45 strains of bacteria to find 9 that passed their safety tests, and then only one of those had a 100-percent response. The sample size is also small: 5/5 sounds a lot less impressive than 100%. I'd expect the true response rate to be substantially lower ("winner's curse").

The bar for an acceptable side effect profile in an FDA-approved drug would also be a lot higher than "five genetically near-identical mice did not show evidence of pathology in a single study."

I'm not saying this work is bad (skimming, it seems fine for what it is, though haven't read in detail), but it's quite preliminary if we're talking about developing a medical treatment that could eventually be deployed in humans. There's a reason it ended up in a mid-tier microbiome journal.

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#124

Post by d--b » Thu, Dec 18, 2025, 4:10 PM UTC

estearum wrote: post #122

d--b wrote: post #112

Earlier quoted context omitted.

If it is the case that there are such treatments (easy to produce, 100% efficacy, no side effect) that cure fairly common deadly disease such as colorectal cancer in mice, and that never make it to human trial, there is something seriously broken about medical research...

No, the issue is that mice are very different from humans. The only thing such a state of affairs clearly indicates is broken is using mice as proto-human test subjects. Which of course, when you state it like that, is obviously suboptimal. But no one knows what to do about it.

Right, yes, at least that study proved that some bacteria eat cancerous cells in at least one mammal.

If that particular bacteria doesn't work in humans it may still trigger a search for a bacteria that does.

Still being optimistic about this :)

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#125

Post by pants2 » Thu, Dec 18, 2025, 4:13 PM UTC

colordrops wrote: post #15

estearum wrote: post #12

Earlier quoted context omitted.

The catch is that there are thousands of promising therapies in animal models/pre-human testing. A very very tiny fraction of them will ever make it to market for a variety of both good and not-good reasons.

What's the difference between a good and not-good reason to not go to market?

In the early 2010s I had a couple friends working at a biotech startup with a moonshot cancer cure. They had amazing results in animal testing, and had raised just enough funding to do a first human trial on a terminal patient.

That patient was hit and killed by a car two days after finishing their treatment.

Along with the CEO's stubborn refusal to give up any more equity in the company, they went under, and the world will never know if that treatment worked.

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#126

Post by estearum » Thu, Dec 18, 2025, 4:14 PM UTC

d--b wrote: post #124

estearum wrote: post #122

Earlier quoted context omitted.

No, the issue is that mice are very different from humans. The only thing such a state of affairs clearly indicates is broken is using mice as proto-human test subjects. Which of course, when you state it like that, is obviously suboptimal. But no one knows what to do about it.

Right, yes, at least that study proved that some bacteria eat cancerous cells in at least one mammal. If that particular bacteria doesn't work in humans it may still trigger a search for a bacteria that does. Still being optimistic about this :)

Yep, it's not wasted effort. This is how science works! Lots of dead ends and then suddenly a breakthrough.

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#127

Post by gus_massa » Thu, Dec 18, 2025, 4:58 PM UTC

z3t4 wrote: post #65

3eb7988a1663 wrote: post #22

Earlier quoted context omitted.

Prevalence of the disease - if it only impacts 1/100 million, going to be hard to ever find sufficient patient population to test and recoup your investment. Existing quality of treatments - if there are already efficacious drugs on the market - how sure are you that this new therapy will be best in class? Only being as good as the status quo is not an ideal competitive position. Conversely, if there is an unmet need…

Also the ethically in blind studies, can't just let some random patients die just to prove that your drug works.

When there is already a known treatment, the control group gets the old known treatment and the other group get the new proposed treatment.

So the comparison is between old and new, to ensure the new treatment is better than the current standard one.

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#128

Post by gus_massa » Thu, Dec 18, 2025, 5:15 PM UTC

estearum wrote: post #122

d--b wrote: post #112

Earlier quoted context omitted.

If it is the case that there are such treatments (easy to produce, 100% efficacy, no side effect) that cure fairly common deadly disease such as colorectal cancer in mice, and that never make it to human trial, there is something seriously broken about medical research...

No, the issue is that mice are very different from humans. The only thing such a state of affairs clearly indicates is broken is using mice as proto-human test subjects. Which of course, when you state it like that, is obviously suboptimal. But no one knows what to do about it.

Mice are good because they are super cheap.

It's useful as a very early test. They used a shotgun approach, they tested 9 bacterias and 1 of them was suspenseful. At least it was suspenseful for 2 weeks, until the study ended. It's very difficult to extrapolate that to the 5 year survival rate in humans.

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#129

Post by gus_massa » Thu, Dec 18, 2025, 5:23 PM UTC

sroussey wrote: post #51

tyre wrote: post #10

Earlier quoted context omitted.

I would be in favor of adding a standardized [in mice] to the titles of all HN submissions about medical breakthroughs. Most of them end up being in mice and many do not reproduce in humans. It would help, at a glance, to know how significant a study's results are.

Maybe we find out why things work in mice and not us.

This works in mice with small tumors for two weeks until the experiment ends. It's quite different form working in humans with big tumors for 5 years.

Mice are good for early tries. The researchers had 9 bacterias and only 1 was successful. Experiments in mice are cheaper and have less ethical problems than experiments in humans.

(Hey! They even injected the cancer cells in mice and waited a week until it grow. Nobody will approve that in humans.)

Re: Gut bacteria from amphibians and reptiles achieve tumor elimination in mice

#130

Post by estearum » Thu, Dec 18, 2025, 6:55 PM UTC

gus_massa wrote: post #128

estearum wrote: post #122

Earlier quoted context omitted.

No, the issue is that mice are very different from humans. The only thing such a state of affairs clearly indicates is broken is using mice as proto-human test subjects. Which of course, when you state it like that, is obviously suboptimal. But no one knows what to do about it.

Mice are good because they are super cheap. It's useful as a very early test. They used a shotgun approach, they tested 9 bacterias and 1 of them was suspenseful. At least it was suspenseful for 2 weeks, until the study ended. It's very difficult to extrapolate that to the 5 year survival rate in humans.

Correct, this is how drug development works.