https://www.science.org/content/blog-post/sarepta-sarepta
Thoughts from Derek Lowe (In The Pipeline).
Also Derek Lowe's previous ones as context (subset I could quickly find),
https://www.science.org/content/blog-post/sarepta-s-approval... ("Sarepta's Approval Woes" (2013))
https://www.science.org/content/blog-post/sarepta-s-duchenne... ("Sarepta's Duchenne Therapy Is A Lot Further Away" (2014))
https://www.science.org/content/blog-post/sarepta-s-day-fda ("Sarepta's Day at the FDA " (2016))
https://www.science.org/content/blog-post/sarepta-gets-appro... ("Sarepta Gets An Approval - Unfortunately" (2016))
https://www.science.org/content/blog-post/gene-therapy-duche... ("Gene Therapy for Duchenne" (2018))
https://www.science.org/content/blog-post/opening-lid-sarept... ("Opening the Lid on Sarepta's Drug Approvals" (2020))
https://www.science.org/content/blog-post/sarepta-tries-agai... ("Sarepta Tries Again" (2023))
https://www.science.org/content/blog-post/sarepta-why ("Sarepta. Why?" (2024))
A thread from yesterday about why gene therapy hasn't reached its potential: https://news.ycombinator.com/item?id=44573193
Interesting point there:
"The other problem is with viral vector based gene therapy is you can’t have it again. You develop antibodies which prevent it from working again, and it could cause a dangerous immune response."
Just wondering - would it make sense to immune-suppress the patient for a short period of administering of the viral-based therapy.
And as they describe that most gene therapies affect only extra-nuclear DNA, and thus have no permanent effect, wouldn't mRNA work better then in such cases - naturally the tech wasn't there 10+ years ago, yet today thanks to COVID it is here.
Edit (due to posting rate limit) in response to comment below:
I was thinking about mRNA coding dystrophin like it was coding COVID protein - should be cheap and easy (well, for some definition of easy in that context) doable, and it would be like a weekly self-injection - no toxicity, etc. Of course fixing the issue once for life would be better, once such cure becomes available, yet for now it would be similar like diabetics have with insulin - hassle for sure, yet it works.
AAV based therapies may have no permanent effect when the cells in question are actively proliferating (and the payload dilutes with each division) but muscle tissue is largely post-mitotic.
mRNA is in comparison very transient (in the range of days, and that's being charitable), even when modified (5' cap, uridine analogs, poly(A) tail) as it was in COVID vaccines. This is fine for vaccines, as you essentially want just a single exposure to the protein with each vaccine dose. You do need dystrophin continuously though (even though the cells are not dividing much, they are still recycling it).
You could argue for delivering gene therapy with mRNA/NLPs in multiple doses over the course of patient's life but that would likely 1) exacerbate toxicity and 2) be super-expensive
mRNA vaccines like the Pfizer and Moderna COVID vaccines don't enter the nucleus nor have a permanent effect. The mRNA breaks down after a few days.
Do we have any studies that show this fast clearance? From what I understand at least one of them used a pseudo-uradine that there isn't an efficient direct metabolic pathway to process, which was kind of the whole point. The idea being it would circulate longer and be "more effective"
The uridine modification was intended to reduce immunogenicity of mRNA - some of our immune cells have pattern-seeking receptors in the TLR family that recognize ssRNA and dsRNA. The presence of modified uridines throws this pattern recognition off. (https://doi.org/10.1016/j.jconrel.2015.08.051)
The modifications to increase mRNA half-life concerned mostly the caps and poly(A) tail. But even with those the persistence was in the range of days (sort of depending on how sensitive a method you picked).
That's right, they use N1-Methylpseudouridine instead of uridine (the nucleoside contained in uracil, which is the U in mRNA sequences) to last a bit longer (but not forever) and to avoid triggering immune reactions to the mRNA itself (the immune system can detect foreign mRNA).
Certainly the vaccine's mRNA sequence breaks down into separate nucleotides. If it did not, continued production of the antigens would cause a chronic immune reaction and/or immune exhaustion that would make the vaccine ineffective.
I don't know what happens to the N1-Methylpseudouridine though. That's an interesting question.
> Certainly the vaccine's mRNA sequence breaks down into separate nucleotides. If it did not, continued production of the antigens would cause a chronic immune reaction and/or immune exhaustion that would make the vaccine ineffective.
I suspect you just described "long COVID" or "vaccine injury" for some fraction of folks.
Also, people are usually like LOL it's just mRNA it goes away
But evidence does show it CAN go back to DNA with mechanisms familiar to anyone edgycated in molecular genetics - https://pubmed.ncbi.nlm.nih.gov/35723296/
Now, that particular study is in whatever cell line, highly dubious how it pertains to a human body, a few steps removed. But if you say "will you see this if you vaccinate 500 million times in 500 million people each with 500 trillion cells" - yea probably you would
Numerous studies have found vax-derived spike persisting for months and even years after vaccination, giving rise to concerns expression of spike can continue long after the claimed 24-48 hours.
A recent study found spike protein persisting for 17 months in the cerebral arteries of stroke victims. [1]
[1] https://www.sciencedirect.com/science/article/pii/S096758682...
That is interesting, but the authors point out:
> In our study, in situ hybridization detected both mRNA derived from the vaccine and mRNA from the SARS-CoV-2 virus. ... our in situ hybridization method has high sensitivity and could detect trace amounts of mRNA, possibly reflecting unrecognized asymptomatic infections. These findings emphasize the need for caution in interpreting the presence of spike protein as exclusively vaccine-related.
We should also note that the study doesn't show that the original vaccine mRNA somehow survived for months, only that mRNA matching the vaccine sequence was detected by complementary probes.
I wonder if, in these cases, the vaccine was administered to someone with an active (but asymptomatic) COVID infection, and the vaccine mRNA was copied by the same RNA-dependent RNA polymerase that copies the viral RNA.
That might explain why both vaccine and viral RNA were found.
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A bloomberg archive.ph article about the same topic - https://archive.ph/9qB0t
Whatever policy we pursue, whatever decision we make, is not forever (at a society level).
When people die, we change policy. When people feel like they cannot get the treatment they need, we change policy.
Unfortunately, this is very complicated and emotionally heavy, and it is much easier to set down the burden on someone else's shoulders, in the form of blame.
We want the FDA to do life critical, complicated and contradictory things, so it's easy to create a narrative that blames the FDA.
The other option besides blame is shared responsibility and humility, but it feels like people are not very good at thinking that way right now.
Nobody "created" a narrative that blames the FDA. The FDA is factually complicit in these deaths. Three review teams and two senior officials voted unanimously against approval, but the (then) head of FDA's CBER was buddies with Sarepta, and so they got approved and three people have died. Nobody created that narrative. It's simply what happened.
> The other option besides blame is shared responsibility and humility, but it feels like people are not very good at thinking that way right now.
Why would they be when cronyism killed people?
Sarepta's drug uses AAV to deliver the payload. I wonder why they chose AAV instead of lipid nanoparticles.
https://medcitynews.com/2025/07/sarepta-gene-therapy-fatalit...
I'm guessing they were looking for preferential delivery to certain cell types, and AAVs just happened to have best profile for those. If anything, LNPs might aggregate in the liver even more than AAVs, which can lead to even worse hepatotoxicity if an immune response happens.
I thought lipid nanoparticles were less prone to generate a immune reaction.
Lipid nanoparticle toxicity has long been an industry concern.
In a profile of Moderna back in 2016, Katalin Karikó (instrumental in the development of mRNA vaccines) mentioned this issue:
“I would say that mRNA is better suited for diseases where treatment for short duration is sufficiently curative, so the toxicities caused by delivery materials are less likely to occur” [1]
[1] https://www.statnews.com/2016/09/13/moderna-therapeutics-bio...
This gene therapy involves a gene called dystrophin, which is one of if not the largest gene in the human genome. Sarepta is actually using a version called microdystrophin, which is a truncated version. It still barely fits into AAV.
Reasons to use AAV: they're going for sustained production of the therapeutic gene, and AAVs are better at doing that than LNPs. LNPs were used in the mRNA COVID vaccine, because they're great at transient production.
To get stable production from an LNP you'd likely have to integrate into the genome, which risks cancer from disrupting oncogenes. You'd also need to package the therapeutic gene with a mechanism of integrating into the genome, like recombinase.
Probably because the HHS secretary is vehemently opposed to lipid nanoparticles.
https://www.axios.com/2025/04/18/rfk-jrs-potential-future-ta...
https://kffhealthnews.org/news/article/nih-grants-mrna-vacci...
> National Institutes of Health officials have urged scientists to remove all references to mRNA vaccine technology from their grant applications, two researchers said, in a move that signaled the agency might abandon a promising field of medical research.
They've been working on this for years. It's not anything to do with the current administration.
Yeah, if not for Germany, the covid vax wouldn't have been unreachable.
Their stock is down 90% over the last 6 months, 37% today. That's not good.
- [deleted]
stock price barely mean anything in recent years
Not for biotech. The stocks in this segment are very sensitive to trial outcomes and drug efficacy
Stocks in biotech also very sensitive to coordinated naked shorting and cellar boxing by hedge funds.
Damn, gene therapy is so promising too
The issue was not the gene therapy itself, but the delivery mechanism. They used a virus to administer the gene therapy, and this virus (like most bloodstream impurities) aggregates in the liver. At low doses this is fine, but at high doses, your body's immune response will be laser-focused on the liver, and you die from the side effects of this response.
Lipid nanoparticles have exactly the same problem. They mostly concentrate in the liver.
Wouldn't anything concentrate in the liver?
if it's so obvious that this is going to produce these side effects, then why on earth did they gamble ?
(because, it definitely look like gambling, like "investors are behind us right now, so we have the money to do it, so let's do it before money runs out")
My brother in commenting they are doing trials. Trials are by nature bets. That’s how we move science forward.
They’re not trying to kill people. There is a hell of a lot more money in _not_ killing people.
Could hemodialysis prevent this?
Yes, dialysis is surprisingly good at filtering out viral particles, but... that's not desirable in this case. After all these viruses are carrying the therapeutic payload, if you filter them out then you might as well not introduce them in the first place.
Ok, I was thinking more of injecting viruses upstream, and filtering them out downstream (preventing them from entering the liver in the first place). Maybe you could even recycle them.
But maybe as treatment if liver problems are detected?
I suppose it's possible at that point, possibly to try and stem the process. The question is just how rapidly this condition emerges, and I suspect (although this is just a suspicion) that the time between onset and a severe reaction is fairly brief. Mostly though the problem is that this is a really complex, whole immune system reaction that's triggered by the AAV in the liver, but simply removing the intial cause probably wouldn't stop the cascade.
I took a look at some of the aftermath reports (i.e. https://pmc.ncbi.nlm.nih.gov/articles/PMC10638066/ and some others) which get into specific details about the course of treatment in several patients who died from this complication. The through-line is an aggressive use of several immune suppressing and modulating therapies to calm the cascade.
I have to admit I can't find any specific discussion about dialysis in that context, so I can only assume that removal of the viral particles would be a case of closing the barn door after the horse escaped.
Yeah I was suspecting they would do the treatment with immunosuppressants. Immune response is an unpredictable killer.
I imagine if these deaths could have been prevented by this one-line HN comment, they would have thought of it.
Maybe a better phrasing of your question would be:
> Why is hemodialysis ineffective for this?
The main reason for my question was this:
Hacker News Guidelines > "Be kind. Don't be snarky. Converse curiously; don't cross-examine. Edit out swipes."
My bad, snark wasn't my intent. I meant it literally. There was an accumulation of toxins, and it seems (to me at least) extremely unlikely that the researchers were not aware of dialysis as a way to remove toxins. So then let's jump to the next level of question.
Apparently the treatment costs $3.2 million. https://en.wikipedia.org/wiki/Delandistrogene_moxeparvovec
Why does the Wikipedia page treat this as a publicly available treatment when it is still undergoing trials?
Probably because of this: Delandistrogene moxeparvovec was approved for medical use in the United States in June 2023.[3][7] It was developed by Sarepta Therapeutics, together with Roche, and is manufactured by Catalent.[8]
It's not the same drug for the latest death this article is focused on...
"Phase I study of SRP-9004".
That seems very expensive for assisted suicide
I've been working on a piece about how humans effectively have hardened firmware, and gene therapies need to do A LOT to try to get around the various defenses our bodies evolved. I should probably finish that article...
If the institutions of science and technology lasted thousands of years evolution would prefer people with the less hardened firmware, as in, the ones to survive and pass their genes would be the ones with the most "hackable" genes.
If "your" genes can be so easily modified (down the line by your children doing gene therapies) there is nothing you are really passing on. In fact you are doing the exact opposite. The best way to pass your genes on is to have them hardened, like they already are and stop any gene editing competition before it begins ;-).
yah what? This is like the CIA arguing for insecure algorithms so they can spy on enemies.
Think again about your statement, what you're saying is the fitest is the easiest to manipulate? Thats just mindboggling bad, cause you'd also be a honey pot for all the other bacteria and viruses out there.
Easiest to manipulate by humans, not necessarily by virus and bacteria, believe it or not virus and bacteria don't think the same way than us; there may an overlap but is likely not a full overlap.
Ok, so you want the CIA only backdoor?
CIA-only labeled-schematics of the CPU and GPU that they don't share with the KGB.
I dont think you understand the underlying tech of crispr, which this tech is done with.
https://news.stanford.edu/stories/2024/06/stanford-explainer...
These tools arn't magic, they use the very thing you'd find a virus or bacteria doing to infect you.
Fair
If science and technology last thousands of years, I'm sure it will progress far past the point where the body's natural resistance to change becomes an obstacle to any kind of treatment.
Are we still talking egg and sperm in a human body and everybody consenting? In that case, how would having hackable genes improve your chances of survival? If that was a dating app filter maybe.
If your body doesn't reject gene therapy, you might live longer and reproduce more.
Imagine all humans have homogeneous advantageous genetic material. We are all healthy and handsome. And then something random targets one or more of such advantageous genes and we are all wiped because we are very homogeneous.
That happens to anything recombinant we produce: crops, cattle, bacteria. That even applies to dog breeds.
"Advantageous" changes as the environment changes. Being a large long lived strong dinosaur is advantageous until meteorite? Then being a small mammal is advantageous. A population explosion of locusts ravages all plants successfully, until a fungus infects and kills almost all, thankfully for locusts some of them which were not "the best" survived that one infection.
Like covid wiped us all right? A deep understanding of our genes means we are more likely to quickly create successful defenses against future hostile organisms, again, the most "hackable" specimens, those in which we could accurately predict the effects of our changes in their genes (including its interactions with virus and vaccines).
And the same homogeneity means that developing a defense for any future hostile organism is much more straightforward, just like e.g. developing software that works on windows is much easier than developing software that works on windows, Linux and mac.
we know genetic diversity is beneficial from observing nature (sexual reproduction has clear evolutionary advantages that you can look into yourself if you like). yours is an interesting hypothesis, but "developing a defense" is something that we get for free from genetic diversity. we can improve our odds of survival using technology, but culling genetic diversity in favor of gene hacking compatibility comes with some tough trade-offs since you're choosing to ~always adapt manually. not to mention the ethical concerns depending on how this condition arises.
Sigh. Covid was a serious illness. We were lucky and able to leverage science that had been in development for a long time to vaccinate against it. We have a deep understanding of many immune mechanisms, and can effectively treat people against some diseases. Vaccines are super effective (until the virus evolves and then they aren't).
This is also happening with other types of pathogens - antibiotic resistant illnesses are on the rise because we used quickly created defenses to eliminate all but the strongest versions of them. We have very few effective anti-fungal medications, and most of those are very risky.
If we were good at developing defenses for homogeneity, farmers all over the world wouldn't be fungi destroying the monocultures we depend on for modern agriculture (bananas and corn are really great examples). Estimates are that as much of 30% of global crops are lost to fungal infections; I sincerely doubt that homogeneity is the panacea you assume it is.
From Google:
> Making fungus-resistant agriculture is challenging because fungi share many cellular similarities with humans, making it difficult to develop fungicides that target fungi without harming plants or humans.
I can see that now, thank you.
Not necessarily, because (1) the “wild” viruses would still exist and evolve, competing with treatments and maybe learning to leverage them, and (2) bad people use science too.
Imagine if random DNA really could just float in and out of the blood streams genetics? We'd be constantly battling random protein production and weird abnormal stuff.
the paywall really cuts down on the readability of this story. a quick google showed plenty of news stories though, their shareprice dropped 40% on the market today.
I'd be curious what the numbers are for the "good" that this therapy does; is there any way that this therapy is still "worth it" at any scale? but I know little about this area so that's a fairly naive question.
The answer is, the therapy does not improve much. It was controversial when it was approved, because the Phase III clinical trial failed to show statistically significant improvement- lots of people in the FDA advocated against approving the drug (even without knowledge of these rare fatal side effects) but were overruled by Peter Marks, head of the the biologics for the FDA under Biden.
It seems to me to be similar to the approval of the three Alzheimer's drugs which don't really show improvement either- it seems like over the past decade the FDA has wanted to approve drugs that might work for diseases where there was no treatment at all (while saying things "delivering hope"). And it's not gone well, and has not been a good idea.
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