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by tetramer 938 days ago
CRISPR is definitely an awesome technology, and I'm glad that after many decades of research, we're finally getting approved treatments as a result.

That being said, I do want to clarify that this isn't a "cure" for sickle cell disease. It is not editing the gene causing sickle cell itself, but rather allowing for increasing production of HbF (fetal hemoglobin) by knocking down a suppressor. Hydroxyurea, a current standard of care option in sickle cell disease, also increases HbF production but response can be variable among patients (but when it works, absolutely improves quality of life!)

In addition, I think we always need to keep in mind potential toxicities and hopefully, we learn more about this when the publication actually comes out. It's important to note that giving this therapy requires giving high dose chemotherapy beforehand, and I'd also be interested in knowing how long this therapy actually lasts as I do expect the product may wane with time.

But still, so excited to see CRISPR technology coming to the public and the potential for this technology in many different disease states!

2 comments

Would people who undergo this treatment become (more) vulnerable to malaria ? This is one potential side effect that was mentioned on a podcast about CRISPR. Something along the lines of "don't underestimate the 'potential benefits' of genetic disorders"
Realistically, this treatment is not going to be available in places with a high prevalence of malaria for a long time, so I don't think this is too much of a concern.
Wouldn’t they just become equal likelihood of getting it compared with people without sickle cell?

This means most people on the planet I think. You could just take a malaria pill.

Says who?

I honestly don’t know, but qualifying as a “cure” doesn’t require fixing the original thing that was broken.

Whether something is classified as a cure or treatment just depends on the extent and permanence of its effectiveness.

Is that not what’s happening here?

Technically no it doesn't. I had thought that curing did mean fixing the problem, but I just googled and it does indeed also mean relieving of the symptoms.

But I think in this case they're right to clarify. I think the low level of common knowledge around gene editing could lead people to believe that this is mutating the sickle cells into healthy cells, which it isn't doing

> I had thought that curing did mean fixing the problem, but I just googled and it does indeed also mean relieving of the symptoms.

Usually curing would mean fixing the problem, or more specifically it would mean permanently eliminating the symptoms. This contrasts with "treatment" temporarily relieving the symptoms.

https://my.clevelandclinic.org/health/articles/24434-cure

> Being cured of a disease means it’s completely gone and isn’t coming back. For many people, cures represent the ultimate treatment goal. Most diseases and conditions aren’t curable.

(This link disagrees with my use of "treatment", saying that "treatment" is any procedure, and "cure" is one of many possible outcomes of a treatment, with temporary relief being another possible outcome. But the point stands that curing definitely does mean fixing the problem.)

Glasses do not cure myopia, but they are so effective at relieving the symptoms, in an inexpensive and noninvasive way, that there is no real need for a cure.

>Usually curing would mean fixing the problem

No, I believe you’re thinking of “problem” in a different way.

A cure permanently relieves symptoms of a disease. The symptoms are what’s “gone and is never coming back.”

That much alone is called a “functional cure”, it’s not just a treatment.

The difference between a cure and a functional cure depends on the disease but in either case, it means it’s not coming back.

> No, I believe you’re thinking of “problem” in a different way.

> A cure permanently relieves symptoms of a disease.

This is a surreal correction for you to make after selectively quoting the first half of my sentence. Let's look at the whole thing:

>> Usually curing would mean fixing the problem, or more specifically it would mean permanently eliminating the symptoms.

Did you have something to add to that?

> but I just googled and it does indeed also mean relieving of the symptoms.

In that sense AIDS is also cured, but in my book it's not, because people with it have to take pills for the rest of their lives and those pills do have serious side effects.

The definition relates to a treatment not the disease.

In your example the question would be, does antiretroviral therapy cure HIV? It does reduce the viral load but not permanently, so no, its not considered a cure.

The answer might change with the treatment. Does a stem cell bone marrow transplant eliminate HIV? Yes, permanently as far as it’s known so HIV is “cured” in this case.

That agrees with the point I was making. They are clarifying that this doesn't make the disease go away, but it sufficiently treats it to the point where it would have little to no effect.

So it's a cure for some definitions of cure, but not all

It might clarify how it actually works, but he’s saying it’s not a cure, and if that’s not factually correct that’s not a good thing.
That's fair, this definitely may be a functional cure for many people and that's absolutely something to be celebrated.

The language around "cure" is complicated in general. We often use it in diseases like cancer but with modern therapies, we do have some patients on long-term therapy making their cancer more of a chronic one - are they cured? On the other hand, we rarely use the word cure with diseases like hypertension or diabetes which can devastating diseases in their own right but can be controlled effectively with medication.

So yes, what should really matter is the actual outcomes - are people living longer? Is their quality of life better? And, with exa-cel/Casgevy, the latter is absolutely true (and the first will be known after time).

Actually, you’re flat out wrong. I have an incurable genetic condition. Unless it is BANG AFTER THIS NO MORE SYMPTOMS then no, it’s just another treatment.

Cure means gone. That’s why Cancer people talk about remission. I’m old enough to remember the talk around curing cancer and then it came back and killed people the medical community walked it back.