Has anyone been following the latest news on treatment for sickle cell anemia? Since many of us are treated with hydroxyurea which is approved for sickle cell anemia, I was wondering if this may be in our future?
"The F.D.A. approved the first gene editing therapy ever, for sickle cell disease, a debilitating blood disorder caused by a single mutated gene. This breakthrough offers hope, but also comes with obstacles."
I was thinking the same when I heard the news.
Unfortunately not. Cystic fibrosis is caused by an inherited mutation and is a loss of a function, so if you can edit the right gene into some cells, so that they can produce the missing enzyme, the whole body can benefit.
In the case of an MPN, the mutation happens during life (not inherited), in one rogue cell to start with. The problem is caused by descendants of that cell making new blood cells when they shouldn't. So it is a 'gain of a function' not a 'loss of a function'. That means that most of the cells in the body have a good copy of the gene already, and to tackle it by gene editing you would have to track down every single mutated cell in the bone marrow to edit its bad gene out, otherwise the problem would continue. It can't be done. There are other promising approaches in the pipeline that will work, though (and would not work with a 'loss of function' disease)
Hydroxyurea is useful in many different conditions and does many different things.
But sickle cell is similar to mpn? No?
Yes, it does have similarities, but in sickle cell the bad gene is inherited and present in all cells in the body, and so all blood cells are defective. Gene editing can produce some stem cells without the mutation that can produce healthy blood cells and reduce the impact of the disease.
In an MPN, there are two differences: firstly, the unwanted platelets and/or red blood cells produced in an MPN are normal cells, the problem is just too many of them.
Secondly,the mutation causing an MPN occurs during life, in just one stem cell, and the MPN develops if that stem cell multiplies and starts to compete with the normal ones. So if you were trying gene editing, you would need to do it on those rogue stem cells, and you would need to find and treat at least most of them, individually. That is just not realistically feasible.
So yes, they have similarities, but you could look at the two diseases as mirror-images of each other.
PS I don't know where I got cystic fibrosis from in my first post!
Thank you: that’s very clear. I had the same hopeful reaction when I saw the research. Pity.
But there are other treatment methods that will work with MPNs and not with sickle cell, and there are other treatments under development...
Very interesting development. I wondered the same about possible gain for MPN. There was a gut kick at the end of the presentation I saw that the cost was $1M per treatment, that insurance company and government comments about coverage and approvals were not available yet. That’s how breakthroughs start though so fingers crossed it makes it.
Non driving gene mutation-ASXL1
A Gene that affects allele reduction in Jak2 by IFN.
FDA Approves Momelotinib for Myelofibrosis With Anemia
High white blood cells 
Revlimid (lenalidomide) for MPN anemia?
