My thoughts on Bluebird bio's LentiGlobin

I'm excited about bluebird's progress in gene therapy but realize it will take at least another 10 years before it is available on the market provided everything goes well. Even then there are so many complications and variables that have to be considered prior to undergoing the therapy.

I reviewed the post ASH slides on LentiGlobin. Undergoing gene therapy requires conditioning with chemo drugs which is strong enough to cause expected mucositis and infection. Infection such as bacteremia and febrile neutropenia which requires aggressive IV antibiotics for weeks in ICU care setting. Furthermore platelets are wiped out which may require platelet transfusions until the patient's own platelets resume production. Even if platelets are not required one is at risk in the interim.

In the small sample size they have evaluated most patients are young < 20 yrs old. What does this mean for the older thalassemia population or then-older population when this therapy is hopefully FDA approved? Older thal patients may be diabetics, have cardiac issues, immunocompromised, splenectomized, etc.

Even though the Globin gene expression seems to be expressed quite positively, especially with the new vector being used by Bluebird, the process of undergoing gene therapy will be grueling.

I hope for the very best for everyone. Let's hope and wish them success and let's bring this therapy home safely so we can benefit from it.

CrazyPharm,

Certainly these studies are in earlier phases and they have used patients who are young and don't have other factors that will interfere with what they hope to study. 

The positives are that, there haven't been any negative effects in this group of patients.  The results have been very good which means there is a good chance that there will be few side effects for most patients and that the results will also be good for most patients.  I think that long term and larger studies will help us understand all of this better. 

There is also a chance that with long term studies they will learn the optimal chemotherapy to administer.   For now the goal is to show that the gene therapy can work.  Maybe in the future less intensive chemo preparation can be shown to have good results as well.  Much will be tapered in the future and as good results continue I think the studies and wider availability of gene therapy will progress quickly. 

I think that Sloan Kettering is beginning to pick up traction again as well - certainly the future for all thalassemia patients will be brighter than what we had expected.  I am also hoping that luspatercept will help many patients as they await gene therapy.  I think that the drug will help many patients become healthier as well. 

I know it seems out of reach at this time - but have hope - because it is much closer than it ever was before

You're absolutely right. I have high hope for luspatercept. I feel this drug is progressing nicely and will be released quicker than gene therapy. It will change the way thalassemia is treated for sure.

10 years is a relatively short period in terms of approval by the FDA. I think it's incredible that such a short time period is predicted.

Yes, gene therapy requires chemo and Bluebird uses chemo similar to what is used in BMT. Very few patients have long lasting problems from this aspect of BMT. The real problems lie in the possibility of rejection and graft vs host disease. These are not possibilities with gene therapy. The early trial participants have shown no long term effects from chemo. Yes, it may affect fertility, so collection of sperm or eggs should be done in advance. In my opinion, even with loss of fertility, the cure is well worth it.

The first patients chosen had milder, closer to intermedia phenotypes. This make sense. You can't start with those who are most transfusion dependent until you see the process is working. As it proves itself in ideal patients, we will see trials opened to far more patients. The one criteria that will have to be met for all trials, is that the patients must be in good health, so there is much incentive to comply with treatment and stay healthy.