You may have heard about the news on the first clinical trial in China that was consisted of inoculating cells modified by the CRISPR/Cas9 technique. In this post, I relaying the original article published in Nature online about the trial (source: http://www.nature.com/news/crispr-gene-editing-tested-in-a-person-for-the-first-time-1.20988?WT.mc_id=SFB_NNEWS_1508_RHBox)
For many of you, CRISPR may not be much explanative except the word that sounds like something being “crispy”. Indeed the technique is.
But let’s understand the technique to better understand why it is a breakthrough. There is a nice video made by iBiology and featuring Dr. Jennifer Doudna (the co-discoverer of CRISPR/Cas9) explaining very nicely exhaustively in lay terms the CRISPR/Cas9 technique that I will quickly resume to keep that post short
CRISPR/Cas9 acts as a little genetic scissors, that permit us to cut and paste genetic data into cells. Stricto sensu it is not new and we have doing it in bacteria, yeasts, plants, fruitflies, zebrafish and mice for a while now. But one thing we have been facing is editing genomes in bigger animals like rats, primates and humans. It is extremely difficult and very poorly efficient.
With CRISPR/Cas9, we suddenly have a magic wand that now makes the impossible-possible by making the gene edition in higher mammals much more easier. Also CRISPR/Cas9 allows us a more targeted editing, precisely.
However the technique has known some possible off-target gene editing, such caveat is enough to raise concerns for patients safety. However, as science goes, there is a rapid interest in the technique and improvements are coming in the fast pace.
In this trial, the investigators have taken immune cells from a patient suffering from a lung cancer and removed a gene called PD-1. PD-1 is a receptor for a molecule called PD-1 ligand, a protein secreted by cancer cells. Upon interactions with PD-1L, PD-1 results in a immune suppression and shutdown of the immune system. By removing PD-1, the immune system is no more silenced and now can target and strike cancer cells. This is a new concept in fighting cancer cells called immunotherapy.
This trial will tell us two things. First if the technique is safe and second if it is efficacious. The treatment appears safe (because the cells have been engineering outside the body and reprogrammed in a dish before being reinserted) but we cannot exclude any severe if not fatal side effects.
The second is the efficacy. There are evidence of PD-1 targeting being a novel treatment that showed promising results in Phase II and III clinical trials. But that will work with lung cancer? We will have to wait and see….
If it works, that would be fantastic and open the possibility to revive the gene therapy that has been mostly stuck in limbo by our lack to insert and correct defective genes in patients.