What are Cell and Gene Therapies?
Watch Educo Life Science Trainer Melody Janssen discuss the basics of Cell and Gene Therapies
We interviewed Educo Life Sciences trainer Melody Janssen to discuss the basics of cell and gene based therapies.
In the interview we discuss:
- What are cell and gene therapies – How are they defined by the FDA and EMA?
- What is a gene therapy and is mRNA a gene therapy?
- What are cell therapies?
- We discuss CAR-T cells and how they can be both a cell and gene therapy.
- What the future holds for cell and gene therapies
Watch the interview here:
What are gene and cell-based therapies?
Before we go into that, let’s start with the fun fact that the FDA talks about gene and cell -based therapies (GCTs) whereas the EMA talks about advanced therapy medicinal products (ATMPs). So, there we already see that terminology can differ vastly between the agencies.
OK, but let’s talk about what is considered gene and cell-based therapies. Gene therapy is defined as an attempt to modify or manipulate the expression of a gene or to alter the biological properties of living cells. Generally speaking, gene therapy has 3 broad modes of actions:
- Replacing a disease-causing gene with a healthy copy of the gene
- Inactivating a disease-causing gene that is not functioning properly
- Introducing a new or modified gene into the body to help treat a disease
What are examples of such therapies?
Luxturna, which is the first in vivo approved gene therapy for inherited retinal disease by the FDA. It was developed by Spark Therapeutics. It works by introducing a functional gene to the cells and thus replacing the disease-causing gene.
What about the COVID mRNA based vaccines? They contain mRNAs, so are they a gene therapy?
Well, if we look closely at the definition of a gene therapy, mRNA based vaccines do not modify or manipulate genes nor do they alter biological properties of cells.
So no, mRNA based vaccines are not considered gene and cell based therapies.
In fact, when we look at RNA molecules, mRNA is only a small fraction of that category. Other categories include interfering and antisense RNAs and though RNA and gene therapy are often mentioned in the same sentence, they’re actually distinct classes of drugs known as nucleic acid therapies.
One exception is the Crispr/Cas9 system, that falls under gene editing and thus gene therapy.
Coming back to an example of a gene therapy, we should not forget the famous CAR T cells, such as Kymriah, which was the first approved CAR T cell therapy for the treatment of Acute Lymphoblastic Leukaemia. CAR T cells are also named cell-based immunotherapy products.
I always thought CAR-T were cell-based therapies. So why is it gene therapy and not cell therapy? Or is it both?
Good question, and again, let’s have a closer look at the definition of gene therapy which includes the phrase: gene therapies alter biological properties of cells.
CAR T cells are a perfect example of such manipulation. Current CAR T cells are made by collecting patient’s own immune cells and then genetically manipulating them ex vivo by adding a gene to the T cells that will then lead to the expression of a chimeric antigen receptor (CAR) before being infused back into the patient. So, CAR T cells are considered a cell-based gene therapy.
What is then considered as cell-based therapies?
These are therapies where human cells are transplanted to replace or repair damaged tissue and/or cells. These cells are not genetically modified (such as CAR T cells are!) and can have a variety of origin such as hematopoetic, adult and embryonic stem cells for autologous and allogeneic therapies.
I am sure you will be surprised that the FDA already approved a cell therapy back in 1997, and cell therapy named Carticel. During this treatment, the patient’s own cartilage cells, commonly called chondrocytes, are removed, and expanded in a lab before being placed back to repair articular cartilage damage in the knee. Since then, several products have been approved across the globe, but far less than for example monoclonal antibodies. Three reasons for the slow growth are challenging manufacturing processes, demanding logistics as products need to be placed back into patients quickly and in case of stem-cell therapies, especially embryonic, the ethical aspect plays a role.
Bottom line is that gene and cell based therapies are exciting new fields to treat and cure diseases with unmet needs but are also complex and we are just at the beginning of harmonizing guidance between regulatory agencies.
Melody teaches on the following courses:
To view all our cell and gene courses follow the link below.