A word processor for genes was tried for the first time to
treat cancer, it was reported this month. A molecular tool, known as CRISPR,
finds and replaces individual genes. In this case, genes were altered to boost
immune response to fight cancer—another cancer-fighting method that is still in
its early years.
So how excited and optimistic should we be? Well, although
the concept of CRISPR was discovered in 1993, it wasn’t fully realized as a
tool until 2013. Since then, it has been hailed as a revolution in molecular
biology, for its ability to select and modify single genes easily. The fact
that it’s gone from a research lab tool to a potential treatment in six years—the
blink of an eye in science—is remarkable.
But important caveats exist. The test reported this month
was ONLY for safety, not to see whether the treatment actually works. This is
known as a Phase 1 clinical trial. The next step is to try it in a larger group
of people, once again only looking for safety. If that Phase II trial goes
well, the treatment will enter the final stage, where it will be tried in a
larger group. If the treatment is succeeds in this Phase III trial, it could go
to market. That whole process will take a minimum of five years.
Caution should perhaps prevail over optimism, though. Gene
therapy—using viruses to replace individual letters in the human genome—was, in
the late ‘90s considered a promising approach to treating many disease. But the
death of one young man in a clinical trial revealed that what was thought to be
a safe, targeted approach was anything but. It took the field 20 years to
recover. The technique is only now being using in a very limited amount of
diseases.
If CRISPR can overcome the safety concerns that hurt the
early days of gene therapy, excitement that this is a viable medical technique
will grow. Perhaps the most interesting glimpse out of this study is how CRISPR
can be coupled with other techniques to affect change in the body—in this case
tweaking the immune system. Immunotherapy in cancer is a young, but promising field.
Finding a targeted way to harness the immune system is no small task. It will
be interesting to see if CRISPR can deliver.
