The first cancer fighting virus has just been approved by the FDA. Are we at the beginning of a new age of viral therapy?
An old enemy is teaching us new tricks
Viruses are one of the best ways of delivering a payload to cells; they've been perfected by evolution to inject their material into us. They may be one of our greatest foes, but they're also changing the face of biology. Gene therapy, gene editing, and now cancer; the miniature virus has become one of the mainstays of modern biology.
“This is huge for the whole field, and for cancer patients. The field is exploding, and this would be another arrow in the quiver that oncologists use.”
The FDA approved the new therapy called Imlygic last week, and it's designed to seek out and destroy melanoma cells. Imlygic is a modified version of the herpes simplex virus type 1, but like most viral therapies researchers tinker with the viruses before use to remove dangerous features. Imlygic both targets tumours and recruits the immune system at the same time - boosting the body's own defences.
While it may be the first approved, there are other similar strategies on the production line involving a tweaked poliovirus for brain tumours and a modified cold virus that fights bladder cancer. Viruses are wonderful tools to puncture and destroy cancer cells and also recruit the aid of the immune system.
“It’s a low-toxicity treatment, and for the right patients you see quite stunning results”
So how does it work?
When the viral load is injected into melanoma cells, it quickly hijacks the cellular machinery and ruptures many of the cells. Imlygic has also been tweaked to increase levels of a protein called GM-CSF - which signals to the immune system's T-cells there's an enemy that needs removing.
Another weapon in combination therapy
This is great news, but like many cancer treatments it's not a golden bullet. It currently costs $65,000 and in clinical trial involving 436 patients with advanced melanoma, it extended survival by 4.4 months. This is a reasonable figure, but hardly a cure. Like many other innovative approaches we've seen emerge lately, it's likely to be more effective in a cocktail of other weaponry. The new war against cancer is likely to involve a many pronged approach, involving immunotherapy, chemotherapy and other options like surgery. Viral additions could be a worthy contributor, but they're not yet a standalone cure.
What's perhaps more exciting is that this is likely just the beginning for viral therapy. Gene therapy trials are at an all time high, and the more we establish modified viruses as safe the more they'll be used in treatment. Gene editing techniques have shown promise at fighting HIV too. Now we've established proof of concept we could soon be looking at viral weaponry against bacterial infections and even other viruses, as well as many other endogenous diseases.
Read more at the Boston Globe