Scientists at Navega Therapeutics in San Diego, California have discovered a way to target DNA to stop pain signals being sent and eliminate pain. In an article published by Pharmafile, the treatment could be available in five years to help sufferers of chronic pain or with long-term pain problems.

Chronic pain is common in the UK with more than 20,000 cases per year and more than 100 million people in the US alone. There is no cure, but many are put on opioid-based painkillers to help manage symptoms, causing tolerance and physical dependence and, in turn, addiction. The work developed at Navega has an advantage over current painkillers, in that it’s not addictive and could help combat the addiction epidemic to opioids.

The CRISPR gene-editing technique has mainly been used in research for rare hereditary diseases, but preliminary studies on mice tested at Navega have shown that this technique can also be used to target and silence pain genes. Previous studies have shown that CRISPR can be used to reverse sickle cell anaemia, and another controversial case with China’s first gene-edited babies claimed to provide HIV resistance by replacing a gene to confers resistance in embryos.

Researchers at Navega used a CRISPR technique called “epi-genome editing” to silence the target pain gene SCN9A rather than replace it. “You can either activate or repress a gene of interest, without creating permanent changes. So, we can repress the gene that’s known to cause sensitivity to pain.” Explained co-founder Ana Moreno. “We are really excited because we have seen, in three different pain models, a decrease in overall pain.

This treatment could be used in cancer patients to replace morphine that is currently used to mask pain from chemotherapy. Chemotherapy is an aggressive form of cancer treatment, and it’s known that more chemotherapy is needed for higher chances of cancer-free survival. Instead of using morphine which leaves patients feeling tired, this new treatment could be more effective to help manage the pain that comes with chemotherapy.

The new method developed uses a “dead” Cas9 protein together with the CRISPR-editing tool, which would be injected into the spine and “infect” neuron cells to silence the target the pain gene. To eliminate the pain completely, all the target cells need to be reached. This hasn’t yet been achieved in mice studies, but it can be possible to vary the amount of pain reduction depending on the dose.

Human trials are set to begin this year, and further research will seek to fully understand the effect this technique may have on humans, as well as understand any side-effects or long-term irreversible consequences that may occur.