New Drug Delivery Method Could Revolutionize Pain Treatment

More than 100 million Americans experience chronic pain and the market for drugs that treat nerve pain is more than $60 billion globally. Although the prevalence of pain is expected to continue growing in the future, the pipeline remains largely ineffective.

Many physicians still prescribe opioids for these patients, despite a lack of evidence proving efficacy and the serious risks of misuse and abuse that are associated with the drugs. While some physicians take a non-drug approach to treating pain, their patients may not experience the immediate results they would like.

A new drug delivery approach blocks pain within the nerve cell and could result in a long-term treatment for chronic pain, according to a study published by Science Translational Medicine.

The authors discovered that the NK1 receptor protein works within the nerve cell. This protein was previously linked to chronic and acute pain and is the receptor of the neuropeptide substance P, a mediator of pain transmission.

Since the receptor has been linked to pain and nervous system conditions, numerous other drug delivery approaches have focused on harnessing the protein, but the efforts have been unsuccessful.

The authors hypothesize that the lack of success during previous attempts could be related to targeting the protein on the surface of the nerve cell rather than inside the cell, according to the new study.

The investigators discovered that the NK1 receptor controls pain only once it is inside the cell, rendering efforts to target the protein outside of the cell ineffective.

In animal models of pain, inhibiting the NK1 receptor inside of the nerve cell was observed to effectively block pain, according to the study.

The approach of targeting receptors inside of the nerve cell present a novel therapeutic strategy for preventing pain and has the potential to advance the landscape of drug delivery.

Through collaboration with cell biologists, pharmacologists, physiologists, and drug delivery experts, the authors were able to create drugs that target NK1 receptors within the nerve cell. The drugs were engineered to have a lipid attachment that targets the receptor when it is located inside of the cell, according to the study.

The investigators discovered that the drug was able to block pain for extended periods of time in multiple animal models of pain.

Although additional studies are needed before confirming that this approach is effective in humans, a novel approach to pain treatment has the potential to attack the opioid epidemic and provide patients with an adequate treatment.

"This is a proof-of-concept study that shows that we can re-engineer current pain drugs and make them more effective,” said researcher Dr Meritxell Canals. “The challenge is now to translate the technology into human clinical trials. This is a complex and challenging path -- but the ultimate benefits to patients with nerve pain are potentially highly significant."