Neuropathic pain is a disorder of the sensorimotor system and is the result of a lesion or damage to the somatosensory pathways in the peripheral nervous system (PNS) or central nervous system (CNS). Currently, the neuropathic pain market is rife with unmet needs, including ineffective treatments and inaccurate diagnosis, which are both caused by the heterogeneity of the symptoms associated with neuropathic pain.
Treatments on the market are not disease-modifying and are based around treating symptoms. The main classes include antidepressants, anticonvulsants, opioids, and topical analgesics. The majority of these are available in generic form and have an average number needed to treat (NNT) of seven. This means that for every seven patients treated, one will show a reduction in pain.
At the 6th International Congress on Neuropathic Pain (NeuPSIG) conference in Gothenburg, Sweden, Dr Didier Bouhassira delivered a lecture stating that there were three ways to improve treatment options for neuropathic pain. The first would be to discover molecules that target the origins of neuropathic pain. According to Dr Bouhassira, a few of the most promising drugs that have this target include Novartis’ EMA401 (in Phase II) and Toray Industries’ TRK700 (in Phase IIa). However, because these drugs are still in the early stages of development, no trials testing their efficacy have been commissioned.
The second option is to increase the amount of data on treatments with inconclusive results, with sodium channel blockers being the main class requiring extra studies. This class has shown the ability to effectively manage pain in patients but the long-term effects of treatment are still unknown.
Dr Bouhassira’s third option covered recycling old treatments by getting them approved for new conditions. In particular, he mentioned the use of botulinum toxin A (Botox), which is approved for chronic migraine and other indications, and non-invasive repetitive transcranial magnetic stimulation (rTMS). Studies have confirmed the analgesic effect of both Botox and rTMS and there is growing clinical evidence confirming their efficacy for neuropathic pain conditions.
Of Dr Bouhassira's three opportunities for growth, the second and third options would yield the best results in the short-term, as they will have an immediate impact on the neuropathic pain market. However, as more is learned about the indication and researchers continue to improve their understanding of the underlying mechanisms that cause pain, companies can look to develop targeted therapies with new molecules.