About Peripheral Neuropathy
- Neuropathic pain is a chronic form of pain related to damage to nerves and their signalling processes.
- This form of pain is generally poorly responsive to current analgesics, does not diminish over time and can increase in both intensity and area.
Incidence Rate and Market Size
This type of pain occurs in the following diseases:
- Cancer – as a side effect of chemotherapy
- HIV infection
- Spinal cord injuries
- Other nerve injuries (e.g. amputation)
Espicom Business Intelligence estimated the 2003 global market for drugs approved for neuropathic pain to be:
- U.S. $2.5 billion
And this is despite limited response rates and efficacy, tolerance and dependency issues, and other side effects of current therapies.
According to Pain Therapeutics-Drugs, Markets and Companies, October 2005, the worldwide market for pain is estimated to be:
- U.S. $50 billion for 2005
- And it is expected to increase to U.S. $75 billion by 2010.
It has been estimated that more than 17 million people in the United States and Europe have diabetes-related polyneuropathy alone.
Current approved treatments for peripheral neuropathy are only targeting the pain threshold level but do not initiate regeneration of the skin nervous fibres.
Science of Peripheral Neuropathy & NRPs Benefits
Peripheral neuropathy (PN) is a peripheral nervous system condition that is associated to diseases like HIV where anti-viral compound induced toxicity leads to PN.
The biggest group of sufferers derives from diabetes patients as well as from chemotherapy-treated cancer patients.
One of the micronutrients responsible to prevent PN in the body is the pro-drug pyridoxine that is converted by the liver to vitamin B6 that is used as co-enzyme for various biochemical reactions in the body.
The daily recommended intake for humans is 1-2mg /kg bodyweight. Paradoxically, long-term daily dosages of 100-150mg/kg lead to the development of reversible neuropathy as being felt in the extremities.
Big diameter nervous endings in the skin are affected and diminished over time causing moderate to severe neuropathic pain.
- An animal model that is mimicking such condition is the megadosage pyridoxine rat model.
- Animals injected with megadosages of pyridoxine show severe motor impairments at the height of pyridoxine blood levels (8 days after start of intoxication).
- Severely intoxicated animals cannot perform easy tasks like beam walking because of severe balancing problems.
So far, known efficacy is shown by the application of the nervous growth factor neurotrophin-3 that is effective when given daily at a 15mg/kg peripheral dosage.
For Peripheral Neuropathy:
- NRP dosages within a range of factor 100 apart are efficacious.
- NRP dosages of ng/kg to μg/kg range are effective in the megadose pyridoxine (pdx) rat model (800mg pdx/kg/day for 8 days)
- NRP prevents death in the μg/kg range within the ultra-high megadose pyridoxine rat model (1200mg pdx/kg/day for 5 days)