Complex regional pain syndrome is a debilitating chronic pain condition causing intense pain particularly in the arms, hands, legs, or feet. This syndrome is characterized by pain, swelling, vasomotor instability, limited range of motion, skin color changes and patchy bone demineralization. CRPS is often regarded to be caused as a result of malfunction of failure of peripheral and central nervous system and therefore also sometimes referred as reflex sympathetic dystrophy syndrome. Complex regional pain syndrome (CRPS) is classified into two similar forms termed as CRPS type 1 (Reflex Sympathetic Dystrophy or RSD) and CRPS type 2 (Causalgia). The former type mentioned has been used for individuals with confirmed nerve injuries while the latter type is used to refer patients without any confirmed nerve injury.
It is noteworthy to mention that the disease prevalence is very low and therefore classified as an orphan disease. Furthermore, since the sympathetic nervous systems affect several systems simultaneously, development of drugs for treating complex regional pain syndrome had been painstaking task for the researchers. However, the expanding knowledge base in neurology and medicine provides unique and underserved market opportunity for drugs and products in complex regional pain syndrome disease.
Presently there is no cure for the disease but drug therapies help in alleviating the pain associated with the disease as wells reduce the progression of the disease. Multimodal therapy is prescribed for the treatment of chronic regional pain syndrome which includes psychotherapy, rehabilitation therapy and drug therapy. Drug therapy for CRPS includes non-steroidal anti-inflammatory drugs (aspirin, ibuprofen, and naproxen) used to treat moderate pain while corticosteroids such as prednisolone and methylprednisolone are prescribed to treat inflammation and edema in the early stages of CRPS. Drugs effective in neuropathic pain are also administered to patients with CRPS.
These drugs include gabapentin, amitryptiline, nortryptiline and duloxetine. Other therapeutic drugs useful in complex regional pain syndrome (CRPS) include oxytocins, morphine, hydrocodone, vicodin, N-methyl-D-aspartate (NMDA) receptor antagonists (dextromethorphan) and botulinum toxin injections. Several emerging therapies are being evaluated for the treating CRPS which include intravenous immunoglobulin (IVIG), ketamine and hyperbaric oxygen therapy.
Administering of calcitonin subcutaneously or by intra-nasal spray over 3-4 weeks is being studied for benefits against CRPS disease. Similarly, the experimental therapies such as motor cortex and deep brain stimulation are also being studied which may provide breakthrough improvement in the CRPS treatment therapy. Recently, Neridronate (amino bisphosphonate) has been studied for its effects on CRPS and has demonstrated significant reduction in symptoms. This molecule has been awarded with orphan designation status by the FDA but has not yet approved. We can expect that this drug molecule may enter the market upon successful completion of clinical trials.
The National Institutes of Health (NIH) supports research on complex regional pain syndrome through funding for the National Institute of Neurogical Disorders and Stroke (NINDS). Some of the companies in the global complex regional pain syndrome (CRPS) therapeutics market which are engaged in the research and development of pain management products for treating CRPS disease include Abiogen Pharma S.p.A., AlgoRx Pharmaceuticals, Inc., Amgen Inc.,Bayer AG, Celgene Corporation, Cell Targeting Technologies, CeNeS Pharmaceuticals plc, Danish Pain Research Center, Eli Lilly & Co., Endo Pharmaceuticals, Forest Laboratories Inc., GlaxoSmithKline plc, Grünenthal GmbH Johnson & Johnson, Justus Liebig University Giessen, King Pharmaceuticals Inc., Lee\'s Pharmaceutical Holdings Limited, National Institute of Nursing Research (NINR), NeurogesX, Inc., Pfizer, Inc., Stichting Achmea Slachtofferhulp Samenleving, and University of California.
