Neuromodulation Therapies – Generating Hope and Revenues in Pain, Epilepsy and Depression
The move to acquire Advanced Neuromodulation Systems by St Jude Medical in October 2005 Systems demonstrated a clear commitment of the company to position itself as a principal provider of minimally invasive techniques to physicians charged with treating patients with diverse disorders and diseases. The hefty $1.3bn price tag applied to this acquisition should provide St Jude Medical access to technology platforms within the field of functional electrical stimulation (FES) targeting use in neuromodulation. Neuromodulation is defined as the therapeutic alteration of activity in the central, peripheral or autonomic nervous systems, electrically or pharmacologically, by means of implanted devices. This area is one which is forecast by companies and analysts alike to be a key revenue generator in the foreseeable future.
FES applies low-level electrical currents to specific parts of the body to restore or improve function. The components that make up an FES system generally comprise electrodes, a stimulator (with built-in controllers), and sensors. Electrodes can be applied to the skin, but to improve patient quality of life measures the more advanced systems are now utilising implanted electrodes and stimulators.
Within these systems the function of the implanted electrodes is to selectively stimulate particular muscles. These components may be fine wire coils inserted in muscles (intramuscular electrodes), flat metal foils placed against the spinal cord or muscle surfaces (epimysial electrodes), or soft cuffs of rubber and metal foil surrounding nerves (nerve electrodes).
Electrodes are connected to stimulators by insulated wires or leads. It is the stimulator which sends electrical signals through the leads to the electrodes where the electrical charge is delivered to the nerve, muscle, or other tissue. The surgery for implanting an FES stimulator is similar to that used in implanting a heart pacemaker. Physicians can monitor and manage the functioning of the entire system through telemetry as stimulators are engineered to possess built-in radio receivers which can be programmed to receive command signals from external control units.
The major applications of neuromodulation are,
Through the acquisition of Applied Bionics, Boston Scientific is positioned with another giant of the medical devices business Medtronic, in a market leading role. Overall market growth is running at between 25-28% per year and is anticipated to maintain this level provided the planned approvals of new products and their uptake in areas of unmet medical need continues. Within the neuromodulation market, some sub-segments of the sector are experiencing growth in the high teens or greater. According to Advanced Neuromodulation Systems, (which currently supplies OEM products to Medtronic) the market for spinal cord stimulation products grew by as much as 22% between 2002 and 2003 within the USA alone, representing a market value in 2003 of $357m. Taking into account other applications, in particular deep brain stimulation and sacral nerve stimulation the market for neurostimulation devices was estimated to be $553m in 2003, growing by an impressive 27% over 2002.
Trends in the market have, for some 2-3 years at least, been seen to follow a gradual move away from the targeting of spinal cord injuries - where the addressable patient population is low (based on CDC data, there are only an estimated 13,800 patients with spinal cord injury treated within US hospitals in 2004) - to devices which can address the needs of other groups of patients where not only is the complexity of the injury lower but the likelihood of achieving clinical benefit is greater. Some experts believe that the sophistication of the technology for treating patients with spinal cord injury is not at a level where widespread use can be recommended. The problem lies in the fact that spinal cord injuries not only damage the spinal cord but there is also destruction of function of the peripheral nerves as well. When the peripheral nerves are lost the achievement of motor function is significantly diminished. Patients with spinal cord injuries themselves express the view that their predominant needs are to access therapies which can alleviate problems with bowel and bladder control and treat or prevent the discomfort from decubitus ulcers associated with long term wheelchair use. For this patient population, the Canadian company Victhom Human Bionics, Inc. describes its urinary implant undergoing clinical trials as a pacemaker for the bladder which is designed to provide relief from urge urinary incontinence.
In line with current shift in treatment trends, developments in FES technology are especially being targeted at stroke patients, patients suffering from chronic pain, drug refractory epilepsy and depression, and hearing loss. Products which are already commercially available or hold greatest promise within the current pipeline are highlighted in the following table,
TABLE 1 – Neuromodulation - Companies, products and markets.
With the US FDA granting approval for the Cyberonics VNS Therapy in TRD the market opportunities for devices to treat/alleviate other CNS disorders displays potential upside. The epilepsy market seems to be one upon which a number of companies have pinned their aspirations. The combined number of patients with epilepsy in the USA, Japan and Western Europe is estimated to be in the region of 6m. Of the total number of epileptics around 50% of these patients suffer from partial onset seizures and within this 3m or so patients 20%, or around 600,000 do not respond to drug treatment. This sub-population of patients represent the main target population for neuromodulation therapies for epilepsy. From a sales and marketing viewpoint, it becomes even more interesting that up to half the drug refractory epileptics who may benefit from neuromodulation therapies are diagnosed with co- morbid depression and may have these symptoms alleviated through principal treatment for their epilepsy.
While device-related therapy cannot take the place of drug therapy in treating epilepsy and major depressive disorders, there are clearly niche areas which are poised to offer commercial hope to the companies which have set their store in the market sectors discussed here.
Author: Dr. Akmal Bhatti, Director