Wednesday, June 13, 2007

NeurogesX Part I

NeurogesX part I



IPO date: 05/02/2007

Market Cap : $101million

Shares Outstanding : 12.49mln

Float: 10.23mln

To be fairly certain, Neurogesx (NGSX) probably isn’t going to make the next blockbuster therapeutic. Neither will they likely generate the kind of buzz with their products as say, Provenge. On the other hand we’ve all recently seen the kind of damage that too much hype can cause and I therefore feel that NGSX deserves some attention if only because both the science and business model are relatively straightforward. Neurogesx states that they are a biopharmaceutical company focused on developing and commercializing novel pain management therapies. More specifically, their main niche involves the area of neuropathic pain. Let’s take a closer look at the details and prevalence of this affliction, focusing specifically on the treatments NGSX has in the pipeline.

Neuropathic pain is caused by diseases or trauma that produce lesions in the central (e.g., stroke, spinal cord injury, multiple sclerosis [MS]) or peripheral (e.g., surgery, diabetic neuropathy, herpes zoster) nervous system Unlike physiologic pain, which serves to warn and protect individuals from possible or actual injury, neuropathic pain serves no useful purpose. Peripheral neuropathy (neural damage in the extremities) is the most common which mainly affects the feet and legs. The most recent studies suggest that more than two million adults in the U.S. suffer from In this disorder, factors such as age, illness, stress or medications can reactivate an otherwise dormant chickenpox virus (varicella-zoster), causing shingles (herpes zoster). The virus travels along nerve fibers, causing pain. When the virus reaches the skin, it produces a rash and blisters. These cases of shingles usually heal within a month, however in roughly 20% of cases the patient continues to feel pain long after the rash and blisters heal. This pain is known as postherpetic neuralgia.

Neuropathic pain is among the most common of the pain syndromes afflicting HIV-infected individuals. It is thought that nearly one third of people with HIV/AIDS experience some peripheral nerve damage caused either by the virus itself, by certain drugs used in the treatment of HIV/AIDS, or by secondary complications from the disease. These symptoms are collectively referred to as Painful HIV-Associated Neuropathy (HIV-DSP).

Almost 16 million Americans had diabetes in 2005. Of these 60-70% of diabetics have mild to severe forms of nervous system damage. While the first sign of diabetic neuropathy is usually numbness, Painful diabetic neuropathy (PDN) often manifests in the form of a burning or other painful sensation most commonly in the feet and lower extremeties.

It should be noted that over the counter analgesics such as acetaminophen and non-steroidal anti inflammatory drugs have not been shown to be highly effective in the treatment of neuropathic pain. The treatments that are available for the above conditions are largely similar and the common underlying mechanism of action is reduction of neuronal hyperexcitability. Topically, Capsaicin creams derived from natural chili pepper plants have long been known to provide temporary relief. Similarly, Lidocaine (topical local anesthetic) patches are also effective for pain management. Both of these treatments last between 4 and 12 hours however, and require multiple applications per day. Both tricyclic antidepressants and serotonin reuptake inhibitors are used to treat neuropathic pain, it should be noted that while generally SSRIs are safer for use in the general population, they have less consistent effects than the TCA class. Finally, anticonvulsants such as phenytoin (Dilantin), carbamazepine (Tegretol) and gabapentin (Neurontin) are frequently prescribed for neuropathic pain and have been shown to be effective in double-blind placebo controlled studies. Some caveats to the anticonvulsant class of medications include a relatively notorious list of adverse side-effects and unpredictable response to the treatment.

In summary, after some in-depth research I would conclude that the therapeutic focus on neuropathic pain does in fact constitute an area of unmet medical needs. The major diseases which cause the neuropathies above; herpes zoster, HIV and above all diabetes are ubiquitous illnesses which I wouldn’t predict to be disappearing or even lessening in the foreseeable future. Furthermore, treatment for these neuropathies (with the exception of topical agents), largely revolve around the secondary analgesic effects of neurological pharmacologics which in some cases may be beneficial if the patient is already depressed. Nevertheless, it seems there is still plenty of room in the market for a more subtle topical treatment option such as Neurogesx has developed.

Next time, Neurogesx flagship product, the trans-capsaicin patch. I’ll also cover their clinical trial status and scientific patents protecting their quasi-novel approach to management of neuropathic pain disorders.

Disclosure: I have no position in NGSX

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