Non-opioid Analgesic Decreases Neuropathic Pain in Trial

December 14, 2010

The drug candidate KRN5500 produced statistically significant results in neuropathy clinical trial.

An experimental non-opioid analgesic drug for neuropathic pain received positive results during a phase 2a clinical study in patients with cancer.

The drug candidate is known as KRN5500 and is being developed by DARA BioSciences, Inc.

More than 80% of the patients in the clinical study had allodynia. The condition manifests as an abnormal pain response to typically non-painful stimuli, such as light touch or temperature changes. Even the light pressure of clothing against the skin or a cold breeze can cause severe pain in patients with this neuropathic pain.

Neuropathic pain has multiple etiologies, including direct nerve trauma, infectious disease, metabolic disease, and drug-induced neuropathies. Chronic neuropathic pain is characterized by an abnormal hypersensitivity to innocuous as well as noxious stimuli, and often persists after initial tissue damage and inflammation appear to have healed.

Painful neuropathy is more commonly caused by non-traumatic conditions than by direct nerve trauma. Prevalence of neuropathic pain in patients that have been treated for cancer is reported to be in the range of 40%. Neuropathic pain in this population has multiple etiologies, including side effects from cancer treatments.

Chemotherapy-induced Peripheral Neuropathy is the most common cause of neuropathic pain in patients with cancer, and in particular, for those patients receiving multi-agent chemotherapy. Clinically, neuropathic pain is difficult to manage and can have a profound impact on quality of life. Although this type of pain sometimes responds well to standard analgesic treatments, currently approved therapeutic agents can have intolerable side effects that prevent reaching the most effective dose.

KRN5500 is a novel non-opioid analgesic agent. The agent it a semi-synthetic derivative of spicamycin:(6-[4-Deoxy-4-[(2E,4E)-tetradecadienoylglycyl]amino-L-glycero-beta-L-manno-heptopyranosyl]amino-9H-purine).

For the study, clinicians conducted two-weekly examinations to determine if KRN5500 was effective in reducing allodynia. For both tests, patients rated their pain on a numeric rating scale of 1 to 10 (1 = no pain/10 = worst pain imaginable), both before the targeted area was stimulated and right afterward.

The KRN5500 treatment group demonstrated a larger median decrease in pain associated with both touch and cold (both touch and cold 33%) compared to placebo (0 and 8%, respectively).

Source: DARA BioSciences, Inc. (GlobeNewswire)

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