A single intravenous injection of KRN5500 (antibiotic spicamycin) produces long-term decreases in multiple sensory hypersensitivities in neuropathic pain

Neuropathic pain is a significant clinical problem. Currently, there are no drugs that produce complete amelioration of this type of pain. We have previously shown that KRN5500, a derivative of the antibiotic spicamycin, produces a prolonged (7-day), and significant reduction in neuropathic pain, but not nociceptive pain. Herein, we provide further evidence for the efficacy of this drug in inhibiting pain after IV injection in a spared nerve injury model of neuropathic pain. A single IV dose of the drug produces an increase in pain thresholds to punctuate mechanical stimuli and to cold stimuli over a period of 7 days, whereas IV injection of the vehicle is without any effect. No change in pain threshold was observed in the contralateral foot. In addition, a significant antiallodynic effect to mechanical stimuli was observed at 1, 2, 4, and 6 wk. The drug may be a potential candidate for cancer-related neuropathic pain as well as a marker for discovery of effective analgesics for neuropathic pain.