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

Heptose-containing bacterial natural products: structures, bioactivities, and biosyntheses

Covering: up to 2020Glycosylated natural products hold great potential as drugs for the treatment of human and animal diseases. Heptoses, known as seven-carbon-chain-containing sugars, are a group of saccharides that are rarely observed in natural products. Based on the structures of the heptoses, the heptose-containing natural products can be divided into four groups, characterized by heptofuranose, highly-reduced heptopyranose, d-heptopyranose, and l-heptopyranose. Many of them possess remarkable biological properties, including antibacterial, antifungal, antitumor, and pain relief activities, thereby attracting great interest in biosynthesis and chemical synthesis studies to understand their construction mechanisms and structure-activity relationships. In this review, we summarize the structural properties, biological activities, and recent progress in the biosynthesis of bacterial natural products featuring seven-carbon-chain-containing sugars. The biosynthetic origins of the heptose moieties are emphasized.

Lost but making progress--Where will new analgesic drugs come from?

There is a critical need for effective new pharmacotherapies for pain. The paucity of new drugs successfully reaching the clinic calls for a reassessment of current analgesic drug discovery approaches. Many points early in the discovery process present significant hurdles, making it critical to exploit advances in pain neurobiology to increase the probability of success. In this review, we highlight approaches that are being pursued vigorously by the pain community for drug discovery, including innovative preclinical pain models, insights from genetics, mechanistic phenotyping of pain patients, development of biomarkers, and emerging insights into chronic pain as a disorder of both the periphery and the brain. Collaborative efforts between pharmaceutical, academic, and public entities to advance research in these areas promise to de-risk potential targets, stimulate investment, and speed evaluation and development of better pain therapies.

A spicamycin derivative (KRN5500) provides neuropathic pain relief in patients with advanced cancer: a placebo-controlled, proof-of-concept trial

CONTEXT

Neuropathic pain in patients with cancer can be difficult to treat effectively.

OBJECTIVES

The purpose of the study was to determine safety and efficacy of KRN5500, a novel, spicamycin-derived, nonopioid analgesic agent, in patients with advanced cancer and neuropathic pain of any etiology.

METHODS

The study was a Phase 2a, multicenter, double-blind, placebo-controlled, dose escalation clinical trial. Patients with refractory neuropathic pain and advanced cancer were randomly assigned 2:1 to receive a maximum of eight single escalating doses of KRN5500 or placebo, ranging from 0.6 to 2.2 mg/m(2). The primary objective was safety and tolerability. The secondary objective was efficacy, measured by change in average pain intensity on a 0-10 numeric rating scale administered one week after the patient's final dose.

RESULTS

Nineteen patients received treatment (KRN5500 n=12; placebo n=7). The most frequently reported adverse events were gastrointestinal symptoms, which were more frequent and severe with KRN5500 than placebo; two (17%) KRN5500 patients discontinued the study because of nausea and vomiting. At study endpoint, KRN5500 exhibited a significant median decrease in pain intensity from baseline of 24% compared with 0% for placebo (P=0.03). The median for largest weekly reduction in target pain intensity was 29.5% for KRN5500 and 0% for placebo patients (P=0.02).

CONCLUSION

This proof-of-concept study for KRN5500 in patients with advanced cancer and any type of neuropathic pain found gastrointestinal adverse events to be the predominant safety concern. The results also provided the first indication of clinical and statistical efficacy in reducing pain intensity.

CNS animal fMRI in pain and analgesia

Animal imaging of brain systems offers exciting opportunities to better understand the neurobiology of pain and analgesia. Overall functional studies have lagged behind human studies as a result of technical issues including the use of anesthesia. Now that many of these issues have been overcome including the possibility of imaging awake animals, there are new opportunities to study whole brain systems neurobiology of acute and chronic pain as well as analgesic effects on brain systems de novo (using pharmacological MRI) or testing in animal models of pain. Understanding brain networks in these areas may provide new insights into translational science, and use neural networks as a "language of translation" between preclinical to clinical models. In this review we evaluate the role of functional and anatomical imaging in furthering our understanding in pain and analgesia.

Natural products to drugs: natural product-derived compounds in clinical trials

Natural product and natural product-derived compounds that are being evaluated in clinical trials or are in registration (as at 31st December 2007) have been reviewed, as well as natural product-derived compounds for which clinical trials have been halted or discontinued since 2005. Also discussed are natural product-derived drugs launched since 2005, new natural product templates and late-stage development candidates.

Antineuropathic Effects of the Antibiotic Derivative Spicamycin KRN5500

Excellence in neuropathic pain management continues to challenge the ability of health care providers. Current medications are helpful but often create significant side effects or simply fail to provide adequate analgesia. We report here on a serendipitous finding of the successful attenuation of neuropathic pain in a patient with long-standing monoclonal gammopathy, Raynaud's disease, and neuropathic pain who received the trial chemotherapeutic agent KRN5500. This finding led to animal studies that have provided support for the possible use of KRN5500 in the treatment of neuropathic pain in humans as well as some insight into the possible mechanism(s) of action of this drug.