Ziconotide Combination Intrathecal Therapy for Noncancer Pain Is Limited Secondary to Delayed Adverse Effects: A Case Series With a 24-Month Follow-Up

Short-Term Outcomes of a High-Volume, Low-Concentration Bolus Starting Dose Technique With Ziconotide: A Case Series

Background and Objectives

There have been numerous recommendations for a starting dose of intrathecal ziconotide. The therapy remains underutilized partially due to reports of inefficacy and/or intolerance. This study describes short‐term outcomes of a high‐volume, low‐concentration bolus (HVLC‐B) ziconotide starting dose technique for patients with chronic spine pain. Intrathecal pumps are available with a Patient Therapy Manager (PTM), or patient‐controlled intrathecal bolus device. Commonly published recommendations for a bolus dose has been 10% of the daily dose. This article describes an inversion of the traditional 10% rule‐of‐thumb. This article describes using the basal rate at a lowest programmable dose and utilizing the bolus for the majority of the medication delivery. Such an inversion may be considered a high volume bolus. The lowest commercially available concentration of ziconotide from the manufacturer is 25 mcg/mL. Pope and Deer (Neuromodulation, 18, 414–420 [2015]) described use of a dilution down to 5 mcg/mL. For purposes of this article, such dilutions to one‐fifth of the commercially available solution are considered sufficiently dilute to qualify for the term “low concentration.” Furthermore, the patients in this analysis received dilutions down to one‐fiftieth of the lowest commercially available solution.

Materials and Methods

A case series of patients with chronic spine pain with or without radicular pain received a starting dose intrathecal ziconotide regimen based on a specific HVLC‐B technique. Efficacy, tolerability, and pump settings are reported and analyzed.

Results

In total, 17 patients were identified who started ziconotide with the specified HVLC‐B starting regimen. One of the 17 patients reported side effects that led to discontinuation of the therapy, although the side effect was not typical of ziconotide but rather likely attributable to other medications the patient was taking. Fifteen of the 17 reported improved pain control with intrathecal ziconotide. Sixteen of the 17 patients remained on intrathecal ziconotide throughout the 4.7‐month average follow‐up period. One patient who failed to obtain pain relief chose to remain on the therapy because of reported resolution of lower limb numbness.

Conclusions

The HVLC‐B starting regimen was effective and well tolerated in this short‐term study of patients with chronic spine pain. More studies are needed to better elucidate long‐term outcomes in larger patient populations.

Advances in venom peptide drug discovery: where are we at and where are we heading?

Introduction: Animal venoms are a complex mixture of bioactive molecules that have evolved over millions of years for prey capture and defense from predators. Venom consists of many different types of molecules, with disulfide-rich peptides being a major component in most venoms. The study of these potent and highly selective molecules has led to the development of venom-derived drugs for diseases such as type 2 diabetes mellitus and chronic pain. As technologies have improved, more bioactive peptides have been discovered from venomous animals. Many of these molecules may have applications as tools for understanding normal and disease physiology, therapeutics, cosmetics or in agriculture.Areas covered: This article reviews venom-derived drugs approved by the FDA and venom-derived peptides currently in development. It discusses the challenges faced by venom-derived peptide drugs during drug development and the future for venom-derived peptides.Expert opinion: New techniques such as toxin driven discovery are expanding the pipeline of venom-derived peptides. There are many venom-derived peptides currently in preclinical and clinical trials that would have remained undiscovered using traditional approaches. A renewed focus on venoms, with advances in technology, will broaden the diversity of venom-derived peptide therapeutics and expand our knowledge of their molecular targets.

Effect of First-Line Ziconotide Intrathecal Drug Therapy for Neuropathic Pain on Disability, Emotional Well-Being, and Pain Catastrophizing

BACKGROUND

Previous studies have shown decreased pain scores with ziconotide as a first-line agent for intrathecal drug therapy (IDT). Subset analysis suggests that patients with neuropathic pain have greater improvement. We prospectively examine the role of first-line ziconotide IDT on the tridimensional pain experience in ziconotide IDT-naive patients with neuropathic pain.

METHODS

We included patients who underwent a successful ziconotide trial and were scheduled for standard-of-care IDT pump placement. Scores were collected at baseline and latest follow-up for the following measures: Short-Form 36 (SF-36), Oswestry Disability Index (ODI), Beck Depression Inventory, and Pain Catastrophizing Scale (PCS). Numeric rating scale (NRS) scores were also collected at each follow-up visit to monitor patients' pain levels and to guide ziconotide dose titration. Responders were identified as patients who had a previously established minimum clinically important difference of a ≥1.2-point reduction in NRS current scores.

RESULTS

Eleven of 14 patients completed long-term follow-up. There were 7 responders based on NRS minimum clinically important difference. At a mean (±standard error of the mean) follow-up of 10.91 ± 0.70 months, SF-36 emotional well-being (P = 0.04), SF-36 pain (P = 0.02), and ODI (P = 0.03) significantly improved for the entire cohort and in responders (SF-36 emotional well-being, P = 0.01; SF-36 pain, P = 0.04; ODI, P = 0.02). PCS-Rumination (P = 0.02), PCS-Helplessness (P = 0.02), and PCS-Total (P = 0.003) scores improved significantly for responders only.

CONCLUSIONS

We show that ziconotide IDT improves pain as well as emotional components and function. Our study adds prospective evidence to the literature on IDT for neuropathic pain, specifically its role in improving disability, emotional well-being, and catastrophizing.

Pain modulatory properties of Phoneutria nigriventer crude venom and derived peptides: A double-edged sword

Phoneutria nigriventer venom (PNV) is a complex mixture of toxins exerting multiple pharmacological effects that ultimately result in severe local pain at the site of the bite. It has been proposed that the PNV-induced pain is mediated by both peripheral and central mechanisms. The nociception triggered by PNV is peripherally mediated by the activation of B₂, 5-HT₄, NMDA, AMPA, NK₁, and NK₂ receptors, as well as TTXS-Na⁺, ASIC, and TRPV1 channels. The activation of tachykinin, glutamate and CGRP receptors along with the production of inflammatory mediators are, at least partially, responsible for the central component of pain. Despite its well established pro-nociceptive properties, PNV contains some toxins with antinociceptive activity, which have been studied in the last few years. The toxins ω-CNTX-Pn4a, ω-CNTX-Pn2a, ω-CNTX-Pn3a, κ-CNTX-Pn1a, U₇-CNTX-Pn1a, δ-CNTX-Pn1a, and Γ-CNTX-Pn1a from PNV, as well as the semi-synthetic peptide PnPP-19 have been tested in different experimental models of pain showing consistent antinociceptive properties. This review aims to discuss the pro- and antinociceptive actions of PNV and its toxins, highlighting possible mechanisms involved in these apparently dualistic properties.

Cancer- and Non-cancer Related Chronic Pain: From the Physiopathological Basics to Management

The prevalence of chronic pain is between 33% to 64% and is due to cancer pain, but it has also been observed in non-cancer patients. Chronic pain is associated with lower quality of life and higher psychological distress and depressive/anxiety disorders in patients without a history of disorder. In this study we evaluated in clinical practice the effectiveness of the intrathecal pump in 140 patients who underwent pain therapy at our Center. These patients were consecutively enrolled from January 2010 to July 2018. Follow-up was carried out over these eight years regarding the infusion modalities. Pain relief was obtained in 71 (50,7%) patients out of the 140 that experienced satisfactory pain control globally. Intrathecal therapy is one of the best options for chronic severe refractory pain. The greatest advantage of this therapy is due to the possibility of treating the pain with minimal dosages of the drug, avoiding the appearance of troublesome side effects.

The Polyanalgesic Consensus Conference (PACC): Recommendations for Trialing of Intrathecal Drug Delivery Infusion Therapy

INTRODUCTION

Intrathecal (IT) drug infusion is an appropriate and necessary tool in the algorithm to treat refractory cancer and noncancer pain. The decision-making steps/methodology for selecting appropriate patients for implanted targeted drug delivery systems is controversial and complicated. Therefore, a consensus on best practices for determining appropriate use of IT drug infusion may involve testing/trialing this therapy before implantation.

METHODS

This current Polyanalgesic Consensus Conference (PACC) update was designed to address the deficiencies and emerging innovations since the previous PACC convened in 2012. A literature search identified publications available since the previous PACC publications in 2014, and relevant sources were contributed by the PACC members. After reviewing the literature, the panel determined the evidence levels and degrees of recommendations. The developed consensus was ranked as strong (>80%), moderate (50-79%), or weak (<49%).

RESULTS

The trialing for IT drug delivery systems (IDDS) remains an area of continued controversy. The PACC recommendations for trialing are presented in 34 consensus points and cover trialing for morphine, ziconotide, and medication admixtures; starting doses and titration practices; measurements of success; trial settings and monitoring; management of systemic opioids during trialing; and the role of psychological evaluation. Finally, the PACC describes clinical scenarios in which IT trialing is required or not required.

CONCLUSION

The PACC provides consensus guidance on best practices of trialing for IDDS implants. In addition, the PACC recommends that no trial may be required in certain patient populations.