In this issue of Scandinavian Journal of Pain, Mayorga et al. report positive efficacy data of mavatrep, a transient receptor potential vanilloid subtype 1 (TRPV1) antagonist, in OA pain [1]. A positive signal of efficacy has been reported previously in dental extraction pain [2], but this is the first report of a signal of efficacy with a TRPV1 antagonist in a chronic pain condition.
1 What is transient receptor potential vanilloid subtype 1 (TRPV1)?
TRPV1 is a cation channel located on peripheral nociceptive fibres, but also in areas involved in nociception in the central nervous system [3,4]. The receptor is activated by heat, capsaicin and low pH and the activity is regulated by inflammatory regulators [5]. The TRPV1 receptor acts as a polymodal signal detector and may be influenced by several simultaneous stimuli, e.g. the thermal activation curve for the TRPV1 receptor is shifted to the left by capsaicin [6].
2 Difficulties in developing this class of analgesic drugs – the TRPVl-anatagonists
Based on these properties, indicating a pivotal role for TRPV1 in nociception, many TRPV1 antagonists have been developed displaying efficacy in animal models of a variety of pain conditions, like inflammatory, osteoarthritis, and neuropathic pain models [5,7]. The clinical development of this class of compounds has so far been challenging, mainly due side effects. The first is an increase in core body temperature, usually mild but sometimes exceeding 39 °C. The other problem has been that subjects experience increased detection thresholds for warmth and pain thresholds for heat pain [7]. The implication of the deficit to sense noxious heat is the possibility for burns in real life situations e.g. when drinking hot beverage or taking a hot shower.
3 Previous aborted attempts to develop TRPVl-anatagonist-analgesic drugs
In a previous study in OA with a TRPV1 antagonist (AZD1386), no signal of efficacy was seen and the study was halted due to elevated liver enzymes in a subset of patients [8]. In that 4-week phase IIA/B study (combined proof of concept and dose-finding), patients were included that had failed treatment with paracetamol and/or NSAIDs. The reason behind the patient selection was a combination of scientific and commercial aspects, potentially positioning the drug as an alternative for patients failing first line treatments of OA pain. The primary variable was the WOMAC pain subscale with 48 h recall, change from baseline to mean of week 2 and 4 [8]. This is an unreliable analgesic effect measurement: Patients are not good at remembering “average” pain.
4 A smart design for developing the TRPVl-antagoist mavatrep
The study by Mayorga et al. [1] is interesting in several aspects, applying measures to reduce variability and thereby increase the possibility to show a potential signal of efficacy. In this case by means of selecting the study population, choosing the primary variable and a 3-way cross-over design.
In the study only patients that had responded to previous treatment with non-opioid analgesics are included. They were also tested for their ability to report pain in a consistent manner using the focused analgesia selection test (FAST), recently published [9]. Subjects defined as “poor pain reporters” (17/63 screened), were excluded.
The primary variable in OA-studies has historically mainly been based on recall of mean pain during a period 12–24 h or a combination of items as in the WOMAC pain subscale (walking, using stairs, in bed, sitting/lying and standing). In the present study the primary variable is based on evoked pain, the sum of pain intensity difference (4-h post-dose) following stair-climbing, using an 11-point (0–10) numeric rating score. Only patients experiencing an increase of pain (PGIC) and with a minimum pain post-stairclimbing ≤4 were included in the study.
Cross-over designs are often used in order to reduce variability [10]. In this case the patients were randomly assigned to 1 of 6 treatment sequences, representing all possible combinations of placebo, naproxen (500 mg bid) and mavatrep (50 mg single dose, due to long half-life). Each sequence was 1 week of treatment followed by one week of wash-out.
To prevent burns, the patients were well informed and were also quizzed to ensure the understanding of the burn prevention measures. Also, patients that were routinely exposed to situations in which they had a risk of sustaining burns were excluded.
5 Mavatrep is superior to the traditional NSAID naproxen (and placebo)
The results shows that mavatrep significantly reduced pain after stair climbing 4h post-dose (p = 0.005), while no significant effect was seen on naproxen (p = 0.229). The analgesic efficacy was further supported by secondary variables, WOMAC (24 h recall) pain, function and stiffness at 2 and 7 days. For this variable also naproxen was effective. Notably, no effect could be seen on pain at rest (4-h SPID) or mean average current pain (NRS-scores, 7 day mean) with mavatrep or naproxen.
6 Mechanism-based, expected adverse effects of mavatrep
Although measures had been taken to reduce burns, 3/33 patients reported mild burns. All patients receiving mavatrep reported adverse events. 79% feeling cold, 61% thermohypoes- thesia, 58% dysgeusia (=distortion of the sense of taste), 36% paresthesia, and 15% feeling warm, all related to the mechanism of action. One patient had a body temperature of 38 °C 2-h post- dosing, that returned to normal within 4 h.
7 Finally a hope for this class of analgesic drugs
The study by Mayorga et al. [1] shows that TRPV1 antagonists may have a role in reducing pain in OA. The study was designed for signal detection and must be seen as such. The study population was highly selected and the high number of target related adverse events might have had impact, as it could un-mask the drug. Even if further studies will prove the efficacy in OA patients, there will still be a substantial challenge to manage the potential for burns in real life situations, when larger numbers of patients will be treated.
There might be a way forward for TRPV1 antagonists if it would be possible to modulate the effects on thermoregulation and the risk for burns associated with the impaired detection of warmth and heat pain. Not only would it reduce those specific side effects, but possibly allow higher exposure and increase the possibility for analgesic efficacy in the clinical setting. In later years a new set of substances, second generation compounds, have been developed that are designed to be modality specific molecules, acting on the capsaicin site, but with or without effects on acid induced TRPV1 activation. The compounds that block acid induced TRPV1 activation elicit profound hyperthermia in rats (for review see [7]). In a recently published study, NEO6860 a TRPV1 antagonist inhibiting capsaicin activation but with little or no effect against heat or acid activation, was studied in healthy subjects. The authors report minor effects on heat pain thresholds and an effect on capsaicin evoked pain and hyperalgesia [11]. Further studies are needed to explore the potential analgesic efficacy in chronic pain patients as well as the safety profile of these types of compounds.
DOI of refers to article: http://dx.doi.org/10.1016/j.sjpain.2017.07.021.
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Conflict of interest: None declared.
References
[1] Mayorga A, Flores CM, Trudeau JJ, Moyer JA, Shalayda K, Frustaci ME, Katz N, Manitpisitkul P, Treister R, Ratcliffe S, Romano G. A randomized study to evaluate the analgesic efficacy of a single dose of the TRPV1 antagonist mavatrep in patients with osteoarthritis. Scan J Pain 2017;17:134–43.Suche in Google Scholar
[2] Quiding H, Jonzon B, Svensson O, Webster L, Reimfelt A, Karin A, Karlsten R, Segerdahl M. TRPV1 antagonistic analgesic effect: a randomized study of AZD1386 in pain after third molar extraction. Pain 2013;154:808–12.Suche in Google Scholar
[3] Caterina MJ, Schumacher MA, Tominaga M, Rosen TA, Levine JD, Julius D. The capsaicin receptor: a heat-activated ion-channel in the pain pathway. Nature 1997;389:816–24.Suche in Google Scholar
[4] Steenland HW, Ko SW, WU L-J, Zhuo M. Hot receptors in the brain. Mol Pain 2006;2:34, http://dx.doi.org/10.1186/1744-8069-2-34.Suche in Google Scholar
[5] Gunthorpe MJ, Chizh BA. Clinical development of TRPV1 antagonists: targeting a pivotal point in the pain pathway. Drug Discov Today 2009;14:56–67.Suche in Google Scholar
[6] Voets T, Droogmans G, Wissenbach U, Janssens A, Flockerzi V, Nilius B. The principle of temperature-dependent gating in cold- and heat-sensitive TRP channels. Nature 2006;430:748–54.Suche in Google Scholar
[7] Kort ME, Kym PR. TRPV1 antagonists: clinical setbacks and prospects for future development. Prog Med Chem 2012;51:57–70.Suche in Google Scholar
[8] Miller F, Bjornsson M, Svensson O, Karlsten R. Experiences with an adaptive design for a dose-finding study in patient with osteoarthritis. Contemp Clin Trials 2014;37:189–99.Suche in Google Scholar
[9] Treister R, Eaton TA, Trudeau JJ, Elder H, Katz NP. Development and preliminary validation of the focused analgesia selection test to identify accurate pain reporters. J Pain Res 2017;10:319–26.Suche in Google Scholar
[10] Gewandter JS, McDermott MP, McKeown A, Hoang K, Iwan K, Kralovic S, Rothstein D, Gilron I, Katz NP, Raja SN, Senn S, Smith SM, Turk DC, Dworkin RH. Reporting of cross-over clinical trials of analgesic treatments for chronic pain: analgesic, anesthetic, and addiction clinical trial translations, innovations, opportunities and networks systematic review and recommendations. Pain 2016;157:2544–51.Suche in Google Scholar
[11] Brown W, Leff RL, Griffin A, Hossack S, Aubray R, Walker P, Chiche DA. Safety, pharmacokinetics, and pharmacodynamics study in healthy subjects of oral NEO6860, a modality selective transient receptor potential vanilloid subtype 1 antagonist. J Pain 2017;18:726–38.Suche in Google Scholar
© 2017 Scandinavian Association for the Study of Pain
Artikel in diesem Heft
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Artikel in diesem Heft
- Observational study
- Perceived sleep deficit is a strong predictor of RLS in multisite pain – A population based study in middle aged females
- Clinical pain research
- Prospective, double blind, randomized, controlled trial comparing vapocoolant spray versus placebo spray in adults undergoing intravenous cannulation
- Clinical pain research
- The Functional Barometer — An analysis of a self-assessment questionnaire with ICF-coding regarding functional/activity limitations and quality of life due to pain — Differences in age gender and origin of pain
- Clinical pain research
- Clinical outcome following anterior arthrodesis in patients with presumed sacroiliac joint pain
- Observational study
- Chronic disruptive pain in emerging adults with and without chronic health conditions and the moderating role of psychiatric disorders: Evidence from a population-based cross-sectional survey in Canada
- Educational case report
- Management of patients with pain and severe side effects while on intrathecal morphine therapy: A case study
- Clinical pain research
- Behavioral inhibition, maladaptive pain cognitions, and function in patients with chronic pain
- Observational study
- Comparison of patients diagnosed with “complex pain” and “somatoform pain”
- Original experimental
- Patient perspectives on wait times and the impact on their life: A waiting room survey in a chronic pain clinic
- Topical review
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- Clinical pain research
- A multi-facet pain survey of psychosocial complaints among patients with long-standing non-malignant pain
- Clinical pain research
- Pain patients’ experiences of validation and invalidation from physicians before and after multimodal pain rehabilitation: Associations with pain, negative affectivity, and treatment outcome
- Observational study
- Long-term treatment in chronic noncancer pain: Results of an observational study comparing opioid and nonopioid therapy
- Clinical pain research
- COMBAT study – Computer based assessment and treatment – A clinical trial evaluating impact of a computerized clinical decision support tool on pain in cancer patients
- Original experimental
- Quantitative sensory tests fairly reflect immediate effects of oxycodone in chronic low-back pain
- Editorial comment
- Spatial summation of pain and its meaning to patients
- Original experimental
- Effects of validating communication on recall during a pain-task in healthy participants
- Original experimental
- Comparison of spatial summation properties at different body sites
- Editorial comment
- Behavioural inhibition in the context of pain: Measurement and conceptual issues
- Clinical pain research
- A randomized study to evaluate the analgesic efficacy of a single dose of the TRPV1 antagonist mavatrep in patients with osteoarthritis
- Editorial comment
- Quantitative sensory tests (QST) are promising tests for clinical relevance of anti–nociceptive effects of new analgesic treatments
- Educational case report
- Pregabalin as adjunct in a multimodal pain therapy after traumatic foot amputation — A case report of a 4-year-old girl
- Editorial comment
- Severe side effects from intrathecal morphine for chronic pain after repeated failed spinal operations
- Editorial comment
- Opioids in chronic pain – Primum non nocere
- Editorial comment
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- Observational study
- The relationship between chronic musculoskeletal pain, anxiety and mindfulness: Adjustments to the Fear-Avoidance Model of Chronic Pain
- Clinical pain research
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- Editorial comment
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- Editorial comment
- Broadening the fear-avoidance model of chronic pain?
- Observational study
- Identifying characteristics of the most severely impaired chronic pain patients treated at a specialized inpatient pain clinic
- Editorial comment
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- Editorial comment
- A case-history illustrates importance of knowledge of drug-interactions when pain-patients are prescribed non-pain drugs for co-morbidities
- Editorial comment
- Why can multimodal, multidisciplinary pain clinics not help all chronic pain patients?
- Topical review
- Individual variability in clinical effect and tolerability of opioid analgesics – Importance of drug interactions and pharmacogenetics
- Editorial comment
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- Clinical pain research
- PhKv a toxin isolated from the spider venom induces antinociception by inhibition of cholinesterase activating cholinergic system
- Clinical pain research
- Lateral Cutaneous Nerve Entrapment Syndrome (LACNES): A previously unrecognized cause of intractable flank pain
- Editorial comment
- Towards a structured examination of contextual flexibility in persistent pain
- Clinical pain research
- Context sensitive regulation of pain and emotion: Development and initial validation of a scale for context insensitive avoidance
- Editorial comment
- Is the search for a “pain personality” of added value to the Fear-Avoidance-Model (FAM) of chronic pain?
- Editorial comment
- Importance for patients of feeling accepted and understood by physicians before and after multimodal pain rehabilitation
- Editorial comment
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- Observational study
- Assessment and treatment at a pain clinic: A one-year follow-up of patients with chronic pain
- Clinical pain research
- Randomized, double-blind, placebo-controlled, dose-escalation study: Investigation of the safety, pharmacokinetics, and antihyperalgesic activity of L-4-chlorokynurenine in healthy volunteers
- Clinical pain research
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- Observational study
- The use of rapid onset fentanyl in children and young people for breakthrough cancer pain
- Original experimental
- Acid-induced experimental muscle pain and hyperalgesia with single and repeated infusion in human forearm
- Original experimental
- Swearing as a response to pain: A cross-cultural comparison of British and Japanese participants
- Clinical pain research
- The cognitive impact of chronic low back pain: Positive effect of multidisciplinary pain therapy
- Clinical pain research
- Central sensitization associated with low fetal hemoglobin levels in adults with sickle cell anemia
- Topical review
- Targeting cytokines for treatment of neuropathic pain
- Original experimental
- What constitutes back pain flare? A cross sectional survey of individuals with low back pain
- Original experimental
- Coping with pain in intimate situations: Applying the avoidance-endurance model to women with vulvovaginal pain
- Clinical pain research
- Chronic low back pain and the transdiagnostic process: How do cognitive and emotional dysregulations contribute to the intensity of risk factors and pain?
- Original experimental
- The impact of the Standard American Diet in rats: Effects on behavior, physiology and recovery from inflammatory injury
- Educational case report
- Erector spinae plane (ESP) block in the management of post thoracotomy pain syndrome: A case series
- Original experimental
- Hyperbaric oxygenation alleviates chronic constriction injury (CCI)-induced neuropathic pain and inhibits GABAergic neuron apoptosis in the spinal cord
- Observational study
- Predictors of chronic neuropathic pain after scoliosis surgery in children
- Clinical pain research
- Hospitalization due to acute exacerbation of chronic pain: An intervention study in a university hospital
- Clinical pain research
- A novel miniature, wireless neurostimulator in the management of chronic craniofacial pain: Preliminary results from a prospective pilot study
- Clinical pain research
- Implicit evaluations and physiological threat responses in people with persistent low back pain and fear of bending
- Original experimental
- Unpredictable pain timings lead to greater pain when people are highly intolerant of uncertainty
- Original experimental
- Initial validation of the exercise chronic pain acceptance questionnaire
- Clinical pain research
- Exploring patient experiences of a pain management centre: A qualitative study
- Clinical pain research
- Narratives of life with long-term low back pain: A follow up interview study
- Observational study
- Pain catastrophizing, perceived injustice, and pain intensity impair life satisfaction through differential patterns of physical and psychological disruption
- Clinical pain research
- Chronic pain disrupts ability to work by interfering with social function: A cross-sectional study
- Original experimental
- Evaluation of external vibratory stimulation as a treatment for chronic scrotal pain in adult men: A single center open label pilot study
- Observational study
- Impact of analgesics on executive function and memory in the Alzheimer’s Disease Neuroimaging Initiative Database
- Clinical pain research
- Visualization of painful inflammation in patients with pain after traumatic ankle sprain using [11C]-D-deprenyl PET/CT
- Original experimental
- Developing a model for measuring fear of pain in Norwegian samples: The Fear of Pain Questionnaire Norway
- Topical review
- Psychoneuroimmunological approach to gastrointestinal related pain
- Letter to the Editor
- Do we need an updated definition of pain?
- Narrative review
- Is acetaminophen safe in pregnancy?
- Book Review
- Physical Diagnosis of Pain
- Book Review
- Advances in Anesthesia
- Book Review
- Atlas of Pain Management Injection Techniques
- Book Review
- Sedation: A Guide to Patient Management
- Book Review
- Basics of Anesthesia