Recent advances in the use of opioids for cancer pain

The pro- and anti-cancer effects of oxycodone are associated with epithelial growth factor receptor level in cancer cells

Background: Oxycodone is an opioid medication used for the treatment of pain in cancer patients. However, little is known on the direct effects of oxycodone on cancer cells. Aim: To determine the effects and mechanisms of oxycodone in cancer cells. Materials and Methods: Proliferation, survival and migration assays were performed on multiple types of cancer cells. Epithelial growth factor receptor (EGFR)/ERK/Akt pathway and oxidative stress were investigated after oxycodone treatment. Results: Oxycodone can either stimulate growth and migration without affecting survival in MDA-468 cells or inhibit growth and survival without affecting migration in SKBR3 and Caco2 cells. In addition, oxycodone can either attenuate or stimulate efficacy of chemotherapeutic drugs in cancer, depending on the type of cancer cells and nature of action of oxycodone as single drug alone. Our mechanism studies suggest that the stimulatory and inhibitory effects of oxycodone are associated with EGFR expression levels in cancer cells. In cancer cells with high EGFR level, oxycodone activates EGFR signaling in cancer cells, leading to stimulatory effects in multiple biological activities, and this is dependent on opioid receptor. In cancer cells with low EGFR level, oxycodone induces mitochondria-mediated caspase activity and oxidative stress and damage, leading to cell death. Conclusions: Our work is the first to demonstrate systematic analysis of oxycodone’s effects and mechanism of action in cancer. The activation of EGFR signaling by oxycodone may provide a new guide in the clinical use of oxycodone, in particular for cancer patients with high EGFR levels.

Oxycodone stimulates normal and malignant hematopoietic progenitors via opioid-receptor-independent-β-catenin activation

Oxycodone is a common type of opioid used for the treatment of moderate to severe pain. Besides its analgesic effects on neuron cells, the effects of oxycodone on other cell types are yet to be elucidated. We previously demonstrated that oxycodone displayed both pro- and anti-cancer effects on bulk cancer cells. This work further investigated the effects of oxycodone on normal and malignant hematopoietic stem cells. Using hematopoietic CD34⁺ cells isolated from normal bone marrow (NBM) or patients with acute myeloid leukemia (AML), we showed that oxycodone activates hematopoietic cells regardless of cell development stage and malignant status. Oxycodone dose-dependently increases colony formation and self-renewal capacity of NBM and AML stem/progenitor cells, and promotes proliferation of AML bulk cells. NBM stem/progenitor cells are more sensitive to oxycodone than AML counterparts. In addition, oxycodone alleviates chemotherapy drug-induced toxicity in AML stem/progenitor cells. Mechanism studies demonstrate that oxycodone acts on hematopoietic cells in an opioid-receptor-independent manner. Oxycodone did not affect epithelial growth factor receptor (EGFR) signaling neither but stimulated Wnt/β-catenin signaling. Rescue studies via depleting β-catenin using genetic and pharmacological approaches confirmed that β-catenin was required for the activation of hematopoietic cells induced by oxycodone. Our work demonstrates 1) the protective role of oxycodone in malignant hematopoietic cells from chemotherapy; 2) stimulatory effects of oxycodone in normal hematopoietic stem cells; and 3) ability of oxycodone in Wnt signaling activation.

Incidence of opioid-induced constipation in Japanese patients with cancer pain: A prospective observational cohort study

This multicenter, prospective, observational cohort study assessed opioid induced constipation (OIC) in Japanese patients with cancer. Eligible patients had stable cancer and an ECOG PS of 0-2. OIC incidence based on the Rome IV diagnostic criteria was determined by patient diary entries during the first 14 days of opioid therapy. The proportion of patients with OIC was calculated for each 1-week period and the overall 2-week study period. Secondary measurements of OIC included the Bowel Function Index (BFI) score (patient assessment administered by physician), spontaneous bowel movements (SBMs) per week (patient assessment), and physician assessments. Medication for constipation was allowed. Two hundred and twenty patients were enrolled. The mean morphine-equivalent dose was 22 mg/day. By Rome IV criteria, the cumulative incidence of OIC was 56% (95% CI: 49.2%-62.9%); week 1, 48% (95% CI: 40.8%-54.6%); week 2, 37% (95% CI: 30.1%-43.9%). The cumulative incidence of OIC was lower in patients who received prophylactic agents for constipation (48% [95% CI: 38.1%-57.5%]) than in patients who did not (65% [95% CI: 55.0%-74.2%]). The cumulative incidences of OIC were 59% (95% CI: 51.9%-66.0%), 61% (95% CI: 54.3%-68.1%), and 45% (95% CI: 38.0%-51.8%) based on BFI scores, physician assessments, and SBM frequency, respectively. Frequency of BMs/week before starting opioids was the most influential factor for the occurrence of OIC. Utilization of prophylactic agents for constipation was associated with a modest effect on reducing the incidence of OIC. The incidences of OIC reported were variable depending on the diagnostic tool involved.

The role of tapentadol as a strong opioid in cancer pain management: a systematic and critical review

AIM

The aim of this review was to assess the role of tapentadol given at medium-high doses in opioid-tolerant patients for cancer pain management in place of step-3 analgesics.

METHODS AND RESULTS

A systematic literature search was performed out of which six studies and one secondary analysis provided data regarding tapentadol used as a step-3 analgesic for this review. Tapentadol, when used at ≥60 mg of oral morphine equivalents in opioid-tolerant patients with cancer pain, or passing from step-2 doses to ≥60 mg of oral morphine equivalents, was well tolerated and effective and could be considered as a flexible drug to be used for the management of moderate-to-severe cancer pain. The limited occurrence of gastrointestinal adverse effects may be a great advantage in the context of a disease like cancer, where multiple causes contribute to nausea, vomiting, or constipation; however, studies of tapentadol given at doses equivalent to step-3 level have some weaknesses, as data from prospective observational studies are poorly generalizable due to a small number of participants, controlled studies do not clearly show a superiority of tapentadol with respect to other opioids, and the sample size is often small.

CONCLUSIONS

More studies are necessary to confirm the role of tapentadol in cancer patients requiring strong opioids for their pain.

OPRM1 c.118A>G Polymorphism and Duration of Morphine Treatment Associated with Morphine Doses and Quality-of-Life in Palliative Cancer Pain Settings

Despite increased attention on assessment and management, pain remains the most persistent symptom in patients with cancer, in particular in end-of-life settings, with detrimental impact on their quality-of-life (QOL). We conducted this study to evaluate the added value of determining some genetic and non-genetic factors to optimize cancer pain treatment. Eighty-nine patients were included in the study for the evaluation of palliative cancer pain management. The regression analysis showed that age, OPRM1 single nucleotide polymorphism (SNP), as well as the duration of morphine treatment were significantly associated with morphine doses at 24 h (given by infusion pump; p = 0.043, 0.029, and <0.001, respectively). The mean doses of morphine decreased with age but increased with the duration of morphine treatment. In addition, patients with AG genotype c.118A>G OPRM1 needed a higher dose of morphine than AA patients. Moreover, metastases, OPRM1 SNP, age, and gender were significantly associated with the QOL in our population. In particular, AA patients for OPRM1 SNP had significantly lower cognitive function than AG patients, a result not previously reported in the literature. These findings could help increase the effectiveness of morphine treatment and enhance the QOL of patients in regards to personalized medicine.

Direct conversion from tramadol to tapentadol prolonged release for moderate to severe, chronic malignant tumour-related pain

Background

A recent randomized‐withdrawal, active‐ and placebo‐controlled, double‐blind phase 3 study showed that tapentadol prolonged release (PR) was effective and well tolerated for managing moderate to severe, chronic malignant tumour‐related pain in patients who were opioid naive or dissatisfied with current treatment (Pain Physician, 2014, 17, 329–343). This post hoc, subgroup analysis evaluated the efficacy and tolerability of tapentadol PR in patients who previously received and were dissatisfied with tramadol for any reason and who had a pain intensity ≥5 (11‐point numerical rating scale) before converting directly to tapentadol PR.

Methods

In the original study, eligible patients had been randomized (2:1) and titrated to their optimal dose of tapentadol PR (100–250 mg bid) or morphine sulphate‐controlled release (40–100 mg bid) over 2 weeks. The present report focuses on results during the titration period for a subgroup of patients randomized to tapentadol PR after having been on tramadol treatment prior to randomization in the study (n = 129). Results for this subgroup are compared with results for all 338 patients who received tapentadol PR during titration (overall tapentadol PR group).

Results

Responder rates (responders: completed titration, mean pain intensity <5 [0–10 scale] and ≤20 mg/day rescue medication during last 3 days) were slightly better for the tramadol/tapentadol PR subgroup (69.8% [90/129]) vs. the overall tapentadol PR group (63.9% [214/335]). Tolerability profiles were comparable for both groups.

Conclusions

Results of this subgroup analysis indicate that patients with cancer pain could safely switch from prior treatment with the weak centrally acting analgesic tramadol directly to the strong centrally acting analgesic tapentadol PR, for an improved analgesic therapy for severe pain.

What does this study add?

Results of this post hoc analysis show that patients who had received prior tramadol therapy could switch directly to tapentadol PR, with the majority (˜70%) experiencing improved efficacy.

[Good clinical practice guide for opioids in pain management: the three Ts - titration (trial), tweaking (tailoring), transition (tapering)]

BACKGROUND AND OBJECTIVES

Achieving good clinical practice in the use of opioids as part of a comprehensive pain management regimen can face significant challenges. Despite guidelines from governmental and pain society/organization sources, there are still significant hurdles. A review of some basic tenets of opioid analgesia based on current published knowledge and experiences about this important healthcare imperative is warranted.

CONTENT

Consistent with guidelines, the literature supports using the lowest total opioid dose that provides adequate pain control with the fewest adverse effects. Titration (or trial) during opioid initiation is a way of starting low and going slow (and assessing the appropriateness of a specific opioid and formulation). Recognizing that multiple factors contribute to an individual's personal experience of pain, the physical, psychological, social, cultural, spiritual, pharmacogenomic, and behavioral factors of the individual patient should be taken into account (tweaking, or tailoring). Finally, for those patients for whom transition (tapering) from opioid is desired, doing so too rapidly can have negative consequences and minimization of problems during this step can be achieved by proper tapering.

CONCLUSION

We conclude that a simultaneously aggressive, yet conservative, approach is advocated in the literature in which opioid therapy is divided into three key steps (the 3 T's): titration (or trial), tweaking (or tailoring), and transition (or tapering). Establishment of the 3 T's along with the application of other appropriate good medical practice and clinical experience/judgment, including non-pharmacologic approaches, can assist healthcare providers in the effort to achieve optimal management of pain.

Ready conversion of patients with well-controlled, moderate to severe, chronic malignant tumor-related pain on other opioids to tapentadol extended release

Background and Objectives

The effectiveness and tolerability of tapentadol extended release (ER), a centrally acting analgesic with μ-opioid receptor agonist and norepinephrine (noradrenaline) reuptake inhibitor activities, have been demonstrated in patients with chronic pain, including those switching directly from prior opioid therapy. The objective of the current study was to evaluate the effectiveness and safety of conversion to oral tapentadol ER (50–250 mg twice daily) from previous around-the-clock strong opioid therapy in patients with moderate to severe, chronic malignant tumor–related cancer pain that was well-controlled.

Methods

This randomized, open-label, phase III study, which was conducted in Japan, included a 1- to 2-week screening period (on previous opioid) and an 8-week, open-label treatment period. Eligible patients, who were taking a strong opioid analgesic and had a mean pain intensity score <4 during the 3 days prior to randomization (adequate pain control on previous strong opioid), were randomized (1:1) to receive twice-daily treatment with tapentadol ER (100–500 mg/day) or morphine sustained release (SR; 20–140 mg/day; reference for assay sensitivity). Initial doses were estimated based on the conversion ratio of tapentadol ER:oxycodone:morphine:fentanyl = 10:2:3:0.03. The primary effectiveness endpoint was the proportion of patients who maintained pain control [change from baseline in mean pain intensity (11-point numerical rating scale) less than +1.5 for 3 consecutive days and no more than two doses of rescue medication per day for 3 consecutive days) during the first week of open-label treatment.

Results

In the tapentadol ER group (n = 50), 84.0 % of patients (42/50; 95 % CI, 70.89–92.83) maintained pain control during Week 1. On the Patient Global Impression of Change, 2.1 % (1/48), 2.1 % (1/48), 22.9 % (11/48), and 50.0 % (24/48) of patients in the tapentadol ER group reported that their overall condition was “very much improved,” “much improved,” “minimally improved,” and “not changed,” respectively, at Week 1 compared with 0 %, 10.7 % (3/28), 28.6 % (8/28), and 53.6 % (15/28) reporting these ratings at Week 8. The sensitivity of effectiveness analyses was validated based on results using morphine SR; 98.0 % (49/50; 95 % CI, 89.35–99.95) of patients in the morphine SR group maintained pain control after 1 week of treatment. The overall safety profile was similar to that demonstrated in previous studies; tapentadol ER was associated with a lower incidence of gastrointestinal treatment-emergent adverse events than morphine SR [38.0 % (19/50) vs. 54.0 % (27/50)], including constipation [12.0 % (6/50) vs. 20.0 % (10/50)] and vomiting [6.0 % (3/50) vs. 26.0 % (13/50)].

Conclusions

Overall, results indicate that conversion from previous strong opioids to tapentadol ER (50–250 mg twice daily) was successful and resulted in safe and effective pain control with improved gastrointestinal tolerability versus morphine SR in patients with moderate to severe cancer-related pain that was well-controlled on their previous opioid.

Electronic supplementary material

The online version of this article (doi:10.1007/s40261-014-0204-3) contains supplementary material, which is available to authorized users.

Genotyping test with clinical factors: better management of acute postoperative pain?

Individualization of acute postoperative pain treatment on an evidence-based decision process is a major health concern. The aim of this study is to investigate the influence of genetic and non-genetic factors on the variability of response to morphine in acute postoperative pain. A group of nighty-five patients undergoing major surgery were included prospectively. At 24 h, a logistic regression model was carried out to determine the factors associated with morphine doses given by a Patient Controlled Analgesia device. The dose of morphine was associated with age (p = 0.011), patient weight (p = 0.025) and the duration of operation (p = 0.030). This dose decreased with patient's age and duration of operation and increased with patient's weight. OPRM1 and ABCB1 polymorphisms were significantly associated with administered dose of morphine (p = 0.038 and 0.012 respectively). Patients with at least one G allele for c.118A>G OPRM1 polymorphism (AG/GG) needed 4 times the dose of morphine of AA patients. Additionally, patients with ABCB1 CT and CC genotypes for c.3435C>T polymorphism were 5.6 to 7.1 times more prone to receive higher dose of morphine than TT patients. Our preliminary results support the evidence that OPRM1/ABCB1 genotypes along with age, weight and duration of operation have an impact on morphine consumption for acute postoperative pain treatment.

Good clinical practice guide for opioids in pain management: the three Ts - titration (trial), tweaking (tailoring), transition (tapering)

BACKGROUND AND OBJECTIVES

Achieving good clinical practice in the use of opioids as part of a comprehensive pain management regimen can face significant challenges. Despite guidelines from governmental and pain society/organization sources, there are still significant hurdles. A review of some basic tenets of opioid analgesia based on current published knowledge and experiences about this important healthcare imperative is warranted.

CONTENT

Consistent with guidelines, the literature supports using the lowest total opioid dose that provides adequate pain control with the fewest adverse effects. Titration (or trial) during opioid initiation is a way of starting low and going slow (and assessing the appropriateness of a specific opioid and formulation). Recognizing that multiple factors contribute to an individual's personal experience of pain, the physical, psychological, social, cultural, spiritual, pharmacogenomic, and behavioral factors of the individual patient should be taken into account (tweaking, or tailoring). Finally, for those patients for whom transition (tapering) from opioid is desired, doing so too rapidly can have negative consequences and minimization of problems during this step can be achieved by proper tapering.

CONCLUSION

We conclude that a simultaneously aggressive, yet conservative, approach is advocated in the literature in which opioid therapy is divided into three key steps (the 3 T's): titration (or trial), tweaking (or tailoring), and transition (or tapering). Establishment of the 3 T's along with the application of other appropriate good medical practice and clinical experience/judgment, including non-pharmacologic approaches, can assist healthcare providers in the effort to achieve optimal management of pain.

Toward a systematic approach to opioid rotation

Patients requiring chronic opioid therapy may not respond to or tolerate the first opioid prescribed to them, necessitating rotation to another opioid. They may also require dose increases for a number of reasons, including worsening disease and increased pain. Dose escalation to restore analgesia using the primary opioid may lead to increased adverse events. In these patients, rotation to a different opioid at a lower-than-equivalent dose may be sufficient to maintain adequate tolerability and analgesia. In published trials and case series, opioid rotation is performed either using a predetermined substitute opioid with fixed conversion methods, or in a manner that appears to be no more systematic than trial and error. In clinical practice, opioid rotation must be performed with consideration of individual patient characteristics, comorbidities (eg, concurrent psychiatric, pulmonary, renal, or hepatic illness), and concurrent medications, using flexible dosing protocols that take into account incomplete opioid cross-tolerance. References cited in this review were identified via a search of PubMed covering all English language publications up to May 21, 2013 pertaining to opioid rotation, excluding narrative reviews, letters, and expert opinion. The search yielded a total of 129 articles, 92 of which were judged to provide relevant information and subsequently included in this review. Through a review of this literature and from the authors’ empiric experience, this review provides practical information on performing opioid rotation in clinical practice.

Pharmacogenetics of opiates in clinical practice: the visible tip of the iceberg

Opioids are the cornerstone of analgesic therapy and are used as a substitution therapy for opiate addiction. Interindividual variability in response to opioids is a significant challenge in the management of pain and substitution. Therefore, treatment with opioids requires a careful individualization of dosage to achieve an appropriate balance of efficacy and adverse effects and, consequently, avoid toxicity, particularly respiratory depression, sedation and for some, cardiac ventricular fibrillations. Many studies have investigated the association between genetic factors and the variability of response to opioids. Variants in genes encoding proteins implied in opioid pharmacokinetics (absorption, distribution, metabolism, excretion and toxicity), together with those implied in opioids direct and indirect pharmacodynamics (genes of opioid receptors and monoaminergic systems), are the most studied. Many association studies have not been replicated. The purpose of this article is to summarize pharmacogenetic data associated with some opioids frequently encountered in managed care settings.

Recent Non-Interventional Advances in Cancer Pain Among Singapore Patients

Introduction: Pain is a common symptom in cancer patients, but very little information about the prevalence, severity, and treatment of pain in cancer patients in Singapore is available. Therefore, our prospective survey in the National Cancer Centre (NCC) outpatients is incorporated in this report. In addition, a review concerning the recent advances on non-interventional pain management in cancer treatment, which is relevant in the context, is discussed. Materials and Methods: For the prospective survey, a questionnaire was distributed for self-administration by patients while waiting for consultation at the NCC outpatient departments. Literature searches on advances in pain management were conducted, reviewed and discussed. Results: In the last decade, there have been advances in pain pharmacology ranging from wider therapeutic options and management approaches to novel delivery techniques. Acupuncture and massage therapy became increasingly popular among cancer patients. Some clinical trials of acupuncture show benefits in palliation of cancer pain. From the prospective survey, 41.2% of the responders reported pain in the past week, and only 70.8% talked to their doctors about their pain. One third of the patients received analgesics. Of these, 86.5% said that they were taking the prescribed medications, however, 37.4% admitted to having difficulties taking them. Non-drug methods were used by 25.4% of the patients. Medicated oil, cream or gel was used by 49.3%; only 2.6% reported use of Chinese herbs. Conclusion: Pain is a significant symptom in outpatients attending a cancer centre, affecting 41.2% of the patients. Although majority of patients who suffered from pain reported this to doctors, much more medical effort is needed to help patients to relieve their pain and proper complementary therapy could be considered. Key words: Cancer outpatients, Complementary therapies, Non-pharmacological pain treatments, Pain prevalence

Acute abdomen in a patient with cancer pain on oxycodone

Opioids are a mainstay of treatment for moderate to severe cancer pain. At present, oxycodone has fewer adverse effects compared to morphine and is widely used for cancer pain therapy. The adverse effects of oxycodone are similar to morphine and include constipation, nausea, and sedation. However, acute abdominal pain is rarely seen. Here, we describe a cancer patient presenting with acute abdomen with stercoral diarrhea. A 54-year-old man with squamous cell carcinoma of the external auditory canal had been taking oxycodone for pain relief. The patient had taken oxycodone for several months and had never complained of either diarrhea or constipation. After an increase in the dosage of oxycodone, he complained of abdominal distension and constipation. After being administered a laxative, he complained of diarrhea and severe abdominal pain. He visited the emergency department and was diagnosed with acute colonic obstruction caused by severe constipation. He self-medicated with oxycodone at dosages of up to 180 mg/day, and this abrupt increase of oxycodone caused stercoral diarrhea. Finally, total blockage of stool developed, resulting in acute abdomen.