Innovative pain therapy with a fixed combination of prolonged-release oxycodone/naloxone: a large observational study under conditions of daily practice

Naloxone-induced analgesia mediated by central kappa opioid system in chronic inflammatory pain

Opioids, which are widely used for the treatment of chronic pain, have an analgesic effect by mainly activating mu-opioid receptor (MOR). Paradoxically, a high dose of naloxone, non-selective opioid receptor antagonist, is also known to induce analgesia, but the underlying mechanism remains unclear. Since kappa-opioid receptor (KOR) and dynorphin (KOR ligand) have been implicated in the naloxone-induced analgesia, we aimed to elucidate its mechanism by focusing on the kappa-opioid system in the brain under inflammatory pain condition. Systemic administration of naloxone (10 mg/kg, i.p.) decreased spontaneous pain behaviors only in complete Freund's adjuvant (CFA)-induced chronic inflammatory pain model but not in the formalin-induced acute pain model. Immunohistochemistry analysis in the CFA model revealed both a significant decrease in MOR expression and an increase in prodynorphin density in the central nucleus of theamygdala (CeA) and nucleus accumbens (NAc) but not in other brain areas. Systemic administration of KOR antagonist (norbinaltorphimine, nor-BNI 10 mg/kg) also decreased spontaneous pain behaviors in the CFA model. Furthermore, microinjection of both naloxone and nor-BNI into NAc and CeA significantly reduced spontaneous chronic pain behavior. Taken together, our results suggest that naloxone-induced analgesia may be mediated by blocking facilitated kappa-opioid systems in the NAc and CeA.

Oxycodone/Naloxone Prolonged Release: A Review in Severe Chronic Pain

Oral oxycodone/naloxone prolonged release (PR) [Targin^®, Targinact^®, Targiniq^®] is a 12-hourly opioid receptor agonist and opioid receptor antagonist fixed-dose combination product that is approved in countries in the EU for the management of severe pain (adequately manageable only with opioid analgesics) in adults. Oral naloxone prevents oxycodone from binding to μ-receptors in the gastrointestinal (GI) tract, thereby counteracting opioid-induced constipation (OIC). In short-term (5- to 12-week) clinical trials of adults with moderate to severe, chronic pain and OIC (OXN3001, OXN3006, OXN3506), oxycodone/naloxone PR significantly improved OIC while providing noninferior analgesia relative to oxycodone PR; results were consistent between cancer and non-cancer patients in OXN3506. Analgesia and improvements in bowel function were sustained with an additional 24-52 weeks of oxycodone/naloxone PR treatment in long-term extension studies. Results in real-world studies were consistent with those in clinical trials. Oxycodone/naloxone PR was generally well tolerated, with nausea, hyperhidrosis, and diarrhoea (generally transient) reported as the most commonly occurring adverse events. Thus, oxycodone/naloxone PR is a useful treatment option to consider in adults with severe chronic pain that can be adequately managed only with opioid analgesics, particularly in those with OIC.

Prolonged release oxycodone and naloxone treatment counteracts opioid-induced constipation in patients with severe pain compared to previous analgesic treatment

OBJECTIVE

Treatment with prolonged-release oxycodone/naloxone (PR OXN) has been shown to improve opioid induced constipation (OIC) in constipated patients. This publication reports on a real-life observational study investigating the efficacy of PR OXN with regard to bowel function in patients switching to PR OXN from WHO step 1, step 2 and step 3 opioids.

METHODS

Patients with chronic pain experiencing insufficient pain relief and/or unacceptable side effects were switched to PR OXN and monitored in this observational study with respect to efficacy regarding bowel function and efficacy regarding pain relief in comparison with previous analgesic therapy. A patient was considered a responder with respect to efficacy if this assessment was "slightly better", "better" or "much better" compared with previous therapy. Bowel function index, pain intensity, quality of life, laxative medication use, and safety analgesic were also evaluated.

RESULTS

A total of 1338 patients (mean [SD] age 64.3 [14.9], 63% female) were observed for 43 [3-166] days (median [range]) during treatment with PR OXN. Overall response rate regarding bowel function efficacy was 82.5%. Patients with symptoms of constipation at study entry obtained a clinically relevant improvement of the bowel function index (BFI) within the first 2 weeks of PR OXN treatment. Non-constipated patients at study entry maintained normal bowel function despite switching to treatment with the opioid PR OXN.

CONCLUSION

In conclusion, treatment with PR OXN results in a significant and clinically relevant improvement of bowel function. During the observation of the treatment with PR OXN patients reported an improvement of quality of life (QoL). More interestingly, non-constipated patients maintained a normal bowel function, showing prevention of constipation despite the use of an opioid.

Opioid-Induced Constipation and Bowel Dysfunction: A Clinical Guideline

OBJECTIVE

To formulate timely evidence-based guidelines for the management of opioid-induced bowel dysfunction.

SETTING

Constipation is a major untoward effect of opioids. Increasing prescription of opioids has correlated to increased incidence of opioid-induced constipation. However, the inhibitory effects of opioids are not confined to the colon, but also affect higher segments of the gastrointestinal tract, leading to the coining of the term "opioid-induced bowel dysfunction."

METHODS

A literature search was conducted using Medline, EMBASE, and EMBASE Classic, and the Cochrane Central Register of Controlled Trials. Predefined search terms and inclusion/exclusion criteria were used to identify and categorize relevant papers. A series of statements were formulated and justified by a comment, then labeled with the degree of agreement and their level of evidence as judged by the Strength of Recommendation Taxonomy (SORT) system.

RESULTS

From a list of 10,832 potentially relevant studies, 33 citations were identified for review. Screening the reference lists of the pertinent papers identified additional publications. Current definitions, prevalence, and mechanism of opioid-induced bowel dysfunction were reviewed, and a treatment algorithm and statements regarding patient management were developed to provide guidance on clinical best practice in the management of patients with opioid-induced constipation and opioid-induced bowel dysfunction.

CONCLUSIONS

In recent years, more insight has been gained in the pathophysiology of this "entity"; new treatment approaches have been developed, but guidelines on clinical best practice are still lacking. Current knowledge is insufficient regarding management of the opioid side effects on the upper gastrointestinal tract, but recommendations can be derived from what we know at present.

A comparison between the administration of oral prolonged-release oxycodone-naloxone and transdermal fentanyl in patients with moderate-to-severe cancer pain: a propensity score analysis

BACKGROUND

Opioids are the most important pharmacological treatment for moderate-to-severe cancer pain, but side effects limit their use. Transdermal fentanyl (TDF) and oral prolonged-release oxycodone-naloxone (OXN-PR) are effective in controlling chronic pain, with less constipation compared to other opioids. However, TDF and OXN-PR have never been directly compared.

PATIENTS AND METHODS

Cancer patients with moderate-to-severe chronic pain were consecutively enrolled in two prospective 28-day trials, received either TDF or OXN-PR, and were assessed at baseline and after 7, 14, 21, and 28 days. The primary endpoint was 28-day analgesic response rate (average pain intensity decrease ≥30% from baseline). Other outcome measures included opioid daily dose changes over time; need for adjuvant analgesics; number of switches; premature discontinuation; presence and severity of constipation; and other adverse drug reactions. To compare the efficacy and the safety of TDF and OXN-PR, we used the propensity score analysis to adjust for heterogeneity between the two patient groups.

RESULTS

Three hundred ten out of 336 patients originally treated (119 TDF and 191 OXN-PR) were included in the comparative analysis. The amount of responders was comparable after TDF (75.3%) and OXN-PR administration (82.9%, not significant [NS]). The final opioid daily dose expressed as morphine equivalent was 113.6 mg for TDF and 44.5 mg for OXN-PR (p<0.0001). A daily opioid dose escalation >5% was less common after OXN-PR (19.3%) than after TDS administration (37.9%, p<0.0001). Opioid switches and discontinuation were similar in both groups. Severe constipation in the two groups was comparable (32.6% after TDF vs 24.7% after OXN-PR, NS). Nausea, vomiting, and dry mouth were significantly less frequent in the OXN-PR group than in the TDF group.

CONCLUSION

Despite a similar analgesic activity in moderate-to-severe cancer pain, OXN-PR is characterized by lower daily dosages, less need for drug escalation, and fewer side effects compared to TDF.

Combatting pain after orthopedic/trauma surgery- perioperative oral extended-release tapentadol vs. extended-release oxycodone/naloxone

BACKGROUND

High post-operative pain scores after "minor" orthopedic/trauma surgery are in part attributed to inadequate prescription of opioid analgesics. Novel concepts aiming to achieve sufficient analgesia while minimizing opioid-related side effects by avoiding fluctuating plasma levels are based on perioperative oral administration of extended-release opioids beginning with the first dose pre-operatively. This is the first study to evaluate analgesic efficacy and side effect rates of extended-release tapentadol compared to oxycodone/naloxone following orthopedic/trauma surgery.

METHODS

This randomized, observer-blinded, active-controlled prospective clinical trial had 2 co-primary endpoints: (1) Analgesic efficacy: Mean pain level on a numeric rating scale (NRS) from 0 to 10 during exercise over 5 days. (2) Safety: Side effect sum score of the following events: Nausea, vomiting, constipation, sedation, vertigo, somnolence. The study was powered to detect superiority of tapentadol for at least one endpoint pending statistical proof of non-inferiority for both endpoints in a first step.

RESULTS

Two hundred sixty-six trauma patients were randomized to receive either tapentadol (n = 133) or oxycodone/naloxone (n = 133). Analgesic efficacy: Mean (±SD) daily pain levels in the first five post-operative days were 2.8 ± 1.3 in both groups. Mean maximum pain intensity during exercise in the first 24 h after surgery was 3.8 ± 1.9 (tapentadol) and 3.8 ± 2.1 (oxycodone/naloxone). Statistically tapentadol was non-inferior but not superior to oxycodone/naloxone.

SAFETY

Vomiting on day 1 occurred in 11%, constipation in 35% of the tapentadol patients and in 16% and 30% of the oxycodone/naloxone patients (p = 0.60 and 0.33), respectively. The incidence of sedation/ vertigo was <10%, that of somnolence <2% in both groups (p > 0.3, respectively). The sum score of side effect events was 51% in the tapentadol vs. 49% in the oxycodone/naloxone group; risk difference 3% [95% CI, -8 to 14%]; p = 0.6). Non-inferiority of tapentadol could not be concluded as the pre-defined non-inferiority margin was exceeded.

CONCLUSIONS

With both concepts, mean maximum pain intensity during exercise within the first 24 h after orthopedic/trauma surgery was reduced to a score of <4. This analgesic efficacy came at the cost of mainly gastro-intestinal side effects. Thus, we now use a prophylaxis against nausea and vomiting and pre-emptive laxatives as part of these concepts.

TRIAL REGISTRATION

https://eudract.ema.europa.eu (EudraCT- Nr. 2011-003238-15 ); October 24th, 2012.

Tolerability of Opioid Analgesia for Chronic Pain: A Network Meta-Analysis

Aim of this study was to study the tolerability of opioid analgesia by performing a network meta-analysis (NMA) of randomized-controlled trials (RCTs) which investigated effectiveness of opioids for the management of chronic pain. Research articles reporting outcomes of RCT/s comparing 2 or more opioid analgesics for the management of chronic pain were obtained by database search. Bayesian NMAs were performed to combine direct comparisons between treatments with that of indirect simulated evidence. Study endpoints were: incidence of adverse events, incidence of constipation, trial withdrawal rate, and patient satisfaction with treatment. Outcomes were also compared with conventional meta-analyses. Thirty-two studies investigating 10 opioid drugs fulfilled the eligibility criteria. Tapentadol treatment was top-ranking owing to lower incidence of overall adverse events, constipation, and least trial withdrawal rate. Tapentadol was followed by oxycodone-naloxone combination in providing better tolerability and less trial withdrawal rate. Patient satisfaction was found to be higher with oxycodone-naloxone followed by fentanyl and tapentadol. These results were in agreement with those achieved with conventional meta-analyses. Tapentadol and oxycodone-naloxone are found to exhibit better tolerability characteristics in comparison with other opioid drugs for the management of chronic pain and are associated with low trial withdrawal rate and better patient satisfaction.

Switching to low-dose oral prolonged-release oxycodone/naloxone from WHO-Step I drugs in elderly patients with chronic pain at high risk of early opioid discontinuation

PURPOSE

Chronic pain has a high prevalence in the aging population. Strong opioids also should be considered in older people for the treatment of moderate to severe pain or for pain that impairs functioning and the quality of life. This study aimed to assess the efficacy and safety of the direct switch to low-dose strong opioids (World Health Organization-Step III drugs) in elderly, opioid-naive patients.

PATIENTS AND METHODS

This was a single-center, retrospective, observational study in opioid-naive patients aged ≥75 years, with moderate to severe chronic pain (>6-month duration) and constipation, who initiated treatment with prolonged-release oxycodone/naloxone (OXN-PR). Patients were re-evaluated after 15, 30, and 60 days (T60, final observation). Response to treatment was defined as an improvement in pain of ≥30% after 30 days of therapy without worsening of constipation.

RESULTS

One-hundred and eighty-six patients (mean ± SD age 80.7±4.7 years; 64.5% women) with severe chronic pain (mean average pain intensity 7.1±1.0 on the 11-point numerical rating scale) and constipation (mean Bowel Function Index 64.1±24.4; 89.2% of patients on laxatives) were initiated treatment with OXN-PR (mean daily dose 11.3±3.5 mg). OXN-PR reduced pain intensity rapidly and was well tolerated; 63.4% of patients responded to treatment with OXN-PR. At T60 (mean daily OXN-PR dose, 21.5±9.7 mg), the pain intensity was reduced by 66.7%. In addition, bowel function improved (mean decrease of Bowel Function Index from baseline to T60, -28.2, P<0.0001) and the use of laxatives decreased. Already after 15 days and throughout treatment, ~70% of patients perceived their status as much/extremely improved. Only 1.6% of patients discontinued treatment due to adverse events.

CONCLUSION

Low-dose OXN-PR in elderly patients naive to opioids proved to be an effective option for the treatment of moderate to severe chronic pain. Large-scale trials are needed to improve clinical guidance in the assessment and treatment of pain in older people.

Long-term efficacy and safety of oxycodone-naloxone prolonged release in geriatric patients with moderate-to-severe chronic noncancer pain: a 52-week open-label extension phase study

BACKGROUND

Two-thirds of older people suffer from chronic pain and finding valid treatment options is essential. In this 1-yearlong investigation, we evaluated the efficacy and safety of prolonged-release oxycodone-naloxone (OXN-PR) in patients aged ≥70 (mean 81.7) years.

METHODS

In this open-label prospective study, patients with moderate-to-severe noncancer chronic pain were prescribed OXN-PR for 1 year. The primary endpoint was the proportion of patients who achieved ≥30% reduction in pain intensity after 52 weeks of treatment, without worsening bowel function. The scheduled visits were at baseline (T0), after 4 weeks (T4), and after 52 weeks (T52).

RESULTS

Fifty patients completed the study. The primary endpoint was achieved in 78% of patients at T4 and 96% at T52 (P<0.0001). Pain intensity, measured on a 0-10 numerical rating scale, decreased from 6.0 at T0 to 2.8 at T4 and to 1.7 at T52 (P<0.0001). Mean daily dose of oxycodone increased from 10 to 14.4 mg (T4) and finally to 17.4 mg (T52). Bowel Function Index from 35.1 to 28.7 at T52. No changes were observed in cognitive functions (Mini-Mental State Examination evaluation), while daily functioning improved (Barthel Index from 53.1 to 61.0, P<0.0001). The Screener and Opioid Assessment for Patients with Pain-Revised score at 52 weeks was 2.6 (standard deviation 1.6), indicating a low risk of aberrant medication-related behavior. In general, OXN-PR was well tolerated.

CONCLUSION

This study of the long-term treatment of chronic pain in a geriatric population with OXN-PR shows satisfying analgesic effects achieved with a stable low daily dose, coupled with a good safety profile and, in particular, with a reduction of constipation, often present during opioid therapy. Our findings support the indications of the American Geriatrics Society, suggesting the use of opioids to treat pain in older people not responsive to acetaminophen or nonsteroidal anti-inflammatory drugs.

Quality of life under oxycodone/naloxone, oxycodone, or morphine treatment for chronic low back pain in routine clinical practice

OBJECTIVE

To compare the quality of life of patients with moderate-to-severe chronic low back pain under treatment with the WHO-step III opioids oxycodone/naloxone, oxycodone, or morphine in routine clinical practice.

STUDY DESIGN

Prospective, 12-week, randomized, open-label, blinded end-point study in 88 medical centers in Germany.

PATIENTS AND METHODS

A total of 901 patients requiring around-the-clock pain treatment with a WHO-step III opioid were randomized to either morphine, oxycodone, or oxycodone/naloxone (1:1:1). Changes from baseline to week 12 in quality of life were assessed using different validated tools (EuroQoL-5 Dimensions [EQ-5D], Short Form 12 [SF-12], quality of life impairment by pain inventory [QLIP]).

RESULTS

EQ-5D weighted index scores significantly improved over the 12-week treatment period under all three opioids (P<0.001) with significantly greater improvements under oxycodone/naloxone (65.2% vs 49.6% for oxycodone and 48.2% for morphine, P<0.001). The proportion of patients without EQ-5D complaints was also significantly higher under oxycodone/naloxone (P<0.001). Although quality of life ratings with the QLIP inventory showed significant improvements in all the three treatment arms, improvements were significantly higher under oxycodone/naloxone than under oxycodone and morphine (P<0.001): 90.7% of all oxycodone/naloxone patients achieved ≥30% improvements in quality of life, 72.8% had ≥50%, and 33.2% ≥70% improvements. Similarly, both physical and mental SF-12 component scores showed significantly greater improvements under oxycodone/naloxone with both scores close to the German population norm after 12 weeks.

CONCLUSION

Treatment with morphine, oxycodone, or oxycodone/naloxone under routine daily practice conditions significantly improved state of health and quality of life of patients with moderate-to-severe low back pain over a 12-week treatment period. Comparison between the treatment groups showed significantly greater improvements for oxycodone/naloxone than for the other two opioids.

Low-dose oral prolonged-release oxycodone/naloxone for chronic pain in elderly patients with cognitive impairment: an efficacy-tolerability pilot study

OBJECTIVE

This pilot study evaluated the efficacy and safety of prolonged-release oxycodone/naloxone (OXN-PR) in older subjects with chronic pain and mild-to-moderate cognitive impairment.

METHODS

This was a prospective, observational, open-label study of 45-day duration. Patients with moderate-to-severe chronic pain and naïve to strong opioids were recruited from nursing homes and Alzheimer's disease centers. OXN-PR was initiated at low doses (5 mg od or bid) and increased to a maximum of 20 mg bid. The primary efficacy endpoint was a pain intensity reduction of ≥30% from baseline (T0) to 15 days after OXN-PR initiation, as assessed by a numerical rating scale or the Pain Assessment in Advanced Dementia scale. Other assessments included the Barthel activities of daily living index, Neuropsychiatric Inventory, Bowel Function Index, and adverse events.

RESULTS

The analysis included 53 patients (mean age, 83.0 years; mean Mini-Mental State Examination score, 18.6) with severe pain (median Numerical Rating Scale/Pain Assessment in Advanced Dementia 6) and substantial impairment in daily functioning (mean Barthel index, 32.2). The primary endpoint was achieved by 92.4% of patients. OXN-PR significantly reduced mean pain intensity from baseline to study end (numerical rating scale, 6.6±1.0 vs 2.3±1.1, P<0.0001; Pain Assessment in Advanced Dementia, 6.9±1.6 vs 0.9±0.8, P<0.0001). Substantial improvements from T0 to T45 in daily functioning (mean Barthel index, 32.2±16.8 vs 53.7±23.9, P<0.0001) and neuropsychiatric symptoms (mean Neuropsychiatric Inventory, 25.5±27.3 vs 8.8±9.0, P<0.0001) were also reported. OXN-PR was well tolerated and did not worsen bowel function.

CONCLUSION

In this pilot study, OXN-PR was effective in improving pain and other symptoms associated with dementia, with a favorable safety and tolerability profile. Large-scale trials in people with dementia are needed to improve clinical guidance for the assessment and treatment of pain in these fragile individuals.

Efficacy and tolerability of oral oxycodone and oxycodone/naloxone combination in opioid-naïve cancer patients: a propensity analysis

Background

World Health Organization step III opioids are required to relieve moderate-to-severe cancer pain; constipation is one of the most frequent opioid-induced side effects. A fixed combination, prolonged-release oxycodone/naloxone (OXN), was developed with the aim of reducing opioid-related gastrointestinal side effects. The objective of this study was to compare the efficacy and safety of prolonged-release oxycodone (OXY) alone to OXN in opioid-naïve cancer patients with moderate-to-severe pain.

Methods

Propensity analysis was utilized in this observational study, which evaluated the efficacy, safety, and quality of life.

Results

Out of the 210 patients recruited, 146 were matched using propensity scores and included in the comparative analysis. In both groups, pain intensity decreased by ≈3 points after 60 days, indicating comparable analgesic efficacy. Responder rates were similar between groups. Analgesia was achieved and maintained with similarly low and stable dosages over time (12.0–20.4 mg/d for OXY and 11.5–22.0 mg/d for OXN). Bowel Function Index (BFI) and laxative use per week improved from baseline at 30 days and 60 days in OXN recipients (−16, P<0.0001 and −3.5, P=0.02, respectively); BFI worsened in the OXY group. The overall incidence of drug-related adverse events was 28.9% in the OXY group and 8.2% in the OXN group (P<0.01); nausea and vomiting were two to five times less frequent with OXN. Quality of life improved to a significantly greater extent in patients receiving OXN compared to OXY (increase in Short Form-36 physical component score of 7.1 points vs 3.2 points, respectively; P<0.001).

Conclusion

In patients with chronic cancer pain, OXN provided analgesic effectiveness that is similar to OXY, with early and sustained benefits in tolerability. The relationship between responsiveness to OXN and clinical characteristics is currently being investigated.

Quality of life and healthcare resource in patients receiving opioids for chronic pain: a review of the place of oxycodone/naloxone

In patients managed with opioids for chronic pain, opioid-induced bowel dysfunction—specifically, opioid-induced constipation (OIC)—is a common side effect, which has a significant impact on quality of life (QoL). The most recent developments for management of OIC are opioid antagonists, including naloxone, a competitive antagonist of peripheral opioid receptors that reverses opioid-induced peripheral gastrointestinal (GI) effects. A prolonged-release formulation of naloxone is available in combination with oxycodone (OXN PR). To review the specific role of OXN PR in the management of chronic pain and OIC and its impact on QoL and healthcare costs, a review of available relevant literature was conducted. Healthcare costs can be up to ten times higher for patients with GI events than for those without. Assessment of QoL in patients with OIC is essential, and multiple tools for its evaluation are available. The Bowel Function Index (BFI), a tool that was specifically developed and validated to measure bowel function in patients with OIC, can be an indication of QoL. In patients with moderate-to-severe chronic pain, randomized trials have demonstrated that OXN PR has equal analgesic efficacy and safety, but results in improved bowel function, compared with prolonged-release oxycodone (Oxy PR) alone. In conclusion, randomized studies using the BFI, as well as real-world clinical practice observations, have demonstrated improved QoL for patients taking OXN PR. This combination should allow more patients to benefit from the analgesic efficacy of opioid therapy and should minimize the side effects of constipation that correspond to improvements in QoL and healthcare offsets.

Development of opioid-induced constipation: post hoc analysis of data from a 12-week prospective, open-label, blinded-endpoint streamlined study in low-back pain patients treated with prolonged-release WHO step III opioids

BACKGROUND

Opioid-induced constipation is the most prevalent patient complaint associated with longer-term opioid use and interferes with analgesic efficacy, functionality, quality of life, and patient compliance.

OBJECTIVES

We aimed to compare the effects of prolonged-release (PR) oxycodone plus PR naloxone (OXN) vs PR oxycodone (OXY) vs PR morphine (MOR) on bowel function under real-life conditions in chronic low-back pain patients refractory to World Health Organization (WHO) step I and/or II analgesics.

RESEARCH DESIGN AND METHODS

This was a post hoc analysis of the complete data set from a prospective, randomized, open-label, blinded endpoint (PROBE) streamlined study (German pain study registry: 2012-0012-05; European Union Drug Regulating Authorities Clinical Trials [EudraCT]: 2012-001317-16), carried out in 88 centers in Germany, where a total of 901 patients requiring WHO step III opioids to treat low-back pain were enrolled and prospectively observed for 3 months. Opioid allocation was based on either optional randomization (n=453) or physician decision (n=448). In both groups, treatment doses could be adjusted as per the German prescribing information, and physicians were free to address all side effects and tolerability issues as usual. The primary endpoint was the proportion of patients maintaining normal bowel function throughout the complete treatment period, assessed with the Bowel Function Index (BFI). Secondary analyses addressed absolute and relative BFI changes, complete spontaneous bowel movements, use of laxatives, treatment emergent adverse events, analgesic effects, and differences between randomized vs nonrandomized patient groups.

RESULTS

BFI changed significantly with all three WHO step III treatments, however significantly less with OXN vs OXY and MOR despite a significantly higher use of laxatives with the latter ones (P<0.001). The percentage of patients who maintained normal BFI scores despite opioid treatment was 54.5% (164/301) with OXN and was significantly superior to those seen with OXY (32.8% [98/300]) (odds ratio [OR]: 2.47, 95% confidence interval [CI]: 1.77-3.44; P<0.001) or MOR (29.7% [89/300]) (OR: 2.84, 95% CI: 2.03-3.97; P<0.001). Absolute BFI changes of ≥12mm 100 mm horizontal visual analog scale (VAS100) vs. baseline were seen for OXN in 41.4%, for OXY in 68.7%, and for MOR in 72.3%. Complete spontaneous bowel movements decreased at least by one per week in 10.3% with OXN vs 42.3% for OXY (OR: 6.39, 95% CI 4.13-9.89; P<0.001) and 42.0% for MOR (OR: 6.31, 95% CI: 4.08-9.76; P<0.001). Overall, 359 treatment emergent adverse events (78 [OXN], 134 [OXY], and 147 [MOR]) in 204 patients (41 [OXN], 80 [OXY], and 83 [MOR]) occurred, most affecting the gastrointestinal (49.3%) and the nervous system (39.3%). Treatment contrasts between randomized vs nonrandomized patients were insignificant.

CONCLUSION

In this post hoc analysis of data from a real-life 12-week study, OXN treatment was associated with a significantly lower risk of opioid-induced constipation, superior tolerability, and significantly better analgesic efficacy compared with OXY and MOR.

Emerging therapies for patients with symptoms of opioid-induced bowel dysfunction

Opioid-induced bowel dysfunction (OIBD) comprises gastrointestinal (GI) symptoms, including dry mouth, nausea, vomiting, gastric stasis, bloating, abdominal pain, and opioid-induced constipation, which significantly impair patients’ quality of life and may lead to undertreatment of pain. Traditional laxatives are often prescribed for OIBD symptoms, although they display limited efficacy and exert adverse effects. Other strategies include prokinetics and change of opioids or their administration route. However, these approaches do not address underlying causes of OIBD associated with opioid effects on mostly peripheral opioid receptors located in the GI tract. Targeted management of OIBD comprises purely peripherally acting opioid receptor antagonists and a combination of opioid receptor agonist and antagonist. Methylnaltrexone induces laxation in 50%–60% of patients with advanced diseases and OIBD who do not respond to traditional oral laxatives without inducing opioid withdrawal symptoms with similar response (45%–50%) after an oral administration of naloxegol. A combination of prolonged-release oxycodone with prolonged-release naloxone (OXN) in one tablet (a ratio of 2:1) provides analgesia with limited negative effect on the bowel function, as oxycodone displays high oral bioavailability and naloxone demonstrates local antagonist effect on opioid receptors in the GI tract and is totally inactivated in the liver. OXN in daily doses of up to 80 mg/40 mg provides equally effective analgesia with improved bowel function compared to oxycodone administered alone in patients with chronic non-malignant and cancer-related pain. OIBD is a common complication of long-term opioid therapy and may lead to quality of life deterioration and undertreatment of pain. Thus, a complex assessment and management that addresses underlying causes and patomechanisms of OIBD is recommended. Newer strategies comprise methylnaltrexone or OXN administration in the management of OIBD, and OXN may be also considered as a preventive measure of OIBD development in patients who require opioid administration.

Noninterventional study of transdermal fentanyl (fentavera) matrix patches in chronic pain patients: analgesic and quality of life effects

Fentanyl is considered to be an effective, transdermal treatment of chronic, cancer, and noncancer pain. This noninterventional, clinical practice-based study, on 426 patients attending 42 practices, assessed a proprietary, Aloe vera-containing, transdermal fentanyl matrix patch (Fentavera), for its analgesic effects, patients' quality of life (QoL) effects, tolerability, and adhesiveness. Study outcomes were mean changes from baseline of patient (11-point scales) and physician (5-point scales) ratings. After 1 and 2 months treatment, there were significant (P < 0.0001) decreases in patients' ratings of pain intensity, and impairment of walking, general activity, sleep quality, and QoL. For each parameter, the patient response rate was >30% at 2 months (response = 2-point decrease on 11-point rating scale). In a large majority of patients, the physicians rated the matrix patch as good or very good for analgesic effect, systemic and local tolerance, and adhesiveness. There were 30 adverse events in 4.2% of patients and analgesic comedications were reduced during treatment compared to before treatment. It is concluded, from this population-based data, that the proprietary, transdermal fentanyl matrix patch is effective and safe for chronic pain management in clinical practice, with significant positive analgesic and QoL effects, while being well tolerated and exhibiting good or very good adhesiveness.

Treatment with prolonged-release oxycodone/naloxone improves pain relief and opioid-induced constipation compared with prolonged-release oxycodone in patients with chronic severe pain and laxative-refractory constipation

PURPOSE

Laxative-refractory opioid-induced constipation (OIC) is defined as OIC despite using 2 laxatives with a different mechanism of action (based on the Anatomical Therapeutic Chemical Classification System level 4 term [contact laxatives, osmotically acting laxatives, softeners/emollients, enemas, and others]). OIC has a significant impact on the treatment and quality of life of patients with severe chronic pain. This noninterventional, observational, real-life study in Belgium investigated the efficacy of prolonged-release oxycodone/naloxone combination (PR OXN) treatment regarding pain relief and OIC compared with previous prolonged-release oxycodone (PR OXY) treatment for laxative-refractory OIC in daily clinical practice.

METHODS

Laxative-refractory OIC patients with severe chronic pain were treated with PR OXN for 12 weeks (3 visits). Pain relief (assessed on a numerical rating scale) and OIC (assessed by using the Bowel Function Index [BFI]) were evaluated at each visit. A responder was defined as a patient who had: (1) no worsening of pain at the last visit compared with visit 1 or a numerical rating scale ≤4 at visit 3/last visit; and (2) a reduction in BFI ≥12 units at visit 3/last visit compared with visit 1; or (3) a BFI ≤28.8 at visit 3/last visit.

FINDINGS

Sixty-eight laxative-refractory OIC patients with severe chronic pain (mean (sd) age 59.8 (13.3) years, 67.6% female and 91.2% non-malignant pain) were treated for 91 days with PR OXN (median daily dose, 20 mg). Treatment with PR OXN resulted in a significant and clinically relevant decrease of pain of 2.1 units (P < 0.001; 95% CI, 1.66-2.54) and of BFI by 48.5 units (P < 0.001; 95% CI, 44.4-52.7) compared with PR OXY treatment; use of laxatives was also significantly reduced (P < 0.001). Approximately 95% of patients were responders, and quality of life (as measured by using the EQ-5D) improved significantly. Adverse events were opioid related, and PR OXN treatment was well tolerated.

IMPLICATIONS

Treatment with PR OXN resulted in a significant and clinically relevant reduction in OIC compared with previous PR OXY treatment for these patients with severe chronic pain and laxative-refractory OIC. Treatment with PR OXN also resulted in a significant improvement in pain relief and quality of life. ClinicalTrials.gov identifier: NCT01710917.

Safety and efficacy of oxycodone/naloxone vs. oxycodone vs. morphine for the treatment of chronic low back pain: results of a 12 week prospective, randomized, open-label blinded endpoint streamlined study with prolonged-release preparations

BACKGROUND

Opioid-induced constipation (OIC) is the most prevalent patient complaint associated with opioid use and interferes with analgesic efficacy.

OBJECTIVES

This PROBE trial compares the overall safety and tolerability of oxycodone/naloxone (OXN) with those of traditional opioid therapy with oxycodone (OXY) or morphine (MOR) in the setting of the German healthcare system.

RESEARCH DESIGN AND METHODS

This was a prospective, randomized, open-label, blinded endpoint (PROBE) streamlined study (German pain study registry: 2012-0012-05; EudraCT: 2012-001317-16), carried out in 88 centers in Germany, where a total of 453 patients, requiring WHO step III opioids to treat low back pain, were randomized to OXN, OXY or MOR (1:1:1) for 3 months. The primary outcome was the percentage of patients without adverse event-related study discontinuations who presented with a combination of a ≥50% improvement of pain intensity, disability and quality-of-life and a ≤50% worsening of bowel function at study end.

RESULTS

Significantly more OXN patients met the primary endpoint (22.2%) vs. OXY (9.3%; OR: 2.80; p < 0.001) vs. MOR (6.3%; OR: 4.23; p < 0.001), with insignificant differences between OXY vs. MOR (p = 0.155). A ≥50% improvement of pain intensity, functional disability and quality-of-life has been found for OXN in 75.0/61.1/66.0% of patients and thus for all parameters significantly more than with OXY (58.9/49.0/48.3; p < 0.001 for each) or MOR (52.5/46.2/37.3; p < 0.001 for each). A total of 86.8% of OXN patients kept normal BFI scores during treatment, vs. 63.6% for OXY (p < 0.001) vs. 53.8% for MOR (p < 0.001). Overall 189 TEAEs (OXN: 45, OXY: 69, MOR: 75) in 92 patients (OXN: 21, OXY: 44, MOR: 37) occurred, most gastrointestinal (50.8%). One limitation is the open-label design, which presents the possibility of interpretive bias.

CONCLUSION

Under the conditions of this PROBE design, OXN was associated with a significantly better tolerability, a lower risk of OIC and a significantly better analgesic efficacy than OXY or MOR.

Efficacy and tolerability of low-dose oral prolonged-release oxycodone/naloxone for chronic nononcological pain in older patients

Purpose

Chronic pain is highly prevalent in older adults. Increasing evidence indicates strong opioids as a valid option for chronic pain management in geriatrics. The aim of this study was to evaluate efficacy and safety of low-dose oral prolonged-release oxycodone–naloxone (OXN-PR) in patients aged ≥70 years.

Methods

This open-label prospective study assessed older patients naïve to strong opioids presenting with moderate-to-severe chronic pain. Patients were prescribed OXN-PR at an initial dose of 10/5 mg/day for 28 days. In case of insufficient analgesia, the initial daily dose could be increased gradually. The primary efficacy measure was change in pain intensity from baseline, assessed by a ten-point Numeric Rating Scale (NRS) at day 28 (T28). Changes in cognitive state, daily functioning, quality of life, constipation, and other adverse events were assessed.

Results

Of 53 patients enrolled (mean 81.7±6.2 years [range 70–92 years]), 52 (98.1%) completed the 28-day observation. At T28, the primary end point (≥30% reduction in mean pain from baseline in the absence of bowel function deterioration) was achieved in 38 patients (71.7%). OXN-PR significantly relieved pain (NRS score –3.26; P<0.0001), as well as daily need for rescue paracetamol (from 86.8% at baseline to 40.4% at T28; P<0.001), and reduced impact of pain on daily activities (Brief Pain Inventory Short Form from 6.2±1.5 to 3.4±2.1; P<0.0001). OXN-PR was also associated with significant improvement in daily functioning (Barthel Index from 53.3±14.1 to 61.3±14.3; P<0.01). No changes were observed in cognitive status and bowel function. OXN-PR was well tolerated; only one patient (1.9%) prematurely withdrew from treatment, due to drowsiness.

Conclusion

Findings from this open-label prospective study suggest that low-dose OXN-PR may be effective and well tolerated for treatment of moderate-to-severe chronic pain in older patients. Besides its effectiveness, these data indicate that low-dose OXN-PR may be considered a safe analgesic option in this fragile population and warrants further investigation in randomized controlled studies.

Patient preference with respect to QoL and reduction in opioid-induced constipation (OIC) after treatment with prolonged-release (PR) oxycodone/naloxone compared with previous analgesic therapy [PREFER study]

OBJECTIVE

The aim of this study was to assess patient preference in terms of quality of life (QoL), analgesia and bowel function for patients with moderate to severe chronic non-malignant pain, when treated with oxycodone PR/naloxone PR compared with the previous WHO-step I and/or WHO-step II analgesic treatment .

STUDY DESIGN

This was a 3-week open-label phase 3b study conducted in Belgium and the Netherlands, after 3 weeks patients could enter an extension phase. Patient preference with respect to QoL for oxycodone PR/naloxone PR treatment compared with previous WHO-step I and/or WHO-step II analgesics was assessed. A patient was considered a responder with respect to QoL if this assessment was 'better' or 'much better' compared with previous WHO-step I or II analgesics at any time point.

RESULTS

Response rate with respect to QoL was 59.2% (95% CI: 51.7-66.8%) for the Full Analysis (FA)-population, for the Per Protocol-population response rate was 71.7% (95% CI: 63.1-80.3%). Explorative analysis showed that response rate with respect to QoL was highest in constipated patients pretreated with WHO-step II analgesics (73.8%). Mean ± SD pain score in the FA-population at start was 74.7 ± 16.6 decreasing to 53.9 ± 24.3 after a median (range) treatment period of 173.5 (31-771) days. For constipated subjects the significant reduction in constipation [improvement of the Bowel Function Index (BFI)], was -24.8 points (95% CI: -17.1 to -32.5). BFI for non-constipated subjects remained well below 28.8. Adverse events with oxycodone PR/naloxone PR treatment were well-known opioid-related adverse events.

CONCLUSION

This study shows that the studied patients previously treated with WHO-step I and/or WHO-step II analgesics prefer treatment with oxycodone PR/naloxone PR with respect to QoL. Moreover, the study shows that treatment with oxycodone PR/naloxone PR significantly reduces OIC in constipated patients and that non-constipated patients do not develop OIC during treatment with oxycodone PR/naloxone PR.

Fixed ratio (2:1) prolonged-release oxycodone/naloxone combination improves bowel function in patients with moderate-to-severe pain and opioid-induced constipation refractory to at least two classes of laxatives

OBJECTIVE

The effects of combined oxycodone/naloxone prolonged release tablets (OXN PR) were investigated in patients with moderate-to-severe chronic cancer-related or non-cancer pain. All patients had opioid-induced constipation (OIC) which persisted despite substantial laxative therapy.

RESEARCH DESIGN AND METHODS

This pooled analysis included 75 patients with OIC at study entry that was refractory to at least two laxatives with different modes of action. Patients completed randomized, double-blind treatment with OXN PR 20-120 mg/day for either 12 weeks (OXN 9001: non-cancer pain study) or 4 weeks (OXN 2001: cancer-related pain study). Analgesia and bowel function were assessed using the Brief Pain Inventory Short Form and Bowel Function Index (BFI), respectively. Use of laxative medication and safety were assessed throughout the studies.

CLINICAL TRIAL REGISTRATION

NCT00513656, EudraCT 2005-002398-57, EudraCT 2005-003510-15.

RESULTS

Statistically and clinically significant improvements in bowel function were observed following double-blind treatment with OXN PR. Mean (SD) reduction in BFI score was 21.2 (28.8) and comparable in patients with cancer-related (19.0 [28.9]) and non-cancer pain (23.3.[29.0]; P ≤ 0.0002). Furthermore, the proportion of patients with a BFI score within normal range (≤28.8) increased from 9.5% at screening to 43.1% at Day 15 of OXN PR. While all patients used ≥2 laxatives of different classes at screening, during study treatment 36% stopped using laxatives (P < 0.001). OXN PR provided effective analgesia, evidenced by stable pain scores during study treatment, and there were no unanticipated adverse events.

CONCLUSIONS

OXN PR significantly improved bowel function and reduced the use of laxatives in patients with OIC, previously unresponsive to at least two different classes of laxatives. OXN also provided effective analgesia for patients with moderate-to-severe cancer-related pain and non-cancer-related pain.

Changes in Quality of Life after 3 months of Usual Care in a Large Sample of Patients with Noncancer Pain: The "QOOL: Quality of Life and Pain" Study

Large-scale observational studies can provide useful information on changes in health outcomes over time. The aim of this study was to investigate the effect of 3 months of usual care on quality of life (QOL) and pain outcomes in noncancer chronic pain patients managed by pain specialists and to examine factors associated with changes in QOL. This was assessed using the EQ-5D and pain outcomes using the Brief Pain Inventory (BPI). Changes in QOL and pain were studied for the overall sample and in subgroups defined by baseline pain severity. Multivariate regression was used to investigate factors associated with change on EQ-5D. Three thousand and twenty-nine patients were included for analysis. After 3 months of usual care, a mean of 40.9% of patients showed improvement on individual EQ-5D dimensions, with the highest rates of improvement seen on the pain/discomfort (50.8%) and anxiety/depression (48.3%) dimensions. The EQ-5D Index increased from a mean (SD) of 0.35 (0.2) to 0.58 (0.21) points between baseline and month 3, and the thermometer from 41.5 (19.4) to 58.7 (17.8), indicating a large effect. Improvements in QOL were larger in those with severe baseline pain. The BPI severity summary score improved from a mean (SD) of 6.5 (1.4) to 4.1 (1.7) and the interference summary score from 6.6 (1.5) to 4.2 (1.9). Changes on the BPI severity and interference scores were associated with changes in the EQ-5D Index and thermometer. In conclusion, 3 months of usual care in noncancer pain patients led to substantial improvements in QOL and pain outcomes.

Oxycodone/Naloxone: role in chronic pain management, opioid-induced constipation, and abuse deterrence

The use of opioids in the treatment of chronic pain is widespread; the prevalence of specific opioids varies from country to country and depends on product availability, national formulary systems, and provider preferences. Patients often receive opioids for legitimate treatment of pain conditions, but on the opposite side of the spectrum, nonmedical use of opioids is a significant public health concern. Opioids are associated with several side effects, and constipation is the most commonly reported and persistent symptom. Unlike some adverse effects associated with opioid use, tolerance does not develop to constipation. Opioid-induced constipation (OIC) is the most prevalent patient complaint associated with opioid use and has been associated with declines in various quality of life measures. OIC can be extremely difficult for patients to tolerate and may prompt patients to decrease or discontinue opioid treatment. Current management strategies for OIC are often insufficient. A prolonged-release formulation of oxycodone/naloxone (OXN) has been investigated for the treatment of nonmalignant and cancer pain and mitigation of OIC, and evidence is largely favorable. Studies have demonstrated the capability of OXN to alleviate OIC while maintaining pain control comparable to oxycodone-only regimens. There is insufficient evidence for OXN efficacy for patients with mild OIC or patients maintained on high doses of opioids, and use in these populations is controversial. The reduction of costs associated with OIC may provide overall cost effectiveness with OXN. Additionally, the presence of naloxone may deter abuse/misuse by those seeking to misuse the formulation by modes of administration other than oral ingestion. Most studies to date have occurred in European countries, and phase 3 trials continue in the United States. This review will include current therapeutic options for pain and constipation, unique characteristics of OXN, evidence related to use of OXN and its place in therapy, discussion of opioid abuse/misuse, and various abuse-deterrent mechanisms, and areas of continuing research.

Effectiveness and tolerability of low-dose oral oxycodone/naloxone added to anticonvulsant therapy for noncancer neuropathic pain: an observational analysis

BACKGROUND

Opioids may alleviate chronic neuropathic pain (NP), but are considered second/third-line analgesia due to their poor gastrointestinal (GI) tolerability. A fixed combination of prolonged-release oxycodone and naloxone (OXN) has been developed to overcome the GI effects. The aim of this analysis was to evaluate analgesic effectiveness and tolerability of low-dose OXN in patients with moderate-to-severe noncancer NP despite analgesia.

METHODS

This retrospective observation of consecutive adult patients, treated open-label for 8 weeks at a single Italian centre, evaluated effectiveness (pain intensity numerical rating scale [NRS], Patients' Global Impression of Change [PGIC], Douleur Neuropathique 4 inventory [DN4] and Chronic Pain Sleep Inventory [CPSI]), doses of daily OXN and adjuvant medication, rescue paracetamol use, bowel function index (BFI), laxative use, and safety.

RESULTS

Of 200 patients (mean age 65.9 years; 54% female) with NP included in the analysis; 97% completed 8 weeks' treatment. At the observation start, all patients were taking anticonvulsants and complained of constipation, and 60% were receiving opioids. Pain intensity and DN4 score decreased significantly by endpoint (NRS p < 0.0001; DN4 p < 0.0001) and need for rescue analgesics abated. Reduction in pain intensity throughout the observation was similar regardless of NP aetiology. According to PGIC, 87.8% of patients were much/extremely improved, CPSI (p < 0.0001) and BFI were significantly improved (p < 0.0001) and laxative use decreased. No differences were found between patients <65 years vs those ≥65 years. OXN was generally well tolerated.

STUDY LIMITATIONS

Study limitations including the retrospective observational design, the lack of a control group and the single-centre design may limit the generalizability of our findings.

CONCLUSIONS

Low-dose OXN (25.0 ± 12.5 mg/day) added to anticonvulsants was highly effective in controlling noncancer NP of varied aetiology, with reduced need for rescue analgesia and improved quality of sleep, and was well tolerated, with improved bowel function and reduced laxative use. The efficacy and tolerability of OXN demonstrated in this real-world setting suggest its utility in this difficult to manage patient population.

Effects of prolonged-release oxycodone/naloxone on pain control, bowel function and quality of life: A prospective observational study

Background and aim

Strong opioids including oxycodone are amongst the most effective analgesics to combat moderate to severe pain of various aetiologies, but opioid-induced bowel dysfunction (OIBD) represents a relevant problem. The rationale for development of a prolonged-release (PR) fixed combination of oxycodone and naloxone was to counteract OIBD. Due to its negligible oral bioavailability, the μ-opioid receptor antagonist naloxone is able to selectively displace opioids from local μ-receptors in the gastrointestinal tract without affecting central opioid binding sites. Pivotal trials of PR oxycodone/naloxone not only demonstrated improved bowel function but also equivalent analgesic efficacy compared to PR oxycodone alone. Controlled clinical trials comparing PR oxycodone/naloxone with strong opioids other than oxycodone are not available. The present study is the first data set aimed at comparing pain control, bowel function, and quality of life (QoL) in patients newly treated with or switched to PR oxycodone/naloxone or other strong opioids during routine clinical practice.

Methods

In this three-arm, prospective observational study, 588 patients with moderate to severe pain of varying aetiologies received either PR oxycodone/naloxone (OXN group and OXN 40/20 group with indicated use of the 40 mg/20 mg dose strength at baseline) or other strong opioids (control group), dosed according to pain severity, for 4–6 weeks. Data documented include pain intensity (NRS), bowel function (Bowel Function Index, BFI), pain-related functional impairment (BPI-SF), QoL (EuroQol EQ-5D-3L), and a global assessment of treatment.

Results

Patients receiving PR oxycodone/naloxone experienced a clinically important reduction in pain intensity and pain-related functional impairment of approximately 40%. The reductions of pain intensity (−2.9 ± 2.3) and pain-related functional impairment (−2.4 ± 2.3) in the OXN group were significantly more pronounced than in the control group (−2.1 ± 2.1 and −1.8 ± 1.7). In the control group, mean reductions in pain intensity did not reach the threshold of ≥30% for at least moderate clinically important differences, although patients were prescribed higher doses of morphine equivalents than OXN group patients. Improvements in bowel function (OXN: −16.0 ± 27.6; control: 3.1 ± 24.4) and QoL (OXN: 20.8 ± 24.2; control: 13.2 ± 23.1) were also significantly more pronounced in the OXN group, with BFI scores reduced to a level that reflects normal bowel function. Results for the OXN 40/20 group receiving higher doses of PR oxycodone/naloxone were in line with those for the OXN group. In the control group, more frequent gastrointestinal adverse events and less favourable ratings of tolerability resulted in a higher rate of treatment discontinuations due to adverse events.

Conclusions

In patients receiving PR oxycodone/naloxone, more favourable outcomes compared with other strong opioids regarding pain control, bowel function, and QoL were observed.

Implications

The present findings underline the value of PR oxycodone/naloxone in the management of patients with moderate to severe chronic pain. The data set further adds to our understanding of the benefits and risks of opioid treatment in routine clinical practice.

Cancer pain therapy with a fixed combination of prolonged-release oxycodone/naloxone: results from a non-interventional study

BACKGROUND

Strong opioids, including oxycodone, are the most effective analgesics used to combat moderate to severe cancer pain, but opioid-induced bowel dysfunction is a relevant problem associated with the therapy. Clinical studies have demonstrated equivalent analgesic efficacy and improved bowel function in treatment with a fixed combination of prolonged-release (PR) oxycodone and PR naloxone compared to oxycodone alone in patients with nonmalignant pain. Here, we report of a prospective, non-interventional study evaluating the effectiveness and safety of PR oxycodone/PR naloxone in a subgroup of patients with severe cancer pain.

PATIENTS AND METHODS

Within the non-interventional multicenter study, 1,178 cancer patients with severe chronic pain received PR oxycodone/PR naloxone, dosed according to pain intensity, for 4 weeks. Recorded variables included pain intensity, patient-reported bowel function (Bowel Function Index), and pain-related functional impairment as a measure of quality of life (QoL).

RESULTS

During treatment with PR oxycodone/PR naloxone, clinically relevant improvements in pain intensity were observed in opioid-naïve patients and in patients pretreated with weak or strong opioids, as reflected by reductions in pain scores of 51%, 53%, and 33%, respectively. Improvement in analgesia was paralleled by a significant reduction of opioid-induced bowel dysfunction in opioid-pretreated patients. The reductions in the mean Bowel Function Index of -20.5 and -36.5 in patients pretreated with weak and strong opioids, respectively, represent clinically relevant improvements in bowel function. Pain-related functional impairment decreased consistently across all seven domains, which is equivalent to a substantial improvement in QoL.

CONCLUSION

This subgroup analysis of cancer patients within a large non-interventional study demonstrates that treatment with PR oxycodone/PR naloxone provides effective analgesia with minimization of bowel dysfunction and improved QoL. These data extend our knowledge of the effectiveness and tolerability of PR oxycodone/PR naloxone to the population of patients with cancer under real-life conditions.

Efficacy and gastrointestinal tolerability of oral oxycodone/naloxone combination for chronic pain in outpatients with cancer: an observational study

Combination opioid agonist/antagonist therapy has been shown to preserve bowel function in patients with chronic cancer pain. This retrospective study evaluated the efficacy and tolerability of prolonged-released fixed-dose oxycodone-naloxone (PR OXN) in consecutive outpatients with chronic cancer pain. Of 206 patients prescribed PR OXN (mean age 61.3 ± 12.9 years; 52.9% female), 31.5% were opioid naïve. PR OXN was associated with a significant decrease in pain score measured on a visual analogue scale over 28 days (P < .0001), without adverse effects on bowel function, nor change in laxative use. PR OXN efficacy and tolerability were similar in opioid-naïve and -experienced patients, and among age-stratified subgroups. No severe side effects occurred. In a real-life outpatient setting, PR OXN provided analgesia without bowel dysfunction in patients with chronic cancer pain.

[Is the pharmacological treatment of constipation in palliative care evidence based? : a systematic literature review]

MATERIALS AND METHODS

To evaluate the evidence for clinically established pharmacological therapies for constipation in palliative care, a systematic literature review was performed in different databases (Cochrane Library, Embase, PubMed, Ovid MEDLINE, CINAHL), textbooks, and publications.

RESULTS

Whereas 130 randomized controlled trials were found with patients outside of palliative care settings, only 10 controlled studies with patients in end-of-life situations were identified: three RCTs with methylnaltrexone and one with the combination of oxycodone and naloxone showed the effect and safety of opiate antagonists for patients who are not at risk of gastrointestinal perforation. There have been no studies which test methylnaltrexone against the optimization of therapy with conventional laxatives. Six other controlled studies of limited quality in design and execution and with only few participants tested naloxone, senna, lactulose, Co-danthramer, an Ayurvedic preparation (Misrakasneham), magnesium hydroxide, fluid paraffin, sodium picosulfate and docusate without finding statistically significant differences in efficacy or side effects. Most patients in these studies had cancer. Only case studies with few patients in palliative care were found for meglumine, neostigmine, and other substances mentioned above.

CONCLUSION

Evidence on medical treatment of constipation in palliative care is sparse and guidelines have to refer to evidence from outside the palliative care setting and to expert opinions. Results from studies with other patient groups can only be transferred with limitations to very ill patients at the end of life who might have a higher risk for potential side effects such as gastrointestinal perforation in case of abdominal tumor manifestation. Therefore further studies are required to evaluate the medical treatment of multiple reasons for constipation in these patients. These studies should focus on feasibility, clinical relevance and quality of life. The English full text version of this article will be available in SpringerLink as of November 2012 (under "Supplemental").

The place of oxycodone/naloxone in chronic pain management

Opioid analgesics are usually effective in the management of severe chronic pain. However, symptoms of opioid-induced bowel dysfunction (OIBD) are common during opioid therapy. Opioid-induced bowel dysfunction is often unsuccessfully managed due to limited effectiveness and numerous adverse effects of traditional laxatives. Newer treatment possibilities directed at the pathomechanism of OIBD comprise combined prolonged-release oxycodone with prolonged-release naloxone (oxycodone/naloxone) tablets. Oxycodone/naloxone provides effective analgesia with limited impact on bowel function as oxycodone displays high oral bioavailability and naloxone act as local antagonist on opioid receptors in the gastrointestinal tract due to nearly complete inactivation in the liver. Oxycodone/naloxone is administered to opioid-naive patients with severe pain and those unsuccessfully treated with weak opioids. Oxycodone/naloxone may be also administered to patients treated with strong opioids who experience intense symptoms of OIBD. Studies conducted to date indicate that oxycodone/naloxone is an important drug in chronic pain management, prevention and treatment of OIBD.

Oxycodone combined with opioid receptor antagonists: efficacy and safety

INTRODUCTION

A mu receptor antagonist combined with oxycodone (OXY) may improve pain control, reduce physical tolerance and withdrawal, minimizing opioid-related bowel dysfunction and act as an abuse deterrent.

AREAS COVERED

The authors cover the use of OXY plus ultra-low-dose naltrexone for analgesia and the use of sustained-release OXY plus sustained-release naloxone to reduce the opioid bowel syndrome. The authors briefly describe the use of sustained-release OXY and naltrexone pellets as a drug abuse deterrent formulation. Combinations of ultra-low-dose naltrexone plus OXY have been in separate trials involved in patients with chronic pain from osteoarthritis and idiopathic low back pain. High attrition and marginal differences between ultra-low-dose naltrexone plus OXY and OXY led to discontinuation of development. Prolonged-release (PR) naloxone combined with PR OXY demonstrates a consistent reduction in opioid-related bowel dysfunction in multiple randomized controlled trials. However, gastrointestinal side effects, including diarrhea, were increased in several trials with the combination compared with PR OXY alone. Analgesia appeared to be maintained although non-inferiority to PR OXY is not formally established. There were flaws to trial design and safety monitoring. Naltrexone has been combined with OXY in individual pellets encased in a capsule. This combination has been reported in a Phase II trial and is presently undergoing Phase III studies.

EXPERT OPINION

Due to the lack of efficacy the combination of altered low-dose naltrexone with oxycodone should cease in development. The combination of sustained release oxycodone plus naloxone reduces constipation with a consistent benefit. Safety has been suboptimally evaluated which is a concern. Although the drug is commercially available in several countries, ongoing safety monitoring particularly high doses would be important.

Controlled-release oxycodone and naloxone in the treatment of chronic low back pain: a placebo-controlled, randomized study

BACKGROUND

For Canadian regulatory purposes, an analgesic study was required to complement previously completed, pivotal studies on bowel effects and analgesia associated with controlled-release (CR) oxycodone⁄CR naloxone.

OBJECTIVES

To compare the analgesic efficacy and safety of CR oxycodone⁄CR naloxone versus placebo in patients with chronic low back pain.

METHODS

Patients requiring opioid therapy underwent a two- to seven-day opioid washout before being randomly assigned to receive either 10 mg⁄5 mg CR oxycodone⁄CR naloxone or placebo every 12 h, titrated weekly according to efficacy and tolerability to 20 mg⁄10 mg, 30 mg⁄15 mg or 40 mg⁄20 mg every 12 h. After four weeks, patients crossed over to the alternative treatment for an additional four weeks. Acetaminophen⁄codeine (300 mg⁄30 mg every 4 h to 6 h as needed) was provided as rescue medication.

RESULTS

Of the 83 randomized patients, 54 (65%) comprised the per-protocol population. According to per-protocol analysis, CR oxycodone⁄CR naloxone resulted in significantly lower mean (± SD)pain scores measured on a visual analogue scale (48.6 ± 23.1 mm versus 55.9 ± 25.4 mm; P=0.0296) and five-point ordinal pain intensity scores (2.1 ± 0.8 versus 2.4 ± 0.9; P=0.0415) compared with placebo. After the double-blinded phase, patients and investigators both preferred CR oxycodone⁄CR naloxone over placebo. These outcomes continued in the 79% of patients who chose to continue receiving CR oxycodone⁄CR naloxone in a six-month, open-label evaluation.

CONCLUSIONS

In patients complying with treatment as per protocol, CR oxycodone⁄CR naloxone was effective for the management of chronic low back pain of moderate or severe intensity.

Prolonged-release oxycodone/naloxone in nonmalignant pain: single-center study in patients with constipation

INTRODUCTION

Opioid treatment for chronic malignant and nonmalignant pain of moderateto-severe intensity is associated with bowel dysfunction leading to constipation; this often requires opioid dose reduction or interruption. Combination opioid agonist/antagonist therapy can restore normal bowel function. A prolonged-released (PR) fixed-dose combination of oxycodone and naloxone has been developed and efficacy has been demonstrated in phase 3 clinical trials.

METHODS

This 2-month, retrospective, singlecenter, observational study assessed the effectiveness and safety of PR oxycodone/naloxone in consecutive nononcological patients with constipation and chronic pain despite analgesic treatment; specific subgroup analyses were performed in opioid-experienced or opioid-naïve patients and in age subgroups. Efficacy was assessed by: intensity of pain; bowel function; effective oxycodone/naloxone dose; Patients' Global Impression of Change (PGIC) scale; rescue paracetamol; and laxative use. Safety evaluations were also performed.

RESULTS

Of 1,051 patients starting on the oxycodone/naloxone combination (32.0% male; mean age 67 ± 13 years, 53.9% opioid naïve), 1,012 completed 2 months of treatment. Overall, PR oxycodone/naloxone was associated with a significant decrease in pain intensity (P < 0.001), a reduced need for rescue paracetamol (P < 0.001), and PGIC score of "very much improved" or "much improved" in 84.0% of patients. Constipation markedly decreased (P < 0.001) despite reduced laxative use (P < 0.001 vs. baseline). The most frequent treatment-emergent adverse events were somnolence (2.0%), dizziness (1.1%), and confusion (1.0%). Clinical differences in endpoints were seen between opioid-naïve and opioid-experienced patients, and among agestratified groups, but efficacy was similar to the overall population.

CONCLUSIONS

Fixed combination PR oxycodone/naloxone was effective and well tolerated in moderate-to-severe chronic pain in patients with constipation, providing analgesia and relief from bowel dysfunction. Consistent efficacy across patient subgroups provides guidance for daily management of chronic pain when therapy options are limited due to bowel dysfunction, regardless of age or previous medication. Supplementary material belonging to this paper is available on SpringerLink.

Combined oral prolonged-release oxycodone and naloxone in chronic pain management

INTRODUCTION

The use of opioids is associated with unwanted adverse effects, particularly opioid-induced constipation (OIC). The adverse effects of opioids on gastrointestinal function are mediated by the interaction with opioid receptors in the gastrointestinal tract. The most common drugs used for relieving OIC are laxatives, which do not address the opioid receptor-mediated bowel dysfunction and do not provide sufficient relief.

AREAS COVERED

This paper discusses the role of a combination of prolonged-release formulation of oxycodone (OX) and naloxone (N) in the prevention and management of OIC, reporting efficacy and safety outcome of controlled studies. In a therapeutic area of great unmet need, the combination tablet of prolonged release of OX and N (PR OXN) could offer patients effective analgesia, while improving opioid-induced bowel dysfunction.

EXPERT OPINION

PR OXN offers a unique and specific mechanism to control OIC in patients receiving chronic opioid therapy. This combination has the potential advantage of preventing OIC, particularly in subgroups of population, like elderly or advanced cancer patients. This approach can decrease the use of laxatives and additional medications, which represent a burden for patients presenting comorbidities requiring multiple medications.

Opioid/naloxone prolonged release combinations for opioid induced constipation

I read with great interest the recent article by Chen et al in a recent issue of your esteemed journal. The article is highly thought provoking. One emerging therapeutic alternative for opioid induced constipation is the emergence of opioid/naloxone prolonged release combinations. For instance, naloxone when administered in a 1:2 ratio with oxycodone reverses the inhibitory effect of oxycodone on the gastrointestinal tract. The advantage of oxycodone/naloxone prolonged release (OXN) is that while its anti-nociceptive efficacy is equivalent to that of oxycodone prolonged release (OXC), it significantly decreases the “Bowel Function Index” thereby ameliorating symptoms of opioid induced constipation to a large extent. Schutter et al in a recent study have reported a decrease in the bowel function index from 38.2 to 15.1. Similarly, Löwenstein et al in another recent study have reported that following a month of therapy, complete spontaneous bowel movements per week is increased from one in OXC therapy to three in OXN therapy.

The Bowel Function Index: a new validated scale for assessing opioid-induced constipation

BACKGROUND

The management of opioid-induced constipation (OIC) is often complicated by the fact that clinical measures of constipation do not always correlate with patient perception. As the discomfort associated with OIC can lead to poor compliance with the opioid treatment, a shift in focus towards patient assessment is often advocated.

SCOPE

The Bowel Function Index * (BFI) is a new patient-assessment scale that has been developed and validated specifically for OIC. It is a physician-administered, easy-to-use scale made up of three items (ease of defecation, feeling of incomplete bowel evacuation, and personal judgement of constipation). An extensive analysis has been performed in order to validate the BFI as reliable, stable, clinically valid, and responsive to change in patients with OIC, with a 12-point change in score constituting a clinically relevant change in constipation.

FINDINGS

The results of the validation analysis were based on major clinical trials and have been further supported by data from a large open-label study and a pharmaco-epidemiological study, in which the BFI was used effectively to assess OIC in a large population of patients treated with opioids. Although other patient self-report scales exist, the BFI offers several unique advantages. First, by being physician-administered, the BFI minimizes reading and comprehension difficulties; second, by offering general and open-ended questions which capture patient perspective, the BFI is likely to detect most patients suffering from OIC; third, by being short and easy-to-use, it places little burden on the patient, thereby increasing the likelihood of gathering accurate information.

CONCLUSION

Altogether, the available data suggest that the BFI will be useful in clinical trials and in daily practice.

Prolonged-release oxycodone/naloxone in the treatment of neuropathic pain - results from a large observational study

OBJECTIVES

Opioids have shown consistent efficacy in neuropathic pain, but opioid-induced bowel dysfunction is a relevant problem. In controlled clinical trials, a fixed-dose combination of prolonged-release (PR) oxycodone/PR naloxone was superior to oxycodone alone in bowel function, while providing effective analgesia. The present report is an analysis of its efficacy and safety in a subgroup of patients with severe chronic neuropathic pain who were treated in a large observational study under real-life conditions.

RESEARCH DESIGN AND METHODS

Dosed according to pain severity, 1488 patients with chronic severe neuropathic pain received PR oxycodone/PR naloxone for up to 4 weeks. Variables included pain severity, patient-reported bowel function (Bowel Function Index; BFI) and quality of life.

RESULTS

During treatment with PR oxycodone/PR naloxone, mean pain intensity decreased in opioid-naive and opioid-pretreated patients. After 4 weeks on treatment, mean BFI scores were reduced from 41.6 ± 31.6 at the initiation visit to 16.5 ± 19.6 (p < 0.001), reflecting normal bowel function. Quality of life was improved by 47%.

CONCLUSIONS

Treatment of severe neuropathic pain with PR oxycodone/PR naloxone provided effective analgesia with the added benefit of favorable effects on bowel function and quality of life.

Quality of life benefits and cost impact of prolonged release oxycodone/naloxone versus prolonged release oxycodone in patients with moderate-to-severe non-malignant pain and opioid-induced constipation: a UK cost-utility analysis

OBJECTIVE

To compare the cost effectiveness of prolonged release oxycodone/naloxone (OXN) tablets (Targinact) and prolonged release oxycodone (OXY) tablets (OxyContin) in patients with moderate-to-severe non-malignant pain and opioid-induced constipation (OIC) from the perspective of the UK healthcare system.

METHODS

A cohort model used data from a phase III randomised, controlled trial (RCT). It calculated the cost difference between treatments by combining the cost of pain therapy with costs of laxatives and other resources used to manage constipated patients. SF-36 scores were converted into EQ-5D utility values to calculate the quality-adjusted life-year (QALY) gains. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

The incremental cost of OXN versus OXY was £159.68 for the average treatment duration of 301 days. OXN gave an incremental QALY gain of 0.0273. The estimated incremental cost-effectiveness ratio (ICER) was £5841.56 per QALY. Sensitivity analyses gave a maximum ICER of £10,347.03. In some scenarios, OXN dominated with a cost saving of up to £4254.70. Probabilistic sensitivity analysis showed that OXN had approximately 96.6% probability of cost effectiveness at the £20,000 threshold.

LIMITATIONS

The model was conservative in predicting the probability of constipation beyond the 12-week RCT period. UK cost of constipation data were limited and based on primary care physician opinion.

CONCLUSIONS

In the base case, direct treatment costs were slightly higher for patients treated with OXN than for those treated with OXY. However, patients treated with OXN experienced a quality of life gain, and had an ICER considerably below thresholds commonly applied in the UK. The model was most sensitive to the estimated cost of constipation with a number of realistic scenarios in the sensitivity analysis demonstrating a cost saving with OXN (OXN dominant). OXN is therefore estimated to be a cost-effective option for treating patients with severe non-malignant pain and OIC.

A randomized, double-blind, active-controlled, double-dummy, parallel-group study to determine the safety and efficacy of oxycodone/naloxone prolonged-release tablets in patients with moderate/severe, chronic cancer pain

OBJECTIVE

An examination of whether oxycodone/naloxone prolonged-release tablets (OXN PR) can improve constipation and maintain analgesia, compared with oxycodone prolonged-release tablets (OxyPR) in patients with moderate/severe cancer pain.

METHODS

Randomized, double-blind, active-controlled, double-dummy, parallel-group study in which 185 patients were randomized to receive up to 120 mg/day of OXN PR or OxyPR over 4 weeks. Efficacy assessments included Bowel Function Index (BFI), Brief Pain Inventory Short-Form (BPI-SF), laxative and rescue medication use. Quality of life (QoL) and safety assessments were conducted.

RESULTS

After 4 weeks, mean BFI score was significantly lower with OXN PR; mean total laxative intake was 20% lower with OXN PR. Mean BPI-SF scores were similar for both treatments and the average rate of analgesic rescue medication use was low and comparable. QoL assessments were stable and comparable with greater improvements in constipation-specific QoL assessments with OXN PR. Overall, rates of adverse drug reactions were similar.

CONCLUSIONS

OXN PR provides superior bowel function in cancer pain patients, compared with OxyPR, without compromising analgesic efficacy or safety. This study confirms that OXN PR is well tolerated and efficacious in cancer pain patients and results are in line with those seen in non-malignant pain patients.

Constipation assessment scales in adults: a literature review including the new Bowel Function Index

Constipation is a common clinical condition and patient and physician perception of the disorder can vary considerably. The assessment of a symptom-based condition such as constipation is challenging, in terms of making the diagnosis, assessing the severity of symptoms and their impact on a patient's quality of life, and assessing response to therapy or changes to symptoms over time. In order to assist physicians in assessing the severity of constipation and its related discomfort, several rating scales have been developed. During the course of a literature search, 16 studies were identified that reported assessment scales based on a selection of varied symptoms of constipation and that evaluated these scales in different groups of individuals; two studies presented stool form as being key to assessing transit time. In the present article, the characteristics and psychometric evaluation of these different constipation assessment scales, including the new Bowel Function Index, are reported with a view to discussing which assessment tool appears to be most robust and/or useful in daily clinical practice.

Opioid antagonists for prevention and treatment of opioid-induced gastrointestinal effects

PURPOSE OF REVIEW

The therapeutic action of opioid analgesics is compromised by peripheral adverse effects, among which constipation is the most disabling as laxatives often fail to provide satisfactory relief. This review highlights recent advances in the specific control of opioid-induced constipation by opioid receptor antagonists with limited systemic bioavailability or a peripherally restricted site of action.

RECENT FINDINGS

The specific management of opioid-induced bowel dysfunction is currently based on three drug entities: oral alvimopan for the shortening of postoperative ileus associated with opioid-induced pain control after bowel resection, subcutaneous methylnaltrexone for the reduction of opioid-induced constipation in patients with advanced illness, and a fixed combination of oral prolonged-release naloxone with prolonged-release oxycodone for the treatment of noncancer and cancer pain. All three drug entities have been shown to attenuate opioid-induced motor stasis in the gut with a favorable adverse effect profile, while the analgesic effect of opioids remains unabated.

SUMMARY

The availability of opioid receptor antagonists with restricted access to the central nervous system provides a novel opportunity to specifically control opioid-induced constipation and other peripheral adverse effects of opioid analgesics. Further studies are needed to evaluate the long-term efficacy, safety and cost-effectiveness of this approach.