Michael Hopp

A randomised controlled trial with prolonged-release oral oxycodone and naloxone to prevent and reverse opioid-induced constipation.

Background: Opioid‐induced constipation can have a major negative impact on patients’ quality of life. This randomised, double‐blinded study evaluated the analgesic efficacy of prolonged‐release (PR) oral oxycodone when co‐administered with PR oral naloxone, and its impact on opioid‐induced constipation in patients with severe chronic pain. Another objective was to identify the optimal dose ratio of oxycodone and naloxone.

Analgesic Efficacy and Safety of Oxycodone in Combination With Naloxone as Prolonged Release Tablets in Patients With Moderate to Severe Chronic Pain

UNLABELLED This randomized, double-blind, placebo- and active-controlled, parallel-group study was designed to demonstrate the superiority of oxycodone in combination with naloxone in a prolonged release (PR) formulation over placebo with respect to analgesic efficacy. The active control group was included for sensitivity and safety analyses, and furthermore to compare the analgesic efficacy and bowel function of oxycodone PR/naloxone PR with oxycodone PR alone. The analgesic efficacy was measured as the time from the initial dose of study medication to multiple pain events (ie, inadequate analgesia) in patients with moderate to severe chronic low back pain. The full analysis population consisted of 463 patients. The times to recurrent pain events were significantly longer in the oxycodone PR/naloxone PR group compared with placebo (P < .0001-.0003); oxycodone PR/naloxone PR reduced the risk of pain events by 42% (P < .0001; full analysis population). The appearance of pain events was comparable for oxycodone PR/naloxone PR versus oxycodone PR, confirming that the addition of naloxone PR to oxycodone PR in a combination tablet did not negatively affect analgesic efficacy of the opioid. Furthermore, oxycodone PR/naloxone PR offers benefits in terms of an improvement in bowel function. In a therapeutic area of great unmet need, therefore, the combination tablet of oxycodone PR/naloxone PR offers patients effective analgesia while improving opioid-induced bowel dysfunction. Taken together with the observation that the safety profile of oxycodone PR/naloxone PR is consistent with that expected from other opioid analgesics except opioid-induced constipation, these findings indicate that the addition of naloxone to oxycodone in a PR combination tablet offers improved tolerability. Oxycodone PR/naloxone PR is therefore a promising new treatment approach for the management of chronic pain. PERSPECTIVE This study evaluated the analgesic efficacy and safety of the combination of oxycodone PR/naloxone PR in chronic nonmalignant pain. Opioids are often reduced in dosage or even discontinued as a result of impaired bowel function, leading to insufficient pain treatment. Not only does oxycodone PR/naloxone PR demonstrate analgesic efficacy comparable with oxycodone PR, but it also improves opioid-induced bowel dysfunction, and may therefore improve the acceptability of long-term opioid treatment for chronic pain.

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.

Prolonged release oxycodone–naloxone for treatment of severe restless legs syndrome after failure of previous treatment: a double-blind, randomised, placebo-controlled trial with an open-label extension

BACKGROUND Opioids are a potential new treatment for severe restless legs syndrome. We investigated the efficacy and safety of a fixed-dose combination of prolonged release oxycodone-naloxone for patients with severe restless legs syndrome inadequately controlled by previous, mainly dopaminergic, treatment. METHODS This multicentre study consisted of a 12-week randomised, double-blind, placebo-controlled trial and 40-week open-label extension phase done at 55 sites in Austria, Germany, Spain, and Sweden. Patients had symptoms for at least 6 months and an International RLS Study Group severity rating scale sum score of at least 15; patients with severe chronic obstructive pulmonary disease or a history of sleep apnoea syndrome were excluded. Patients were randomly assigned (1:1) to either study drug or matched placebo with a validated interactive response technology system in block sizes of four. Study drug was oxycodone 5·0 mg, naloxone 2·5 mg, twice per day, which was up-titrated according to investigators opinion to a maximum of oxycodone 40 mg, naloxone 20 mg, twice per day; in the extension, all patients started on oxycodone 5·0 mg, naloxone 2·5 mg, twice per day, which was up-titrated to a maximum of oxycodone 40 mg, naloxone 20 mg, twice per day. The primary outcome was mean change in severity of symptoms according to the International RLS Study Group severity rating scale sum score at 12 weeks. This study is registered with ClinicalTrials.gov (number NCT01112644) and with EudraCT (number 2009-011107-23). FINDINGS We screened 495 patients, of whom 306 were randomly assigned and 276 included in the primary analysis (132 to prolonged release oxycodone-naloxone vs 144 to placebo). 197 patients participated in the open-label extension. Mean International RLS Study Group rating scale sum score at randomisation was 31·6 (SD 4·5); mean change after 12 weeks was -16·5 (SD 11·3) in the prolonged release oxycodone-naloxone group and -9·4 (SD 10·9) in the placebo group (mean difference between groups at 12 weeks 8·15, 95% CI 5·46-10·85; p<0·0001). After the extension phase, mean sum score was 9·7 (SD 7·8). Treatment-related adverse events occurred in 109 of 150 (73%) patients in the prolonged release oxycodone-naloxone group and 66 of 154 (43%) in the placebo group during the double-blind phase; during the extension phase, 112 of 197 (57%) had treatment-related adverse events. Five of 306 (2%) patients had serious treatment-related adverse events when taking prolonged release oxycodone-naloxone (vomiting with concurrent duodenal ulcer, constipation, subileus, ileus, acute flank pain). INTERPRETATION Prolonged release oxycodone-naloxone was efficacious for short-term treatment of patients with severe restless legs syndrome inadequately controlled with previous treatment and the safety profile was as expected. Our study also provides evidence of open-label long-term efficacy of this treatment. Opioids can be used to treat patients with severe restless legs syndrome who have had no benefit with first-line drugs. FUNDING Mundipharma Research.

Meeting the Challenges of Opioid-Induced Constipation in Chronic Pain Management – A Novel Approach

Opioid analgesics are the cornerstone of pain management for moderate-to-severe cancer pain and, increasingly, chronic noncancer pain. Despite proven analgesic efficacy, the use of opioids is commonly associated with frequently dose-limiting constipation that seriously impacts on patients’ quality of life. Agents currently used to manage opioid-induced constipation (OIC), such as laxatives, do not address the underlying opioid receptor-mediated cause of constipation and are often ineffective. A significant need therefore exists for more effective treatment options. A novel approach for selectively and locally antagonizing the gastrointestinal effects of opioids involves the coadministration of a μ-opioid receptor antagonist with negligible systemic availability, such as oral naloxone. Combination therapy with prolonged-release (PR) oxycodone plus PR naloxone has been shown to provide effective analgesia while preventing or reducing constipation. The current article highlights this novel strategy in its potential to significantly improve the quality of life of patients suffering from chronic pain, affording patients the benefit of full analgesia, without the burden of OIC.

Efficacy and safety of combined prolonged-release oxycodone and naloxone in the management of moderate/severe chronic non-malignant pain: results of a prospectively designed pooled analysis of two randomised, double-blind clinical trials

BackgroundTwo randomised 12-week, double-blind, parallel-group, multicenter studies comparing oxycodone PR/naloxone PR and oxycodone PR alone on symptoms of opioid-induced bowel dysfunction in patients with moderate/severe non-malignant pain have been conducted.MethodsThese studies were prospectively designed to be pooled and the primary outcome measure of the pooled data analysis was to demonstrate non-inferiority in 12-week analgesic efficacy of oxycodone PR/naloxone PR versus oxycodone PR alone. Patients with opioid-induced constipation were switched to oxycodone PR and then randomised to fixed doses of oxycodone PR/naloxone PR (n = 292) or oxycodone PR (n = 295) for 12 weeks (20-80 mg/day).ResultsNo statistically significant differences in analgesic efficacy were observed for the two treatments (p = 0.3197; non-inferiority p < 0.0001; 95% CI -0.07, 0.23) and there was no statistically significant difference in frequency of analgesic rescue medication use. Improvements in Bowel Function Index score were observed for oxycodone PR/naloxone PR by Week 1 and at every subsequent time point (-15.1; p < 0.0001; 95% CI -17.3, -13.0). AE incidence was similar for both groups (61.0% and 57.3% of patients with oxycodone PR/naloxone PR and oxycodone PR alone, respectively).ConclusionsResults of this pooled analysis confirm that oxycodone PR/naloxone PR provides effective analgesia and suggest that oxycodone PR/naloxone PR improves bowel function without compromising analgesic efficacy.Trial registration numbersClinicalTrials.gov identifier: NCT00412100 and NCT00412152

Low absolute bioavailability of oral naloxone in healthy subjects.

OBJECTIVE To determine the absolute bioavailability of naloxone from oral doses ranging from 5 mg to 120 mg. MATERIALS AND METHODS In this open-label study, 28 healthy subjects received naloxone 1 mg (0.4 mg/ml) as an intravenous infusion (reference treatment), and the following oral doses as prolonged release (PR) naloxone tablets: 5 mg, 20 mg, 40 mg, 80 mg and 120 mg. The pharmacokinetic characteristics of 40 mg administered per rectum were also investigated. Each subject received five of the seven treatments as single doses with a 7 day washout between doses. Pharmacokinetic blood sampling and safety monitoring were performed for 24 h after the intravenous dose, and 72 h after the oral and rectal doses. RESULTS The mean absolute bioavailability of naloxone from the orally administered PR tablets was very low, ranging from 0.9% for the 5 mg dose to 2% for the 40, 80 and 120 mg doses, based on AUC(t) values. The pharmacokinetics of naloxone were linear across the range of oral doses. Where AUC(inf) values were calculated, these confirmed the results based on AUC(t) values (mean absolute bioavailability ranging from 1.9% to 2.2% for the 20 mg to 120 mg oral doses). The absolute bioavailability of naloxone was higher following rectal administration compared with oral administration, but was still low at 15%. CONCLUSIONS The mean oral absolute bioavailability of naloxone in this study was ≤ 2% at doses ranging from 5 mg to 120 mg.

Single- and multiple-dose pharmacokinetic evaluation of oxycodone and naloxone in an opioid agonist/antagonist prolonged-release combination in healthy adult volunteers

BACKGROUND There is an increasing body of evidence supporting the need for prophylactic management of the adverse events (AEs) associated with long-term opioid use in patients with chronic pain. Symptoms of bowel dysfunction, such as constipation, may have a significant impact on a patients quality of life and willingness to continue opioid therapy, and therefore should be managed proactively to ensure that the patient can continue effective pain management. The fixed-dose combination (FDC) prolonged-release (PR) oxycodone/naloxone (OXN) may be an effective therapeutic approach to delivering analgesia, with a reduced risk for opioid-induced constipation. OBJECTIVE The aim of this paper was to report the pharmacokinetic results from a single-dose study and a multiple-dose bioequivalence study of OXN versus separate formulations of oxycodone PR and naloxone PR administered concurrently in healthy subjects. METHODS Both studies were open-label, randomized crossover studies in healthy adult male and female subjects. In the single-dose study, subjects were randomly assigned to 1 of 4 treatment groups: OXN FDC (44 x 10/55-mg, 2 x 20/110-mg, or 1 x 40/20-mg dose strength [each given at a total combined dose of 40/220 mg]) or oxycodone PR 40 mg + naloxone PR 20 mg given in separate formulations. In the multiple-dose study, 34 subjects were randomly assigned to 1 of 3 treatment groups: OXN FDC 40/20 mg, oxycodone PR 40 mg, or naloxone PR 20 mg. Treatments were considered bioequivalent if the 90% CIs for relative bioavailability calculations fell within a predetermined range of 80% to 125%. AEs were assessed by the investigator at each study visit. RESULTS The single-dose study included 28 subjects (22 men, 6 women; mean [SD] age, 32.3 [5.44] years; weight, 75.5 [9.3] kg; and body mass index [BMI], 24.2 [2.5] kg/mm(2)). The mean plasma oxycodone concentration-time curves for OXN and oxycodone PR + naloxone PR were similar. With oxycodone, the mean (SD) AUC(t) values with OXN 10/5, 20/10, and 40/20 mg and oxycodone PR + naloxone PR were 473.49 (72.16), 491.22 (82.18), 488.89 (91.04), and 502.28 (84.13) ng . h/mL, respectively; mean C(max) values were 34.91 (4.36), 35.73 (4.93), 34.46 (5.03), and 40.45 (4.71) ng/mL. For naloxone-3-glucuronide (the primary analyte of naloxone), the mean (SD) AUC(t) values with OXN 10/5, 20/10, and 40/20 mg and oxycodone PR + naloxone PR were 539.93 (142.24), 522.45 (128.57), 520.10 (133.18), and 523.37 (119.75) ng . h/mL, respectively; mean C(max) values were 62.01 (15.96), 63.62 (19.51), 61.95 (18.37), and 63.55 (16.75) ng/mL. There were no statistically significant differences between the treatments, and each of the treatment comparisons resulted in 90% CIs within the range for bioequivalence. The multiple-dose steady-state bioequivalence study included 34 subjects (28 men, 6 women; mean [SD] age, 36 [9.4] years; weight,78.9 [11.7] kg; and BMI, 24.6 [1.9] kg/m(2)). No significant differences were observed between the treatments, with the exception of naloxone-3-glucuronide C(min,ss) values. Mean C(min,ss) values of 22.6 and 24.0 ng/mL were obtained for the OXN combination and naloxone PR tablet, respectively. In the multiple-dose study, the most frequently reported AEs with OXN,oxycodone PR, and naloxone PR were headache (7%, 26%, and 17%, respectively), anorexia (10%, 16%, and 13%), and nausea (10%, 13%, and 7%). CONCLUSIONS The results from the single-dose study were consistent with the regulatory definition of bioequivalence of the FDCs and single components across the range of doses administered. The pharmacokinetic properties of the OXN FDC were similar to those of oxycodone PR + naloxone PR given as separate formulations, based on the regulatory definition. These findings were consistent with the results of the multiple-dose steady-state bioequivalence study. In this population of healthy volunteers, the pharmacokinetic properties of oxycodone apparently were not significantly influenced by administering oxycodone in a combination product, and the availability of naloxone-3-glucuronide from OXN was similar to that from the naloxone PR tablet. These findings suggest that the coadministration of oxycodone PR and naloxone PR in an FDC would not significantly affect the bioavailability of either of its constituents in these subjects.

Naloxone as part of a prolonged release oxycodone/naloxone combination reduces oxycodone-induced slowing of gastrointestinal transit in healthy volunteers

Objectives: This exploratory study in healthy volunteers investigated the effect of single doses of oxycodone on gastrointestinal (GI) transit time and the degree to which a single dose of naloxone reverses the oxycodone-induced effect. Methods: Fifteen healthy male volunteers received: oxycodone 10 and 20 mg, oxycodone/naloxone 10/5 and 20/10 mg (all as prolonged release tablets) and placebo. Each dose was radiolabelled and administered with a capsule containing radiolabelled resin (surrogate for GI contents). Results: Scintigraphic analysis showed that 20 mg oxycodone significantly increased colon arrival time (mean 7.19 vs 5.15 h for placebo, p = 0.0159). Mean colon arrival time for oxycodone/naloxone 20/10 mg (5.16 h) was similar to placebo, although the difference between oxycodone/naloxone 20/10 mg versus oxycodone 20 mg was not significant (p = 0.0653). Colonic geometric centre analysis showed a significant increase in mean time for the resin to reach the colon following oxycodone 10 and 20 mg compared with placebo (increases of 5.3 and 8.8 h). There was no significant effect of naloxone at the lower dose; however, oxycodone/naloxone 20/10 mg significantly reduced mean colonic transit time by 2.1 h (p = 0.0376). Conclusion: A single dose of oxycodone 20 mg significantly prolonged GI transit time but this effect was reduced by co-administration of naloxone.

A liposome hydrogel with polyvinyl-pyrrolidone iodine in the local treatment of partial-thickness burn wounds.

Local treatment of burn injuries with conventional anti-infective preparations does not provide the moist environment that promotes fast wound healing. In a randomized controlled trial the effects of liposome polyvinyl-pyrrolidone-iodine (PVP-I) hydrogel, a novel formulation of PVP-I in a liposome hydrogel with high water-binding capacity, were investigated in 43 patients with partial-thickness burn wounds in an intraindividual comparison with a conventional silver-sulfadiazine cream. Treatment with liposome PVP-I hydrogel resulted in significantly faster complete healing of the burn wounds compared with silver-sulfadiazine cream (9.9 ± 4.5 days versus 11.3 ± 4.9; P < 0.015). The cosmetic result (smoothness, elasticity, appearance) was rated as excellent for 37.0% of study wounds with liposome PVP-I hydrogel compared with 13.0% of wounds treated with silver-sulfadiazine cream. Local tolerability was good; handling and change of dressing were rated as easy. Local treatment with liposome PVP-I hydrogel thus provides fast wound healing with a favorable cosmetic result.