Fixed combination of oxycodone with naloxone: a new way to prevent and treat opioid-induced constipation

Pharmacological prevention and treatment of opioid-induced constipation in cancer patients: A systematic review and meta-analysis

BACKGROUND

Cancer-related pain often requires opioid treatment with opioid-induced constipation (OIC) as its most frequent gastrointestinal side-effect. Both for prevention and treatment of OIC osmotic (e.g. polyethylene glycol) and stimulant (e.g. bisacodyl) laxatives are widely used. Newer drugs such as the peripherally acting µ-opioid receptor antagonists (PAMORAs) and naloxone in a fixed combination with oxycodone have become available for the management of OIC. This systematic review and meta-analysis aims to give an overview of the scientific evidence on pharmacological strategies for the prevention and treatment of OIC in cancer patients.

METHODS

A systematic search in PubMed, Embase, Web of Science and the Cochrane Library was completed from inception up to 22 October 2022. Randomized and non-randomized studies were systematically selected. Bowel function and adverse drug events were assessed.

RESULTS

Twenty trials (prevention: five RCTs and three cohort studies; treatment: ten RCTs and two comparative cohort studies) were included in the review. Regarding the prevention of OIC, three RCTs compared laxatives with other laxatives, finding no clear differences in effectivity of the laxatives used. One cohort study showed a significant benefit of magnesium oxide compared with no laxative. One RCT found a significant benefit for the PAMORA naldemedine compared with magnesium oxide. Preventive use of oxycodone/naloxone did not show a significant difference in two out of three other studies compared to oxycodone or fentanyl. A meta-analysis was not possible. Regarding the treatment of OIC, two RCTs compared laxatives, of which one RCT found that polyethylene glycol was significantly more effective than sennosides. Seven studies compared an opioid antagonist (naloxone, methylnaltrexone or naldemedine) with placebo and three studies compared different dosages of opioid antagonists. These studies with opioid antagonists were used for the meta-analysis. Oxycodone/naloxone showed a significant improvement in Bowel Function Index compared to oxycodone with laxatives (MD -13.68; 95 % CI -18.38 to -8.98; I2 = 58 %). Adverse drug event rates were similar amongst both groups, except for nausea in favour of oxycodone/naloxone (RR 0.51; 95 % CI 0.31-0.83; I2 = 0 %). Naldemedine (NAL) and methylnaltrexone (MNTX) demonstrated significantly higher response rates compared to placebo (NAL: RR 2.07, 95 % CI 1.64-2.61, I2 = 0 %; MNTX: RR 3.83, 95 % CI 2.81-5.22, I2 = 0 %). With regard to adverse events, abdominal pain was more present in treatment with methylnaltrexone and diarrhea was significantly more present in treatment with naldemedine. Different dosages of methylnaltrexone were not significantly different with regard to both efficacy and adverse drug event rates.

CONCLUSIONS

Magnesium oxide and naldemedine are most likely effective for prevention of OIC in cancer patients. Naloxone in a fixed combination with oxycodone, naldemedine and methylnaltrexone effectively treat OIC in cancer patients with acceptable adverse events. However, their effect has not been compared to standard (osmotic and stimulant) laxatives. More studies comparing standard laxatives with each other and with opioid antagonists are necessary before recommendations for clinical practice can be made.

Insights into the Current and Possible Future Use of Opioid Antagonists in Relation to Opioid-Induced Constipation and Dysbiosis

Opioid receptor agonists, particularly those that activate µ-opioid receptors (MORs), are essential analgesic agents for acute or chronic mild to severe pain treatment. However, their use has raised concerns including, among others, intestinal dysbiosis. In addition, growing data on constipation-evoked intestinal dysbiosis have been reported. Opioid-induced constipation (OIC) creates an obstacle to continuing treatment with opioid analgesics. When non-opioid therapies fail to overcome the OIC, opioid antagonists with peripheral, fast first-pass metabolism, and gastrointestinal localized effects remain the drug of choice for OIC, which are discussed here. At first glance, their use seems to only be restricted to constipation, however, recent data on OIC-related dysbiosis and its contribution to the appearance of several opioid side effects has garnered a great of attention from researchers. Peripheral MORs have also been considered as a future target for opioid analgesics with limited central side effects. The properties of MOR antagonists counteracting OIC, and with limited influence on central and possibly peripheral MOR-mediated antinociception, will be highlighted. A new concept is also proposed for developing gut-selective MOR antagonists to treat or restore OIC while keeping peripheral antinociception unaffected. The impact of opioid antagonists on OIC in relation to changes in the gut microbiome is included.

Current challenges in optimizing systemic therapy for patients with pancreatic cancer: expert perspectives from the Australasian Gastrointestinal Trials Group (AGITG) with invited international faculty

INTRODUCTION

Despite recent progress, the outlook for most patients with pancreatic cancer remains poor. There is variation in how patients are managed globally due to differing interpretations of the evidence, partly because studies in this disease are challenging to undertake. This article collates the evidence upon which current best practice is based and offers an expert opinion from an international faculty on how latest developments should influence current treatment paradigms. Areas covered: Optimal chemotherapy for first and subsequent lines of therapy; optimal management of locally advanced, non-metastatic cancer including the role of neoadjuvant chemo(radio)therapy, current evidence for adjuvant chemotherapy, major advances in pancreatic cancer genomics and challenges in supportive care particularly relevant to patients with pancreatic cancer. For each section, literature was reviewed by comprehensive search techniques, including clinical trial websites and abstracts from international cancer meetings. Expert commentary: For each section, a commentary is provided. Overall the challenges identified were: difficulties in diagnosing pancreatic cancer early, challenges for performing randomised clinical trials in all stages of the disease, some progress in systemic therapy with new agents and in identifying molecular subtypes that may be clinically relevant and move towards personalized therapy, but still, pancreatic cancer remains a very poor prognosis cancer with significant palliative care needs.

Nanoconjugated NAP as a Potent and Periphery Selective Mu Opioid Receptor Modulator To Treat Opioid-Induced Constipation

Opioids are the mainstay for cancer and noncancer pain management. However, their use is often associated with multiple adverse effects. Among them, the most common and persistent one is probably opioid-induced constipation (OIC). Periphery selective opioid antagonists may alleviate the symptoms of OIC without compromising the analgesic effects of opioids. Recently our laboratories have identified one novel lead compound, 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-[(4'-pyridyl)acetamido]morphinan (NAP), as a peripherally selective mu opioid receptor ligand carrying subnanomolar affinity to the mu opioid receptor and over 100-folds of selectivity over both the delta and kappa opioid receptors, with reasonable oral availability and half-life, and potential to treat OIC. Nanoparticle-based drug delivery systems are now widely considered due to their technological advantages such as good stability, high carrier capacity, low therapeutic side effects, etc. Herein we report nanoparticle supported NAP as a potential candidate for OIC treatment with improved peripheral selectivity over the original lead compound NAP.

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.

Intractable restless legs syndrome: role of prolonged-release oxycodone-naloxone

Restless legs syndrome (RLS) is a common neurological disorder characterized by an irresistible urge to move the legs accompanied by uncomfortable sensations that occur at night or at time of rest. Pharmacological therapy should be limited to patients who suffer from clinically relevant symptoms. Chronic RLS is usually treated with either a dopamine agonist (pramipexole, ropinirole, rotigotine) or an α2δ calcium-channel ligand (gabapentin, gabapentin enacarbil, pregabalin). Augmentation is the main complication of long-term dopaminergic treatment, and frequently requires a reduction of current dopaminergic dose or a switch to non-dopaminergic medications. Opioids as monotherapy or add-on treatment should be considered when alternative satisfactory regimens are unavailable and the severity of symptoms warrants it. In a recent Phase III trial, oxycodone-naloxone prolonged release (PR) demonstrated a significant and sustained effect on patients with severe RLS inadequately controlled by previous treatments. The adverse-event profile was consistent with the safety profile of opioids. The most frequent adverse events were fatigue, constipation, nausea, headache, hyperhidrosis, somnolence, dry mouth, and pruritus. Adverse events were usually mild or moderate in intensity. No cases of augmentation were reported. Oxycodone-naloxone PR is approved for the second-line symptomatic treatment of adults with severe to very severe idiopathic RLS after failure of dopaminergic treatment. Further studies are needed to evaluate if oxycodone-naloxone PR is equally efficacious as a first-line treatment. Moreover, long-term comparative studies between opioids, dopaminergic drugs and α2δ ligands are needed.

Is oxycodone/naloxone effective and safe in managing chronic pain of a fragile elderly patient with multiple skin ulcers of the lower limbs? A case report

Skin ulcers are a common issue in the elderly, as physiological loss of skin elasticity, alterations in microcirculation, and concomitant chronic diseases typically occur in advanced age, thereby predisposing to these painful lesions. Wound-related pain is often associated with skin ulcers and negatively impacts both the patient's quality of life and, indirectly, wound healing. Pain management is an ongoing issue in the elderly, and remains underestimated and under-treated in this fragile population. Recent guidelines suggest the use of opioids as the frontline treatment of moderate and severe pain in nononcological pain in the elderly. However, due to the concerns of adverse reactions, drug interactions, and addiction, clinicians frequently hesitate to prescribe opioids. This case report describes an elderly diabetic patient with multiple ulcers of the lower limbs suffering wound-related pain. In our report, oxycodone/naloxone has proved to be an effective and safe drug, providing pain relief as well as increased compliance when redressing wounds and faster healing compared to that in similar patients. Our case provides anecdotal evidence, supported by other studies, to justify future, larger studies on chronic pain using this therapy.

Therapeutic effect of activated carbon-induced constipation mice with Lactobacillus fermentum Suo on treatment

The aim of this study was to investigate the effects of Lactobacillus fermentum Suo (LF-Suo) on activated carbon-induced constipation in ICR (Institute of Cancer Research) mice. ICR mice were orally administered with lactic acid bacteria for 9 days. Body weight, diet intake, drinking amount, defecation status, gastrointestinal transit and defecation time, and the serum levels of MTL (motilin), Gas (gastrin), ET (endothelin), SS (somatostatin), AChE (acetylcholinesterase), SP (substance P), VIP (vasoactive intestinal peptide) were used to evaluate the preventive effects of LF-Suo on constipation. Bisacodyl, a laxative drug, was used as a positive control. The normal, control, 100 mg/kg bisacodyl treatment, LB (Lactobacillus bulgaricus)-, LF-Suo (L)- and LF-Suo (H)-treated mice showed the time to the first black stool defecation at 90, 218, 117, 180, 155 and 137 min, respectively. By the oral administration of LB-, LF-Suo (L), LF-Suo (H) or bisacodyl (100 mg/kg), the gastrointestinal transit was reduced to 55.2%, 72.3%, 85.5% and 94.6%, respectively, of the transit in normal mice, respectively. In contrast to the control mice, the serum levels of MTL, Gas, ET, AChE, SP and VIP were significantly increased and the serum levels of SS were reduced in the mice treated with LF-Suo (p < 0.05). By the RT-PCR (reverse transcription–polymerase chain reaction) and western blot assays, LF-Suo increased the c-Kit, SCF (stem cell factor), GDNF (glial cell line-derived neurotrophic factor) and decreased TRPV1 (transient receptor potential vanilloid 1), NOS (nitric oxide synthase) expressions of small intestine tissue in mice. These results demonstrate that lactic acid bacteria has preventive effects on mouse constipation and LF-Suo demonstrated the best functional activity.

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.

Long-term safety and efficacy of oxycodone/naloxone prolonged-release tablets in patients with moderate-to-severe chronic cancer pain

Aim

To evaluate the long-term safety and efficacy of prolonged-release oxycodone/naloxone (OXN PR) and its impact on quality of life (QoL), in patients with moderate-to-severe cancer pain.

Methods

This was an open-label extension (OLE) of a 4 week, randomized, double-blind (DB) study in which patients with moderate-to-severe cancer pain had been randomized to OXN PR or oxycodone PR (OxyPR). During the OLE phase, patients were treated with OXN PR capsules (≤20/60 mg/day) for ≤24 weeks. Outcome measures included safety, efficacy and QoL.

Results

One hundred and twenty-eight patients entered the OLE, average pain scores based on the modified Brief Pain Inventory—Short Form were low and stable over the 24-week period. The improvement in bowel function and constipation symptoms as measured by the Bowel Function Index and patient assessment of constipation in patients treated with OXN PR during the 4-week DB study was maintained. In patients treated with OxyPR during the DB phase, bowel function and constipation symptoms were improved during the OLE. In the DB and in the OLE, health status and QoL were similar for patients treated with OXN PR and OxyPR. There were no unexpected safety or tolerability issues.

Conclusions

In patients with moderate-to-severe cancer pain, long-term use of OXN PR is well tolerated and effective, resulting in sustained analgesia, improved bowel function and improved symptoms of constipation.

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.

Design, synthesis, and biological evaluation of 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-[(4'-pyridyl)carboxamido]morphinan derivatives as peripheral selective μ opioid receptor Agents

Peripheral selective μ opioid receptor (MOR) antagonists could alleviate the symptoms of opioid-induced constipation (OIC) without compromising the analgesic effect of opioids. However, a variety of adverse effects were associated with them, partially due to their relatively low MOR selectivity. NAP, a 6β-N-4'-pyridyl substituted naltrexamine derivative, was identified previously as a potent and highly selective MOR antagonist mainly acting within the peripheral nervous system. The noticeable diarrhea associated with it prompted the design and synthesis of its analogues in order to study its structure-activity relationship. Among them, compound 8 showed improved pharmacological profiles compared to the original lead, acting mainly at peripheral while increasing the intestinal motility in morphine-pelleted mice (ED(50) = 0.03 mg/kg). The slight decrease of the ED(50) compared to the original lead was well compensated by the unobserved adverse effect. Hence, this compound seems to be a more promising lead to develop novel therapeutic agents toward OIC.

Prolonged-release Oxycodone/Naloxone in Postoperative Pain Management: From a Randomized Clinical Trial to Usual Clinical Practice

Objective:

These studies evaluated the feasibility of using oral prolonged-release oxycodone/naloxone (OXN PR) for the management of acute postoperative pain.

Methods:

Three studies were undertaken: (i) the analgesic efficacy of OXN PR was compared with prolonged-release oxycodone (OXY PR) in patients with knee arthroplasty in an immediate postoperative period (IPOP) study; (ii) OXN PR treatment was compared with other opioids during rehabilitation after knee arthroplasty in a noninterventional study (NIS); and (iii) surgical patients on other opioids were switched to OXN PR postoperatively during a quality improvement programme (QIP).

Results:

In the IPOP study, the pain intensity at rest score decreased by a similar amount in the OXN PR and OXY PR groups, indicating similar analgesic efficacies. In the NIS, patient assessments indicated enhanced efficacy and tolerability for OXN PR compared with other opioids. The QIP indicated significant improvements in bowel function and less difficulty passing urine at the end of OXN PR treatment compared with baseline. No safety concerns were raised.

Conclusions:

The analgesic efficacies of OXN PR and OXY PR were similar in postoperative pain settings. OXN PR reduced the degree of restriction in relation to patients carrying out physio - therapy compared with other opioids, and improved bowel and bladder function.

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.