Reductions in All-Cause Mortality Associated with the Use of Methylnaltrexone for Opioid-Induced Bowel Disorders: A Pooled Analysis.

OBJECTIVE: Preclinical and clinical studies suggest that activation of the µ-opioid receptor may reduce overall survival and increase the risk for all-cause mortality in patients with cancer and noncancer pain. Methylnaltrexone, a selective, peripherally acting µ-opioid receptor antagonist, has demonstrated efficacy for the treatment of opioid-induced constipation. This retrospective analysis of 12 randomized, double-blind, placebo-controlled studies of methylnaltrexone evaluated the treatment of opioid-induced bowel disorders in patients with advanced illness or noncancer pain. METHODS: The risk of all-cause mortality within 30 days after the last dose of study medication during the double-blind phase was compared between methylnaltrexone and placebo groups. The data were further stratified by cancer vs noncancer, age, gender, and acute vs chronic diagnoses. RESULTS: Pooled data included 2,526 methylnaltrexone-treated patients of which 33 died, and 1,192 placebo-treated patients of which 35 died. The mortality rate was 17.8 deaths/100 person-years of exposure in the methylnaltrexone group and 49.5 deaths/100 person-years of exposure for the placebo group. The all-cause mortality risk was significantly lower among patients receiving methylnaltrexone compared with placebo (hazard ratio: 0.399, 95% confidence interval: 0.25, 0.64; P = .0002), corresponding to a 60% risk reduction. Significant risk reductions were observed for those receiving methylnaltrexone who had cancer or chronic diagnoses. Methylnaltrexone-treated patients had a significantly reduced mortality risk compared with placebo regardless of age or gender. CONCLUSIONS: Methylnaltrexone reduced all-cause mortality vs placebo treatment across multiple trials, suggesting methylnaltrexone may confer survival benefits in patients with opioid-induced bowel disorders taking opioids for cancer-related or chronic noncancer pain.

Pharmacokinetics of Buprenorphine Buccal Film and Orally-administered Oxycodone in a Respiratory Study: An Analysis of Secondary Outcomes from a Randomized Controlled Trial.

OBJECTIVE: To evaluate pharmacokinetic (PK) parameters and oxygen saturation as markers of abuse potential after administration of buprenorphine buccal film (BBF) and immediate-release (IR) oxycodone. METHODS: This was a secondary analysis of data from a phase I randomized controlled trial. A total of 19 healthy subjects who self-identified as recreational opioid users were enrolled, with 15 completing the study. Subjects were administered 300, 600, and 900 µg BBF; 30 and 60 mg orally-administered oxycodone; and placebo. For PK analysis, blood samples were collected before dosing and at 0.5, 1, 2, 3, 4, and 6 h postdose. Respiratory drive/ventilatory response to hypercapnia and oxygen saturation were evaluated before dosing and up to 8 h after administration of test drugs. RESULTS: Median time to maximum concentration (Tmax) was 2.17 h for 900 µg BBF and 1.17 h for 60 mg oxycodone and was similar across all doses for each drug. Mean maximum concentration (Cmax) was 1.06 ng/mL for 900 µg BBF and 132 ng/mL for 60 mg oxycodone. The abuse quotient, defined as Cmax/Tmax, was substantially higher for oxycodone compared to BBF. Respiratory depression (maximum decrease in minute ventilation) was similar for all 3 doses of BBF, consistent with a potential ceiling effect. In addition, respiratory depression occurred sooner with oxycodone vs BBF, and a greater mean decrease in oxygen saturation was observed for oxycodone 30- and 60-mg doses, compared with BBF. CONCLUSION: These results indicate that BBF may have a decreased risk of abuse and respiratory depression compared with the full µ-opioid receptor agonist oxycodone. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT03996694.

Ventilatory Response to Hypercapnia as Experimental Model to Study Effects of Oxycodone on Respiratory Depression.

BACKGROUND: Opioid analgesics used to treat pain can cause respiratory depression. However, this effect has not been extensively studied, and life-threatening, opioid-induced respiratory depression remains difficult to predict. We tested the ventilatory response to hypercapnia for evaluating the pharmacodynamic effect of a drug on respiratory depression. METHODS: We conducted a randomized, placebo-controlled, double-blind, crossover study on 12 healthy adult males. Subjects received 2 treatments (placebo and immediate-release oxycodone 30 mg) separated by a 24-hour washout period. Subjects inhaled a mixture of 7% carbon dioxide, 21% oxygen, and 72% nitrogen for 5 minutes to assess respiratory depression. Minute ventilation, respiratory rate, tidal volume, flow rate, end-tidal CO2, and oxygen saturation were recorded continuously at pre-dose and 30, 60, 120, and 180 minutes post-dose. The primary endpoint was the effect on the ventilatory response to hypercapnia at 60 minutes post-dose, as assessed by the slope of the linear relationship between minute ventilation and end-tidal CO2. RESULTS: At 60 minutes post-dose, subjects had a mean slope of 2.4 in the oxycodone crossover period, compared to 0.1 in the placebo period (mean difference, 2.3; 95% CI: 0.2 to 4.5; p = 0.035). Statistical significance was likewise achieved at the secondary time points (30, 120, and 180 minutes post-dose, p <0.05). CONCLUSIONS: This model for testing ventilatory response to hypercapnia discriminated the effect of 30 mg of oxycodone vs. placebo for up to 3 hours after a single dose. It may serve as a method to predict the relative effect of a drug on respiratory depression.

Wooden Chest syndrome: The atypical pharmacology of fentanyl overdose.

WHAT IS KNOWN AND OBJECTIVE: A large percentage of opioid overdose fatalities involve fentanyl or one of its legal or illegal analogs (F/FAs). Is there something about the pharmacology of these drugs that make them unusually dangerous in an overdose? COMMENT: Some of the reasons for the dangers of overdose of F/FAs is their high potency and low cost (that leads to wide distribution). But it is rarely asked if the basic pharmacology of F/FAs differ in some fundamental way from conventional opioids such as morphine and heroin. In addition to centrally mediated respiratory depression via opioid receptors, F/FAs cause rigidity in the key respiratory muscles of the chest, upper airway and diaphragm ("wooden chest syndrome," WCS) by a non-opioid mechanism. WHAT IS NEW AND CONCLUSION: WCS is an atypical pharmacology of F/FAs. Because of its rapid onset and non-opioid mechanism, WCS makes F/FA overdose particularly dangerous.

Open-Label Adhesion Performance Studies of a New Lidocaine Topical System 1.8% versus Lidocaine Patches 5% and Lidocaine Medicated Plaster 5% in Healthy Subjects.

PURPOSE: The primary objective was to evaluate adhesion performance of the lidocaine topical system 1.8% for 12 hours in healthy human subjects in three studies: as a single product (Study 1) and versus other lidocaine topical products (lidocaine patch 5% and lidocaine medicated plaster 5% [Study 2] and generic lidocaine patch 5% [Study 3]). Safety of the lidocaine topical system 1.8%, with a skin irritation focus, was a secondary objective. PATIENTS AND METHODS: All three studies were open-label, randomized, Phase 1 adhesion performance studies in healthy adult volunteers (N=125). Lidocaine topical products were applied for 12 hours per test, per study arm. Adhesion of all test products was scored at 0, 3, 6, 9, and 12 hours post-application. Skin irritation was scored after product removal or when a product detached. RESULTS: Overall, the majority (≥75%) of subjects treated with the lidocaine topical system 1.8% demonstrated ≥90% adhesion (FDA adhesion score 0) throughout the 12-hour administration period versus 13.6% of subjects treated with lidocaine patch 5%, 15.9% of subjects treated with lidocaine medicated plaster 5%, and 0% of subjects treated with the generic lidocaine patch 5%. There were no complete detachments with the lidocaine topical system 1.8%, whereas 4.5% of lidocaine patch 5% and lidocaine medicated plaster 5% detached, and 29% of generic lidocaine patch 5% detached. Minimal skin irritation was observed with each lidocaine topical product. CONCLUSION: Across three studies, lidocaine topical system 1.8% demonstrated superior adhesion performance versus the three other products tested. Skin irritation was minimal across products and studies. CLINICALTRIALSGOV: NCT04312750, NCT04320173, NCT04319926.

The Physiology and Maintenance of Respiration: A Narrative Review.

Chronic pain is one of the most common reasons adults seek medical care and is often managed with opioid analgesics; however, opioids may cause respiratory depression by suppressing various components of respiration. Respiration is the physiological process that facilitates gas exchange and is mediated through the proper function of and communication among central neural control (respiratory drive), sensory input systems, the lungs, and the muscles involved in respiration. Normal respiratory function can be dampened with the use of central nervous system (CNS) depressants and/or underlying health conditions. Patients with chronic pain are often exposed to CNS depressants other than opioids, including benzodiazepines, barbiturates, nonbenzodiazepine sedative-hypnotics, and ethanol, which can function synergistically with opioids to increase the risk of respiratory depression. Some patients may also have underlying health issues, such as obstructive sleep apnea, that can be exacerbated with the use of opioids and other CNS depressants and further contribute to respiratory depression. Clinicians should have a thorough understanding of respiration, recognize how various CNS depressants suppress it, and take necessary steps to mitigate the risk of opioid-induced respiratory depression by collaborating with a multidisciplinary team (i.e., sleep and pain specialists), choosing appropriate medications, and educating patients on the proper use and storage of opioids.

A Phase I Placebo-Controlled Trial Comparing the Effects of Buprenorphine Buccal Film and Oral Oxycodone Hydrochloride Administration on Respiratory Drive.

INTRODUCTION: Buprenorphine is a partial µ-opioid receptor agonist that, unlike full µ-opioid receptor agonists, has been shown to have a ceiling effect on respiratory depression. Buprenorphine buccal film (BBF) is approved by the US Food and Drug Administration for use in patients with chronic pain severe enough to require daily, around-the-clock, long-term opioid treatment and for whom alternative treatment options are inadequate. This study was conducted to compare the effects of BBF and immediate-release oral oxycodone hydrochloride administration on respiratory drive, as measured by the ventilatory response to hypercapnia (VRH) after drug administration. METHODS: Subjects (N = 19) were men and women, ages 27-41 years, self-identifying as recreational opioid users who were not physically dependent on opioids as determined via a Naloxone Challenge Test. Respiratory drive was evaluated by measuring VRH through the assessment of the maximum decrease in minute ventilation (Emax) after administration of each treatment. The treatments utilized in this study included 300, 600, and 900 µg BBF; 30 and 60 mg orally administered oxycodone; and placebo (each separated by a 7-day washout period). Effects on respiratory drive were assessed using a double-blind, double-dummy, six-treatment, six-period, placebo-controlled, randomized crossover design. Statistical analyses were performed using a linear mixed-effects model. RESULTS: The least squares mean differences in minute volume Emax (L/min, versus placebo) were as follows: 300 µg BBF (+ 1.24, P = 0.529), 600 µg BBF (+ 0.23, P = 0.908), 900 µg BBF (+ 0.93, P = 0.637), 30 mg oxycodone (- 0.79, P = 0.687), and 60 mg oxycodone (- 5.23, P = 0.010). CONCLUSIONS: BBF did not significantly reduce respiratory drive at any dose compared with placebo, including at the maximum available prescription dose of 900 µg. Administration of oxycodone resulted in a significant dose-dependent decrease in respiratory drive. These data suggest that BBF may be a safer treatment option than full µ-opioid receptor agonists for patients with chronic pain. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT03996694.

A Renal Impairment Subgroup Analysis of the Safety and Efficacy of Naldemedine for the Treatment of Opioid-Induced Constipation in Patients with Chronic Non-Cancer Pain Receiving Opioid Therapy.

PURPOSE: Naldemedine, an oral, peripherally acting µ-opioid receptor antagonist approved for the treatment of opioid-induced constipation (OIC), is renally excreted. This subgroup analysis integrated data from 3 Phase 3 trials (COMPOSE-1, COMPOSE-2, COMPOSE-3) to evaluate the safety and efficacy of naldemedine in patients with renal impairment (RI). PATIENTS AND METHODS: Patients age 18-80 years with chronic non-cancer pain (CNCP) and OIC received oral naldemedine 0.2 mg or placebo once daily. RI subgroups consisted of patients with normal function (baseline glomerular filtration rate ≥90 mL/min/1.73 m2), mild (≥60 to <90 mL/min/1.73 m2), and moderate (≥30 to <60 mL/min/1.73 m2) RI. Safety assessments based on ≤12 weeks of treatment from all 3 studies included incidence of treatment-emergent adverse events (TEAEs). Efficacy was based on the proportion of responders in COMPOSE-1 and COMPOSE-2 only, defined as ≥3 spontaneous bowel movements (SBMs)/week and a ≥1-SBM/week increase from baseline for ≥9 of 12 weeks and ≥3 of the last 4 weeks. RESULTS: In total, 2328 patients were included in this analysis. The incidence of TEAEs was similar in the naldemedine and placebo groups (overall, 47.1% vs 45.6%; normal, 44.6% vs 43.6%; mild RI, 49.0% vs 44.7%; moderate RI, 46.6% vs 55.9%). GI-related TEAEs occurred more frequently in the naldemedine group versus placebo (overall, 21.8% vs 13.8%; normal, 21.6% vs 12.5%; mild RI, 22.6% vs 14.7%; moderate RI, 18.0% vs 14.2%). A significantly greater proportion of patients in the naldemedine 0.2 mg group were responders versus the placebo group (overall, 50.1% vs 34.1%, P<0.0001; normal, 52.0% vs 39.3%; mild RI, 48.3% vs 30.3%; moderate RI, 52.5% vs 31.7%). CONCLUSION: This integrated analysis confirmed that OIC treatment with naldemedine 0.2 mg was generally well tolerated and effective in patients with CNCP and mild or moderate RI. Safety and efficacy results were consistent with the overall population. CLINICALTRIALSGOV REGISTRATION: COMPOSE-1: NCT01965158; COMPOSE-2: NCT01993940; COMPOSE-3: NCT01965652.

Relative Oral Bioavailability of an Abuse-Deterrent, Immediate-Release Formulation of Oxycodone, Oxycodone ARIR in a Randomized Study.

INTRODUCTION: Oxycodone ARIR is a novel oral, abuse-deterrent, immediate-release (IR) formulation with physical and chemical properties that deter misuse and abuse by non-oral routes. In this single-dose pharmacokinetic study, we assessed the relative bioavailability of oxycodone for Oxycodone ARIR and IR oxycodone, and the effect of food on Oxycodone ARIR following oral administration. METHODS: This open-label, randomized study in healthy adults compared the relative bioavailability of Oxycodone ARIR 30 mg to IR oxycodone 30 mg under fasted conditions, and Oxycodone ARIR under fed versus fasted conditions. Pharmacokinetic parameters included area under the concentration-time curve from time 0 to the last measured concentration (AUC0-t) and the maximum oxycodone plasma concentration (Cmax). Equivalence was determined using an analysis of variance of the least-squares means. RESULTS: Fifty-eight subjects completed the study. Under fasted conditions, AUC0-t was 4% lower (90% CI 92.5-98.7%) and mean Cmax was 14% lower (90% CI 78.8-94.3%) for Oxycodone ARIR versus IR oxycodone. AUC0-t was 23% higher (90% CI 119.1-127.0%) and mean Cmax was higher (90% CI 108.6-129.4%) when Oxycodone ARIR was administered in the fed versus fasted state. Common adverse events included nausea, headache, and dizziness. CONCLUSION: In this single-dose pharmacokinetic evaluation, fasted Oxycodone ARIR 30 mg had similar bioavailability to and is expected to have the same efficacy and safety profile as IR oxycodone. When administered in the fed state, pharmacokinetic parameters were slightly higher; however, these differences were considered not clinically meaningful and show that Oxycodone ARIR can be administered with or without food. FUNDING: This study was funded by Inspirion Delivery Sciences, LLC. Daiichi Sankyo, Inc. funded the journal's article processing charges and open access fee. Plain language summary available for this article.

Desmetramadol Has the Safety and Analgesic Profile of Tramadol Without Its Metabolic Liabilities: Consecutive Randomized, Double-Blind, Placebo- and Active Comparator-Controlled Trials.

Desmetramadol is an investigational analgesic consisting of (+) and (-) enantiomers of the tramadol metabolite O-desmethyltramadol (M1). Tramadol is racemic and exerts analgesia by monoaminergic effects of (-)-tramadol and (-)-M1, and by the opioid (+)-M1. Tramadol labeling indicates cytochrome P450 (CYP) isozyme 2D6 ultrarapid metabolizer can produce dangerous (+)-M1 levels, and CYP2D6 poor metabolizers insufficient (+)-M1 for analgesia. We hypothesized that desmetramadol could provide the safety and analgesia of tramadol without its metabolic liabilities. We conducted consecutive double-blind, randomized, placebo-controlled, 3 segment cross-over trials A and B to investigate the steady-state pharmacokinetics and analgesia of 20 mg desmetramadol and 50 mg tramadol in 103 healthy participants without (n = 43) and with (n = 60) cotreatment with the CYP inhibitor paroxetine. In the absence of CYP inhibition (trial A), 20 mg desmetramadol and 50 mg tramadol dosed every 6 hours gave equivalent steady-state (+)-M1, similar adverse events, and analgesia significantly greater than placebo, but equal to each other. In trial B, CYP inhibition significantly depressed tramadol steady-state (+)-M1, reduced its adverse events, and led to insignificant analgesia comparable with placebo. In contrast, CYP inhibition in trial B had no deleterious effect on desmetramadol (+)-M1 or (-)-M1, which gave significant analgesia as in trial A and superior to tramadol (P = .003). Desmetramadol has the safety and efficacy of tramadol without its metabolic liabilities. CLINICALTRIALS.GOV REGISTRATIONS: NCT02205554, NCT03312777 PERSPECTIVE: To our knowledge, this is the first study of desmetramadol in humans and the first to show it provides the same safety and analgesia as tramadol, but without tramadol's metabolic liabilities and related drug-drug interactions. Desmetramadol could potentially offer expanded safety and usefulness to clinicians seeking an alternative to schedule II opioids.

Effects of intravenous oxycodone alone or in combination with naltrexone on measures of respiratory depression: a randomized placebo-controlled study.

BACKGROUND: Abuse of prescription opioids, particularly by intravenous (IV) administration, can cause respiratory depression and death. ALO-02, an abuse-deterrent opioid formulation, is designed to release sequestered naltrexone upon manipulation by crushing, thereby antagonizing the pharmacologic effects of oxycodone. This exploratory post-hoc analysis examined the effects of IV administration of simulated crushed ALO-02 on end-tidal carbon dioxide (EtCO2), a surrogate marker of respiratory depression. METHODS: Data were obtained from a randomized, double-blind, placebo-controlled, three-way crossover study in nondependent recreational opioid users that evaluated the abuse potential of IV administered oxycodone 20 mg + naltrexone 2.4 mg (simulating crushed ALO-02) versus oxycodone 20 mg or placebo. EtCO2 was measured as a secondary endpoint using noninvasive capnography at baseline and postdose intervals, up to 24 h. RESULTS: Baseline EtCO2 (mean ± standard error of the mean (SEM)) values (n = 33) were similar across treatments: 33.5 ± 0.9, 33.5 ± 0.8, and 34.0 ± 0.7 mmHg for oxycodone 20 mg + naltrexone 2.4 mg, oxycodone 20 mg, and placebo, respectively. After dosing, mean ± SEM of the maximum effect (Emax) on EtCO2 was 37.5 ± 0.6, 40.5 ± 0.8, and 36.9 ± 0.6 mmHg for oxycodone 20 mg + naltrexone 2.4 mg, oxycodone 20 mg, and placebo, respectively. Emax values were significantly lower for oxycodone 20 mg + naltrexone 2.4 mg versus oxycodone 20 mg (p = 0.0005), and not different from placebo (p > 0.05). CONCLUSIONS: This abuse-potential study suggests that naltrexone released from ALO-02 tampering by crushing attenuates oxycodone-induced increase of EtCO2 in nondependent recreational opioid users.

Real-world misuse, abuse, and dependence of abuse-deterrent versus non-abuse-deterrent extended-release morphine in Medicaid non-cancer patients.

OBJECTIVE: Opioids with abuse-deterrent properties may reduce widespread abuse, misuse, and diversion of these products. This study aimed to quantify misuse, abuse, dependence, and health resource use of extended-release morphine sulfate with sequestered naltrexone hydrochloride (ER-MSN; EMBEDA®), compared with non-abuse-deterrent extended-release morphine (ERM) products in Medicaid non-cancer patients. METHODS: Administrative medical and pharmacy claims data were analyzed for 10 Medicaid states from 1 January 2015, to 30 June 2016. Patients were included if they received a prescription for ER-MSN or any oral, non-abuse-deterrent ERM. Index date was the date of first prescription for an ER-MSN or ERM. Abuse/dependence, non-fatal overdose, emergency department (ED) visits, and ED/inpatient readmissions were determined for each participant. An overall measure of misuse and abuse was also calculated. To account for differences in follow-up, all counts are expressed per 100 patient-years. RESULTS: There were 4,857 patients who received ER-MSN and 10,357 who received an ERM. The average age in the two cohorts was approximately 45 years old. From pre-index to follow-up, the number of patients per 100 patient-years with a diagnosis code indicating abuse or dependence increased by 0.91 (95% confidence interval [CI]: 0.85, 0.97) in the ER-MSN cohort and 2.23 (95% CI: 2.14, 2.32) in the ERM cohort. The number of patients per 100 patient-years with an opioid-related non-fatal overdose increased by 0.05 (95% CI: 0.04, 0.06) in the ER-MSN cohort compared with 0.11 (95% CI: 0.09, 0.13) in the ERM cohort. The opioid abuse overall composite score increased by 1.36 (95% CI: 1.24, 1.48) in the post-index period in the ER-MSN cohort compared to 3.21 (95% CI: 3.10, 3.32) in the ERM cohort. CONCLUSION: Misuse, abuse, and dependence events were numerically lower in patients receiving ER-MSN compared with those receiving ERM products.

A Randomized, Double-Blind, Double-Dummy, Placebo-Controlled, Intranasal Human Abuse Potential Study of Oxycodone ARIR, a Novel, Immediate-Release, Abuse-Deterrent Formulation.

OBJECTIVE: Prescription opioid abuse continues to be a public health concern. Oxycodone ARIR is an immediate-release (IR) oxycodone tablet composed of multiple overlapping barriers that deter manipulation of the tablet for non-oral abuse. DESIGN: This randomized, double-blind, double-dummy, active- and placebo-controlled, four-way crossover, intranasal human abuse potential study assessed the pharmacodynamics and pharmacokinetics of crushed intranasal oxycodone ARIR compared with crushed intranasal IR oxycodone and intact oral oxycodone ARIR. OUTCOME MEASURES: Pharmacodynamic end points included mean maximum drug liking (Emax), as measured by subjects on a bipolar 100-mm visual analog scale (primary), and desire to take the drug again, overall drug liking, drug high, and good effects (secondary). Pharmacokinetic assessments included peak concentration and time to peak concentration. RESULTS: Twenty-nine subjects completed the treatment phase. Crushed intranasal oxycodone ARIR demonstrated a significant reduction of 46.9% and 23.4% in drug liking Emax compared with crushed intranasal IR oxycodone and intact oral oxycodone ARIR, respectively (P < 0.0001 for both). Significant reductions also were observed in desire to take the drug again, drug high, overall drug liking, and good effects when comparing crushed intranasal oxycodone ARIR with crushed intranasal IR oxycodone and intact oral oxycodone ARIR (P < 0.001 for all). Crushed intranasal oxycodone ARIR exhibited lower peak oxycodone plasma concentrations and slower time to peak concentration compared with crushed intranasal IR oxycodone and intact oral oxycodone ARIR. All treatments were well tolerated; adverse effects were typical of opioids or intranasal administration. CONCLUSIONS: These data indicate that oxycodone ARIR has the potential to reduce abuse via the intranasal route.

Oral methylnaltrexone is efficacious and well tolerated for the treatment of opioid-induced constipation in patients with chronic noncancer pain receiving concomitant methadone.

PURPOSE: To evaluate the safety and efficacy of oral methylnaltrexone for opioid-induced constipation (OIC). PATIENTS AND METHODS: This was a post hoc analysis of patients receiving methadone in a randomized, double-blind, placebo-controlled, Phase 3 trial. The trial included adults with chronic noncancer pain for ≥2 months receiving opioid doses ≥50 mg/day of oral morphine equivalents for ≥14 days and with a history of OIC. Patients were assigned to oral methylnaltrexone (150, 300, or 450 mg) or placebo once daily (QD) for 4 weeks followed by 8 weeks as needed. Percentage of dosing days that resulted in a rescue-free bowel movement (RFBM) within 4 hours of dosing was assessed during QD dosing (primary efficacy endpoint). Other endpoints included percentage of responders (ie, ≥3 RFBMs/week, with an increase of ≥1 RFBM/week from baseline for ≥3 of the 4 weeks) during QD dosing and change in weekly number of RFBMs. Adverse events were assessed. RESULTS: Concomitant methadone was reported in 120 patients (oral methylnaltrexone: 150 mg [n=33], 300 mg [n=30], and 450 mg [n=31]; placebo [n=26]). Oral methylnaltrexone-treated patients had significant increases in mean percentage of dosing days with RFBMs within 4 hours of dosing during weeks 1-4 with 300 mg (33.6%; P<0.01) and 450 mg (38.2%; P<0.001) vs placebo; improvements with 150 mg (20.0%) vs placebo (15.1%) did not reach statistical significance. The percentage of responders was greater vs placebo, but not significant, for the higher doses during the QD period (150 mg [39.4%], 300 mg [60.0%], 450 mg [67.7%], and placebo [38.5%]). Change from baseline in the mean number of weekly RFBMs (weeks 1-4) was significantly greater with oral methylnaltrexone 450 mg vs placebo (least-squares mean difference vs placebo, 1.2; P=0.04); no significant differences were found for 300 or 150 mg. Oral methylnaltrexone was well tolerated at all doses; few patients discontinued treatment. CONCLUSION: Oral methylnaltrexone, particularly 450 mg, was efficacious and safe for treating OIC in these patients.

Oral methylnaltrexone does not negatively impact analgesia in patients with opioid-induced constipation and chronic noncancer pain.

PURPOSE: An oral formulation of methylnaltrexone has been developed for treating opioid-induced constipation (OIC). This manuscript examines the impact of oral methylnaltrexone, a peripherally acting µ-opioid receptor antagonist, on opioid analgesia. METHODS: This Phase III, randomized, double-blind, placebo-controlled trial, evaluated changes in pain intensity scores (0= no pain to 10= worst possible pain) and opioid use in adults with chronic noncancer pain. Patients taking ≥50 mg/day oral morphine equivalent dose (MED) for ≥14 days before screening with less than three rescue-free bowel movements/week received oral methylnaltrexone 150 mg/day (n=201), 300 mg/day (n=201), 450 mg/day (n=200), or placebo (n=201) once daily for 4 weeks followed by 8 weeks of oral methylnaltrexone as needed. RESULTS: The primary condition requiring opioid use was back pain (68.2% of 803 patients). Baseline pain intensity scores were similar among treatment groups (mean range, 6.2-6.4) and remained stable throughout the 4-week double-blind (mean range, 6.1-6.5) and 8-week as needed (mean range, 6.3-6.5) periods. Baseline mean MED was comparable between oral methylnaltrexone 150 mg (200.0 mg/day), methylnaltrexone 450 mg (218.0 mg/day), and placebo (209.7 mg/day), but was slightly higher in the oral methylnaltrexone 300-mg group (252.6 mg/day). Nonsignificant, minimal changes in mean MED were observed after 4 weeks of treatment (214.5-235.6 mg/day) and at the end of the as needed phase (202.3-234.9 mg/day). The percentage of patients who initiated new opioid medications during the 4-week, once-daily dosing period was generally similar among the oral methylnaltrexone 150-mg, 300-mg, and 450-mg groups (44.8%, 43.3%, and 35.0%, respectively), the oral methylnaltrexone combined group (41.0%), and the placebo group (39.8%). The most common newly initiated opioid medications during this once-daily period were oxycodone (oral methylnaltrexone groups combined, 14.6%; placebo, 12.4%) and morphine (oral methylnaltrexone combined, 10.1%; placebo, 7.0%). CONCLUSION: Oral methylnaltrexone does not elicit opioid withdrawal or interfere with opioid analgesia.

Efficacy of Lubiprostone for the Treatment of Opioid-Induced Constipation, Analyzed by Opioid Class.

Objectives: To examine the efficacy and safety of lubiprostone for the treatment of opioid-induced constipation (OIC) in patients by opioid class received. Design: Data were pooled from three phase III, randomized, double-blind, placebo-controlled studies. Subjects/Setting: Adults with chronic noncancer pain receiving opioid therapy for 30 or more days and diagnosed with OIC. Methods: Overall mean change from baseline in spontaneous bowel movement (SBM) frequency, overall treatment response (≥1 SBM/week improvement over baseline SBM frequency in all treatment weeks with available data and ≥3 SBMs/week for ≥9 of the 12 weeks of treatment), and OIC-related symptoms were examined in patients taking opioids. Data were pooled and analyzed by opioid group. Results: In patients receiving phenanthrene opioids (e.g., oxycodone; N = 1,159), lubiprostone significantly increased overall mean changes in SBM frequency from baseline (P = 0.0001), increased overall response rate (P = 0.0024), and improved OIC symptoms (P ≤ 0.0229) vs placebo. Patients receiving phenylpiperidine opioids (e.g., fentanyl; N = 137) had significant improvement in SBM frequency (P = 0.0129) and favorable trends in response rates (21.4% vs 9.8%; P = 0.0723) and OIC symptoms vs placebo. Efficacy was not observed in overall analyses of patients receiving diphenylheptane opioids (e.g., methadone), although an increase in SBM frequency was observed in patients who received a morphine-equivalent daily dose of 200 or fewer mg, suggesting a dose-dependent negative interference of this opioid class on lubiprostone effects. For all groups, the lubiprostone adverse event profile was similar; the most common treatment-emergent adverse events were nausea and diarrhea. Conclusions: In patients using commonly prescribed opioids, lubiprostone is effective and generally well tolerated for the treatment of OIC.

Intranasal Pharmacokinetics of Morphine ARER, a Novel Abuse-Deterrent Formulation: Results from a Randomized, Double-Blind, Four-Way Crossover Study in Nondependent, Opioid-Experienced Subjects.

Objective: To investigate the pharmacokinetics (PK) of Morphine ARER, an extended-release (ER), abuse-deterrent formulation of morphine sulfate after oral and intranasal administration. Methods: This randomized, double-blind, double-dummy, placebo-controlled, four-way crossover study assessed the PK of morphine and its active metabolite, M6G, from crushed intranasal Morphine ARER and intact oral Morphine ARER compared with crushed intranasal ER morphine following administration to nondependent, recreational opioid users. The correlation between morphine PK and the pharmacodynamic parameter of drug liking, a measure of abuse potential, was also evaluated. Results: Mean maximum observed plasma concentration (Cmax) for morphine was lower with crushed intranasal Morphine ARER (26.2 ng/mL) and intact oral Morphine ARER (18.6 ng/mL), compared with crushed intranasal ER morphine (49.5 ng/mL). The time to Cmax (Tmax) was the same for intact oral and crushed intranasal Morphine ARER (1.6 hours) and longer for crushed intranasal morphine ER (1.1 hours). Higher mean maximum morphine Cmax, Tmax, and abuse quotient (Cmax/Tmax) were positively correlated with maximum effect for drug liking (R2 ≥ 0.9795). Conclusion: These data suggest that Morphine ARER maintains its ER profile despite physical manipulation and intranasal administration, which may be predictive of a lower intranasal abuse potential compared with ER morphine.

Long-term use of naldemedine in the treatment of opioid-induced constipation in patients with chronic noncancer pain: a randomized, double-blind, placebo-controlled phase 3 study.

The long-term safety of naldemedine, a peripherally acting µ-opioid receptor antagonist, was evaluated in patients with opioid-induced constipation and chronic noncancer pain in a 52-week, randomized, double-blind, phase 3 study. Eligible adults who could be on a routine laxative regimen were randomized 1:1 to receive once-daily oral naldemedine 0.2 mg (n = 623) or placebo (n = 623). The primary endpoint was summary measures of treatment-emergent adverse events (AEs). Additional endpoints included opioid withdrawal on the Clinical Opiate Withdrawal Scale and the Subjective Opiate Withdrawal Scale, pain intensity on Numeric Rating Scale, frequency of bowel movements, and constipation-related symptoms and quality of life on the Patient Assessment of Constipation Symptoms and Patient Assessment of Constipation Quality of Life scales, respectively. Treatment-emergent AEs (naldemedine, 68.4% vs placebo, 72.1%; difference: -3.6% [95% confidence interval: -8.7 to 1.5]) and treatment-emergent AEs leading to study discontinuation (6.3% vs 5.8%; difference: 0.5% [-2.2 to 3.1)] were reported for similar proportions of patients. Diarrhea was reported more frequently with naldemedine (11.0%) vs placebo (5.3%; difference: 5.6% [2.6-8.6]). There were no meaningful differences between groups in opioid withdrawal or pain intensity. Sustained significant improvements in bowel movement frequency and overall constipation-related symptoms and quality of life were observed with naldemedine (P ≤ 0.0001 vs placebo at all time points). Naldemedine was generally well tolerated for 52 weeks and did not interfere with opioid-mediated analgesia or precipitate opioid withdrawal. Naldemedine significantly increased bowel movement frequency, improved symptomatic burden of opioid-induced constipation, and increased patients' quality of life vs placebo.