Study Evaluating the Efficacy and Safety of Subcutaneous Methylnaltrexone (MOA-728) for the Treatment of Opioid-Induced-Constipation

Study Overview
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Brief Summary
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The primary purpose of this study is to evaluate the safety, efficacy, and tolerability of subcutaneous (injection beneath the skin) MOA-728 versus placebo in adult Asian subjects with opioid-induced constipation associated with advanced illness (ie, a terminal illness such as incurable cancer or other end-stage disease) or chronic nonmalignant pain.

Detailed Description
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Subjects received subcutaneous methylnaltrexone (also referred to as MOA-728 or MNTX) or placebo every other day beginning on Day 1 up to a maximum of 7 doses during the 2-week double-blind period. Inclusion criteria for this study included subjects with advanced illness or subjects with chronic nonmalignant pain. The actual study population included only subjects with cancer-related advanced illness. All subjects who completed the double-blind treatment phase of this study could elect to receive methylnaltrexone during a 12-week open-label extension study, provided eligibility criteria were met. Subjects who did not continue in the open-label extension study had a follow-up visit 2 weeks after their last dose of test article.

Official Title
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A Multicenter, Randomized, Double-Blind, Placebo-Controlled, And Parallel-Group Study Of Subcutaneous Methylnaltrexone (MOA-728) For The Treatment Of Opioid-Induced Constipation In Adult Subjects

Conditions
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Constipation

Intervention / Treatment
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* Drug: Methylnaltrexone
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women who are at least 18 years of age, and who have a diagnosis of advanced illness with anticipated life expectancy >= 1 month; Is receiving a regular dose of opioids for the control of pain; Has a diagnosis of opioid induced constipation; Is on a stable laxative regimen. Exclusion Criteria: Has a known or suspected mechanical gastrointestinal obstruction, or any potential non-opioid cause of bowel dysfunction contributed to constipation; Has evidence of current fecal impaction; Has evidence of active diverticulitis, or peritonitis, or a history of bowel surgery within 30 days before test article administration; Has a body weight less than 27 kg Has any major illness/condition that, in the investigator's judgment, will substantially increase the risk associated with the subject's participation in and completion of the study, or could preclude the evaluation of the subject's response.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Methylnaltrexone double-blind<br>Methylnaltrexone once every other day. | Drug: Methylnaltrexone<br>* Subjects received 0.6 mL (12 mg) every other day if weight ≥ 62kg; 0.4 mL (8 mg) every other day if weight between 38 and < 62 kg; or 0.0075 mL/kg (0.15 mg/kg) every other day if weight between 27 and <38 kg. Study duration: 2 weeks double-blind period (MNTX treatments) followed by 12 weeks open-label extension period (MNTX treatments).<br>* Other names: MNTX;|
| Placebo Comparator: Placebo<br>Placebo once every other day. | Drug: Placebo<br>* Subjects received matching placebo injections. Study duration: 2 weeks double-blind period (placebo treatments) followed by 12 weeks open-label extension period (MNTX treatments).<br>|
| Other: Methylnaltrexone open-label<br>Subjects who completed the double-blind period had the option to receive methylnaltrexone once every other day during a 12-week, open-label extension period. | Drug: Methylnaltrexone<br>* Subjects received 0.6 mL (12 mg) every other day if weight ≥ 62kg; 0.4 mL (8 mg) every other day if weight between 38 and < 62 kg; or 0.0075 mL/kg (0.15 mg/kg) every other day if weight between 27 and <38 kg. Study duration: 2 weeks double-blind period (MNTX treatments) followed by 12 weeks open-label extension period (MNTX treatments).<br>* Other names: MNTX;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Proportion of Subjects Having a Rescue-free Bowel Movement (RFBM) Within 4 Hours After the First Injection. | There were 2 co-primary endpoints for this study. This measurement is the first of the 2 co-primary endpoints. This endpoint measures the percentage of patients who had an RFBM within 4 hours after the first dose of test article during the double-blind period; data are expressed as percentages of patients for the MNTX and placebo groups. To qualify as rescue free, the bowel movement could not occur within 6 hours after a rectal intervention (ie, rectal suppository, enema, manual disimpaction). Note that efficacy results (primary and secondary outcomes) are presented for the double-blind period only. Therefore, no efficacy results are presented for the open-label period. | Up to 4 hours after the first injection | 
| The Proportion of Subjects Having a Rescue-free Bowel Movement (RFBM) Within 4 Hours After Each Dose During Double-blind Period. | This measurement is the second of the 2 co-primary endpoints. This endpoint measures the percentage of patients who had an RFBM within 4 hours after each dose of test article during the double-blind period; data are expressed as percentages of patients by dose (first, second, third, fourth, etc.) for the MNTX and placebo groups. The definition of RFBM is described above (see first co-primary endpoint). | Within 4 Hours After Each Dose During the 2 weeks Double-Blind Period | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Injections Resulting in RFBM Within 4 Hours After Test Article Administration. | This endpoint measures the percentage of injections resulting in RFBMs within 4 hours after test article administration during the double-blind period. The percentage of injections resulting in RFBMs is calculated for each patient and then data are expressed as the mean (± standard deviation) percentage for the MNTX and placebo groups. The definition of RFBM is described above (see first co-primary endpoint). | Within 4 Hours After Each Dose During the 2 weeks Double-Blind Period | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Opioid Induced Constipation