RELISTOR Tablets

The efficacy of RELISTOR tablets in the treatment of OIC in patients with chronic non-cancer pain was evaluated in a randomized, double-blind, placebo-controlled study (Study 1). This study compared 4-week treatment of RELISTOR tablets 450 mg orally once daily with placebo.

A total of 401 patients (200 RELISTOR, 201 placebo) were enrolled and treated in the double-blind period. Patients had a history of chronic non-cancer pain for which they were taking opioids. The most common pain condition requiring opioid use was back pain. Other frequently reported primary pain conditions were arthritis, neurologic/neuropathic pain, joint/extremity pain, and fibromyalgia. Prior to screening, patients were receiving opioid therapy for pain for 1 month or longer (median daily baseline oral morphine equivalent dose of 156 mg) and had OIC (less than 3 spontaneous bowel movements per week during the screening period). Constipation due to opioid use had to be associated with 1 or more of the following: A Bristol Stool Form Scale score of 1 or 2 for at least 25% of the bowel movements (BM), straining during at least 25% of the BMs or a sensation of incomplete evacuation after at least 25% of the BMs.

Patients were required to be on a stable opioid regimen (daily dose 50 mg or more of oral morphine equivalents per day) a minimum of 2 weeks prior to the screening visit and received their opioid medication during the study as clinically needed. The median duration of OIC at baseline was 53 months (4 years). The mean patient age was 52 years (range 23 to 78 years), 64% were female, and 84% of patients were Caucasian.

Eligible patients were required to discontinue all previous laxative therapy and use only the study-permitted rescue laxative (bisacodyl tablets). If patients did not have a bowel movement for 3 consecutive days during the study, they were permitted to use rescue medication (up to 3 bisacodyl tablets taken orally once during a 24-hour period). Bisacodyl tablets were taken 5 hours or longer and up to 8 hours after study drug administration. If rescue treatment with bisacodyl tablets did not result in a bowel movement, a second dose of bisacodyl or an enema 24 hours after rescue was permitted. Enema use was permitted after rescue with bisacodyl tablets had failed at least once.

A responder analysis was performed which defined the proportion of patients with 3 or more spontaneous bowel movements (SBMs)/week, with an increase of 1 or more SBM/week over baseline, for 3 or more out of the first 4 weeks of the treatment period. A SBM was defined as a bowel movement that occurred without laxative use during the previous 24 hours . Table 8presents the proportion of patients who responded during the double-blind treatment period in the intent-to-treat (ITT) population, which included all randomized patients who received at least one dose of double-blind study medication. 

CI = confidence interval; ITT = intent-to-treat;   
aDifference for active treatment vs. placebo;   
*A responder is defined as a patient with 3 or more SBMs/week, with an increase of 1 or more SBM/week over baseline, for 3 or more out of the first 4 weeks of the treatment period. 

RELISTOR Injection

The efficacy of RELISTOR injection in the treatment of OIC in patients with chronic non-cancer pain were evaluated in a randomized, double-blind, placebo-controlled study (Study 2). This study compared 4-week treatment of RELISTOR injection 12 mg administered subcutaneously once daily with placebo.

A total of 312 patients (150 RELISTOR, 162 placebo) were enrolled and treated in the double-blind period. Patients had a history of chronic non-cancer pain for which they were taking opioids. The majority of patients had a primary diagnosis of back pain; other primary diagnoses included joint/extremity pain, fibromyalgia, neurologic/neuropathic pain, and rheumatoid arthritis. Prior to screening, patients had been receiving opioid therapy for pain for 1 month or longer (median daily baseline oral morphine equivalent dose of 161 mg) and had OIC (less than 3 spontaneous bowel movements per week during the screening period). Constipation due to opioid use had to be associated with 1 or more of the following: A Bristol Stool Form Scale score of 1 or 2 for at least 25% of the bowel movements (BM), straining during at least 25% of the BMs or a sensation of incomplete evacuation after at least 25% of the BMs.

Patients were required to be on a stable opioid regimen (daily dose 50 mg or more of oral morphine equivalents per day) for at least 2 weeks before the screening visit and received their opioid medication during the study as clinically needed. The median duration of OIC at baseline was 59 months (5 years). The median patient age at baseline was 49 years, 62% were females and 90% were Caucasian.

Eligible patients were required to discontinue all previous laxative therapy and use only the study-permitted rescue laxative (bisacodyl tablets). If patients did not have a bowel movement for 3 consecutive days during the study, they were permitted to use rescue medication (up to 4 bisacodyl tablets taken orally once during a 24-hour period). Rescue laxatives were prohibited until at least 4 hours after taking an injection of study medication.

A responder analysis was performed which defined the proportion of patients with 3 or more (SBMs) per week for each of the 4 weeks of the double-blind period. A SBM was defined as a bowel movement that occurred without laxative use during the previous 24 hours. Table 9presents the proportion of patients who responded during the double-blind treatment period in the modified intent-to-treat (mITT) population, which included all randomized subjects who received at least one dose of double-blind study medication. 

CI = confidence interval; mITT = modified intent-to-treat;

Following the first dose, 33% of patients in the RELISTOR treatment group had a SBM within 4 hours and approximately half of patients had a SBM prior to the second dose of RELISTOR injection.