Efficacy of duloxetine in patients with knee osteoarthritis or chronic low back pain with early pain reduction: An exploratory post-hoc analysis of Japanese phase 3, 1-year extension studies.

BACKGROUND: Two previous phase 3, double-blind, randomized, placebo-controlled trials showed that duloxetine 60 mg/day for 14 weeks significantly improved pain and quality of life in Japanese patients with knee osteoarthritis or chronic low back pain. In their open-label extension studies, these improvements were maintained for ≥48 weeks. This post-hoc analysis assessed the relationship between initial response to duloxetine and long-term pain reduction and quality of life in patients with knee osteoarthritis or chronic low back pain. METHODS: Patients (knee osteoarthritis: N = 43; chronic low back pain: N = 41) were subdivided based on extent of pain reduction from baseline to Week 4 of duloxetine (≥30%, 10-30%, or <10% reduction in Brief Pain Inventory-Severity average pain score). Outcome measures were changes from baseline for Brief Pain Inventory-Severity and Brief Pain Inventory-Interference at regular intervals up to Week 65. RESULTS: Mean change from baseline in Brief Pain Inventory-Severity was greater in patients with ≥30% early pain reduction than in patients with <10% early pain reduction through Week 27 for both conditions, and also Weeks 47-65 for back pain. Compared with the <10% early pain reduction group, mean change from baseline in the average of seven Brief Pain Inventory-Interference domain scores was greater in the ≥30% or 10-30% early pain reduction groups for knee osteoarthritis (except Weeks 63-65), and in the ≥30% early pain reduction group for chronic low back pain through Week 19. CONCLUSIONS: These results suggest that patients with knee osteoarthritis who respond well to duloxetine in the first month might experience sustained, long-term pain relief with generally greater quality-of-life improvement than patients with poor initial response. Patients with chronic low back pain who had strong initial response may experience a greater long-term pain relief, but not greater quality-of-life improvement, than patients with poor initial response.

Efficacy of duloxetine for multisite pain in patients with knee pain due to osteoarthritis: An exploratory post hoc analysis of a Japanese phase 3 randomized study.

BACKGROUND: Central sensitization, including dysfunction of descending inhibitory pain pathways, may contribute to multisite pain in patients with chronic musculoskeletal conditions. Duloxetine is a centrally acting analgesic that effectively reduces pain in patients with knee osteoarthritis. Here we assessed the efficacy of duloxetine (60 mg/day) in Japanese patients (N = 353) with pain due to knee osteoarthritis based on the number of painful body sites, determined using the Michigan Body Map. METHODS: Post hoc analysis of a phase 3, randomized, placebo-controlled trial (ClinicalTrials.gov; NCT02248480). RESULTS: At Week 14, the change from baseline in Brief Pain Inventory-Severity average pain score ("pain reduction") was significantly greater with duloxetine compared with placebo in patients with 3, 4, or ≥5 painful sites, but not in patients with 1 or 2 painful sites. In patients with ≥3 painful sites (57% of patients), pain reduction was significantly greater with duloxetine (n = 100) compared with placebo (n = 101) throughout the study (least squares mean change from baseline to Week 14: -2.68 vs -1.68). Greater pain reduction with duloxetine (n = 77) than placebo (n = 75) also occurred in patients with ≤2 painful sites, although the between-group difference was significant only at Week 4. CONCLUSIONS: These results are consistent with duloxetine enhancing the activity of descending inhibitory pain pathways that are dysfunctional in patients with central sensitization and multisite pain. In addition, these results suggest that duloxetine may be an effective choice of analgesic for patients with knee osteoarthritis and multisite pain.

An open-label, long-term, phase III extension trial of duloxetine in Japanese patients with fibromyalgia.

OBJECTIVES: We aimed to evaluate the long-term safety and efficacy of duloxetine 60 mg in Japanese patients with fibromyalgia enrolled from a preceding randomized, placebo-controlled, phase III duloxetine trial. METHODS: This was a long-term, open-label extension study. Patients received oral duloxetine once daily at a dose of 20 mg for 1 week, followed by 40 mg for 1 week, and then 60 mg for 48 weeks. The primary outcome was the frequency of adverse events (AEs) and adverse drug reactions (ADRs) of duloxetine. Efficacy and health outcomes were assessed. RESULTS: In total, 149 patients were enrolled from the preceding study. The median length of treatment was 364.0 days. The incidence of AEs and ADRs was 92.6 and 63.8%, respectively. ADRs occurring at an incidence of ≥5% were somnolence, constipation, nausea, weight increase, thirst, and malaise. The proportion of patients with mild, moderate, and severe AEs was 80.5, 10.1, and 2.0%. There were no serious treatment-related AEs in this study. The Brief Pain Inventory average pain score improved at all time-points compared with baseline (mean change ± standard deviation at Week 50 was -1.31 ± 1.70). CONCLUSIONS: Duloxetine was safe and effective in the long-term treatment of Japanese patients with fibromyalgia.

Efficacy and Safety of Duloxetine in Children and Adolescents with Major Depressive Disorder in Japan: A Randomized Double-Blind Placebo-Controlled Clinical Trial Followed by an Open-Label Long-Term Extension Trial.

Objective: The goal of this study was to evaluate the efficacy and safety of duloxetine in children and adolescents (9-17 years of age) with major depressive disorder (MDD) in Japan. Methods: This study consists of two clinical trials. First, a 6-week, randomized double-blind placebo-controlled clinical trial (RCT) was conducted. The primary endpoint of RCT was the change in Children's Depression Rating Scale-Revised (CDRS-R) total scores from baseline. Following RCT, an open-label long-term extension trial (OLE) was conducted to investigate the longer-term safety of duloxetine for ∼1 year. Results: In RCT, CDRS-R total score changes from baseline to 6 weeks after the start of administration (primary endpoint) were -21.03 in the duloxetine group (n = 74) and -22.42 in the placebo group (n = 74). No significant difference was observed in the primary endpoint between the groups (p = 0.5587). In addition, no significant difference was observed in secondary endpoints such as CDRS-R response rates. The proportion of patients with ≥1 treatment-emergent adverse event (TEAE) in RCT was significantly higher in the duloxetine group (78.7%) than in the placebo group (62.2%), and most were mild or moderate in severity. Changes in CDRS-R total scores during OLE, in consecutive patients from the duloxetine group in RCT (n = 63), or placebo group (n = 59) in RCT, and newly enrolled patients (n = 28), were -12.1, -11.3, and -17.8, respectively. The proportion of patients with ≥1 TEAE in OLE was 90.5%, 88.1%, and 89.3% in the respective groups, and most of them were mild or moderate in severity. Conclusions: Duloxetine did not show superiority to placebo in efficacy in children and adolescents with MDD in Japan. Overall reported TEAEs were consistent with the currently available duloxetine safety profile and no new safety finding was observed in the two clinical trials.

Efficacy And Safety Of Controlled-Release Oxycodone For The Management Of Moderate-To-Severe Chronic Non-Cancer Pain In Japanese Patients: Results From An Open-Label Study.

PURPOSE: To assess the efficacy and safety of S-8117, an oral, controlled-release formulation of oxycodone hydrochloride, in Japanese patients with chronic non-cancer pain (CNCP). PATIENTS AND METHODS: In this multicenter, non-randomized, open-label, 2-part (part 1, dose-titration followed by maintenance period; part 2, long-term administration period) study at 38 centers in Japan (2013-2015), adult patients with CNCP for ≥12 weeks were administered S-8117. The primary endpoint was proportion of patients with successful maintenance of pain control in part 1 and long-term safety in part 2. Secondary endpoints included time to inadequate analgesia, rate of transition to the maintenance period, and discontinuation due to inadequate analgesia/adverse events (AEs), Brief Pain Inventory (BPI) pain severity, BPI pain interference, 36-item Short Form Health Survey (SF-36) score, and Western Ontario and McMaster Universities (WOMAC) index, Subjective Opioid Withdrawal Scale (SOWS), Clinical Opioid Withdrawal Scale (COWS), Dependency-2-A (D-2-A), and Dependency-2-B (D-2-B) questionnaires. RESULTS: Of 130 patients (mean age, 63.6 years; women, 62.3%) in the dose-titration period, 95 entered the maintenance period; 60 of 83 who entered the long-term administration period completed it. The proportion of patients (95% confidence interval) with successful maintenance of pain control, transition to maintenance period, and discontinuation due to inadequate analgesia/AEs was 78.9% (69.4-86.6), 73.1% (64.6-80.5), and 21.1% (13.4-30.6), respectively. Time to inadequate analgesia could not be estimated. Changes from baseline in BPI, SF-36, and WOMAC index scores suggested improvements in pain relief and quality of life. Based on the SOWS, COWS, D-2-A and D-2-B questionnaires, no patient developed clinically relevant withdrawal syndrome or was ascertained to have developed drug dependence. Overall, the incidence of treatment-emergent AEs (TEAEs) was 93.8%; most common TEAEs were constipation (49.2%), nausea (42.3%), nasopharyngitis (34.6%), and somnolence (32.3%). CONCLUSION: These results demonstrate the efficacy and safety of S-8117 in Japanese patients with CNCP.

Efficacy and safety of controlled-release oxycodone for the management of moderate-to-severe chronic low back pain in Japan: results of an enriched enrollment randomized withdrawal study followed by an open-label extension study.

BACKGROUND: Oxycodone is one of the options for the management of CLBP in patients with an inadequate response to other analgesics. However, oxycodone is not yet approved for noncancer pain in Japan. Here, we assessed the efficacy and long-term safety of S-8117, a controlled-release oxycodone formulation, for the management of Japanese CLBP patients. PATIENTS AND METHODS: An initial enriched enrollment randomized withdrawal, double-blind, placebo-controlled, 5-week phase III trial was conducted across 54 centers in Japan to assess the efficacy of S-8117 vs placebo in moderate-to-severe CLBP patients. Subsequently, a 52-week, open-label, single-arm study was conducted across 53 centers in Japan to evaluate the long-term safety of S-8117. The primary endpoint was the time to inadequate analgesic response during 35 days of the double-blind period. Secondary endpoints were the percentages of patients with inadequate analgesic response, discontinuation rate due to inadequate analgesic effects or AEs, and changes in scores of BPI severity, BPI pain interference, SF-36, and Roland-Morris Disability Questionnaire. Safety was assessed as the incidence of AEs and ADRs. RESULTS: Of the 189 patients enrolled in the double-blind study, 130 patients who completed the initial titration period were randomized 1:1 to receive either S-8117 (n=62) or placebo (n=68). Baseline characteristics were comparable across the study groups. The time to inadequate analgesic response was significantly longer in patients treated with S-8117 than placebo (P=0.0095). Secondary endpoints corroborated the efficacy of S-8117 vs placebo. Overall, 478 AEs were reported in 73/75 patients in the long-term study. The most frequent ADRs were somnolence, constipation, and nausea. No case of drug dependence was reported in the long-term study. CONCLUSION: Short-term efficacy vs placebo and long-term safety of S-8117 were demonstrated for the management of Japanese patients with moderate-to-severe CLBP.

Response to duloxetine in patients with knee pain due to osteoarthritis: an exploratory post hoc analysis of a Japanese Phase III randomized study.

PURPOSE: To assess whether patients with knee osteoarthritis pain who have early pain reduction or treatment-related adverse events of special interest (TR-AESIs; constipation, decreased appetite, malaise, nausea, somnolence, thirst) with duloxetine treatment are more likely to have later improvements in pain and quality of life (QOL) relative to placebo than patients without these early indicators. PATIENTS AND METHODS: This was a post hoc analysis of 14-week randomized trial of Japanese patients with knee osteoarthritis pain (Brief Pain Inventory [BPI]-Severity average pain score ≥4) receiving duloxetine 60 mg/day (n=177 analyzed) or placebo (n=176). Primary trial outcome was change from baseline in BPI-Severity average pain at Week 14. Subgroups included early pain reduction (≥30%, 10%-30%, or <10% decrease in BPI-Severity average pain at Week 4) and early TR-AESIs (with/without TR-AESIs by Week 2). Measures included changes from baseline in BPI-Severity average pain, QOL (BPI-Interference, Western Ontario and McMaster Universities Osteoarthritis Index), Patient Global Impression of Improvement (PGI-I), and response rate (proportion achieving ≥30% or ≥50% pain reduction at Week 14). RESULTS: The ≥30% early pain reduction subgroup (n=93) had significantly greater improvements in pain, QOL, and PGI-I and higher ≥30% and ≥50% response rates than placebo; the 10%-30% (n=45) and the <10% (n=33) pain reduction subgroups did not show the same (except 10%-30% group: PGI-I at Week 10 and some QOL at Weeks 10 and/or 14). Both TR-AESI subgroups (with, n=52; without, n=125) had significantly greater improvements in pain, PGI-I, and most QOL measures and higher response rates than placebo. CONCLUSION: Early efficacy responses to duloxetine treatment, but not early TR-AESIs, may predict later pain reduction and QOL improvements in Japanese patients with knee osteoarthritis pain. CLINICALTRIALSGOV: NCT02248480.

Safety and efficacy of duloxetine in Japanese patients with chronic knee pain due to osteoarthritis: an open-label, long-term, Phase III extension study.

PURPOSE: To assess long-term safety, tolerability, and efficacy of duloxetine in Japanese patients with chronic knee pain due to osteoarthritis. METHODS: In this open-label extension study (NCT02335346), Japanese patients with knee osteoarthritis and pain (Brief Pain Inventory [BPI] - Severity average pain score ≥4 at start of randomized trial) who had previously received duloxetine 60 mg/day or placebo for 14 weeks in a double-blind randomized trial entered the extension and received duloxetine 60 mg/day for 48 weeks. The primary outcome was safety/tolerability, secondary outcomes were change in BPI-Severity (BPI-S) average pain, BPI-Interference (BPI-I), Patient Global Impression-Improvement (PGI-I), Clinical Global Impression-Improvement (CGI-I), 36-item Short-Form Health Survey (SF36), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and exploratory outcomes were knee range of motion (efficacy outcome) and Kellgren-Lawrence grade (safety outcome). RESULTS: Of 323 patients who completed the randomized trial, 93 (50 placebo, 43 duloxetine) entered the extension. Most patients (85, 91.4%) experienced an adverse event, most commonly constipation, nasopharyngitis, somnolence, and dry mouth (≥10% of patients). There were eight serious adverse events in seven patients and no deaths. No obvious duloxetine-related changes were observed in laboratory tests, vital signs, or electrocardiograms. The change from baseline in BPI-S average pain score was significant throughout the extension. Significant reductions in BPI-I, PGI-I, CGI-I, WOMAC, and SF36 scores were also maintained through 52 weeks. There were no substantial changes in range of motion or Kellgren-Lawrence grade. CONCLUSION: In Japanese patients with chronic knee pain due to osteoarthritis, long-term treatment with duloxetine was well tolerated and associated with sustained improvements in pain and health-related quality of life without radiographic deterioration.

Duloxetine in patients with diabetic peripheral neuropathic pain in Japan: a randomized, doubleblind, noninferiority comparative study with pregabalin.

PURPOSE: Duloxetine and pregabalin are recommended as first-line treatments for diabetic peripheral neuropathic pain (DPNP). However, studies have not reported a direct comparison between duloxetine and pregabalin. We conducted a postmarketing, randomized, double-blind study to assess the noninferiority of duloxetine compared with pregabalin after 12 weeks of treatment in adult patients with DPNP in Japan (NCT02417935). PATIENTS AND METHODS: Patients (N = 303) with distal symmetrical DPNP were randomized to and were administered duloxetine (40-60 mg/day) or pregabalin (300-600 mg/day). The primary endpoint was the change from baseline in weekly mean of the 24-hour average pain score (numeric rating scale [NRS]). Noninferiority of duloxetine compared with pregabalin was assessed with the primary endpoint at week 12. Secondary measures, including night pain and worst pain, Brief Pain Inventory-Severity and Interference rating short form (BPI-SF), Clinical Global Impression of Improvement (CGI-I), Patient Global Impression of Improvement (PGI-I), and Neuropathic Pain Symptom Inventory (NPSI), health outcome measures (EuroQol 5-Dimension index and VAS), and safety were also assessed. RESULTS: For the 24-hour NRS average pain score, the difference between the duloxetine and pregabalin groups was 0.072 (95% CI: - 0.295, 0.439), and the upper bound of the 95% CI (0.439) did not exceed the predefined noninferiority margin (0.51), at the end of the study period. For secondary outcome measures (night pain, worst pain, BPI-SF, CGI-I, PGI-I, NPSI) and health outcome measures, both the duloxetine and pregabalin treatment groups showed an improvement from baseline with no significant between-group difference. Duloxetine and pregabalin were well tolerated and the safety profiles were consistent with previously reported results. CONCLUSION: This study demonstrated the noninferior efficacy of duloxetine compared with pregabalin in the treatment of adult patients with DPNP. The safety analyses showed an acceptable tolerability based on safety profiles of duloxetine and pregabalin.

Response to duloxetine in chronic low back pain: exploratory post hoc analysis of a Japanese Phase III randomized study.

PURPOSE: Duloxetine is efficacious for chronic low back pain (CLBP). This post hoc analysis of a Japanese randomized, placebo-controlled trial (ClinicalTrials.gov, NCT01855919) assessed whether patients with CLBP with early pain reduction or treatment-related adverse events of special interest (TR-AESIs; nausea, somnolence, constipation) have enhanced responses to duloxetine. PATIENTS AND METHODS: Patients (N = 456) with CLBP for ≥6 months and Brief Pain Inventory (BPI) average pain severity score of ≥4 were randomized (1:1) to duloxetine 60 mg/day or placebo for 14 weeks. Primary outcome was change from baseline in BPI average pain severity score (pain reduction). Subgroup analyses included early pain reduction (≥30%, 10%-30%, or <10% at Week 4) and early TR-AESIs (with or without TR-AESIs by Week 2). Measures included changes from baseline in BPI average pain severity score and BPI Interference scores (quality of life; QOL), and response rate (≥30% or ≥50% pain reduction at Week 14). RESULTS: Patients with ≥30% early pain reduction (n = 108) or early TR-AESIs (n = 50) had significantly greater improvements in pain and QOL than placebo-treated patients (n = 226), whereas patients with 10%-30% (n = 63) or <10% (n = 48) pain reduction did not; patients without early TR-AESIs (n = 180) had significant improvements in pain at Week 14. Response rates (≥30%/≥50% pain reduction) were 94.4%/82.4%, 66.7%/49.2%, and 25.0%/18.8% for patients with ≥30%, 10%-30%, and <10% early pain reduction, respectively, 74.0%/64.0% for patients with early TR-AESIs, 67.2%/54.4% for patients without early TR-AESIs, and 52.2%/39.4% for placebo. CONCLUSION: Early pain reduction or TR-AESIs may predict which CLBP patients are most likely to respond to duloxetine with improvements in pain and QOL.

Duloxetine 60 mg for chronic low back pain: post hoc responder analysis of double-blind, placebo-controlled trials.

INTRODUCTION: Duloxetine has demonstrated efficacy in chronic low back pain (CLBP). We examined the predictors of response to duloxetine for CLBP. PATIENTS AND METHODS: This was a post hoc analysis of pooled data from 4 double-blind, ran-domized, placebo-controlled trials of duloxetine (60 mg/day for 12-14 weeks) in adult patients with CLBP. Primary outcome was proportion of patients with ≥30% reduction in Brief Pain Inventory (BPI) average pain ("pain reduction") at 12-14 weeks. The proportion of patients with ≥30% and ≥50% (secondary outcome) pain reduction in duloxetine and placebo groups was compared. Variables for responder analyses were early improvement (≥15% pain reduction at Week 2), sex, age, baseline BPI average pain score, duration of CLBP, and number of painful body sites according to the Michigan Body Map (≥2 vs 1 [isolated CLBP]; 1 trial); relative risk (RR) and 95% confidence interval (CI) were calculated. RESULTS: Compared with placebo (n = 653), a greater proportion of duloxetine-treated patients (n = 642) achieved ≥30% (59.7% vs 47.8%; P < 0.001) and ≥50% pain reduction (48.6% vs 35.1%; P < 0.001). Among duloxetine-treated patients, early improvement was associated with greater likelihood of ≥30% (RR [95% CI], 2.91 [2.30-3.67]) or ≥50% (3.24 [2.44-4.31]) pain reduction. Women were slightly more likely than men to achieve ≥30% (RR [95% CI], 1.14 [1.00-1.30]) or ≥50% (1.17 [0.99-1.38]) pain reduction. Response rates were similar between age, CLBP duration, and baseline BPI average pain score subgroups. Patients with ≥2 painful sites were more likely to respond to duloxetine 60 mg relative to placebo than patients with isolated CLBP (RR, duloxetine vs placebo [95% CI]: ≥30% reduction, ≥2 painful sites 1.40 [1.18-1.66], isolated CLBP 1.07 [0.78-1.48]; ≥50% reduction, ≥2 painful sites 1.51 [1.20-1.89], isolated CLBP 1.23 [0.81-1.88]). CONCLUSION: Early pain reduction was indicative of overall response. Patients with multiple painful sites had more benefit from duloxetine than patients with isolated CLBP.

Effect of spinal monoaminergic neuronal system dysfunction on pain threshold in rats, and the analgesic effect of serotonin and norepinephrine reuptake inhibitors.

Dysfunction in the central serotonin (5-HT) and norepinephrine (NE) systems cause depression and pain. Descending spinal pain modulatory pathways are important in the analgesic mechanisms of antidepressants, particularly serotonin and norepinephrine reuptake inhibitors (SNRIs). While many non-clinical studies have demonstrated the roles of central monoaminergic systems in pain, there is little evidence to illuminate the direct contribution of spinal descending pain modulatory systems independently of depressive-like behavior. To examine the effects of dysfunction of spinal monoaminergic systems on pain sensitivity, we established a rat chronic pain model by administering lumbar-intrathecal reserpine to minimize its influence on brain. Lumbar-intrathecal reserpine evoked persistent mechanical hypersensitivity and corresponding reductions in spinal 5-HT and NE concentrations (from 767.2 to 241.6ng/g and from 455.9 to 41.7ng/g, respectively after reserpine 30nmol). Lumbar-intrathecal reserpine did not deplete brain monoamines or bring about depressive-like behavior in the forced swim test. Spinal monoamines depletion-induced pain sensitivity was ameliorated by lumbar-intrathecal administration of the SNRIs (duloxetine and milnacipran) in dose-dependent manners. These suggest that increased pain sensitivity could be induced by dysfunction solely of the descending pain modulatory system, regardless of depressive-like behavior, and lumbar-intrathecal administration of SNRIs could ameliorate the pain sensitivity which might be mediated by affecting the descending pain modulatory system in the spinal cord, not via their antidepressant effects.

An epidemiologic internet survey of fibromyalgia and chronic pain in Japan.

OBJECTIVE: To determine the epidemiologic features and symptom characteristics of fibromyalgia (FM) in Japan, and compare them with those for other chronic pain (CP) diagnoses. METHODS: An internet survey was conducted in June and July 2011. The questionnaire consisted of 111 questions, including assessments of the Japanese version of the 2010 American College of Rheumatology preliminary diagnostic criteria for FM, the Japanese Fibromyalgia Impact Questionnaire, and additional questions regarding pain and lifestyle. RESULTS: The questionnaire was completed by 20,407 male and female respondents in all prefectures of Japan. Of the survey population, 2,524 respondents (12.4%) reported symptoms consistent with CP; of these, 425 (2.1%) reported symptoms consistent with FM. Among respondents with FM and CP, 61% and 53%, respectively, were women. Pain severity and Widespread Pain Index scores were significantly higher in respondents meeting the diagnostic criteria for FM than in those meeting the criteria for CP. In terms of symptom severity scores, the proportions of respondents reporting the 3 major symptoms as "highly applicable" and greater numbers of 41 somatic symptoms were higher among respondents with FM than among those with CP. The incidence of FM in the present survey was similar to that reported (1.7%) in a study of FM in Japan in 2003, despite the use of the newer, easier to use 2010 diagnostic criteria. CONCLUSION: Because FM usually presents with more severe and more widely distributed pain, as well as more nonpainful symptoms than CP, our results suggest that FM is a different clinical phenotype of CP.