Effects of milnacipran on the multidimensional aspects of fatigue and the relationship of fatigue to pain and function: pooled analysis of 3 fibromyalgia trials.

BACKGROUND: Fatigue is a core symptom in fibromyalgia that can negatively affect a patient's quality of life. OBJECTIVE: The objective of this study was to analyze fatigue-related data from 3 randomized, placebo-controlled trials of milnacipran (n = 3109) in fibromyalgia patients. METHODS: Fatigue was assessed with the Multidimensional Fatigue Inventory (MFI). Treatment effects were evaluated by changes in MFI total scores and identifying patients with improvement of 30% or greater from baseline. Path analyses were conducted to evaluate direct and indirect effects of treatment on fatigue. RESULTS: Patients had high levels of baseline fatigue; mean MFI total score was 68.1 (of 100). After 3 months of stable-dose treatment, patients receiving milnacipran 100 and/or 200 mg/d had significant improvement in MFI total and subscale scores (P < 0.05 vs placebo). The largest treatment effect was found in patients with equal to or greater than 20% to 40% fatigue improvement. Significantly more patients met the threshold of 30% or greater with milnacipran (100 mg/d, 17.6%; 200 mg/d, 15.2%) than with placebo (9.9%); odds ratios for this responder status were 1.93 and 1.63, respectively (P < 0.05 for both doses). Path analyses indicated that up to 28% of fatigue improvement may be attributed to direct milnacipran effects (ie, not indirectly through effects on pain or other symptoms). CONCLUSIONS: Fibromyalgia patients in the milnacipran studies had high levels of baseline fatigue. Patients receiving milnacipran had statistically significant and clinically meaningful reductions in fatigue that were not completely attributable to indirect treatment effects through pain reduction. Evaluating and managing fatigue are an important clinical concern when treating patients with fibromyalgia.

Relationships among pain, depressed mood, and global status in fibromyalgia patients: post hoc analyses of a randomized, placebo-controlled trial of milnacipran.

BACKGROUND: Patients with fibromyalgia often experience depressive symptoms in addition to chronic pain and other characteristic symptoms associated with this disorder. OBJECTIVE: To examine the relationships among pain, depressive symptoms, and global status in a clinical trial of milnacipran for fibromyalgia. METHODS: Data from a randomized, double-blind study (milnacipran 100 mg/d, n = 516; placebo, n = 509) were analyzed. Treatment outcomes included quantitative changes in pain and Beck depression inventory (BDI) scores, mean Patient Global Impression of Change (PGIC) scores, and three responder endpoints: patients with ≥30% pain improvement, PGIC score ≤2, and patients meeting both pain and PGIC responder criteria (2-measure composite responders). Correlations and path analyses were conducted to evaluate relationships among improvements in depressive symptoms, pain, and PGIC. RESULTS: Patients receiving milnacipran had greater decreases in mean pain scores, lower mean PGIC endpoint scores, and higher responder rates regardless of baseline severity of depressive symptoms. The highest responder rates were found in patients with greater than four-point improvement in BDI scores (milnacipran vs. placebo: pain, 57.5% vs. 39.0%; PGIC, 60.1% vs. 38.2%; 2-measure composite, 49.0% vs. 27.9%; all p < 0.01), although significant differences between treatment groups were also found in patients with no improvement or worsening of depressive symptoms. Correlations between changes in BDI and changes in pain or PGIC were low (r ≤ 0.3). Path analyses indicated 87.2% of pain reduction to be a direct effect of milnacipran treatment. CONCLUSION: Symptom improvements with milnacipran were only weakly associated with baseline depressive symptoms and were largely independent of improvements in depressive symptomatology.

Efficacy and safety of milnacipran 100 mg/day in patients with fibromyalgia: results of a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To assess the efficacy and safety of milnacipran at a dosage of 100 mg/day (50 mg twice daily) for monotherapy treatment of fibromyalgia. METHODS: A double-blind, placebo-controlled trial was performed to assess 1,025 patients with fibromyalgia who were randomized to receive milnacipran 100 mg/day (n = 516) or placebo (n = 509). Patients underwent 4-6 weeks of flexible dose escalation followed by 12 weeks of stable-dose treatment. Two composite responder definitions were used as primary end points to classify the response to treatment. The 2-measure composite response required achievement of ≥30% improvement from baseline in the pain score and a rating of "very much improved" or "much improved" on the Patient's Global Impression of Change (PGIC) scale. The 3-measure composite response required satisfaction of these same 2 improvement criteria for pain and global status as well as improvement in physical function on the Short Form 36 (SF-36) physical component summary (PCS) score. RESULTS: After 12 weeks of stable-dose treatment, a significantly greater proportion of milnacipran-treated patients compared with placebo-treated patients showed clinically meaningful improvements, as evidenced by the proportion of patients meeting the 2-measure composite responder criteria (P < 0.001 in the baseline observation carried forward [BOCF] analysis) and 3-measure composite responder criteria (P < 0.001 in the BOCF). Milnacipran-treated patients also demonstrated significantly greater improvements from baseline on multiple secondary outcomes, including 24-hour and weekly recall pain score, PGIC score, SF-36 PCS and mental component summary scores, average pain severity score on the Brief Pain Inventory, Fibromyalgia Impact Questionnaire total score (all P < 0.001 versus placebo), and Multidimensional Fatigue Inventory total score (P = 0.036 versus placebo). Milnacipran was well tolerated by most patients, with nausea being the most commonly reported adverse event (placebo-adjusted rate of 15.8%). CONCLUSION: Milnacipran administered at a dosage of 100 mg/day improved pain, global status, fatigue, and physical and mental function in patients with fibromyalgia.

A pooled analysis of two randomized, double-blind, placebo-controlled trials of milnacipran monotherapy in the treatment of fibromyalgia.

Milnacipran has been shown to significantly improve the pain, global well-being, and physical function of fibromyalgia (FM), and is approved by the U.S. Food and Drug Administration for the management of this disorder. Post hoc analyses of data from two pivotal trials were conducted to further assess the clinical benefits of milnacipran, to determine the impact of baseline pain severity on treatment outcomes, and to confirm the safety and tolerability of this medication in patients with FM. Patients in these trials were randomized to placebo (n=624), milnacipran 100 mg/day (n=623), or milnacipran 200 mg/day (n=837). Two different composite responder analyses were used to evaluate efficacy: a 2-measure analysis, requiring ≥30% improvement from baseline visual analog scale 24-hour recall pain scores and a Patient Global Impression of Change (PGIC) score of "very much improved" or "much improved"; and a 3-measure analysis, requiring a ≥6-point improvement from baseline in SF-36 Physical Component Summary scores in addition to the pain and PGIC criteria. Additionally, a pooled analysis of mean changes from baseline pain scores was conducted in order to evaluate the efficacy of milnacipran over the entire course of treatment. At 3 months, composite responder rates were significantly higher in the milnacipran treatment groups than in the placebo group (2- and 3-measure composite responder analyses: P ≤ 0.001, both doses vs. placebo). These improvements were not dependent on baseline pain severity. Similar composite responder results were observed in patients who continued treatment for up to 6 months. Significant improvements in mean pain scores were seen with both doses of milnacipran vs. placebo as early as 1 week after treatment initiation and were sustained for up to 6 months of milnacipran treatment. The most common adverse events associated with milnacipran were nausea, headache, and constipation.

Durability of therapeutic response to milnacipran treatment for fibromyalgia. Results of a randomized, double-blind, monotherapy 6-month extension study.

OBJECTIVE: To evaluate the durability of improvement and long-term efficacy of milnacipran treatment in fibromyalgia, to assess efficacy in patients re-randomized from placebo to milnacipran, and to collect additional information on the tolerability and efficacy of long-term treatment with milnacipran. DESIGN: A total of 449 patients who successfully completed a 6-month lead-in study enrolled in this 6-month extension study (87.7% of eligible subjects). Patients initially receiving milnacipran 200 mg/day during the lead-in study were maintained at 200 mg/day (n = 209); patients initially assigned to placebo or milnacipran 100 mg/day were re-randomized (1:4) to either 100 mg/day (n = 48) or 200 mg/day (n = 192) of milnacipran for an additional 6 months of treatment. Efficacy assessments included visual analog scale pain ratings, Fibromyalgia Impact Questionnaire (FIQ) total score, and Patient Global Impression of Change (PGIC). RESULTS: Patients continuing on milnacipran demonstrated a sustained reduction in pain over the full 12-month period. Additional beneficial effects were also maintained, as indicated by the PGIC and FIQ. Patients initially assigned to either placebo or milnacipran 100 mg/day in the lead-in study and subsequently re-randomized to milnacipran 200 mg/day in the extension study experienced further improvements in their mean pain scores, FIQ total scores, and PGIC ratings at 1 year. Milnacipran treatment was generally well tolerated. The most commonly reported newly emergent adverse event was nausea. CONCLUSIONS: In addition to confirming that milnacipran safely and effectively improves the multiple symptoms of fibromyalgia, these data indicate that milnacipran provides 1-year durable efficacy in this patient population.

Efficacy and safety of memantine in children with autism spectrum disorder: Results from three phase 2 multicenter studies.

Three phase 2 trials were conducted to assess the efficacy and long-term safety of weight-based memantine extended release (ER) treatment in children with autism spectrum disorder. MEM-MD-91, a 50-week open-label trial, identified memantine extended-release treatment responders for enrollment into MEM-MD-68, a 12-week randomized, double-blind, placebo-controlled withdrawal trial. MEM-MD-69 was an open-label extension trial in which participants from MEM-MD-68, MEM-MD-91, and open-label trial MEM-MD-67 were treated ⩽48 weeks with memantine extended release. In MEM-MD-91, 517 (59.6%) participants were confirmed Social Responsiveness Scale responders at week 12; mean Social Responsiveness Scale total raw scores improved two to three times a minimal clinically important difference of 10 points. In MEM-MD-68, there was no difference between memantine and placebo on the primary efficacy parameter, the proportion of patients with a loss of therapeutic response (defined as ⩾10-point increase from baseline in Social Responsiveness Scale total raw score). MEM-MD-69 exploratory analyses revealed mean standard deviation improvement in Social Responsiveness Scale total raw score of 32.4 (26.4) from baseline of the first lead-in study. No new safety concerns were evident. While the a priori-defined efficacy results of the double-blind trial were not achieved, the considerable improvements in mean Social Responsiveness Scale scores from baseline in the open-label trials were presumed to be clinically important.

Milnacipran for the treatment of fibromyalgia in adults: a 15-week, multicenter, randomized, double-blind, placebo-controlled, multiple-dose clinical trial.

BACKGROUND: Preclinical and clinical studies have suggested that milnacipran, a dual norepinephrine-serotonin reuptake inhibitor, may be efficacious in the treatment of fibromyalgia (FM). OBJECTIVE: This study was conducted to evaluate the efficacy and tolerability of milnacipran in treating the multiple domains of FM. METHODS: This was a multicenter, double-blind, placebo-controlled trial. Adult patients (age 18-70 years) who met 1990 American College of Rheumatology criteria for FM were randomized to receive milnacipran 100 mg/d, milnacipran 200 mg/d, or placebo for 15 weeks. Because this was a pivotal registration trial, the primary end points were chosen to investigate efficacy for 2 potential indications: the treatment of FM and the treatment of FM pain. Thus, the 2 primary efficacy end points were rates of FM composite responders and FM pain composite responders. FM composite responders were defined as patients concurrently experiencing clinically meaningful improvements in the following 3 domain criteria: pain (> or = 30% improvement, as recorded in an electronic diary); patients' global status (a rating of very much improved or much improved on the Patient Global Impression of Change [PGIC] scale); and physical function (a > or = 6-point improvement on the 36-item Short-Form Health Survey [SF-36] Physical Component Summary score). FM pain composite responders were defined as those who met the pain and PGIC criteria. Adverse events reported by patients or observed by investigators were recorded throughout the trial. RESULTS: Of 2270 patients screened, 1196 were randomized to receive milnacipran 100 mg/d (n = 399), milnacipran 200 mg/d (n = 396), or placebo (n = 401). The majority of patients were female (96.2%) and white (93.5%). The population had a mean age of 50.2 years, a mean baseline weight of 180.8 pounds, and a mean baseline body mass index of 30.6 kg/m(2). Compared with placebo, significantly greater proportions of milnacipran-treated patients were FM composite responders (100 mg/d: P = 0.01; 200 mg/d: P = 0.02) and FM pain composite responders (100 mg/d: P = 0.03; 200 mg/d: P = 0.004). Milnacipran was associated with significant improvements in pain after 1 week of treatment (100 mg/d: P = 0.004; 200 mg/d: P = 0.04), as well as significant improvements in multiple secondary efficacy end points, including global status (PGIC: P<0.001 for both doses), physical function (SF-36 physical functioning domain-100 mg/d: P < 0.001; 200 mg/d: P = 0.02), and fatigue (Multidimensional Fatigue Inventory- 100 mg/d: P = 0.04). The most commonly reported adverse events with milnacipran were nausea (100 mg/d, 34.3%; 200 mg/d, 37.6%), headache (18.0% and 17.7%, respectively), and constipation (14.3% and 17.9%). Adverse events resulted in premature study discontinuation in 19.5% and 23.7% of those who received milnacipran 100 and 200 mg/d, respectively, compared with 9.5% of placebo recipients. CONCLUSION: In these adult patients with FM, both doses of milnacipran (100 and 200 mg/d) were associated with significant improvements in pain and other symptoms. Clinical Trials Identification Number: NCT00098124.

Safety and Efficacy of Memantine in Children with Autism: Randomized, Placebo-Controlled Study and Open-Label Extension.

OBJECTIVE: Abnormal glutamatergic neurotransmission is implicated in the pathophysiology of autism spectrum disorder (ASD). In this study, the safety, tolerability, and efficacy of the glutamatergic N-methyl-d-aspartate (NMDA) receptor antagonist memantine (once-daily extended-release [ER]) were investigated in children with autism in a randomized, placebo-controlled, 12 week trial and a 48 week open-label extension. METHODS: A total of 121 children 6-12 years of age with Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM-IV-TR)-defined autistic disorder were randomized (1:1) to placebo or memantine ER for 12 weeks; 104 children entered the subsequent extension trial. Maximum memantine doses were determined by body weight and ranged from 3 to 15 mg/day. RESULTS: There was one serious adverse event (SAE) (affective disorder, with memantine) in the 12 week study and one SAE (lobar pneumonia) in the 48 week extension; both were deemed unrelated to treatment. Other AEs were considered mild or moderate and most were deemed not related to treatment. No clinically significant changes occurred in clinical laboratory values, vital signs, or electrocardiogram (ECG). There was no significant between-group difference on the primary efficacy outcome of caregiver/parent ratings on the Social Responsiveness Scale (SRS), although an improvement over baseline at Week 12 was observed in both groups. A trend for improvement at the end of the 48 week extension was observed. No improvements in the active group were observed on any of the secondary end-points, with one communication measure showing significant worsening with memantine compared with placebo (p = 0.02) after 12 weeks. CONCLUSIONS: This trial did not demonstrate clinical efficacy of memantine ER in autism; however, the tolerability and safety data were reassuring. Our results could inform future trial design in this population and may facilitate the investigation of memantine ER for other clinical applications.

Preliminary experience using milnacipran in patients with juvenile fibromyalgia: lessons from a clinical trial program.

BACKGROUND: There are no approved medications for juvenile fibromyalgia (JFM), a disorder that is often under-diagnosed. The effects of milnacipran, a drug approved for the management of fibromyalgia (FM) in adults, was assessed in a clinical trial program for JFM. METHODS: Patients, ages 13-17 years who met the Yunus and Masi criteria for JFM and/or 1990 American College of Rheumatology criteria for FM, were enrolled in a responder-enriched, randomized withdrawal trial. After receiving open-label milnacipran (8 weeks), patients with ≥50 % improvement in pain underwent double-blind randomization (1:2) to either placebo or continuing treatment with milnacipran (8 weeks). All patients, including those who did not meet the randomization criteria for double-blind withdrawal, were allowed to enter an extension study with open-label milnacipran (up to 52 weeks). The primary endpoint was loss of therapeutic response (LTR) during the double-blind period. Additional outcome measures included the Patient Global Impression of Severity (PGIS), Pediatric Quality of Life Inventory (PedsQL: Generic Core Scales, Multidimensional Fatigue Scale), and Multidimensional Anxiety Scale for Children (MASC). Safety assessments included adverse events (AEs), vital signs, electrocardiograms, and laboratory tests. RESULTS: The milnacipran program was terminated early due to low enrollment. Because only 20 patients were randomized into the double-blind withdrawal period, statistical analyses were not conducted for the LTR endpoint. However, 116 patients entered the open-label period of the initial study and 57 participated in the open-label extension study. Their experience provides preliminary information about the use of milnacipran in JFM patients. During both open-label periods, there were mean improvements in pain severity, PGIC, PedsQL, and MASC scores. No unexpected safety issues were detected. The most commonly reported treatment-emergent AEs were nausea, headache, vomiting, and dizziness. Mean increases in heart rate and blood pressure were observed, and were consistent with the AE profile in adults with FM. CONCLUSIONS: The open-label findings provide preliminary evidence that milnacipran may improve symptoms of JFM, with a safety and tolerability profile that is consistent with the experience in adult FM patients. Future trial designs for JFM should consider the relatively low recognition of this condition compared to adult FM and the difficulties with enrollment. TRIAL REGISTRATION: NCT01328002 ; NCT01331109.

Milnacipran effects on 24-hour ambulatory blood pressure and heart rate in fibromyalgia patients: a randomized, placebo-controlled, dose-escalation study.

OBJECTIVE: To characterize milnacipran effects on systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) in fibromyalgia patients using 24-hour ambulatory blood pressure monitoring (ABPM). METHODS: This dose-escalation study included a 7-week double-blind treatment period and 2-week single-blind discontinuation period. Patients were randomized 2:1 to milnacipran (n = 210) or placebo (n = 111), with 50% of patients classified as 'hypertensive' at baseline (SBP ≥130 mmHg, DBP ≥85 mmHg, or current antihypertensive medication). Analyses were conducted at Weeks 4 and 7, after milnacipran dosages were escalated to 100 and 200 mg/day, respectively. Outcome measures included changes from baseline in mean ambulatory SBP, DBP, and heart rate for the 12-hour periods following the morning dose (post-AM dose) or evening dose (post-PM dose), and the entire 24-hour monitoring period. Primary outcome parameter was change from baseline in mean SBP for the 12-hour period post-AM dose. Safety analyses included adverse events and sitting vital sign readings taken at study visits. RESULTS: Milnacipran increased ABPM vital signs at Week 4 (100 mg/day) and Week 7 (200 mg/day). Increases in the 12-hour period post-AM dose were similar at Weeks 4 and 7 (both visits: SBP and DBP, 4 to 5 mmHg; HR, 13 to 14 bpm). Mean increases in ambulatory vital signs were generally comparable between hypertensive and normotensive patients over 24-hour periods. Normal patterns of diurnal variation in blood pressure and heart rate were maintained in patients receiving milnacipran. Sitting vital signs were consistent with ABPM findings. Nausea was the most common adverse event observed with milnacipran. CONCLUSIONS: Fibromyalgia patients receiving milnacipran in this ABPM study had mean increases in blood pressure and heart rate that were consistent with those observed in clinical efficacy trials. Diurnal variation was preserved and changes were not greater in hypertensive patients than in non-hypertensive patients. These findings cannot necessarily be generalized to other patient populations. CLINICAL TRIAL REGISTRATION: This study was registered on clinicaltrials.gov (ID: NCT00618956).

Efficacy of long-term milnacipran treatment in patients meeting different thresholds of clinically relevant pain relief: subgroup analysis of a randomized, double-blind, placebo-controlled withdrawal study.

BACKGROUND: Fibromyalgia patients from a long-term, open-label study of milnacipran (50-200 mg/day) were eligible to participate in a 12-week, randomized, placebo-controlled withdrawal study. The withdrawal study evaluated loss of therapeutic response in patients who achieved ≥50% pain improvements after receiving up to 3.25 years of milnacipran. This post-hoc analysis investigated whether patients who met lower thresholds of pain improvement also experienced worsening of fibromyalgia symptoms upon treatment withdrawal. METHOD: Among patients who received milnacipran ≥100 mg/day during the long-term study, three subgroups were identified based on percentage of pain reduction at randomization: ≥50% (protocol-defined "responders"; n=150); ≥30% to <50% (patients with clinically meaningful pain improvement; n=61); and <30% (n=110). Efficacy assessments included the visual analog scale (VAS) for pain, Fibromyalgia Impact Questionnaire-Revised (FIQR), 36-Item Short-Form Health Survey Physical Component Summary (SF-36 PCS), and Beck Depression Inventory (BDI). RESULTS: In the ≥30 to <50% subgroup, significant worsening in pain was detected after treatment withdrawal. The difference between placebo and milnacipran in mean VAS score changes for this subgroup (+9.0, P<0.05) was similar to the difference in protocol-defined responders (+9.4, P<0.05). In the <30% subgroup, no worsening in pain was observed in either treatment arm. However, patients in this subgroup experienced significant worsening in FIQR scores after treatment withdrawal (placebo, +6.9; milnacipran, -2.8; P<0.001), as well as worsening in SF-36 PCS and BDI scores. CONCLUSION: Patients who experienced ≥30% to <50% pain reduction with long-term milnacipran had significant worsening of fibromyalgia symptoms after treatment withdrawal. These results suggest that the conventional ≥30% pain responder cutoff may be adequate to demonstrate efficacy in randomized withdrawal studies of fibromyalgia. Patients in the <30% pain reduction subgroup had worsening scores on the FIQR and other multidimensional measures after treatment withdrawal, indicating the importance of identifying and managing the multiple symptoms of fibromyalgia.

A 3-year, open-label, flexible-dosing study of milnacipran for the treatment of fibromyalgia.

OBJECTIVES: To evaluate the effects of long-term milnacipran treatment in fibromyalgia patients. METHODS: Patients completing a previous milnacipran study were eligible to participate in this long-term (up to 3.25 y), open-label study. After washout, dose escalation, and 8 weeks of stable-dose treatment (100 mg/d), patients received flexible doses of milnacipran (50 to 200 mg/d) for the remainder of the study. Safety evaluations included adverse events and vital signs. Clinical measures included weekly recall pain (visual analog scale [VAS]), Patient Global Disease Status (PGDS), and the Short Form-36 Health Survey (SF-36, including the Physical Component Summary [PCS] and Mental Component Summary scores). Cohort analyses were conducted to assess the effects of milnacipran over varying periods of time. RESULTS: Of 1227 patients entering the study, 585 (47.7%) were classified as completers, including 379 (30.9%) patients who were currently enrolled when the study was administratively terminated. Mean duration of treatment was 19 months, with 206 patients reaching the final visit and receiving 36 to 38 months of study treatment. The percentage of patients with ≥1 treatment-emergent adverse event was 88.3%, with nausea (25.9%) and headache (13.4%) being the most common events. Discontinuations due to adverse events occurred in 20.9% of patients. Potentially clinically significant increases in blood pressure or heart rate occurred in ≤1.1% of patients. Mean improvement from baseline in weekly recall VAS pain was 17.6; improvements in global status (PGDS) and physical functioning (SF-36 PCS) were also observed. In all patient cohorts, these improvements were observed by month 3 and remained relatively constant over time. At final study visit in the 3-year cohort, 70.3% of patients rated their overall fibromyalgia as "much improved" or "very much improved." DISCUSSION: No new safety concerns were identified in this long-term study. Sustained symptom improvements were found in fibromyalgia patients who received up to 3.25 years of milnacipran treatment.

Results of switching to milnacipran in fibromyalgia patients with an inadequate response to duloxetine: a phase IV pilot study.

BACKGROUND: The purpose of this study was to evaluate the safety, tolerability, and efficacy of milnacipran following a direct switch from duloxetine in fibromyalgia patients experiencing inadequate clinical response to duloxetine after receiving treatment for 6 weeks or longer. METHODS: This exploratory study included 107 patients with fibromyalgia who had been treated with duloxetine 60 mg/day for at least 4 weeks prior to enrollment. Following a 2-week open-label period on duloxetine, patients who had visual analog scale pain scores ≥ 40 and were dissatisfied with current treatment were randomized 4:1 to milnacipran 100 mg/day (n = 86) or placebo (n = 21) for 10 weeks of double-blind treatment. The small placebo group was included solely to blind the study and minimize expectation bias among patients and investigators, and there was no preplanned statistical comparison between treatment groups. The primary efficacy parameter was the percentage of patients rating themselves as "much improved" or "very much improved" on the Patient Global Impression of Change (PGIC) at the final visit. Other efficacy parameters included changes in one-week recall visual analog scale pain, Fibromyalgia Impact Questionnaire Revised (FIQR), and Multiple Ability Self-Report Questionnaire (MASQ). RESULTS: Of patients switched to milnacipran, 32.9% were classified as PGIC responders, and they also demonstrated improvement in visual analog scale pain, FIQR total, and MASQ total scores (mean changes from baseline were -12.3, -7.77, and -2.39, respectively). Nausea and dizziness were the most common treatment-emergent adverse events in patients switched to milnacipran, reported in 21% and 15%, respectively, of patients in this group. CONCLUSION: Results from this exploratory study suggest that switching from duloxetine to milnacipran may be beneficial in some patients with fibromyalgia who have an inadequate response to duloxetine. Further research investigating the efficacy and safety of switching fibromyalgia therapies is warranted.

Continuing efficacy of milnacipran following long-term treatment in fibromyalgia: a randomized trial.

INTRODUCTION: Previous studies of long-term treatment response in fibromyalgia and other chronic pain states have generally been limited to approximately one year, leaving questions about the longer-term durability of response. The purpose of this study was to demonstrate continuing efficacy of milnacipran by characterizing changes in pain and other fibromyalgia symptoms after discontinuing long-term treatment. The mean length of milnacipran treatment at the time of randomized withdrawal was 36.1 months from initial exposure to milnacipran (range, 17.9 to 54.4 months). METHODS: After completing a long-term, open-label, lead-in study of milnacipran (which followed varying periods of exposure in previous studies), adult patients with fibromyalgia entered the four-week open-label period of the current study for evaluation of ongoing treatment response. After the four-week period to confirm new baseline status, 151 patients taking milnacipran ≥100 mg/day and reporting ≥50% improvement from pre-milnacipran exposure in Visual Analogue Scale (VAS) pain scores were classified as responders. These responders entered the 12-week, double-blind withdrawal period in which they were randomized 2:1 to continue milnacipran or switched to placebo. The prespecified primary parameter was loss of therapeutic response (LTR), defined as increase in VAS pain score to <30% reduction from pre-milnacipran exposure or worsening of fibromyalgia requiring alternative treatment. Adverse events and vital signs were also monitored. RESULTS: Time to LTR was shorter in patients randomized to placebo than in patients continuing milnacipran (P < 0.001). Median time to LTR was 56 days with placebo and was not calculable for milnacipran, because less than half of the latter group of patients lost therapeutic response by study end. Additionally, 81% of patients continuing on milnacipran maintained clinically meaningful pain response (≥30% improvement from pre-milnacipran exposure), compared with 58% of patients switched to placebo (sensitivity analysis II; P < 0.001). The incidences of treatment-emergent adverse events were 58% and 47% for placebo and milnacipran, respectively. Mean decreases in blood pressure and heart rate were found in both groups, with greater decreases for patients switched to placebo. CONCLUSIONS: Continuing efficacy of milnacipran was demonstrated by the loss of effect following withdrawal of treatment in patients who received an average of three years of milnacipran treatment. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01014585.