Difelikefalin in Black/African American Hemodialysis Patients with Moderate-to-Severe Pruritus: Post hoc Analysis of KALM-1 and KALM-2.

INTRODUCTION: Black and African American (AA) people are over-represented in the kidney failure population; therefore, the safety and efficacy of difelikefalin in Black/AA patients was evaluated. METHODS: This was a post hoc, pooled exploratory subgroup analysis of the Phase 3 KALM-1 and -2 studies. Patients undergoing hemodialysis (HD) who had moderate-to-severe chronic kidney disease-associated pruritus (CKD-aP) at enrollment were stratified into self-reported Black/AA or White subgroups. Patients were randomized (1:1) to receive intravenous (IV) difelikefalin 0.5 µg/kg or placebo for 12 weeks. Difelikefalin efficacy was assessed with validated patient-reported outcome questionnaires: 24-h Worst Itch Numerical Rating Scale (WI-NRS), 5-D itch, and Skindex­10. RESULTS: There were 249 (29.3%) patients from the KALM studies that self-identified as Black/AA (n = 135 difelikefalin; n = 114 placebo). Clinically meaningful (≥3-point) reduction in WI-NRS score was achieved by 47.9% of Black/AA patients with difelikefalin versus 24.6% with placebo (p < 0.001). More Black/AA patients achieved a ≥5-point 5-D itch total improvement (54.9% vs. 35.7%; p = 0.013) and a ≥15-point Skindex-10 score improvement with difelikefalin versus placebo (49.0% vs. 28.9%; p = 0.006) compared with White patients. Incidence of treatment-emergent adverse events (TEAEs) was higher for Black/AA patients (difelikefalin: 78.5%; placebo: 70.8%) versus White patients (difelikefalin: 64.8%; placebo: 61.8%). CONCLUSION: In this post hoc analysis, difelikefalin was efficacious in the Black/AA population and had an acceptable safety profile.

CKD-Associated Pruritus and Clinical Outcomes in Nondialysis CKD.

Rationale & Objective: Itching is a frequent symptom experienced by people with chronic kidney disease (CKD). We investigated the associations of CKD-associated pruritus (CKD-aP) with clinical outcomes. Study Design: This was a longitudinal cohort study. Setting & Participants: Patients from Brazil, France, and the United States enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) from 2013 to 2021, an international prospective cohort study of adults with nondialysis dependent CKD, and an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2 were included. Exposure: CKD-aP was self-reported by response to the question: "During the past 4 weeks, to what extent were you bothered by itchy skin?" Outcomes: The outcomes were as follows: CKD progression, kidney replacement therapy (KRT) initiation, mortality, hospitalization, cardiovascular events, infection events. Analytical Approach: Associations with time-to-event outcomes were investigated using Cox proportional hazards models adjusted for potential confounders. Results: There were 4,410 patients from 91 clinics with a median age of 69 years and a median eGFR at patient questionnaire completion of 29 (21-38) mL/min/1.73 m2. The proportion of patients not at all, somewhat, moderately, very much, and extremely bothered by itchy skin was 49%, 27%, 13%, 7%, and 3%, respectively. Patients with more advanced stages of CKD, older age, and greater comorbidities reported to be more likely bothered by itchy skin. Among patients at least moderately bothered, 23% were prescribed at least 1 pharmacotherapy (35% in the United States, 19% in France, 4% in Brazil), including antihistamine (10%), gabapentin (6%), topical corticosteroids (4%), pregabalin (3%), or sedating antihistamine (3%). The HR (95% CI) for patients extremely (vs not at all) bothered was 1.74 (1.11-2.73) for all-cause mortality, 1.56 (1.11-2.18) for all-cause hospitalization, and 1.84 (1.22-2.75) for cardiovascular events. As CKD-aP severity increased, patients also had higher rates of infection events (P = 0.04); CKD-aP severity was not associated with KRT initiation (P = 0.20) or CKD progression (P = 0.87). Limitations: The limitations were 25% nonresponse rate, recall bias, and residual confounding factors. Conclusions: These results demonstrate a strong association between severe itch and clinical outcomes, providing the nephrology community new insights into the possible adverse consequences of CKD-aP in individuals with nondialysis CKD, and warrant further exploration. Plain-Language Summary: Chronic kidney disease-associated pruritus (CKD-aP) is a common disturbing symptom of chronic kidney disease (CKD). This article analyzes longitudinal data from the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) to describe prevalence of CKD-aP in 4,410 individuals with nondialysis CKD, and its association with clinical outcomes. We found that 51% of the surveyed population were bothered by pruritus. CKD-aP was more prevalent in those with more advanced stages of CKD, older age, and with more comorbid conditions. Compared to those not at all bothered by pruritus, those who were extremely bothered had a higher risk of all-cause mortality, hospitalizations, and cardiovascular events. Severity of CKD-aP was not associated with CKD progression or initiation of kidney replacement therapy.

Difelikefalin improves itch-related sleep disruption in patients undergoing haemodialysis.

BACKGROUND: Poor sleep quality is associated with increased mortality and lower quality of life in patients with chronic kidney disease-associated pruritus (CKD-aP). Difelikefalin reduces itch in patients with CKD-aP undergoing haemodialysis. This post hoc analysis of Phase 3 studies (3105 and the pooled dataset from KALM-1 and KALM-2) evaluated whether itch reduction in CKD-aP improved sleep quality. METHODS: Itch intensity was assessed in patients undergoing haemodialysis, who had moderate-to-severe CKD-aP treated with intravenous difelikefalin (0.5 µg/kg, three times weekly) (N = 222, Study 3105; N = 426, KALM-1/-2) or placebo (N = 425, KALM-1/-2) for 12 weeks, using the Worst Itch Intensity Numerical Rating Scale (WI-NRS). Sleep quality was assessed using the sleep disability question of the 5-D itch scale (5­D SDQ) in all studies and, in Study 3105, with the Sleep Quality Numeric Rating Scale (SQ-NRS). RESULTS: Greater improvements in sleep quality were observed in patients with ≥ 3-point, versus < 3-point WI-NRS improvement using SQ-NRS in Study 3105 (mean [95% confidence interval]: -5.2 [-5.6, -4.8] vs -1.5 [-2.0, -1.0]) and 5-D SDQ in KALM-1/-2 (-1.8 [-2.1, -1.6] vs -0.8 [-1.1, -0.4]). SQ-NRS and WI-NRS scores correlated strongly at baseline and Week 12 in Study 3105 (Spearman correlation coefficient: 0.77 and 0.84, respectively). Correlations were also observed between 5-D SDQ and WI-NRS scores in Study 3105 and KALM­1/­2. CONCLUSIONS: In patients undergoing haemodialysis with moderate-to-severe CKD-aP, itch reduction with intravenous difelikefalin was associated with improved sleep quality. As disturbed sleep may contribute to mortality and morbidity in CKD-aP, difelikefalin may help to address a major clinical burden by improving sleep quality, secondary to itch relief.

The Burden of Pruritus Associated With CKD: A Mixed Methods Analysis Among Patients Undergoing Dialysis.

Rationale & Objective: Despite its prevalence and distress to patients, chronic kidney disease-associated pruritus (CKD-aP) is poorly characterized, which may contribute to the condition's underdiagnosis and inadequate management. This study aimed to understand the symptom experience of patients with CKD-aP and the extent to which pruritus impacts their lives. Study Design: Mixed methods study including one-on-one qualitative interviews and completion of the Skindex-10 Questionnaire (measuring itch-related quality of life). Setting & Participants: A total of 23 patients undergoing hemodialysis and reporting pruritus at 4 dialysis centers in the United States. Analytical Approach: Interviews followed a semistructured guide that included targeted and follow-up questions to elicit discussion of patients' symptoms of pruritus, including frequency and variability, impact on activities of daily living, and emotional and social functioning. Interviews were digitally audio-recorded. A coding dictionary was developed from transcripts to analyze themes and concepts. Results: Participants described their itch with various terms, including "numbness," "pain," and "tingling" on their skin. Itch affected multiple areas but especially the back, usually occurred daily, and was often worse at night. For some, itching was a constant experience. Patients relieved their itch through scratching and various off-label treatments; some reported skin damage from excessive scratching and most indicated treatments provided limited relief. Pruritus considerably disrupted physical function, including sleep, daily activities, social functioning and relationships, and emotional and psychological wellbeing. All participants reported being bothered by their itching during the past week on the Skindex-10 Questionnaire. Limitations: All participants were from the United States, so the findings may not be generalizable to other countries. Conclusions: Although symptom experience varies considerably, CKD-aP causes severe distress for many patients undergoing hemodialysis and can profoundly impair their quality of life. The results of this study show the impact of itch from patients' perspectives and highlight the need for greater awareness and better management of this condition. Plain-Language Summary: Patients with chronic kidney disease often experience itching, or pruritus, but its importance to patients is regularly overlooked. This study used one-on-one interviews to investigate patients' experiences of chronic kidney disease-associated pruritus and how it impacts their lives. We found that participants experienced itch on various body areas and used different words to describe their itch (eg, "numbness" and "pain"). Some reported skin damage from excessive scratching, and many used off-label treatments and other interventions (eg, rubbing alcohol and multiple showers daily), which provided limited relief. For many, itching was experienced daily and severely disrupted sleep, daily activities, interactions with others, and mental wellbeing. These findings reveal chronic kidney disease-associated pruritus severely impacts patients and highlights the need for improved management of this condition.

Safety and Effectiveness of Difelikefalin in Patients With Moderate-to-Severe Pruritus Undergoing Hemodialysis: An Open-Label, Multicenter Study.

Rationale & Objective: Individuals with chronic kidney disease frequently suffer from chronic kidney disease-associated pruritus (CKD-aP), impacting sleep quality and quality of life (QoL) and increasing the likelihood of depression. Difelikefalin is a kappa-opioid receptor agonist recently approved in the United States for the treatment of moderate-to-severe CKD-aP in hemodialysis patients. Study 3105 was conducted to further assess the safety of difelikefalin and the effects on pruritus and QoL. Study Design: Open-label, multicenter, single-arm intervention trial. Setting & Participants: Maintenance hemodialysis patients with moderate-to-severe CKD-aP at enrollment. Intervention: Intravenous difelikefalin 0.5 µg/kg after each hemodialysis session for 12 weeks. Outcomes: The primary outcome was safety of difelikefalin. Secondary outcomes included: effectiveness of reducing itch intensity, assessed by the Worst Itching Intensity Numerical Rating Scale (WI-NRS); improving itch-related QoL, assessed with 5-D itch and Skindex-10 scales; and improvement of sleep, assessed with the Sleep Quality Numerial Rating Scale. Clinically meaningful thresholds for improvement in itch and QoL were previously established in this population. Results: Among 222 participants with baseline WI-NRS ≥5, mean [standard deviation] WI-NRS was 7.6 [1.3], mean age 58 years, 55% were male, and mean dialysis duration was 5.9 years; 197 participants (89%) completed treatment. Treatment-related treatment-emergent adverse events were reported in 16 participants (7.2%); those most commonly reported were somnolence (1.8%), hypoesthesia (1.4%), nausea (0.9%), and dizziness (0.9%). No deaths or serious treatment-emergent adverse events were considered treatment-related. Clinically meaningful reduction in itch intensity (≥3-point improvement) was reported by 74% of participants, with 70% and 63% also reporting a clinically relevant improvement in QoL as measured by 5-D itch and Skindex-10. Sleep quality improvement (≥3-point reduction on the Numerical Rating Scale) was reported in 66% of participants. Limitations: No placebo control group. Conclusions: Difelikefalin was well tolerated, and treatment was associated with clinically meaningful improvements in itch intensity and itch-related QoL measures as well as improvements in sleep quality among individuals receiving hemodialysis who had moderate-to-severe CKD-aP, providing important insights into expected real-world effectiveness. Funding: Cara Therapeutics. Trial Registration: NCT03998163.

Safety and Tolerability of Difelikefalin for the Treatment of Moderate to Severe Pruritus in Hemodialysis Patients: Pooled Analysis From the Phase 3 Clinical Trial Program.

Rationale & Objective: We report a pooled safety analysis of intravenous difelikefalin in participants with moderate to severe chronic kidney disease-associated pruritus (CKD-aP) treated by hemodialysis in 4 phase 3 clinical studies. Study Design: KALM-1 and KALM-2 were randomized, double-blind, placebo-controlled, pivotal phase 3 studies; CLIN3101 (52 weeks) and CLIN3105 (12 weeks) were open-label studies. Setting & Participants: Adults with moderate to severe CKD-aP treated by hemodialysis in North America, Europe, and the Asia-Pacific region. Intervention: At least 1 intravenous placebo or difelikefalin dose of 0.5 mcg/kg for up to 64 weeks. Outcomes: Safety. Results: Safety analyses were conducted with 848 participants in the placebo-controlled cohort (424 participants each in the difelikefalin and placebo groups) and in 1,306 participants in the all-difelikefalin-exposure cohort. In the placebo-controlled cohort, the most commonly reported treatment-emergent adverse events (TEAEs), occurring in ≥2% of participants receiving difelikefalin and with a ≥1% higher incidence than placebo, were diarrhea (9.0% and 5.7%, respectively); dizziness (6.8% and 3.8%, respectively); nausea (6.6% and 4.5%, respectively); gait disturbances, including falls (6.6% and 5.4%, respectively), hyperkalemia (4.7% and 3.5%, respectively); headache (4.5% and 2.6%, respectively); somnolence (4.2% and 2.4%, respectively); and mental status changes (3.3% and 1.4%, respectively). These were mostly mild or moderate, with few leading to discontinuation. Incidence rates of TEAEs, serious TEAEs, and discontinuations because of TEAEs did not increase with long-term exposure. Three participants (0.7%) in the difelikefalin group and 5 participants (1.2%) in the placebo group died during the study. Limitations: Pooled data from studies with different designs. Conclusions: Intravenous difelikefalin demonstrated an acceptable safety profile, was generally well tolerated with long-term use, and may address the unmet treatment need for patients with CKD-aP treated by hemodialysis. Funding: Cara Therapeutics, Inc. Trial Registration: KALM-1 is registered as NCT03422653, KALM-2 as NCT03636269, CLIN3101 as NCT03281538, and CLIN3105 as NCT03998163.

Efficacy of Difelikefalin for the Treatment of Moderate to Severe Pruritus in Hemodialysis Patients: Pooled Analysis of KALM-1 and KALM-2 Phase 3 Studies.

Rationale & Objective: Chronic kidney disease-associated pruritus (CKD-aP) in patients treated by hemodialysis (HD) impairs quality of life (QoL). Difelikefalin, a selective κ-opioid receptor agonist, decreased the intensity of CKD-aP in patients undergoing HD. This pooled analysis evaluated difelikefalin's efficacy and the itch-related QoL overall and in subgroups defined by demographics or disease characteristics. Study Design: In KALM-1 and KALM-2, participants were randomized (1:1) to receive intravenous difelikefalin or placebo 3 times/wk for 12 weeks, followed by a 52-week open-label extension. Setting & Participants: Adults with moderate to severe CKD-aP treated by HD in North America, Europe, and the Asia-Pacific region. Intervention: Intravenous difelikefalin at 0.5 mcg/kg or placebo. Outcomes: Itch intensity (Worst Itching Intensity Numerical Rating Scale [WI-NRS]) and itch-related QoL (Skindex-10 and 5-D Itch questionnaires). Results: 851 participants were randomized (difelikefalin, n = 426; placebo, n = 425). This pooled analysis demonstrated early     (week 1), sustained difelikefalin efficacy, with significantly greater achievement of ≥3-point WI-NRS reduction with difelikefalin (51.1%) versus placebo (35.2%; P < 0.001). Achievement of a ≥4-point WI-NRS reduction was significantly greater with difelikefalin (38.7%) versus placebo (23.4%; P < 0.001). Difelikefalin reduced itch intensity in subgroups based on age, sex, anti-itch medication use, the presence of specific medical conditions, and gabapentin or pregabalin use. More participants receiving difelikefalin versus placebo achieved clinically meaningful decreases of ≥15 points on the Skindex-10 scale (55.5% vs 40.5%, respectively; P < 0.001) and ≥5 points on the 5-D Itch scale (52.1% vs 42.3%, respectively; P = 0.01), with sustained 5-D Itch effects up to 64 weeks. Limitations: Subgroup samples were small. The WI-NRS, Skindex-10, and 5-D Itch are not used in routine clinical care of dialysis patients; therefore, findings may not reflect the real-world effectiveness of difelikefalin. Conclusions: Difelikefalin demonstrated rapid, sustained efficacy, with consistent results in diverse populations of patients treated by HD. Funding: Cara Therapeutics, Inc. Trial Registration: The KALM-1 trial is registered as NCT03422653 and the KALM-2 trial is registered as NCT03636269.

Psychometric validation and meaningful change thresholds of the Worst Itching Intensity Numerical Rating Scale for assessing itch in patients with chronic kidney disease-associated pruritus.

BACKGROUND: Chronic kidney disease-associated pruritus (CKD-aP) is characterized by persistent itch that often leads to substantially impaired quality of life. The Worst Itching Intensity Numerical Rating Scale (WI-NRS) is a single-item patient-reported outcome measure in which patients indicate the intensity of the worst itching they experienced over the past 24 h. Here, we evaluated the content validity and psychometric properties of the WI-NRS and confirmed the threshold of meaningful change in hemodialysis patients with moderate-to-severe CKD-aP. METHODS: Content validity interviews were conducted in 23 patients. Psychometric properties of the WI-NRS were assessed using data from one phase 2 (N = 174) and two phase 3 (N = 848) clinical trials investigating an anti-pruritic treatment. Anchor-based methods were used to confirm meaningful within-patient change score thresholds in the phase 3 trial patients and mixed-method exit interviews (N = 70) contributed further insight. RESULTS: Content validity interviews indicated patients considered the WI-NRS to be straightforward, comprehensive, and relevant. Test-retest reliability was strong in both trial cohorts (intraclass correlation coefficients > 0.75). Construct validity analyses indicated high correlation between the WI-NRS and other measures of itch. Anchor-based analyses showed a reduction of ≥ 3 points from baseline score represented an appropriate clinically meaningful within-patient change on the WI-NRS. In the exit interviews, all patients with a reduction ≥ 3 points considered the change meaningful. CONCLUSIONS: The WI-NRS is a reliable, valid, and responsive measure of itch intensity for patients with moderate-to-severe CKD-aP. These results support its use to assess treatment efficacy and in clinical evaluation and management of pruritus in hemodialysis patients.

Itching is a distressing medical condition common in patients with chronic kidney disease, especially those undergoing hemodialysis. The itch often leads to skin damage due to a continuous and uncontrollable urge to scratch. It affects about 60% of hemodialysis patients and can be severe enough to seriously affect quality of life. At present, there are no approved therapies. To evaluate whether new treatments for itch are effective, clinicians need to assess if the intensity of itch decreases over time. However, because itch intensity can only be measured accurately by the person experiencing it, a measure is required that can be easily understood and used by patients. This study evaluated a scale in which patients mark a number between '0' (corresponding to no itch) and '10' (the worst itching imaginable), to describe the worst itch intensity they experienced over the last 24 hours. Using data from three clinical trials of a novel treatment for itch in patients undergoing hemodialysis with moderate-to-severe pruritus, we found that the scale was reliable in repeat-testing experiments, and mirrored other methods of measuring changes in itch. In interviews, patients said they found the scale straightforward and easy to complete. Our analysis and patients' opinions showed a 3-point reduction in itch intensity on the scale represented a meaningful improvement. These findings support the use of this scale to assess the efficacy of new treatments and in clinical evaluation and management of pruritus in patients with chronic kidney disease.

Self-reported Pruritus and Clinical, Dialysis-Related, and Patient-Reported Outcomes in Hemodialysis Patients.

RATIONALE & OBJECTIVE: Chronic kidney disease (CKD)-associated pruritus, generalized itching related to CKD, affects many aspects of hemodialysis patients' lives. However, information regarding the relationship between pruritus and several key outcomes in hemodialysis patients remains limited. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: 23,264 hemodialysis patients from 21 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4 to 6 (2009-2018). EXPOSURE: Pruritus severity, based on self-reported degree to which patients were bothered by itchy skin (5-category ordinal scale from "not at all" to "extremely"). OUTCOMES: Clinical, dialysis-related, and patient-reported outcomes. ANALYTICAL APPROACH: Cox regression for time-to-event outcomes and modified Poisson regression for binary outcomes, adjusted for potential confounders. RESULTS: The proportion of patients at least moderately bothered by pruritus was 37%, and 7% were extremely bothered. Compared with the reference group ("not at all"), the adjusted mortality HR for patients extremely bothered by pruritus was 1.24 (95% CI, 1.08-1.41). Rates of cardiovascular and infection-related deaths and hospitalizations were also higher for patients extremely versus not at all bothered by pruritus (HR range, 1.17-1.44). Patients extremely bothered by pruritus were also more likely to withdraw from dialysis and miss hemodialysis sessions and were less likely to be employed. Strong monotonic associations were observed between pruritus severity and longer recovery time from a hemodialysis session, lower physical and mental quality of life, increased depressive symptoms, and poorer sleep quality. LIMITATIONS: Residual confounding, recall bias, nonresponse bias. CONCLUSIONS: Our findings demonstrate how diverse and far-reaching poor outcomes are for patients who experience CKD-associated pruritus, specifically those with more severe pruritus. There is need for change in practice patterns internationally to effectively identify and treat patients with pruritus to reduce symptom burden and improve quality of life and possibly even survival.

A Phase 3 Trial of Difelikefalin in Hemodialysis Patients with Pruritus.

BACKGROUND: Difelikefalin is a peripherally restricted and selective agonist of kappa opioid receptors that are considered to be important in modulating pruritus in conditions such as chronic kidney disease. METHODS: In this double-blind, placebo-controlled, phase 3 trial, we randomly assigned patients undergoing hemodialysis who had moderate-to-severe pruritus to receive either intravenous difelikefalin (at a dose of 0.5 µg per kilogram of body weight) or placebo three times per week for 12 weeks. The primary outcome was the percentage of patients with an improvement (decrease) of at least 3 points from baseline at week 12 in the weekly mean score on the 24-hour Worst Itching Intensity Numerical Rating Scale (WI-NRS; scores range from 0 to 10, with higher scores indicating greater itch intensity). The secondary outcomes included the change from baseline in itch-related quality-of-life measures, the percentage of patients with an improvement of at least 4 points in the WI-NRS score at week 12, and safety. RESULTS: A total of 378 patients underwent randomization. A total of 82 of 158 patients (51.9%) in the difelikefalin group had a decrease of at least 3 points in the WI-NRS score (primary outcome), as compared with 51 of 165 (30.9%) in the placebo group. The imputed percentage of patients with a decrease of at least 3 points in the WI-NRS score was 49.1% in the difelikefalin group, as compared with 27.9% in the placebo group (P<0.001). Difelikefalin also resulted in a significant improvement from baseline to week 12 in itch-related quality of life as measured by the 5-D itch scale and the Skindex-10 scale. The imputed percentage of patients with a decrease of at least 4 points in the WI-NRS score at week 12 was significantly greater in the difelikefalin group than in the placebo group (37.1% [observed data: 64 of 158 patients] vs. 17.9% [observed data: 35 of 165 patients], P<0.001). Diarrhea, dizziness, and vomiting were more common in the difelikefalin group than in the placebo group. CONCLUSIONS: Patients treated with difelikefalin had a significant reduction in itch intensity and improved itch-related quality of life as compared with those who received placebo. (Funded by Cara Therapeutics; KALM-1 ClinicalTrials.gov number, NCT03422653.).

Evaluation of the Ototoxicity Potential of Once-Daily, Single-Entity Hydrocodone in Patients with Chronic Pain: Results of Two Phase-3 Clinical Studies.

BACKGROUND: Use/misuse of the opioid combination hydrocodone-acetaminophen has been associated with permanent hearing loss. Although reports have been rare, this potential effect can have significant detrimental effect on patients' overall quality of life. To date, the ototoxic effect of hydrocodone alone has not been systematically investigated. OBJECTIVE: In this report, we aimed to evaluate the potential ototoxicity of a novel, single-entity, once-daily, extended-release hydrocodone tablet (Hysingla® ER; HYD). STUDY DESIGN: Clinical study. SETTING: Audiology clinics in US. METHODS: Results from 1207 patients in two phase 3 clinical studies were evaluated: A placebo-controlled study with an enriched enrollment, randomized withdrawal design in patients with chronic low back pain, and an open-label, long-term, safety study in patients with chronic nonmalignant and non-neuropathic pain. Comprehensive audiologic assessments (comprising pure-tone air-conduction audiometry in the conventional [0.25-8 kHz] and ultra-high [10-16 kHz] frequencies, pure-tone bone-conduction audiometry, tympanometry, speech reception thresholds, and word recognition) were conducted at baseline and end-of-studies; air-conduction audiometry was conducted periodically during the studies. All audiologic assessments were performed in audiology clinics in the United States by licensed audiologists. The primary endpoint was changes from baseline in pure-tone air-conduction thresholds in the conventional frequencies during the studies. These trials are registered with ClinicalTrials.gov, identifiers NCT01400139 and NCT01452529. RESULTS: During the studies, mean changes from baseline in air-conduction thresholds were clinically unremarkable. Bidirectional variability across all test frequencies was observed; 82% of patients did not experience significant threshold changes during the studies, 7% had potential hearing decrement, and 10% experienced hearing sensitivity improvement. No notable differences were observed between patients receiving HYD and placebo or between different HYD doses. CONCLUSION: No ototoxic signal was observed for single-entity hydrocodone tablets at the dosages and treatment durations investigated. Key words: Audiologic monitoring, clinical trials, hydrocodone, opioids, ototoxicity monitoring, sensorineural hearing loss.

Efficacy and Safety of Once-Daily Extended-Release (ER) Hydrocodone in Individuals Previously Receiving ER Morphine for Chronic Pain.

OBJECTIVES: This post hoc analysis examined the effectiveness and safety of hydrocodone bitartrate (HYD) in patients with moderate-to-severe chronic pain who were previously taking extended-release morphine (morphine ER) for pain management. STUDY DESIGN: The primary analysis was an open-label, 12-month study. SETTING: The study was conducted in 88 sites in the United States. METHODS: The study was approved by an institutional review board. Eligible patients were enrolled and titrated to a once-daily dose of HYD 20, 40, 60, 80, or 120 mg for a 45-day period. The subgroup of patients in this report was using morphine ER prior to study entry. After achieving a stable HYD daily dose, patients entered a 12-month maintenance period during which additional dose adjustment could be made and nonopioid or short-acting opioid medications could be received. Average pain over the last 24 hours was recorded daily (on a scale of 0 to 10) Patients completed the Brief Pain Inventory (BPI) short form, which assessed pain severity and the interference of pain in daily life, every 4 weeks during the maintenance period. Safety was assessed routinely. RESULTS: Of the 26 patients who switched from morphine ER to HYD, 19 entered the maintenance period. At study entry, mean "average pain over the last 24 hours" was scored as 5.21. This was reduced to 3.90 by the time patients entered the maintenance phase; this level of pain control was maintained over the 12-month period, with 16 patients requiring no further HYD dose adjustment. BPI scores decreased for both pain severity and pain interference during the maintenance period. HYD was well tolerated. CONCLUSIONS: The results of this subgroup analysis suggest that rotation from morphine ER to once-daily HYD in patients with moderate-to-severe chronic pain maintains or improves pain relief and does not increase safety concerns.

Long-term effectiveness and safety of once-daily, single-entity, extended-release hydrocodone in patients of ≥75 years of age with moderate to severe nonmalignant and nonneuropathic pain.

In elderly (≥75 years) individuals, age-associated physiologic changes and a higher prevalence of comorbidities, polypharmacy, and increased susceptibility to medication-induced side effects complicate pain management. Hysingla® ER (HYD) is a once-daily, single-entity, extended-release hydrocodone formulation approved for the treatment of chronic pain that is insufficiently controlled by alternative treatments. In this post-hoc analysis of a previously reported study, the effectiveness and safety of HYD for the treatment of moderate-to-severe chronic pain among the elderly (≥75 years) for a 52-week duration was investigated. HYD dose administered during the maintenance period-remained relatively stable and provided clinically meaningful decreases in mean "pain over the last 24 h" and pain interference scores. Patients achieved pain control without additional non-study opioid use at the end of the study. Adverse events were typical of opioids. In summary, HYD provided clinically meaningful reduction of pain scores in elderly patients that were maintained over a 52-week period.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations.

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for "precision medicine" or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

Pharmacokinetic Profile and Sustained 24-hour Analgesia of a Once-daily Hydrocodone Bitartrate Extended-release Tablet with Abuse-deterrent Properties.

PURPOSE: The purpose of this study was to evaluate the pharmacokinetics (PK) and 24-hour analgesic effectiveness of once-daily, single-entity, extended-release hydrocodone (HYD) with abuse-deterrent properties. METHODS: Four studies were included. Three open-label PK studies had the following designs: single-dose, 5-treatment, 4-period, crossover, dose-proportionality study; HYD 120 mg for 5 days (steady-state study 1); 2-treatment, 2-period, multiple-dose crossover study assessing the relative bioavailability of HYD 30 mg and hydrocodone 7.5 mg/ibuprofen 200 mg administered every 6 hours (steady-state study 2). A long-term, open-label study assessed the safety and effectiveness of HYD 20 to 120 mg in patients during a 52-week maintenance period. FINDINGS: Thirty-one, 25, and 22 healthy subjects completed the dose-proportionality study, steady-state study 1, and steady-state study 2, respectively, while 410 patients with moderate to severe chronic nonmalignant and non-neuropathic pain completed the long-term effectiveness study. Mean systemic exposure and peak plasma concentration were dose proportional after administration of single doses of HYD 20 to 120 mg. Pharmacokinetic profiles were comparable at day 1 and day 5 after administration of HYD 120 mg once daily. Once-daily HYD 30 mg was associated with lower-fluctuating plasma hydrocodone concentrations compared with immediate-release hydrocodone 7.5 mg/ibuprofen 200 mg administered every 6 hours. In the long-term study, pain control was consistent over the 24-hour dosing interval. IMPLICATIONS: Once-daily HYD exhibits linear, dose-proportional PK properties and is associated with a lower variability in plasma hydrocodone concentrations when compared with an immediate-release hydrocodone combination product. Notably, analgesia provided by HYD is sustained during the 24-hour dosing interval. ClinicalTrials.gov identifier: NCT01400139 (Study 4).

Buprenorphine Transdermal System Improves Sleep Quality and Reduces Sleep Disturbance in Patients with Moderate-to-Severe Chronic Low Back Pain: Results from Two Randomized Controlled Trials.

OBJECTIVE: To evaluate the impact of buprenorphine (Butrans®) transdermal System (BTDS) treatment on sleep outcomes for patients with moderate-to-severe chronic low back pain (CLBP). METHODS: Two enriched-enrollment, randomized-withdrawal, double-blind, controlled trials examined BTDS treatment for patients with moderate-to-severe CLBP. Trial I evaluated BTDS 10 and 20 mcg/hour against a placebo control among opioid-naïve patients. Trial II compared BTDS 20 mcg/hour against a lower-dose control (BTDS 5 mcg/hour) among opioid-experienced patients. The patient-reported Medical Outcomes Study Sleep Scale (MOS-SS) assessed overall sleep quality (Sleep Problems Index [SPI]), Disturbance, and other sleep outcomes. In each trial, MOS-SS scores were compared between target treatment and control arms during the 12-week double-blind phase. Correspondence of changes in sleep outcomes and pain severity and the degree to which pain reduction mediates treatment impact on sleep outcomes were examined. RESULTS: Medical Outcomes Study Sleep Scale scores were collected from 541 (Trial I) and 441 (Trial II) patients prior to randomization and from 369 (Trial I) and 274 (Trial II) patients at week 12. Patients receiving target treatment showed statistically significantly more improvement in SPI and Disturbance scores at 12 weeks than their respective controls (Ps < 0.05). Improvements in SPI and Disturbance for target treatment arms were statistically larger those of the controls by week 4 of the double-blind phase. The clinical significance of these differences was not determined. Pain reduction predicted improvements in sleep outcomes. CONCLUSION: Buprenorphine Transdermal System improved sleep quality and disturbance for opioid-naïve and opioid-experienced patients with moderate-to-severe CLBP. Benefits of BTDS for these sleep outcomes emerged within 4 weeks and were maintained over the entire 12-week treatment period.

A Subgroup Analysis Found no Diminished Response to Buprenorphine Transdermal System Treatment for Chronic Low Back Pain Patients Classified with Depression.

BACKGROUND: Chronic pain (CP) patients with depression typically exhibit worse post-treatment outcomes than nondepressed CP patients. The cause is often assumed to reflect a differential response to treatment, neglecting other potential explanations, such as the continuation of differences in pretreatment outcomes. This post hoc analysis examines whether worse post-treatment outcomes for depressed patients with chronic low back pain (CLBP) are driven by reduced treatment efficacy. METHODS: Data were from opioid-naïve adult patients with moderate-to-severe CLBP who participated in a randomized, placebo-controlled, double-blind clinical trial of Butrans(®) (buprenorphine) Transdermal System (BTDS) for pain relief. Depression screening was based on baseline SF-36v2 Mental Health subscale scores. Patient-reported measures of pain severity, pain interference, quality of life, sleep problems, and functional disability were administered at screening and during the study. Differential treatment efficacy for each outcome was examined using analysis of covariance models that included interaction terms between treatment arm and depression status. RESULTS: At baseline, patients classified as depressed showed greater pain interference, lower quality of life, more sleep problems, and greater functional disability than nondepressed patients; the two groups did not differ in pain severity. No statistically significant interactions between treatment arm and depression status were observed. The direction of improvement post-treatment favored the depressed group on nine of seventeen outcomes. CONCLUSIONS: Results do not support a differential response to BTDS treatment between depressed and nondepressed CLBP patients across a variety of patient-reported outcomes. These findings raise the question of whether depressed mood actually moderates the effectiveness of treatment in CP patients.

12-Month safety and effectiveness of once-daily hydrocodone tablets formulated with abuse-deterrent properties in patients with moderate to severe chronic pain.

OBJECTIVE: To characterize the long-term safety and effectiveness of Hysingla™ ER, single-entity, once-daily, extended-release hydrocodone bitartrate tablets formulated with abuse-deterrent properties (HYD), offering a new treatment option for appropriate patients with chronic pain. DESIGN: An open-label study with a dose-titration period (up to 45 days) and a maintenance period (12 months). PATIENTS, PARTICIPANTS: A total of 922 patients with chronic nonmalignant and non-neuropathic moderate to severe pain received open-label HYD tablets 20-120 mg; 728 of these achieved a stabilized dose of HYD at the end of dose-titration and entered the maintenance period. RESULTS: The safety profile was similar to that of other oral opioid analgesics, without new or unexpected safety concerns. The most frequent treatment-emergent adverse events (AEs; ≥ 5 percent) were those commonly associated with the use of systemic µ-opioid analgesics, including nausea, constipation, vomiting, fatigue, dizziness, somnolence, and headache. There were 77 (8 percent) patients with a total of 109 nonfatal treatment-emergent serious AEs. Few patients discontinued due to lack of therapeutic effect overall (6 percent), especially during the 12-month maintenance period (4 percent). Pain relief, sleep, functional health, and activities of daily living all improved at the end of the dose-titration period with HYD. These improvements were maintained through the 12-month maintenance period with stable HYD doses and without increase in concomitant supplemental analgesic medications. CONCLUSIONS: This long-term study demonstrated the safety and long-term maintenance of analgesic effect of HYD without continued need for dose increase.

A multicenter, randomized, double-blind, placebo-controlled trial to assess the efficacy and safety of single-entity, once-daily hydrocodone tablets in patients with uncontrolled moderate to severe chronic low back pain.

OBJECTIVES: This multicenter, randomized, double-blind, placebo-controlled study with an enriched enrollment, randomized withdrawal design was conducted to evaluate the analgesic efficacy and safety of single-entity, once-daily hydrocodone 20 to 120 mg tablets (HYD) in opioid-naive and opioid-experienced patients with uncontrolled moderate to severe chronic low back pain (CLBP). RESEARCH DESIGN AND METHODS: The primary endpoint was week 12 pain intensity scores (11-point scale, 0 = no pain) using a mixed effect model with repeated measures incorporating a pattern mixture model framework. Responder analysis was a secondary endpoint. Safety was assessed. RESULTS: Out of 905 patients who were treated with HYD during the open-label titration period, 588 (65%) were randomized to continue to receive HYD (n = 296, 20 - 120 mg taken once daily, average daily dose 57 mg) or a matching placebo (n = 292). HYD demonstrated superior pain reduction (p = 0.0016); this result was supported by sensitivity analyses using different approaches to handling missing data. Proportions of patients achieving ≥ 30 and ≥ 50% improvement in pain from screening to week 12 also favored HYD (p = 0.0033 and 0.0225, respectively). HYD was generally well tolerated. CONCLUSIONS: HYD was shown to be an efficacious treatment for CLBP in this study. There were no new or unexpected safety concerns detected.

Efficacy and safety of once-daily, extended-release hydrocodone in individuals previously receiving hydrocodone/acetaminophen combination therapy for chronic pain.

BACKGROUND: Hydrocodone/acetaminophen combination analgesics are frequently prescribed for chronic pain management; however, acetaminophen presents potential hepatotoxicity to patients and thus dose limitations. These opioid medications are also widely abused. Once-daily, single-entity hydrocodone (Hysingla™ ER tablets [HYD]) is a novel formulation with abuse-deterrent properties for the management of chronic pain and represents a suitable option for those patients receiving analgesics containing the same opioid analgesic, hydrocodone. This post-hoc analysis evaluated the efficacy and safety of HYD in patients whose primary pre-study analgesic was hydrocodone/acetaminophen analgesics (23-31% of the study populations). METHODS: Data were analyzed from two Phase III trials, a 12-week randomized, placebo-controlled trial (RCT) and an open-label, 52-week trial. In both trials, a dose-titration period with HYD was followed by respective periods of fixed-dose double-blind (randomized controlled trial [RCT]) or open-label, flexible-dose maintenance treatment. Pain intensity was assessed using a numerical rating scale (0-10, 0 = no pain). For the RCT, primary and sensitivity analyses of pain scores used different approaches to handle missing data. Safety data for both studies were summarized. RESULTS: In the RCT, the mean baseline pain score was 7.3. Pain relief was greater with HYD than placebo during double-blind treatment. In the open-label, flexible-dose trial, the majority of patients were maintained on their titrated dose. Mean baseline pain score was 6.3, about 57% of patients completed the 1-year maintenance period, and mean pain scores were between 3.6 and 4.1 during the maintenance period. Use of supplemental pain medication decreased or was maintained during the maintenance treatment with HYD. Adverse events in both trials were typical of those associated with opioid analgesics. CONCLUSION: In patients whose primary pretrial analgesic was hydrocodone/acetaminophen combination tablets, single-entity HYD was effective in reducing pain intensity and in maintaining analgesia over time without need for continued dose increase. HYD's safety and tolerability profiles were similar to other opioid analgesics.