Safety differences across androgen receptor inhibitors in nonmetastatic castration-resistant prostate cancer.

Approval of apalutamide, enzalutamide and darolutamide has transformed the treatment landscape and guideline recommendations for patients with nonmetastatic castration-resistant prostate cancer but now raises the issue of decision-making regarding treatment selection. In this perspective, we discuss the efficacy and safety of these second-generation androgen receptor inhibitors and propose that for patients with nonmetastatic castration-resistant prostate cancer, safety considerations for these treatments are especially important. We examine these considerations in the context of patient and caregiver preferences as well as patient clinical characteristics. We further posit that consideration of treatments' safety profiles should include not only the initial direct impacts from potential treatment-emergent adverse events and drug-drug interaction events, but also the full cascade of potentially avoidable healthcare complications.

Prostate cancer is one of the most common cancers in men. Because male hormones fuel the growth of prostate cancer cells, initial treatments generally focus on reducing these hormones to very low levels. Although these treatments are usually effective in controlling the cancer in the short term, over time, patients often stop responding to them. These patients need more advanced treatments to control their prostate cancer. For patients whose cancer has not spread to other body parts ('nonmetastatic castration-resistant prostate cancer'), more advanced treatment options were unavailable until recently, but during 2018­2019, three novel therapies became available. These new therapies have raised the question of how to choose a particular therapy when deciding on a patient's treatment regimen. Here we contend that patient safety is critical when deciding among these treatments, which are all similarly effective in terms of helping patients to live longer. We review the key differences of each drug's safety profile among these treatments. We assert that treatment selection should consider patients' preferences and clinical characteristics, as the latter can influence the potential for serious harm when treatment-related complications arise. Finally, treatment selection should consider the multiple after-effects that can occur following a treatment-related safety event.

Indirect Comparison of Darolutamide versus Apalutamide and Enzalutamide for Nonmetastatic Castration-Resistant Prostate Cancer.

PURPOSE: No published head-to-head randomized trials have compared the safety and efficacy of darolutamide vs apalutamide or enzalutamide in nonmetastatic castration-resistant prostate cancer. This study compares prespecified adverse events and metastasis-free survival associated with darolutamide vs apalutamide, and darolutamide vs enzalutamide, via matching-adjusted indirect comparisons. MATERIALS AND METHODS: Individual patient data from the phase III ARAMIS trial (NPLACEBO=553; NDAROLUTAMIDE=943) were selected and reweighted to match the inclusion criteria and baseline characteristics published for the phase III SPARTAN (NPLACEBO=401; NAPALUTAMIDE=806) and PROSPER (NPLACEBO=468; NENZALUTAMIDE=933) trials. Only baseline factors consistently reported across trials were included as matching covariates. Both indirect comparisons matched on age, prostate specific antigen level and doubling time, Eastern Cooperative Oncology Group performance status, Gleason score, and bone-sparing agent use. Darolutamide vs apalutamide also matched on prior surgery and darolutamide vs enzalutamide also matched on region. Risk differences and odds ratios were calculated for adverse events and hazard ratios for metastasis-free survival. RESULTS: No differences in metastasis-free survival hazard ratios were found after matching in either comparison. However, fall, fracture and rash rates were statistically significantly lower in favor of darolutamide vs apalutamide. Fall, dizziness, mental impairment, fatigue and severe fatigue rates were statistically significantly lower in favor of darolutamide vs enzalutamide. CONCLUSIONS: While metastasis-free survival did not differ across drugs in these cross-trial indirect comparisons, darolutamide showed a favorable safety and tolerability profile in prespecified adverse events vs apalutamide and enzalutamide. Consideration of these adverse events is important in clinical decision-making and treatment selection in nonmetastatic castration-resistant prostate cancer.

Dupilumab Versus Cyclosporine for the Treatment of Moderate-to-Severe Atopic Dermatitis in Adults: Indirect Comparison Using the Eczema Area and Severity Index.

Dupilumab is approved for uncontrolled moderate-to-severe atopic dermatitis (AD); cyclosporine is approved for severe AD for ≤ 1 year. The efficacy/effectiveness of these treat-ments was compared indirectly. Regression models used pooled patient-level data to estimate response (Eczema Area and Severity Index (EASI) EASI-50/EASI-75 at weeks 12-16 and 24-30) to dupilumab 300 mg every 2 weeks (CHRONOS [NCT02260986]) or cyclosporine (University Medical Center). Models were adjusted for sex, baseline EASI, and thymus and activation-regulated chemokine level. A total of 106 patients received dupilumab (+ topical cortico-steroids; + TCS), and 57 received cyclosporine (+ TCS). Among University Medical Center patients, estimated EASI-50 responders were, dupilumab vs. cyclosporine, 91% vs. 77% (p = 0.038; weeks 12-16), and 96% vs. 67% (p < 0.0001; weeks 24-30); EASI-75 responders were 78% vs. 56% (p = 0.016; weeks 12-16) and 80% vs. 47% (p <0.001; weeks 24-30). Among CHRONOS patients, estimated EASI-50 responders were 90% vs. 74% (p <0.038; weeks 12-16) and 92% vs. 53% (p < 0.0001; weeks 24-30); EASI-75 responders were 75% vs. 52% (p = 0.016; weeks 12-16) and 74% vs. 40% (p <0.001; weeks 24-30), respectively. These results suggest a higher relative efficacy of dupilumab vs. cyclosporine.

Clinical Outcomes Before and After Prucalopride Treatment: An Observational Study in Patients With Chronic Idiopathic Constipation in the United States.

INTRODUCTION: This real-world US-based claims study compared constipation-related symptoms and complications 6 months before and after prucalopride initiation in adults with chronic idiopathic constipation (CIC). METHODS: This observational, retrospective cohort analysis used the IBM MarketScan Commercial Claims and Encounters Database and the Medicare Supplemental Database (January 2015-June 2020). Prucalopride-treated patients (≥18 years old) who had ≥1 constipation-related International Classification of Diseases, Tenth Revision, Clinical Modification ( ICD-10-CM ) diagnosis code during the baseline or study period were included. The proportions of patients with constipation-related symptoms (abdominal pain, abdominal distension [gaseous], incomplete defecation, and nausea) and constipation-related complications (anal fissure and fistula, intestinal obstruction, rectal prolapse, hemorrhoids, perianal venous thrombosis, perianal/perirectal abscess, and rectal bleeding) were examined. Constipation-related symptoms and complications were identified using ICD-10-CM , ICD-10 - Procedure Coding System , or Current Procedural Terminology codes. Data were stratified by age (overall, 18-64 years, and ≥65 years). RESULTS: This study included 690 patients: The mean (SD) patient age was 48.0 (14.7) years, and 87.5% were women. The proportions of patients overall with constipation-related symptoms decreased 6 months after prucalopride initiation (abdominal pain [50.4% vs 33.3%, P < 0.001]; abdominal distension [gaseous] [23.9% vs 13.3%, P < 0.001]; and nausea [22.6% vs 17.7%, P < 0.01]; no improvements observed for incomplete defecation). Similarly, the proportions of patients overall with constipation-related complications decreased 6 months after prucalopride initiation (intestinal obstruction [4.9% vs 2.0%, P < 0.001]; hemorrhoids [10.7% vs 7.0%, P < 0.05]; and rectal bleeding [4.1% vs 1.7%, P < 0.05]). DISCUSSION: This study suggests that prucalopride may be associated with improved constipation-related symptoms and complications 6 months after treatment initiation.

Payer formulary tier increases of apixaban: how patients respond and potential implications.

OBJECTIVE: To assess potential impacts of formulary tier increases of apixaban-an efficacious oral anticoagulant (OAC) for preventing stroke in patients with atrial fibrillation (AF)-on patients' prescription drug plan (PDP) switching and OAC treatment patterns. METHODS: Nationwide claims data for Medicare beneficiaries with Parts A, B, and D (100% sample) were used to assess apixaban-treated AF patients who faced a formulary tier increase for apixaban in 2017 by their Part D PDP. Patients' out-of-pocket (OOP) costs for apixaban were described, along with PDP switching and OAC treatment patterns. RESULTS: Among 1845 included patients, 97.7% had apixaban on tier 3 of their plan's formulary in 2016 and faced its increase to tier 4 for 2017. Approximately 4% (N = 81) of patients pre-emptively switched to a different PDP for 2017 with almost all switching to plans with apixaban on a lower formulary tier and 85.2% continuing apixaban treatment. Among the 96% (N = 1764) of patients who remained on the same PDP for 2017, over half (57.5%) continued apixaban treatment, despite increased OOP costs ($54 vs. $135 for a 30-day supply in 2016 vs. 2017). Only 12.4% of those who remained on the same plan for 2017 switched to another OAC, while as much as 30.1% discontinued OACs. These discontinuers exhibited higher comorbidity burdens than patients continuing on any OAC. CONCLUSION: The majority of patients continued on apixaban despite higher OOP cost, suggesting patients' reluctance to change treatment for non-medical reasons; however, 30% of patients discontinued OAC treatment after higher apixaban tier placement.

Journey to anticoagulant access following payer rejection of apixaban.

OBJECTIVES: To investigate the journey to oral anticoagulant (OAC) access following formulary-related rejection of apixaban (Eliquis) and evaluate characteristics associated with failure to achieve OAC access among patients with atrial fibrillation (AF). STUDY DESIGN: Retrospective study using the Optum Market Clarity Data from January 2016 through February 2020. METHODS: Patients had at least 1 claim rejection for apixaban due to prior authorization (PA), formulary exclusion (FE), or quantity limit (QL) and at least 1 AF diagnosis on or before the rejected claim. Descriptive statistics summarized transaction journeys by type of formulary restriction. Multivariable regression assessed patient characteristics associated with not receiving an OAC within 60 days after initial rejection. RESULTS: Among 18,434 patients in the analytic sample, QL was the most common reason for rejection (68.7%), followed by PA (21.2%) and FE (10.2%). Most patients received a paid OAC claim within 60 days after rejection (82.2%-85.5% across restriction types). Mean time from rejection to paid claim ranged from 5.2 to 10.7 days among patients with a paid OAC claim and 12.4 to 17.6 days among those with multiple attempts before OAC receipt. Characteristics associated with higher odds of not receiving OAC treatment included being male, beingAfrican American, having Medicaid coverage, possessing a high stroke risk score, exhibiting no evidence of prior apixaban treatment, and being prescribed a low dose of apixaban on the initial rejected claim. CONCLUSIONS: Most patients with a claim rejection for apixaban received approval for apixaban within 60 days, suggesting that initial rejection merely created a delay in treatment. Vulnerable populations were at greater risk of not receiving a paid OAC claim.

Long-term results of carbidopa/levodopa enteral suspension across the day in advanced Parkinson's disease: Post-hoc analyses from a large 54-week trial.

Introduction: Carbidopa/levodopa enteral suspension (CLES) previously demonstrated reduction in total daily OFF from baseline by over 4 hours in advanced Parkinson's disease patients across 54 weeks. Evidence on CLES's long-term effectiveness on patterns of motor-symptom control throughout the day remains limited. Methods: We present post-hoc analyses of a large, open-label study of CLES monotherapy (N = 289). Diary data recorded patients' motor states at 30-minute intervals over 3 days at baseline and weeks 4, 12, 24, 36, and 54. Adjusted generalized linear mixed models assessed changes from baseline at each timepoint for four outcome measures: time to ON without troublesome dyskinesia (ON-woTD) after waking, motor-symptom control as measured by motor states' durations throughout the day, number of motor-state transitions, and presence of extreme fluctuations (OFF to ON with TD). Results: Patients demonstrated short-term (wk4) and sustained (wk54) improvement in all outcomes compared to baseline. At weeks 4 and 54, patients were more likely to reach ON-woTD over the course of their day (HR: 1.86 and 2.51, both P < 0.0001). Across 4-hour intervals throughout the day, patients also experienced increases in ON-woTD (wk4: 58-65 min; wk54: 60-78 min; all P < 0.0001) and reductions in OFF (wk4: 50-61 min; wk54: 56-68 min; all P < 0.0001). At weeks 4 and 54, patients' motor-state transitions were reduced by about half (IRR: 0.53 and 0.49, both P < 0.0001), and fewer patients experienced extreme fluctuations (OR: 0.22 and 0.15, both P < 0.0001). Conclusion: CLES monotherapy was associated with significant long-term reductions in motor-state fluctuations, faster time to ON-woTD upon awakening, and increased symptom control throughout the day.

Payer formulary exclusions of apixaban: how patients respond and potential implications.

In recent years, US payers have increased usage of formulary exclusions as a means to help manage costs. Earlier this year, one of the largest pharmacy benefit managers in the country added Eliquis (apixaban), the most widely used anticoagulant, to its list of excluded medicines from its formulary, raising concerns by physicians and patients. In this commentary, we examine the potential impacts of formulary exclusion of a drug like apixaban-a treatment for patients with atrial fibrillation and venous thromboembolism to help prevent stroke and clotting events and which has been demonstrated to have a strong efficacy and safety profile. We discuss the effect of formulary exclusions on patients' ability to access the most clinically appropriate treatment for their health needs, along with possible effects on their health and well-being. We also report descriptive results on apixaban-treated patients with traditional Medicare coverage who faced a formulary exclusion of apixaban in 2017, and these patients' observed behaviors. We found that the majority of these patients remained on apixaban either through pre-emptively switching to a different Part D drug plan with apixaban coverage or applying for formulary exception. Our findings suggest that formulary exclusion did not help to achieve the goal of switching patients to less costly medications but created additional hurdles for patients to access their preferred treatment and increased patient burden. Alternative ways to manage payer costs may be needed to help avoid poor outcomes and reduce the burden placed on patients in their efforts to access life-saving medications.

The Hospitalization-Related Costs of Adverse Events for Novel Androgen Receptor Inhibitors in Non-Metastatic Castration-Resistant Prostate Cancer: An Indirect Comparison.

INTRODUCTION: Three novel androgen receptor inhibitors are approved in the USA for the treatment of non-metastatic castration-resistant prostate cancer (nmCRPC): apalutamide, enzalutamide, and darolutamide. All three therapies have demonstrated prolonged metastasis-free survival in their respective phase III trials, with differing safety profiles. The objective of this study was to compare the mean per-patient costs of all-cause adverse events (AEs) requiring hospitalization between darolutamide versus apalutamide and enzalutamide for nmCRPC in the USA. METHODS: All-cause grade ≥ 3 AEs with corresponding any-grade AEs reported among at least 10% of patients in any arm of the ARAMIS (darolutamide), SPARTAN (apalutamide), and PROSPER (enzalutamide) trials were selected for inclusion in the primary analyses. After matching-adjusted indirect comparison, AE costs were calculated by multiplying the AE rates from the trials by their respective unit costs of hospitalization taken from the US Healthcare Cost and Utilization Project (HCUP) database. Sensitivity analyses which further included any-grade AEs reported among at least 5% of patients were also performed. RESULTS: After reweighting and adjusting for the trials' placebo arms, the mean per-patient AE costs were $1021 and $387 lower for darolutamide than for apalutamide and enzalutamide, respectively, over the trials' duration (SPARTAN and PROSPER, 43 months; ARAMIS, 48 months). For darolutamide vs. apalutamide, the largest drivers of the per-patient cost differences were fracture (adjusted difference $416), hypertension ($143), and rash ($219); for darolutamide vs. enzalutamide, they were fatigue not including asthenia ($290) and hypertension including increased blood pressure (i.e., any AE of hypertension or with elevated blood pressure not yet classified as hypertension) ($60). The results of the sensitivity analyses were consistent with the primary results. CONCLUSIONS: Patients with nmCRPC treated with darolutamide in ARAMIS incurred lower AE-related costs (USD), as determined using HCUP costing data, compared with patients treated with either apalutamide (in SPARTAN) or enzalutamide (in PROSPER).

Patterns of Daily Motor-Symptom Control with Carbidopa/Levodopa Enteral Suspension Versus Oral Carbidopa/Levodopa Therapy in Advanced Parkinson's Disease: Clinical Trial Post Hoc Analyses.

INTRODUCTION: A clinical trial in advanced Parkinson's disease (APD) has established the superiority of carbidopa/levodopa enteral suspension (CLES) in reducing total patient "off" time (OFF) and increasing total "on" time without troublesome dyskinesia (ON-woTD) over orally administered immediate-release carbidopa/levodopa tablets (IR-CL). However, temporal patterns of these improvements throughout the waking day have not been examined. In this analysis, time to ON-woTD after waking and patterns of motor-symptom control throughout the waking day were compared between CLES and IR-CL. METHODS: Post hoc analyses of APD patient-diary data from the phase 3 randomized controlled trial were used to compare changes in time to ON-woTD after waking, motor-symptom control throughout the waking day, occurrence of extreme fluctuations between OFF and "on" with troublesome dyskinesia, and motor-state transitions with CLES versus IR-CL from baseline to week 12. RESULTS: The sample included 33 CLES-treated and 30 IR-CL-treated patients. Among the CLES group, the percentage of patient days achieving ON-woTD within 30 min of waking was three times higher at week 12 versus baseline (33% vs. 11%, p = 0.0043); no significant change occurred with IR-CL. When the waking day was divided into four 4-h periods, CLES versus IR-CL treatment produced significantly greater reductions in OFF during three periods, and two periods had increased ON-woTD. Fewer CLES-treated patients had extreme fluctuations at week 12 (3% vs. 23%, p = 0.0224) compared to IR-CL-treated patients. From baseline to week 12, CLES-treated patients had greater reductions in the average number of motor-state transitions compared to IR-CL-treated patients (- 1.6, p = 0.0295). CONCLUSION: CLES-treated patients experienced a more rapid onset of ON-woTD after waking and greater consistency of ON-woTD throughout their waking day than IR-CL-treated patients.

In advanced Parkinson's disease, patients' motor-symptom states (such as "on" time without troublesome dyskinesia [good "on" time] and "off" time), and the timing at which they occur, can impact patients' quality of life and ability to complete activities of daily living. Carbidopa/levodopa enteral suspension is administered continuously into the jejunum, potentially reducing some of the motor-state variation that is common with orally administered carbidopa/levodopa, including delayed "on" time after waking and transitions between "off" and "on" throughout the day. In post hoc analyses of clinical trial data, patterns of motor-states across the waking day were compared between carbidopa/levodopa enteral suspension and orally administered immediate-release carbidopa/levodopa at week 12. Outcomes included time to good "on" after waking; occurrence of extreme fluctuations between "off" time and "on" time with troublesome dyskinesia; time in each motor-state during 4-h intervals across the day; and frequency of motor-state transitions. Three times as many carbidopa/levodopa enteral suspension-treated patients achieved good "on" within 30 min of waking after 12 weeks versus baseline, whereas no significant change was observed for the orally administered immediate-release carbidopa/levodopa group. Compared to orally administered immediate-release carbidopa/levodopa-treated patients, fewer carbidopa/levodopa enteral suspension-treated patients experienced extreme fluctuations, had greater reductions in motor-state transitions, and greater reductions in duration of "off" during three of the four intervals in the day. These findings provide a first look at the impact of carbidopa/levodopa enteral suspension on motor-state patterns throughout the day, and suggest that carbidopa/levodopa enteral suspension provides more consistent motor-symptom control and predictable benefit throughout the day than orally administered carbidopa/levodopa.

Clinical Outcomes and Health-Care Resource Use Associated With Reslizumab Treatment in Adults With Severe Eosinophilic Asthma in Real-World Practice.

BACKGROUND: Reslizumab, an anti-IL-5 monoclonal antibody, is indicated as add-on maintenance treatment for adults with severe eosinophilic asthma. RESEARCH QUESTION: What are the real-world outcomes associated with reslizumab use in patients with severe eosinophilic asthma in a US clinical practice? STUDY DESIGN AND METHODS: In this retrospective study, patient-level data from adults treated with reslizumab were obtained from center- and panel-based medical chart reviews. Eligible patients had available medical records and treatment history for ≥ 6 months before initiation of reslizumab treatment (index date) to ≥ 7 months after reslizumab initiation. The primary outcome was response to reslizumab treatment, based on clinical expert predefined definitions of response. Other outcomes included clinical asthma exacerbations (CAEs), use of maintenance oral corticosteroids (OCS), FEV1 percent predicted, Asthma Control Test (ACT) score, and health-care resource use (HRU). RESULTS: Medical charts were obtained for 215 patients. Most patients (58.6%) showed an excellent response, 16.3% showed a clinically meaningful response, 21.9% showed a partial response, and 3.3% were nonresponders or treatment failures. A significant reduction was observed in the proportion of patients experiencing a CAE in a 6-month period (from 86.0% to 40.5%; P < .001) and in the mean number of CAEs per patient (2.84 [SD, 2.41] vs 0.94 [SD, 1.86]) after reslizumab initiation. Improvements were observed in FEV1 percent predicted (65.1% [SD, 20.5%] vs 73.1% [SD, 23.1%]; P < .001) and in ACT scores (13.8 [SD, 4.2] vs 18.6 [SD, 4.0]; P < .001) before to after reslizumab initiation. Among patients using maintenance OCS at baseline, more than half discontinued use of these by approximately 10 months after reslizumab initiation. Significant reductions in asthma-related HRU were observed after reslizumab initiation. INTERPRETATION: In clinical practice, reslizumab may have been initiated in response to heavy symptom burden and CAEs. Reslizumab was associated with improved clinical and patient-reported outcomes and significant reductions in asthma-related HRU.

The burden of tardive dyskinesia secondary to antipsychotic medication use among patients with mental disorders.

Objective: To assess the impact of developing tardive dyskinesia (TD), both with and without other pre-existing extrapyramidal symptoms (EPS), on healthcare resource utilization (HRU) among patients with mental disorders receiving antipsychotic medications. Methods: Data on patients receiving antipsychotics who had schizophrenia, major depressive disorder or bipolar disorder were extracted from a Medicaid claims database. Separate cohorts of TD patients with and without other EPS ("TD + EPS" and "TD non-EPS") were constructed and matched to patients in a non-TD/EPS control cohort at a ∼1:5 ratio. HRU outcomes were assessed using descriptive statistics and difference-in-differences techniques over baseline and follow-up periods defined as the 6 months before and after TD development, respectively. Results: The TD + EPS (n = 289) and TD non-EPS (n = 394) cohorts were matched with 1398 and 1922 control patients, respectively. The percentage of patients with all-cause and mental-disorder-related inpatient admissions increased from baseline to follow-up in the TD + EPS (12.8% and 12.5%, respectively) and TD non-EPS (16.0% and 13.5%) cohorts; by contrast, slight decreases (∼3%) in these outcomes were observed in the matched controls. Difference-in-differences analyses demonstrated that development of TD was associated with a statistically significant increase of ∼15-19% in the percentage of patients with all-cause and mental-disorder-related inpatient admissions/visits. The within-cohort change from baseline to follow-up in the use of potential drugs for TD or EPS was similar between the TD cohorts and their matched controls. Conclusions: This study demonstrates a significant economic burden associated with developing TD, as captured by increased HRU including inpatient admissions and ER visits.

Drivers of treatment patterns in patients with chronic lymphocytic leukemia stopping ibrutinib or idelalisib therapies.

Novel therapies including kinase inhibitors (KI) have led to high and durable response in patients with chronic lymphocytic leukemia (CLL), however, some patients stop therapy. This study evaluates reasons for treatment changes among CLL patients who stopped KI in real-world practice. Sixty-nine US oncologists/hematologists provided patient-level data abstracted from charts of CLL adult patients who initiated a KI and later (1) switched to another anti-neoplastic regimen (Switched cohort), (2) discontinued the KI and remained untreated (Discontinued cohort), or (3) restarted the same KI after an interruption of ≥60 days (Restarted cohort). Demographics, clinical/treatment characteristics, and reasons for stopping, restarting, and switching the KI therapy were described. In the Switched cohort, reasons for stopping included disease progression (72.5%), low/no disease activity (3.9%), adverse event [AE]/ intolerance/comorbidity (15.7%), and planned cellular therapies (7.9%). In the Discontinued cohort, approximately half (46.0%) of patients stopped KI therapy because they were terminally ill/died, or were moved to best supportive care - these patients were older, had more severe disease, and high comorbidity burden. The other half (54.0% of patients) stopped due to low/no disease activity (24.0%), AEs/toxicity (12.0%), or patient-requested drug holiday (18.0%). In the Restarted cohort, the most common reasons for stopping KIs were patient request (37.3%), AEs/intolerance (31.4%), and economic reasons (10%). Patients restarted when disease progressed (60.8%) or when they recovered from the AE (33%). Reasons for KI stop and subsequent treatment patterns were varied and multifactorial, suggesting heterogeneous disease management and a need for more evidence around supporting strategies and physician education.

Inpatient Admissions and Costs Associated with Persistent Use of Dalfampridine Extended-Release in Multiple Sclerosis: A Claims Database Analysis.

BACKGROUND: While the clinical benefits of dalfampridine extended-release (D-ER) have been established in patients with multiple sclerosis (MS) through multiple clinical trials, there is limited real-world data on D-ER use, in particular the persistent use of D-ER, and associated acute care resource utilization and costs. OBJECTIVE: To examine the real-world association of D-ER use and inpatient admissions and costs among patients with MS. METHODS: This study was a retrospective observational claims analysis of the MarketScan database (April 2009-March 2014). Eligible patients consisted of adult enrollees aged 18-64 years who had (a) 12 months of continuous private plan enrollment preceding (baseline) and following (follow-up) the first D-ER claim; (b) ≥ 2 MS diagnosis codes with ≥ 1 during the baseline period; (c) ≥ 2 consecutive D-ER claims; and (d) no alternate gait-impairing etiologies during the baseline and follow-up periods. Patients were separated into 2 D-ER cohorts in the main analysis: persistent (≥ 360 days of D-ER supply) and nonpersistent (< 360 days of supply) users. Sensitivity analyses were conducted, examining additional breakdowns of days of supply within the nonpersistent cohort. Inpatient admissions (all-cause and MS-related) and health care expenditures were calculated and compared between the cohorts during follow-up using Wilcoxon rank-sum and chi-square tests. Regression models were conducted, controlling for age, sex, MS relapses, comorbidities, disease-modifying therapy use, and other baseline factors, including inpatient admissions and costs. RESULTS: Of 1,598 eligible patients, 719 (45.0%) were persistent D-ER users, and 879 (55.0%) were nonpersistent D-ER users. The 2 cohorts had similar demographic and clinical characteristics, with mean (SD) ages of 51.0 (8.4) and 50.6 (8.6) years and were 71.3% and 66.6% female, respectively. Compared with nonpersistent D-ER use, persistent D-ER use was associated with lower odds of all-cause inpatient admissions (OR = 0.58, P = 0.010) and MS-related inpatient admissions (OR = 0.50, P = 0.004). Persistent use was also associated with lower inpatient expenditures for all-cause admissions ($669 vs. $1,515, P = 0.002) and MS-related admissions ($388 vs. $891, P = 0.008). CONCLUSIONS: Persistent D-ER use was associated with significantly lower rates of all-cause and MS-related inpatient admissions and costs. DISCLOSURES: Funding for this research and medical writing assistance was provided by Acorda Therapeutics. The study sponsor was involved in all stages of the study research and manuscript preparation. Guo and Niyazov were employees of Acorda Therapeutics at the time of this study and may own stock/stock options. Wu, Macaulay, Terasawa, and Schmerold are employees of Analysis Group, which received consultancy fees from Acorda Therapeutics for this project. Krieger was a consultant for Acorda Therapeutics for this project and has the following additional financial interests to report: consulting/advisory board work with Bayer, Biogen, EMD Serono, Novartis, Genentech, Genzyme, and Teva. Study concept and design were contributed by Guo, Niyazov, Macaulay, and Wu. Macaulay, Terasawa, Schmerold, and Wu helped prepare the data, and data interpretation was performed by Krieger, Guo, Niyazov, and Macaulay, along with Terasawa and Wu. The manuscript was written by Terasawa and Schmerold, along with Macaulay, and revised by all the authors. A portion of the current research was presented in poster format at the 2106 American Academy of Neurology Annual Meeting, which took place in Vancouver, BC, Canada, on April 15-21, 2016.