Evan Kantor

Comparative Effectiveness Without Head-to-Head Trials: A Method for Matching-Adjusted Indirect Comparisons Applied to Psoriasis Treatment with Adalimumab or Etanercept

The absence of head-to-head trials is a common challenge in comparative effectiveness research and health technology assessment. Indirect cross-trial treatment comparisons are possible, but can be biased by cross-trial differences in patient characteristics. Using only published aggregate data, adjustment for such biases may be impossible. Although individual patient data (IPD) would permit adjustment, they are rarely available for all trials. However, many researchers have the opportunity to access IPD for trials of one treatment, a new drug for example, but only aggregate data for trials of comparator treatments. We propose a method that leverages all available data in this setting by adjusting average patient characteristics in trials with IPD to match those reported for trials without IPD. Treatment outcomes, including continuous, categorical and censored time-to-event outcomes, can then be compared across balanced trial populations.The proposed method is illustrated by a comparison of adalimumab and etanercept for the treatment of psoriasis. IPD from trials of adalimumab versus placebo (n = 1025) were re-weighted to match the average baseline characteristics reported for a trial of etanercept versus placebo (n = 330). Reweighting was based on the estimated propensity of enrolment in the adalimumab versus etanercept trials. Before matching, patients in the adalimumab trials had lower mean age, greater prevalence of psoriatic arthritis, less prior use of systemic treatment or phototherapy, and a smaller mean percentage of body surface area affected than patients in the etanercept trial. After matching, these and all other available baseline characteristics were well balanced across trials. Symptom improvements of ≥75% and ≥90% (as measured by the Psoriasis Area and Severity Index [PASI] score at week 12) were experienced by an additional 17.2% and 14.8% of adalimumab-treated patients compared with the matched etanercept-treated patients (respectively, both p < 0.001). Mean percentage PASI score improvements frombaseline were also greater for adalimumab than for etanercept at weeks 4, 8 and 12 (all p < 0.05). Matching adjustment ensured that this indirect comparison was not biased by differences in mean baseline characteristics across trials, supporting the conclusion that adalimumab was associated with significantly greater symptom reduction than etanercept for the treatment of moderate to severe psoriasis.

Comparative efficacy of nilotinib and dasatinib in newly diagnosed chronic myeloid leukemia: a matching-adjusted indirect comparison of randomized trials.

Abstract Objective: Nilotinib and dasatinib have not been directly compared in a randomized trial for the treatment of newly diagnosed chronic myeloid leukemia in the chronic phase (CML-CP). The purpose of this study was to indirectly compare rates of major molecular response (MMR), progression-free survival (PFS) and overall survival by month 12 with nilotinib and dasatinib treatment of newly diagnosed CML-CP. Methods: Individual patient data from a randomized trial of nilotinib vs. imatinib (ENESTnd) and published summary data from a separate randomized trial of dasatinib vs. imatinib (DASISION) were utilized. A matching-adjusted indirect comparison was conducted by weighting individual patients treated with nilotinib to match baseline characteristics reported for dasatinib-treated patients, including age, gender, ECOG performance status and hematology lab values. After matching, efficacy outcomes were compared for patients treated with nilotinib 300 mg twice daily vs. dasatinib 100 mg once daily. Patients randomized to imatinib 400 mg once daily in each trial were used to assess the adequacy of the matching. Results: Before matching, patients randomized to nilotinib in ENESTnd (n = 273) were older, with a lower median platelet count and more favorable performance status compared to patients randomized to dasatinib in DASISION (n = 259). After matching, all baseline characteristics were balanced across treatment groups. Matched patients treated with nilotinib vs. dasatinib experienced significantly higher rates of MMR (56.8 vs. 45.9%, p = 0.014) and overall survival (99.5 vs. 97.3%, p = 0.046) and numerically higher rates of PFS (98.8 vs. 96.5%). Matched imatinib arms showed no statistically significant or clinically meaningful differences in these outcomes. Limitations: Baseline measures unavailable in one or both trials could not be matched. Adverse event rates were not formally compared across trials due to differences in reporting. Conclusion: Nilotinib was associated with significantly higher rates of MMR and overall survival compared with dasatinib by month 12 in the treatment of newly diagnosed CML-CP.

Comparative Efficacy of Vildagliptin and Sitagliptin in Japanese Patients with Type 2 Diabetes Mellitus A Matching-Adjusted Indirect Comparison of Randomized Trials

AbstractBackground and Objective: Vildagliptin and sitagliptin are oral dipeptidyl peptidase 4 inhibitors approved in Japan for the treatment of type 2 diabetes mellitus when adequate glycaemic control is not achieved with diet, exercise or sulphonylureas. The aim of this study was to compare 12-week glycaemic control with vildagliptin 50 mg twice daily versus sitagliptin 50 or 100 mg once daily in Japanese patients with type 2 diabetes. Methods: Randomized trials of vildagliptin or sitagliptin in Japanese patients were identified from the literature. Individual patient data were obtained for vildagliptin trials. In the absence of a head-to-head randomized trial, a matching-adjusted indirect comparison was conducted by weighting individual patients from vildagliptin trials to match average baseline characteristics published for sitagliptin trials, including age, sex, body mass index, glycosylated haemoglobin (HbA1c), fasting plasma glucose (FPG) and diabetes duration. After matching, HbA1c change from baseline to week 12, the primary endpoint in each trial, was compared between balanced populations treated with vildagliptin and sitagliptin. Separate comparisons were conducted for vildagliptin 50 mg twice daily versus sitagliptin 50 mg and 100 mg once daily. Results: Two trials of vildagliptin and three trials of sitagliptin were identified for Japanese patients. Across all included trials, a total of 264 patients were treated with vildagliptin 50 mg twice daily, 235 were treated with sitagliptin 50 mg once daily and 145 were treated with sitagliptin 100 mg once daily. Mean baseline HbA1c ranged from 7.4% to 7.8% per trial. Before matching, significant (p<0.05) cross-trial differences included lower mean HbA1c (by 0.2–0.3%) and higher FPG (by 5–13 mg/dL) in vildagliptin trials. After matching, all baseline characteristics were balanced between treatment groups. Combining matched trials, vildagliptin 50 mg twice daily was associated with significantly greater absolute HbA1c reduction by 0.28% compared with sitagliptin 50mg once daily (95% CI 0.15, 0.41; p<0.001) and by 0.35% compared with sitagliptin 100mg once daily (95% CI 0.07, 0.62; p = 0.013). Conclusion: After adjusting for baseline differences among trials of vildagliptin and sitagliptin in Japanese patients with type 2 diabetes, vildagliptin 50 mg twice daily was associated with significantly greater HbA1c reduction than sitagliptin 50 mg or 100 mg once daily.

Implications of early treatment among Medicaid patients with Alzheimer's disease

The objective of this study was to examine the effect of treatment timing on risk of institutionalization of Medicaid patients with Alzheimers disease (AD) and to estimate the economic implications of earlier diagnosis and treatment initiation.

Everolimus and sunitinib for advanced pancreatic neuroendocrine tumors: a matching-adjusted indirect comparison

BackgroundEverolimus and sunitinib have been approved for the treatment advanced pancreatic neuroendocrine tumors, but have not been compared to each other in a randomized trial and have not demonstrated prolonged overall survival compared to placebo. This study aimed to indirectly compare overall and progression-free among everolimus, sunitinib and placebo across separate randomized trials.MethodsA matching adjusted indirect comparison was conducted in which individual patient data from the pivotal trial of everolimus (n = 410) were adjusted to match the inclusion criteria and average baseline characteristics reported for the pivotal trial of sunitinib (n = 171). Prior to matching, trial populations differed in baseline performance status and prior treatments. After matching, these and all other available baseline characteristics were balanced between trials.ResultsCompared to the placebo arm in the sunitinib trial, everolimus was associated with significantly prolonged overall survival (HR = 0.61, 95% CI = 0.38-0.98, p = 0.042).Compared to sunitinib, everolimus was associated with similar progression-free (hazard ratio for death (HR) = 0.84, 95% CI = 0.46–1.53, p = 0.578) and overall survival (HR = 0.81, 95% CI = 0.49–1.31, p = 0.383).ConclusionAfter adjusting for observed cross-trial differences, everolimus treatment was associated with longer overall survival than the placebo arm in the sunitinib trial for advanced pancreatic neuroendocrine tumors.

Matching-adjusted indirect comparison of adalimumab vs etanercept and infliximab for the treatment of psoriatic arthritis

Abstract Objectives: No head-to-head trial has compared the efficacy of adalimumab vs etanercept and infliximab for psoriatic arthritis (PsA). This study implements a matching-adjusted indirect comparison technique to address that gap. Methods: Patient-level data from a placebo-controlled trial of adalimumab (ADEPT) were re-weighted to match average baseline characteristics from pivotal published trials of etanercept and infliximab. ADEPT patients were re-weighted by odds of enrollment in comparator trials, estimated using logistic regression. Matched-on characteristics included PsA duration, age, gender, severity, active psoriasis, and concomitant treatment. After matching, placebo-adjusted treatment arms were compared at weeks 12 (or 14) and 24. Outcomes included ACR20/50/70, PsARC, HAQ, and modified TSS. PASI50/75/90 were compared for patients with active psoriasis. Cost per responder (CPR) was assessed in the US and Germany using matching-adjusted end-points and drug list prices. Statistical significance was assessed using weighted t-tests. Results: After matching, adalimumab-treated patients had greater placebo-adjusted rates of ACR70 and PASI50/75/90 at week 24 compared with etanercept (all p < 0.05). Adalimumab patients had a higher placebo-adjusted rate of ACR70 than infliximab at week 14 (p = 0.034). Adalimumab treatment had lower CPR for ACR70 and PASI50/75/90 compared with etanercept at week 24, in both the US and Germany (all p < 0.02). Adalimumab had lower CPR than infliximab for all outcomes at week 24 (all p < 0.05). Conclusion: Adalimumab is associated with higher ACR70 and PASI50/75/90 response rates than etanercept at week 24 and a higher ACR70 response rate than infliximab at week 14. Adalimumab has significant advantages over etanercept and infliximab in CPR across multiple end-points. Key limitations: The matching-adjusted indirect comparison method cannot account for unobserved differences in patient characteristics across trials, and only a head-to-head randomized clinical trial can fully avoid the limitations of indirect comparisons. CPR findings are limited to the US and German markets, and may not be generalizable to other markets with different relative pricing.

Comparing healthcare costs of Medicaid patients with postherpetic neuralgia (PHN) treated with lidocaine patch 5% versus gabapentin or pregabalin

Abstract Objective: To compare healthcare resource utilization and costs of postherpetic neuralgia (PHN) patients initiating lidocaine patch 5% (lidocaine patch) or oral gabapentin/pregabalin. Methods: Patients with PHN diagnosis, or herpes zoster diagnosis and ≥30 days PHN-recommended treatment were selected from de-identified Medicaid claims data from Florida, Iowa, Missouri, and New Jersey, 1999–2007. Patients initiated monotherapy with lidocaine patch or gabapentin/pregabalin after PHN diagnosis, had continuous eligibility 6 months before (baseline) and 6 months after (study period) medication index date, and were ≥18 years old. Lidocaine patch patients were matched to gabapentin/pregabalin patients based on their propensity to initiate treatment. Study period resource utilization and costs from a Medicaid perspective were compared between treatment groups using univariate analysis. Results: Matched patients were on average 61.3 years old, approximately 73% were women, and 55% had other painful conditions during the baseline period. 6-month per patient PHN-related prescription drug costs were similar for matched lidocaine patch (n = 312) and gabapentin/pregabalin (n = 312) patients (

Duloxetine Use in Chronic Low Back Pain

854 vs. 820, p = 0.75), while PHN-related medical costs appeared lower in the lidocaine patch group (

Descriptive analysis of Medicaid patients with postherpetic neuralgia treated with lidocaine patch 5

145 vs. 353, p = 0.12). Furthermore, there were no statistically significant differences between treatment groups during the observation period in overall resource utilization, total prescription drug costs, and total medical costs per patient. Conclusions: In spite of higher list prices, PHN patients treated with lidocaine patch cost no more than patients treated with gabapentin or pregabalin in terms of overall healthcare costs over the 6-month study period. The study suggests that PHN-related medical costs may be lower among lidocaine patch patients. Limitations: Findings are based on a Medicaid sample and may not be generalizable to all PHN patients.

Duloxetine Use in Employees with Low Back Pain: Treatment Patterns and Direct and Indirect Costs

BackgroundLittle is known about the real-world treatment patterns and costs of patients with chronic low back pain (CLBP) who are treated with duloxetine compared with those receiving other non-surgical treatments.ObjectiveOur objective was to compare the real-world treatment patterns and costs between patients with CLBP who initiated duloxetine and matched controls who initiated another non-surgical treatment.MethodsThe study sample was selected from a US privately insured claims database (2004–8). Selected patients were aged 18–64 years, and had a low back pain (LBP) diagnosis (per Healthcare Effectiveness Data and Information Set [HEDIS] specifications) with a subsequent CLBP-qualifying diagnosis recorded ≥90 days after the initial LBP diagnosis. Duloxetine-treated patients had ≥1 duloxetine prescription within 6 months after CLBP diagnosis, no prior duloxetine claim, and continuous eligibility ≥12 months before first LBP diagnosis and ≥6 months after index duloxetine prescription (study period). Because duloxetine patients had higher rates of co-morbidities, 553 duloxetine-treated patients were matched to 553 control patients who initiated another non-surgical LBP treatment based on propensity score and time from first LBP diagnosis to treatment initiation. A subset (n = 103 each) of matched employees with disability data was also analysed to assess work loss. Main outcomes measures included study period treatment rates and direct (medical and drug) costs from a third-party payer perspective and employee indirect (work-loss) costs. McNemar tests were used to compare LBP treatment rates. Bias-corrected bootstrapping t-tests were used to compare costs.ResultsAfter matching, the two groups had balanced baseline characteristics including demographics, LBP diagnostic categories, co-morbidity profiles, resource use, treatment patterns and mean direct costs. During the 6-month study period, matched duloxetine-treated patients had significantly lower rates of other pharmacological therapy (e.g. 56.2% vs 64.9% narcotic opioids, p = 0.0024; 34.9% vs 49.5% NSAIDs, p<0.0001) and non-invasive therapy (28.8% vs 38.5% chiropractic therapy, p = 0.0007; 25.5% vs 35.4% physical therapy, p = 0.0004; 17.5% vs 28.4% exercise therapy, p<0.0001) than controls. Duloxetine-treated patients versus controls had similar back surgery rates (2.2% vs 3.8%; p = 0.1127) and similar direct costs (