Cost Effectiveness of Durvalumab in Unresectable Stage III NSCLC: 4-Year Survival Update and Model Validation from a UK Healthcare Perspective.

BACKGROUND: In the phase III PACIFIC study, durvalumab improved survival versus placebo in patients with unresectable stage III non-small-cell lung cancer (NSCLC) whose disease had not progressed after platinum-based concurrent chemoradiotherapy. The appraisal by the UK's National Institute for Health and Care Excellence (NICE) included a cost-effectiveness analysis based on an early data readout from PACIFIC [March 2018 data cut-off (DCO); median follow-up duration 25.2 months; range 0.2-43.1]. Uncertainties regarding long-term survival outcomes with durvalumab led to some challenges in estimating the cost effectiveness of this therapy. OBJECTIVE: Here, we validate the survival extrapolations used in the original company base-case analysis by benchmarking them against updated survival data from the 4-year follow-up analysis of PACIFIC (i.e. approximately 4 years after the last patient was randomised; March 2020 DCO; median follow-up duration 34.2 months; range 0.2-64.9). Moreover, we update the original analysis with these more mature survival data to examine the consistency of key economic outputs with the original analysis. METHODS: The original analysis used a semi-Markov (state-transition) approach and was based on patients whose tumours expressed programmed cell death-ligand 1 on ≥ 1% of cells (to reflect the European licence for durvalumab). We benchmarked the survival extrapolations used in the original company base-case analysis against survival data from the 4-year follow-up of PACIFIC and updated the cost-effectiveness analysis with these more mature survival data. Early deaths avoided by the adoption of durvalumab into the UK Cancer Drugs Fund (CDF) in March 2019 were estimated using the 4-year follow-up survival data and an assumed uptake of 125 patients/year (lower estimate) and 367 patients/year (higher estimate). RESULTS: The original company base-case analysis had a good visual fit with the observed overall survival (OS) distribution for the durvalumab arm and accurately predicted the 48-month OS rate (predicted 55%; observed 55%); by comparison, the fit was less precise for the placebo arm, for which the analysis underestimated the 48-month OS rate (predicted 32%; observed 38%). In the updated company base-case analysis, durvalumab yielded 2.51 incremental quality-adjusted life-years (QALYs) (- 0.43 vs. the original company base-case analysis), corresponding to an incremental cost-effectiveness ratio of £22,665/QALY (+£3298 vs. the original analysis), which falls within the upper bound of NICE's willingness-to-pay threshold (£30,000/QALY gained). We estimate that between 31 and 91 early patient deaths may have been avoided by the adoption of durvalumab into the CDF. CONCLUSIONS: These findings reinforce the patient benefit observed with durvalumab in unresectable stage III NSCLC, support the routine use and cost effectiveness of this therapy, and demonstrate how appropriate modelling can inform the early adoption of therapies by payers to achieve patient benefit.

Based on the results of a clinical trial, the European Medicines Agency approved durvalumab for the treatment of adults with a specific type of advanced lung cancer whose tumours cannot be removed surgically and whose disease has not progressed after chemotherapy and radiotherapy. The UK's National Institute for Health and Care Excellence (NICE) invites companies to submit cost-effectiveness analyses to help with decision making about adopting new therapies. The company included an analysis based on early trial data that suggested durvalumab was cost effective compared with other previous treatments. As patients in the study at the time of the initial submission to NICE were only followed for approximately 2 years, the long-term survival benefit that could be achieved with durvalumab was uncertain. Therefore, NICE recommended durvalumab for use within the Cancer Drugs Fund (CDF) to allow patients to access the drug while more data were being collected. Here, we demonstrate that the original cost-effectiveness model accurately predicted the rates of long-term survival for patients receiving durvalumab and that durvalumab remains a cost-effective use of healthcare resources based on recently published data from the trial (which added approximately 2 further years of follow-up). Moreover, we estimate that adopting durvalumab into the CDF may have avoided 31­91 early patient deaths from lung cancer. These findings support NICE's early decision to make durvalumab available within the CDF and the adoption of durvalumab for routine use within the UK national health service.

Estimating Lifetime Benefits Associated with Immuno-Oncology Therapies: Challenges and Approaches for Overall Survival Extrapolations.

BACKGROUND: Standard parametric survival models are commonly used to estimate long-term survival in oncology health technology assessments; however, they can inadequately represent the complex pattern of hazard functions or underlying mechanism of action (MoA) of immuno-oncology (IO) treatments. OBJECTIVE: The aim of this study was to explore methods for extrapolating overall survival (OS) and provide insights on model selection in the context of the underlying MoA of IO treatments. METHODS: Standard parametric, flexible parametric, cure, parametric mixture and landmark models were applied to data from ATLANTIC (NCT02087423; data cut-off [DCO] 3 June 2016). The goodness of fit of each model was compared using the observed survival and hazard functions, together with the plausibility of corresponding model extrapolation beyond the trial period. Extrapolations were compared with updated data from ATLANTIC (DCO 7 November 2017) for validation. RESULTS: A close fit to the observed OS was seen with all models; however, projections beyond the trial period differed. Estimated mean OS differed substantially across models. The cure models provided the best fit for the new DCO. CONCLUSIONS: Standard parametric models fitted to the initial ATLANTIC DCO generally underestimated longer-term OS, compared with the later DCO. Cure, parametric mixture and response-based landmark models predicted that larger proportions of patients with metastatic non-small cell lung cancer receiving IO treatments may experience long-term survival, which was more in keeping with the observed data. Further research using more mature OS data for IO treatments is needed.

Systematic literature review and meta-analysis of dual therapy with fenofibrate or fenofibric acid and a statin versus a double or equivalent dose of statin monotherapy.

OBJECTIVE: To assess the efficacy of fenofibrate and statin dual therapy versus a double or equivalent dose of statin monotherapy. METHODS: A systematic literature search and meta-analysis was performed for publications before 1 January 2014 in MEDLINE, Embase, and BIOSIS Previews, among others. RESULTS: The difference in percentage change from baseline was in favor of dual therapy versus a double dose of statin monotherapy for triglycerides (difference -20%; standard error [SE] 2.6%) and HDL-C (8.7%; SE 1.2%), but not for LDL-C (8.4%; SE 1.5%), non-HDL-C (2.8%; SE 1.1%), total cholesterol (4.5%; SE 1.0%) and apolipoprotein B (2.6%; SE 1.1%). For high intensity statins, the difference in percentage change from baseline was in favor of dual therapy versus equivalent statin monotherapy for triglycerides (-17%; SE 2.6%) and for HDL-C (8.7%; SE 1.9%). The difference in percentage change from baseline for LDL-C was 6% (SE 1.7%), implying a greater reduction in LDL-C with statin monotherapy. For moderate intensity statins, the difference in percentage change from baseline was in favor of dual therapy versus equivalent statin monotherapy for triglycerides (-24.2%; SE 1.2%) and HDL-C (8.2%; SE 0.9%). LDL-C decreased 2.2% (SE 1.4%) more with dual therapy. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: When aiming to change HDL-C or triglycerides, dual therapy is to be preferred to doubling the statin dose; conversely, doubling the statin dose is to be preferred when aiming to reduce LDL-C. If the aim is both to change HDL-C or triglycerides and to reduce LDL-C, the importance of the three outcomes may need to be weighed depending on the intensity of the statin. Combining high intensity statin therapy with fenofibrate improves the effect on HDL-C and triglycerides, but lowers the effect on LDL-C. Combining a moderate intensity statin with fenofibrate improves the effect on HDL-C and triglycerides without reducing the effect on LDL-C. There is a need for long-term randomized clinical trials to compare dual therapy versus doubling the statin dose to assess the importance of improvement in HDL-C and triglycerides versus improvement in LDL-C in terms of cardiovascular outcomes. Further, the addition of ezetimibe to statin/fenofibrate therapy may be of interest.

Betahistine plus piracetam dual therapy versus betahistine monotherapy for peripheral vestibular vertigo: a confounder-corrected subanalysis of the OSVaLD study.

INTRODUCTION: This subanalysis compared the efficacy of betahistine plus piracetam dual therapy versus betahistine monotherapy using data from OSVaLD, a 3 month, open-label, observational study conducted in 2272 patients with peripheral vestibular vertigo. Of the 1898 patients included in the original efficacy population, 1076 were from countries where betahistine plus piracetam dual therapy was prescribed to >1 patient; 114 of these 1076 patients (11%) received the dual therapy and 567 (53%) were treated with betahistine monotherapy; these patients were selected for analysis. METHODS: Efficacy was assessed using the Dizziness Handicap Inventory (DHI) total and subscale scores. Propensity-score matching was used to correct potential differences in patient baseline characteristics between treatment groups. In addition, a subgroup analysis evaluated 103 patients treated with betahistine because of insufficient efficacy with their existing treatment. RESULTS: In the propensity-score matched, total-population evaluation, improvements in the DHI total and subscale scores were numerically greater in the betahistine plus piracetam group (n = 88) versus the betahistine group (n = 89) (DHI total, -42.9 vs. -37.6, respectively; DHI physical, -12.1 vs. -10.4; DHI emotional, -13.5 vs. -13.2) and statistically significant for the DHI functional score (-17.3 vs. -14.0, respectively, p = 0.01). The percentage of patients with no impairment at final visit was 27% with betahistine and 47% with betahistine plus piracetam; odds ratio: 2.3, 95% confidence interval: 1.3-2.4 (p = 0.007). Similar results were obtained in the subgroup analyses for patients whose current vertigo treatment was insufficient. The overall incidence of adverse events was low and similar in both groups, and there were no discontinuations due to drug-related adverse events. CONCLUSIONS: By using propensity-score matching, which controls for potential heterogeneity in patient baseline characteristics and small patient numbers, the results of this analysis suggest that combined betahistine and piracetam may be more effective than betahistine alone in patients with peripheral vestibular vertigo.

The impact of 2-dose routine measles, mumps, rubella, and varicella vaccination in France on the epidemiology of varicella and zoster using a dynamic model with an empirical contact matrix.

PURPOSE: Varicella has a high incidence affecting the vast majority of the population in France and can lead to severe complications. Almost every individual infected by varicella becomes susceptible to herpes zoster later in life due to reactivation of the latent virus. Zoster is characterized by pain that can be long-lasting in some cases and has no satisfactory treatment. Routine varicella vaccination can prevent varicella. The vaccination strategy of replacing both doses of measles, mumps, and rubella (MMR) with a combined MMR and varicella (MMRV) vaccine is a means of reaching high vaccination coverage for varicella immunization. The objective of this analysis was to assess the impact of routine varicella vaccination, with MMRV in place of MMR, on the incidence of varicella and zoster diseases in France and to assess the impact of exogenous boosting of zoster incidence, age shift in varicella cases, and other possible indirect effects. METHODS: A dynamic transmission population-based model was developed using epidemiological data for France to determine the force of infection, as well as an empirically derived contact matrix to reduce assumptions underlying these key drivers of dynamic models. Scenario analyses tested assumptions regarding exogenous boosting, vaccine waning, vaccination coverage, risk of complications, and contact matrices. FINDINGS: The model provides a good estimate of the incidence before varicella vaccination implementation in France. When routine varicella vaccination is introduced with French current coverage levels, varicella incidence is predicted to decrease by 57%, and related complications are expected to decrease by 76% over time. After vaccination, it is observed that exogenous boosting is the main driver of change in zoster incidence. When exogenous boosting is assumed, there is a temporary increase in zoster incidence before it gradually decreases, whereas without exogenous boosting, varicella vaccination leads to a gradual decrease in zoster incidence. Changing vaccine efficacy waning levels and coverage assumptions are still predicted to result in overall benefits with varicella vaccination. IMPLICATIONS: In conclusion, the model predicted that MMRV vaccination can significantly reduce varicella incidence. With suboptimal coverage, a limited age shift of varicella cases is predicted to occur post-vaccination with MMRV. However, it does not result in an increase in the number of complications. GSK study identifier: HO-12-6924.

Cost-effectiveness of routine varicella vaccination using the measles, mumps, rubella and varicella vaccine in France: an economic analysis based on a dynamic transmission model for varicella and herpes zoster.

PURPOSE: Each year in France, varicella and zoster affect large numbers of children and adults, resulting in medical visits, hospitalizations for varicella- and zoster-related complications, and societal costs. Disease prevention by varicella vaccination is feasible, wherein a plausible option involves replacing the combined measles, mumps, and rubella (MMR) vaccine with the combined MMR and varicella (MMRV) vaccine. This study aimed to: (1) assess the cost-effectiveness of adding routine varicella vaccination through MMRV, using different vaccination strategies in France; and (2) address key uncertainties, such as the economic consequences of breakthrough varicella cases, the waning of vaccine-conferred protection, vaccination coverage, and indirect costs. METHODS: Based on the outputs of a dynamic transmission model that used data on epidemiology and costs from France, a cost-effectiveness model was built. A conservative approach was taken regarding the impact of varicella vaccination on zoster incidence by assuming the validity of the hypothesis of an age-specific boosting of immunity against varicella. FINDINGS: The model determined that routine MMRV vaccination is expected to be a cost-effective option, considering a cost-effectiveness threshold of €20,000 per quality-adjusted life-year saved; routine vaccination was cost-saving from the societal perspective. Results were driven by a large decrease in varicella incidence despite a temporary initial increase in the number of zoster cases due to the assumption of exogenous boosting. In the scenario analyses, despite moderate changes in assumptions about incidence and costs, varicella vaccination remained a cost-effective option for France. IMPLICATIONS: Routine vaccination with MMRV was associated with high gains in quality-adjusted life-years, substantial reduction in the occurrences of varicella- and zoster-related complications, and few deaths due to varicella. Routine MMRV vaccination is also expected to provide reductions in costs related to hospitalizations, medication use, and general-practitioner visits, as well as indirect costs, and it is expected to be a cost-effective intervention in France (GSK study identifier: HO-12-6924).

Progression-free survival with fulvestrant 500 mg and alternative endocrine therapies as second-line treatment for advanced breast cancer: a network meta-analysis with parametric survival models.

BACKGROUND: Ouwens et al. and Jansen have presented methods for (network) meta-analysis of survival data by using a multidimensional treatment effect as an alternative to the synthesis of constant hazards ratios, which allow for a better fit to the data and the expected survival of competing interventions for cost-effectiveness analysis. However, results may be sensitive to the assumed underlying survival function. OBJECTIVE: To estimate the expected progression-free survival (PFS) for fulvestrant 500 mg versus alternative hormonal therapies for postmenopausal women with advanced breast cancer who relapsed previously by means of a network meta-analysis of currently available randomized controlled trials using alternative underlying survival functions. METHODS: Eleven randomized controlled trials were included that evaluated fulvestrant 500 mg (n = 3), fulvestrant 250 mg (n = 5), fulvestrant 250 mg loading dose (n = 3), anastrozole 1 mg (n = 3), megestrol acetate (n = 4), letrozole 2.5 mg (n = 3), letrozole 0.5 mg (n = 3), and exemestane (n = 2). PFS percentages and numbers at risk were derived from Kaplan-Meier curves and combined by means of Bayesian network meta-analysis on the basis of the difference in the shape and scale parameters of the Weibull, log-normal, and log-logistic parametric survival functions. RESULTS: The log-normal distribution provided the best fit, suggesting that the proportional hazard assumption was not valid. Based on the difference in expected PFS, it was found that fulvestrant 500 mg is more efficacious than fulvestrant 250 mg, megestrol acetate, and anastrozole (-5.73 months; 95% credible interval [CrI]-10.67,-1.67). Expected PFS for fulvestrant 500 mg ranged from 10.87 (95% CrI 9.21, 13.07) to 17.02 (95% CrI 13.33, 22.02) months for the Weibull versus log-logistic distribution. CONCLUSIONS: Fulvestrant 500 mg is expected to be more efficacious than fulvestrant 250 mg, megestrol acetate, and anastrozole 1 mg and at least as efficacious as exemestane and letrozole 2.5 mg in terms of PFS among postmenopausal women with advanced breast cancer after failure on endocrine therapy. The findings were not sensitive to the distribution, although the expected PFS varied substantially, emphasizing the importance of performing sensitivity analyses.

Systematic review and network meta-analysis of overall survival comparing 3 mg/kg ipilimumab with alternative therapies in the management of pretreated patients with unresectable stage III or IV melanoma.

OBJECTIVE: To compare the overall survival (OS) of patients treated with 3 mg/kg ipilimumab versus alternative systemic therapies in pretreated unresectable stage III or IV melanoma patients. METHODS: A systematic literature search was performed to identify relevant randomized clinical trials. From these trials, Kaplan-Meier survival curves for each intervention were digitized and combined by means of a Bayesian network meta-analysis (NMA) to compare different drug classes. RESULTS: Of 38 trials identified, 15 formed one interlinked network by drug class to allow for an NMA. Ipilimumab, at a dose of 3 mg/kg, was associated with a greater mean OS time (18.8 months; 95% credible interval [CrI], 15.5-23.0 months) than single-agent chemotherapy (12.3 months; 95% CrI, 6.3-28.0 months), chemotherapy combinations (12.2 months; 95% CrI, 7.1-23.3 months), biochemotherapies (11.9 months; 95% CrI, 7.0-22.0 months), single-agent immunotherapy (11.1 months; 95% CrI, 8.5-16.2 months), and immunotherapy combinations (14.1 months; 95% CrI, 9.0-23.8 months). CONCLUSION: Results of this NMA were in line with previous findings and suggest that OS with ipilimumab is expected to be greater than with alternative systemic therapies, alone or in combination, for the management of pretreated patients with unresectable stage III or IV melanoma.

Efficacy of once-daily indacaterol relative to alternative bronchodilators in COPD: a patient-level mixed treatment comparison.

OBJECTIVE: Indacaterol was evaluated versus placebo, formoterol, and salmeterol in randomized controlled trials. No direct comparisons, however, are available for indacaterol 150 µg with formoterol or indacaterol 300 µg with salmeterol. Indacaterol trial evidence was synthesized to provide coherent estimates of indacaterol 150 µg and indacaterol 300 µg relative to formoterol, salmeterol, and tiotropium. METHODS: Four randomized controlled trials were combined with Bayesian mixed treatment comparisons by using individual patient-level data. End points of interest were trough forced expiratory volume in 1 second (FEV(1)), St. George's Respiratory Questionnaire (SGRQ) total score and response (≥ 4 points), and Transition Dyspnea Index total score and response (≥ 1 point). RESULTS: Indacaterol 150 µg demonstrated a higher FEV(1) than did formoterol at 12 weeks and 6 months (0.10 L difference; 95% credible interval [CrI] = 0.06-0.14), as did indacaterol 300 µg versus salmeterol (0.06 L difference at 12 weeks; CrI = 0.02-0.10; 0.06 L at 6 months; CrI = 0.02-0.11). Regarding SGRQ, indacaterol 150 µg demonstrated a comparable proportion of responders versus formoterol, as did indacaterol 300 µg versus salmeterol. In comparison to tiotropium, indacaterol 150 µg demonstrated a greater proportion of responders (odds ratio = 1.52 at 12 weeks; CrI 1.15-2.00). For Transition Dyspnea Index, indacaterol 150 µg and formoterol showed a similar response. Indacaterol 300 µg was more efficacious than salmeterol (odds ratio = 1.65 at 12 weeks; CrI 1.16-2.34). Overall, indacaterol 150 µg showed the greatest efficacy for SGRQ and indacaterol 300 µg for FEV(1) and Transition Dyspnea Index. CONCLUSION: Indacaterol is expected to be comparable to formoterol, salmeterol, and tiotropium, providing higher FEV(1) than formoterol and salmeterol and greater improvement in the SGRQ total score than tiotropium. Indacaterol 150 µg provided comparable improvement in dyspnea, while indacaterol 300 µg demonstrated the greatest response overall.

Enhanced secondary analysis of survival data: reconstructing the data from published Kaplan-Meier survival curves.

BACKGROUND: The results of Randomized Controlled Trials (RCTs) on time-to-event outcomes that are usually reported are median time to events and Cox Hazard Ratio. These do not constitute the sufficient statistics required for meta-analysis or cost-effectiveness analysis, and their use in secondary analyses requires strong assumptions that may not have been adequately tested. In order to enhance the quality of secondary data analyses, we propose a method which derives from the published Kaplan Meier survival curves a close approximation to the original individual patient time-to-event data from which they were generated. METHODS: We develop an algorithm that maps from digitised curves back to KM data by finding numerical solutions to the inverted KM equations, using where available information on number of events and numbers at risk. The reproducibility and accuracy of survival probabilities, median survival times and hazard ratios based on reconstructed KM data was assessed by comparing published statistics (survival probabilities, medians and hazard ratios) with statistics based on repeated reconstructions by multiple observers. RESULTS: The validation exercise established there was no material systematic error and that there was a high degree of reproducibility for all statistics. Accuracy was excellent for survival probabilities and medians, for hazard ratios reasonable accuracy can only be obtained if at least numbers at risk or total number of events are reported. CONCLUSION: The algorithm is a reliable tool for meta-analysis and cost-effectiveness analyses of RCTs reporting time-to-event data. It is recommended that all RCTs should report information on numbers at risk and total number of events alongside KM curves.

Survival time outcomes in randomized, controlled trials and meta-analyses: the parallel universes of efficacy and cost-effectiveness.

OBJECTIVES: Many regulatory agencies require that manufacturers establish both efficacy and cost-effectiveness. The statistical analysis of the randomized, controlled trial (RCT) outcomes should be the same for both purposes. The question addressed by this article is the following: for survival outcomes, what is the relationship between the statistical analyses used to support inference and the statistical model used to support decision making based on cost-effectiveness analysis (CEA)? METHODS: We performed a review of CEAs alongside trials and CEAs based on a synthesis of RCT results, which were submitted to the National Institute for Health and Clinical Excellence (NICE) Technology Appraisal program and included survival outcomes. We recorded the summary statistics and the statistical models used in both efficacy and cost-effectiveness analyses as well as procedures for model diagnosis and selection. RESULTS: In no case was the statistical model for efficacy and CEA the same. For efficacy, relative risks or Cox regression was used. For CEA, the common practice was to fit a parametric model to the control arm, then to apply the hazard ratio from the efficacy analysis to predict the treatment arm. The proportional hazards assumption was seldom checked; the choice of model was seldom based on formal criteria, and uncertainty in model choice was seldom addressed and never propagated through the model. CONCLUSIONS: Both inference and decisions based on CEAs should be based on the same statistical model. This article shows that for survival outcomes, this is not the case. In the interests of transparency, trial protocols should specify a common procedure for model choice for both purposes. Further, the sufficient statistics and the life tables for each arm should be reported to improve transparency and to facilitate secondary analyses of results of RCTs.

Network meta-analysis of parametric survival curves.

To inform health-care decision-making, treatments are often compared by synthesizing results from a number of randomized controlled trials. The meta-analysis may not only be focused on a particular pairwise comparison, but can also include multiple treatment comparisons by means of network meta-analysis. For time-to-event outcomes such as survival, pooling is typically based on the hazard ratio (HR). The proportional hazards assumption that underlies current approaches of evidence synthesis is not only often implausible, but can also have a huge impact on decisions based on differences in expected outcomes, such as cost-effectiveness analysis. The application of a constant HR implies the assumption that the treatment only has an effect on one characteristic of the survival distribution, while commonly used survival distributions, like the Weibull distribution, have both a shape and a scale parameter. Instead of using constant HRs, this paper proposes meta-analysis of treatment effects based on the shape and scale parameters of parametric survival curves. The model for meta-analysis is extended for network meta-analysis and illustrated with an example. Copyright © 2011 John Wiley & Sons, Ltd.

Maximin D-optimal designs for longitudinal mixed effects models.

In this article, the optimal selection and allocation of time points in repeated measures experiments is considered. D-optimal cohort designs are computed numerically for the first- and second-degree polynomial models with random intercept, random slope, and first-order autoregressive serial correlations. Because the optimal designs are locally optimal, it is proposed to use a maximin criterion. It is shown that, for a large class of symmetric designs, the smallest relative efficiency over the model parameter space is substantial.