Cross-disciplinary mathematical modelling to benefit healthcare - could clinical pharmacology play an enabling role?

Clinical pharmacology is often the nexus in any cross-disciplinary team that is seeking solutions for human healthcare issues. The use and application of real-world data and artificial intelligence to better understand our ecosystem has influenced our view at the world and how we do things. This has resulted in remarkable advancements in the healthcare space and development of personalized medicines with great attributes from the application of models and simulations, contributing to a more efficient healthcare development process. A cross-disciplinary symposium was held in December 2023, whereby experts from different scientific disciplines engaged in a high-level discussion on the opportunities and challenges of mathematical models in different fields, possible future developments and decision making. A strong interlink amongst the disciplines represented was apparent, with clinical pharmacology identified as the one which integrates various scientific disciplines. Deliberate and strategic cross-disciplinary dialogues are required to break out of the silos and implement integration for efficiency and cost-effectiveness of novel interventions.

Pharmacokinetic parameter driven outcomes model predicts a reduction in bleeding events associated with BAY 81-8973 versus antihemophilic factor (recombinant) plasma/albumin-free method in a Chinese healthcare setting.

BACKGROUND: Long-term prophylactic therapy is considered the standard of care for hemophilia A patients. This study models the long-term clinical and cost outcomes of two factor VIII (FVIII) products using a pharmacokinetic (PK) simulation model in a Chinese population. METHODS: Head-to-head PK profile data of BAY 81-8973 (KOVALTRY®) and antihemophilic factor (recombinant) plasma/albumin-free method (rAHF-PFM, ADVATE®) were applied to a two-state (alive and dead) Markov model to simulate blood FVIII concentrations at a steady state in prophylactically-treated patients with hemophilia A. Worsening of the Pettersson score was simulated and decline was associated with the probability of having orthopaedic surgery. The only difference between the compounds was FVIII concentration at a given time; each subject was treated with 25 IU/kg every 3 days. The model used a lifetime horizon, with cycle lengths of 1 year. RESULTS: Cumulative bleeding events, joint bleeding events, and major bleeding events were reduced by 19.3% for BAY 81-8973 compared to rAHF-PFM. Hospitalizations and hospitalization days were also reduced by 19.3% for BAY 81-8973 compared to rAHF-PFM. BAY 81-8973 resulted in both cost savings and a gain in quality adjusted life years (QALYs) compared to rAHF-PFM. CONCLUSION: Based on modeled head-to-head comparisons, differences in PK-properties between BAY 81-8973 and rAHF-PFM result in a reduced number of bleeding events, leading to reduced costs and increased quality of life for BAY 81-8973. These results should be used to inform clinical practice in China when caring for patients with severe hemophilia A.

Quality-adjusted survival with first-line cabozantinib or sunitinib for advanced renal cell carcinoma in the CABOSUN randomized clinical trial (Alliance).

BACKGROUND: Cabozantinib Versus Sunitinib as Initial Targeted Therapy for Patients With Metastatic Renal Cell Carcinoma of Poor or Intermediate Risk: The Alliance A031203 CABOSUN Trial (CABOSUN) was a randomized, open-label, phase 2 trial evaluating first-line cabozantinib versus sunitinib in patients with advanced renal cell carcinoma (aRCC). This post hoc analysis evaluated quality-adjusted survival using Quality-adjusted Time Without Symptoms of disease or Toxicity of treatment (Q-TWiST). METHODS: Survival plots for cabozantinib and sunitinib (650-day follow-up) were partitioned into 3 health states: time spent before disease progression without toxicity (TWiST; toxicity based on National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0] grade 3/4 adverse events), time spent before disease progression with toxicity (TOX; durations of adverse events based on published literature), and time after disease recurrence (relapse) or progression to death (REL). Q-TWiST was the sum of the mean time spent in each state, with each state weighted to reflect patient preferences (from 0 [worst] to 1 [best]) using utility scores. TWiST was always weighted as 1. Overall survival and time to disease progression were based on all randomized patients (157 patients); TOX was based on all randomized and treated patients (150 patients). RESULTS: Across all utility combinations tested, Q-TWiST was found to be longer with cabozantinib versus sunitinib (range of differences, +24 days to +137 days). Q-TWiST differences that were found to be statistically significant (+92 days [95% confidence interval, 5-178 days] to +137 days [95% confidence interval, 60-214 days]) were of a clinically meaningful effect size (≥80 days), and were based on utility values that included those considered relevant for patients with aRCC (REL utility weight of 0.355, TOX utility weight of 0-1, and TWiST utility weight of 1). CONCLUSIONS: In patients with aRCC, first-line cabozantinib was found to provide longer quality-adjusted survival compared with sunitinib. These findings may help to inform clinical decision making. LAY SUMMARY: Cabozantinib and sunitinib are drugs that are used to treat patients with advanced kidney cancer. Clinical trials have shown that cabozantinib offers benefits over sunitinib, giving patients more time before their cancer progresses. It is important that this additional time before disease progression does not come at the expense of patients' quality of life, which can be affected by treatment side effects and/or ongoing cancer symptoms. Both quantity and quality of life are central to optimal treatment. In the current analysis of patients with advanced kidney cancer who were initiating treatment for the first time, cabozantinib provided more quality time before cancer progression compared with sunitinib.

Empirical Testing of Alternative Search Methods to Retrieve Utility Values for Health Economic Modelling.

OBJECTIVES: The objective of this study is to compare different information retrieval methods that can be used to identify utility inputs for health economic models. METHODS: The usual practice of using systematic review methods was compared with two alternatives (iterative searching and rapid review), using a health technology assessment (HTA) case study in ulcerative colitis (UC). We analysed whether there were differences in the utility values identified when using the alternative search methods. Success was evaluated in terms of time, burden and relevance of identified information. The identified utility values were tested in an executable health economic model developed for UC, and the model results were compared. RESULTS: The usual practice of using systematic review search approaches identified the most publications but was also the least precise method and took longest to complete. The inclusion of data from the different search methods in the model did not lead to different conclusions across search methods. CONCLUSIONS: In this case study, usual practice was less efficient and resulted in the same health economic model conclusions as the alternative search methods. Further case studies are required to examine whether this conclusion might be generalisable.

Second-line cabozantinib versus nivolumab in advanced renal cell carcinoma: Systematic review and indirect treatment comparison.

BACKGROUND: Nivolumab and cabozantinib, two new treatment options for previously-treated advanced/metastatic renal cell carcinoma (aRCC), have recently been approved. METHODS: Two independent reviewers performed study selection, data extraction, and risk of bias assessment. Indirect treatment comparisons were carried out by directly assessing HR differences and statistical modeling of Kaplan-Meier curves from these two trials. RESULTS: Publications identified showed that no head-to-head comparisons had been carried out. Two indirect treatment comparisons used agreed that there was no significant difference in OS between cabozantinib and nivolumab and that cabozantinib significantly improved PFS compared to nivolumab. CONCLUSIONS: The field of aRCC treatments is evolving rapidly, creating opportunities for individualized treatments and challenges for clinicians to keep up with the evidence. In lieu of availability of direct comparisons of all options, advanced modeling results presented herein can help to inform and improve personalized treatments.

Cost-effectiveness of overactive bladder treatments: from the US payer perspective.

AIM: To assess the cost-effectiveness of onabotulinumtoxinA (onabotA), implantable sacral nerve stimulation devices, percutaneous tibial nerve stimulation, anticholinergic medications and mirabegron compared with best supportive care (BSC) for management of refractory overactive bladder (OAB). METHODS: A Markov model was developed to compare the cost-effectiveness of treatment options with BSC over a 10-year time horizon. Resource utilization, discontinuation rates and costs were derived from unpublished and published sources. Quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios were reported. RESULTS: Treatment with onabotA 100U produced the largest gain in QALYs (7.179) and lowest estimated incremental cost-effectiveness ratio ($32,680/QALY) of all assessed treatments compared with BSC. CONCLUSION: Compared with BSC, onabotA 100U was the most cost-effective treatment option for patients with refractory OAB.

Cost-effectiveness comparison of cabozantinib with everolimus, axitinib, and nivolumab in the treatment of advanced renal cell carcinoma following the failure of prior therapy in England.

PURPOSE: The aim of this study was to compare the cost-effectiveness of cabozantinib with the standard of care in England in adult patients with advanced renal cell carcinoma (aRCC), following prior vascular endothelial growth factor receptor (VEGFR)-targeted therapy. METHODS: We developed a partitioned-survival model with three health states to assess the cost-effectiveness of cabozantinib and its comparators. The model time horizon was 30 years. Efficacy and safety data were derived from pivotal clinical trials (METEOR: NCT01865747, CheckMate025: NCT01668784, and AXIS: NCT00678392). METEOR data were used for a direct comparison of cabozantinib and everolimus. Cabozantinib and nivolumab were compared indirectly, whereas equal efficacy for axitinib and everolimus was assumed based on a previously published expert opinion. For all efficacy endpoints, the best-fitting log-logistic or fractional polynomial curves were used to estimate outcomes. Utilities were converted from the 5-level EQ-5D version instrument applied during the METEOR study for specific health states. Reductions in utility scores due to adverse events were applied. English costs (eg, drug prices) and resource use (eg, visit to consultant) data were used. RESULTS: The total treatment cost was estimated to be 84,136 Great British Pounds (GBP) per patient treated with cabozantinib. The health gains were 2.26 life-years (LYs) and 1.78 quality-adjusted LYs (QALYs). The incremental cost-effectiveness ratios (ICERs) versus axitinib and everolimus were 98,967 GBP/QALY and 137,450 GBP/QALY, respectively. Cabozantinib was less costly and more effective than nivolumab; the incremental cost was -6,742 GBP and the QALY difference was 0.18. CONCLUSION: Treatment with cabozantinib was more effective than treatment with axitinib or everolimus but was associated with higher total costs. When compared with nivolumab, cabozantinib represents an efficient option with nominally better efficacy and lower costs.

Cabozantinib Versus Standard-of-Care Comparators in the Treatment of Advanced/Metastatic Renal Cell Carcinoma in Treatment-naïve Patients: a Systematic Review and Network Meta-Analysis.

BACKGROUND: Cabozantinib has recently been evaluated as a first-line treatment in advanced renal cell carcinoma (aRCC). OBJECTIVE: To indirectly assess efficacy of cabozantinib versus standard-of-care (SoC) comparators in the first-line treatment of aRCC. METHODS: We conducted a systematic literature review (SLR) to identify randomized controlled studies in the first-line setting for aRCC. The outcomes analyzed were overall survival (OS) and progression-free survival (PFS). A network meta-analysis (NMA) was conducted comparing OS and PFS hazard ratios (HRs). RESULTS: Thirteen studies were identified in the SLR to be eligible for inclusion in the NMA. The overall study populations were heterogeneous in terms of risk groups; some studies included favorable risk patients. In intermediate-risk patients, HRs (95% confidence interval) for PFS were 0.52 (0.33, 0.82), 0.46 (0.26, 0.80), 0.20 (0.12, 0.36), and 0.37 (0.20, 0.68) when cabozantinib was compared with sunitinib, sorafenib, interferon (IFN), or bevacizumab plus IFN, respectively. In poor-risk patients, the NMA also demonstrated significant superiority in terms of PFS for cabozantinib; HRs were 0.31 (0.11, 0.90), 0.22 (0.06, 0.87), 0.16 (0.04, 0.64), and 0.20 (0.05, 0.88), when cabozantinib was compared with sunitinib, temsirolimus, IFN, or bevacizumab plus IFN, respectively. When the overall study populations were compared, the results were similar to the subgroup analyses. OS HRs in all analyses favored cabozantinib, but were not statistically significant. CONCLUSIONS: The results suggest that cabozantinib significantly increases PFS in intermediate-, and poor-risk subgroups when compared to standard-of-care comparators. Although overall populations included favorable risk patients in some studies, the results seen were consistent with the subgroup analyses.

Cabozantinib versus everolimus, nivolumab, axitinib, sorafenib and best supportive care: A network meta-analysis of progression-free survival and overall survival in second line treatment of advanced renal cell carcinoma.

BACKGROUND: Relative effect of therapies indicated for the treatment of advanced renal cell carcinoma (aRCC) after failure of first line treatment is currently not known. The objective of the present study is to evaluate progression-free survival (PFS) and overall survival (OS) of cabozantinib compared to everolimus, nivolumab, axitinib, sorafenib, and best supportive care (BSC) in aRCC patients who progressed after previous VEGFR tyrosine-kinase inhibitor (TKI) treatment. METHODOLOGY & FINDINGS: Systematic literature search identified 5 studies for inclusion in this analysis. The assessment of the proportional hazard (PH) assumption between the survival curves for different treatment arms in the identified studies showed that survival curves in two of the studies did not fulfil the PH assumption, making comparisons of constant hazard ratios (HRs) inappropriate. Consequently, a parametric survival network meta-analysis model was implemented with five families of functions being jointly fitted in a Bayesian framework to PFS, then OS, data on all treatments. The comparison relied on data digitized from the Kaplan-Meier curves of published studies, except for cabozantinib and its comparator everolimus where patient level data were available. This analysis applied a Bayesian fixed-effects network meta-analysis model to compare PFS and OS of cabozantinib versus its comparators. The log-normal fixed-effects model displayed the best fit of data for both PFS and OS, and showed that patients on cabozantinib had a higher probability of longer PFS and OS than patients exposed to comparators. The survival advantage of cabozantinib increased over time for OS. For PFS the survival advantage reached its maximum at the end of the first year's treatment and then decreased over time to zero. CONCLUSION: With all five families of distributions, cabozantinib was superior to all its comparators with a higher probability of longer PFS and OS during the analyzed 3 years, except with the Gompertz model, where nivolumab was preferred after 24 months.

OnabotulinumtoxinA in the treatment of overactive bladder: a cost-effectiveness analysis versus best supportive care in England and Wales.

The cost-effectiveness of onabotulinumtoxinA (BOTOX(®)) 100 U + best supportive care (BSC) was compared with BSC alone in the management of idiopathic overactive bladder in adult patients who are not adequately managed with anticholinergics. BSC included incontinence pads and, for a proportion of patients, anticholinergics and/or occasional clean intermittent catheterisation. A five-state Markov model was used to estimate total costs and outcomes over a 10-year period. The cohort was based on data from two placebo-controlled trials and a long-term extension study of onabotulinumtoxinA. After discontinuation of initial treatment, a proportion of patients progressed to downstream sacral nerve stimulation (SNS). Cost and resource use was estimated from a National Health Service perspective in England and Wales using relevant reference sources for 2012 or 2013. Results showed that onabotulinumtoxinA was associated with lower costs and greater health benefits than BSC in the base case, with probabilistic sensitivity analysis indicating an 89 % probability that the incremental cost-effectiveness ratio would fall below £20,000. OnabotulinumtoxinA remained dominant over BSC in all but two scenarios tested; it was also economically dominant when compared directly with SNS therapy. In conclusion, onabotulinumtoxinA appears to be a cost-effective treatment for overactive bladder compared with BSC alone.

Simulation and comparison of progression-free survival among patients with non-squamous non-small-cell lung cancer receiving sequential therapy.

OBJECTIVES: In recent years, the treatment landscape in advanced non-squamous non-small-cell lung cancer (nsNSCLC) has changed. New therapies (e.g., bevacizumab indicated in first line) have become available and other therapies (e.g., pemetrexed in first line and second line) moved into earlier lines in the treatment paradigm. While there has been an expansion of the available treatment options, it is still a key research question which therapy sequence results in the best survival outcomes for patients with nsNSCLC. METHODS: A therapy-sequencing disease model that approximates treatment outcomes in up to five lines of treatment was developed for patients with nsNSCLC. The primary source of data for progression-free survival (PFS) and time to death was published pivotal trial data. All patients were treatment-naïve and in the PFS state, received first-line treatment with either bevacizumab-based therapy or doublet chemotherapy (including the option of pemetrexed + cisplatin). Patients would then progress to a subsequent line of therapy, remain in PFS or die. In case of progression, it was assumed that each survivor would receive a subsequent line of therapy, based on EMA licensed therapies. Weibull distribution curves were fitted to the data. RESULTS: All bevacizumab-based first-line therapy sequences analyzed achieved total PFS of around 15 months. Bevacizumab + carboplatin + paclitaxel (first line) → pemetrexed (second line) → erlotinib (third line) → docetaxel (fourth line) resulted in total mean PFS time of 15.7 months, for instance. Sequences with pemetrexed in combination with cisplatin in first line achieved total PFS times between 12.6 and 12.8 months with a slightly higher total PFS time achieved when assuming pemetrexed continuation therapy in maintenance after pemetrexed + cisplatin in first-line induction. Overall survival results followed the same trend as PFS. CONCLUSION: The model suggests that treatment-sequencing strategies starting with a bevacizumab-based combination in first line yield better survival outcomes than those starting with pemetrexed-based combinations, a result that is attributable to the possibility of one further line of treatment with first-line bevacizumab-based treatment sequences.

Societal savings in patients with advanced non-squamous non-small-cell lung cancer receiving bevacizumab-based versus non-bevacizumab-based treatments in France, Germany, Italy, and Spain.

BACKGROUND: The purpose of this study was to investigate the savings accrued using bevacizumab-based treatment for non-small-cell lung cancer from the societal perspective, taking only public costs into account, in France, Germany, Italy, and Spain. METHODS: Societal costs were estimated by collecting and analyzing labor costs, carer costs, sickness benefits, disability benefits, and home care benefits. Cost inputs were derived from publicly available databases or from the published literature. Expert opinion was only used if no other source was available. Efficacy data from two randomized clinical trials were used. The time horizon in the health economic model was lifetime. Efficacy and costs were discounted by 3.5%. All main model parameters were tested in deterministic and probabilistic sensitivity analyses. RESULTS: Mean incremental savings to society per patient ranged from €2277 in Italy to €4461 in Germany. The results were most sensitive to the change in proportion of patients working fulltime and the proportion of patients who were able to return to work. CONCLUSION: This analysis shows that bevacizumab-based treatment in non-small-cell lung cancer is associated with more savings to society compared to standard chemotherapy in terms of increased productivity and decreased social benefits paid to patients who are able to work in France, Germany, Italy, and Spain.

Clinical and cost effectiveness of bevacizumab + FOLFIRI combination versus FOLFIRI alone as first-line treatment of metastatic colorectal cancer in South Korea.

BACKGROUND: Bevacizumab has been extensively investigated in combination with various standard chemotherapies in the treatment of metastatic colorectal cancer (mCRC). However, a comparison to irinotecan + infusional 5-fluorouracil/leucovorin (FOLFIRI) is lacking. OBJECTIVE: To explore clinical effectiveness and cost-effectiveness of adding bevacizumab to a regimen of FOLFIRI for the first-line treatment of mCRC in the Republic of Korea by conducting an indirect treatment comparison. METHODS: A health-economic model was developed to investigate the possible health outcomes (life-years gained [LYG]), direct costs, and incremental cost-effectiveness ratio (ICER) of adding bevacizumab to a FOLFIRI regimen. Data on progression-free and overall survival were derived from randomized clinical trials and were used in the indirect treatment comparison. The annual discount rate for costs and outcomes was 5%. A lifetime horizon of 8 years was used. Sensitivity analyses were carried out on all pivotal model assumptions. RESULTS: Incremental mean overall survival among patients treated with bevacizumab + FOLFIRI varied between 8.6 and 15.7 months compared with patients treated with FOLFIRI alone. The deterministic base-case result was 1.177 LYG. The discounted ICERs ranged from µ31.8 to µ39.5 million/LYG, with the base-case result being µ34.5 million/LYG. Treatment effect had the most impact on the outcomes in this model. CONCLUSIONS: Although there is no formal threshold for ICER per LYG in Korea, funding may be considered for bevacizumab + FOLFIRI, particularly if the severity and end-of-life nature of mCRC is taken into account.

Cost-effectiveness of bevacizumab-based therapy versus cisplatin plus pemetrexed for the first-line treatment of advanced non-squamous NSCLC in Korea and Taiwan.

AIMS: The aim of this analysis is to investigate the mean incremental costs and life expectancy associated with two first-line treatments for advanced non-squamous non-small cell lung cancer (NSCLC) in Korea and Taiwan; bevacizumab plus cisplatin and gemcitabine (BevCG) and cisplatin plus pemetrexed (CP). METHODS: A health economic (area under curve) model with three health states was developed to assess health outcomes (life-years gained [LYG]), direct costs, and incremental cost-effectiveness ratio (ICER). Progression-free survival (PFS) and overall survival (OS) were derived from randomized clinical trials and used in an indirect comparison in order to estimate their cost effectiveness. A life-time horizon was used. Costs and outcomes were discounted yearly by 5% in Korea and by 3% in Taiwan. RESULTS: The incremental LYG for the BevCG patients compared with patients treated with CP were 1.10 (13.2 months) in Korea and 1.19 (14.3 months) in Taiwan. The incremental costs were 37,439,968 ($ 33,322) in Korea and NT$ 1,910,615 ($ 64,541) in Taiwan. The incremental cost-effectiveness ratio was 34,064,835 ($ 30,318) in Korea and NT$ 1,607,960 ($ 54,317) in Taiwan. The inputs tested in one-way sensitivity analyses had very little impact on the overall cost effectiveness. CONCLUSION: This analysis shows that BevCG is more costly but is also associated with additional life-years in Korea and Taiwan. The ICER per LYG suggests that BevCG is a cost-effective therapy when compared to CP for patients with advanced NSCLC in Korea and Taiwan.