Linked Pharmacometric-Pharmacoeconomic Modeling and Simulation in Clinical Drug Development

Kinetic Modeling for BT200 to Predict the Level of Plasma-Derived Coagulation Factor VIII in Humans

Lack of Factor VIII (FVIII) concentrates is one of limiting factors for Hemophilia A prophylaxis in resource-limited countries. Rondaptivon pegol (BT200) is a pegylated aptamer and has been shown to elevate the level of von Willebrand Factor (VWF) and FVIII in previous studies. A population pharmacokinetic model for BT200 was built and linked to the kinetic models of VWF and FVIII based on reasonable assumptions. The developed PK/PD model for BT200 described the observed kinetic of BT200, VWF, and FVIII in healthy volunteers and patients with mild-to-moderate hemophilia A from two clinical trials. The developed model was evaluated using an external dataset in patients with severe hemophilia A taking recombinant FVIII products. The developed and evaluated PK/PD model was able to describe and predict concentration-time profiles of BT200, VWF, and FVIII in healthy volunteers and patients with hemophilia A. Concentration-time profiles of FVIII were then predicted following coadministration of plasma-derived FVIII concentrate and BT200 under various dosing scenarios in virtual patients with severe hemophilia A. Plasma-derived products, that contain VWF, are more accessible in low-resource countries as compared to their recombinant counterparts. The predicted time above 1 and 3 IU/dL FVIII in one week was compared between scenarios in the absence and presence of BT200. A combination dose of 6 mg BT200 once weekly plus 10 IU/kg plasma-derived FVIII twice weekly maintained similar coverage to a 30 IU/kg FVIII thrice weekly dose in absence of BT200, representing only 22% of the FVIII dose per week.

Cost-utility analysis of add-on vericiguat for the treatment of chronic heart failure with reduced ejection fraction in China

OBJECTIVE

This study aimed to evaluate the cost-utility of the addition of vericiguat for treating chronic heart failure (CHF) in China from the healthcare payer's perspective.

METHODS

A Markov model was built to estimate the cost and utility of treating CHF using vericiguat plus standard treatment (vericiguat group) vs. standard treatment alone (standard treatment group). The clinical parameters (mortality of cardiovascular and hospitalization rate of HF) were calculated according to the VICTORIA clinical trial. The HF cost and utility data were obtained from the literature published in China. One-way sensitivity analysis and probability sensitivity analysis were performed.

RESULTS

According to the 13-year model, vericiguat was more expensive (155599.07 CNY vs. 259396.83 CNY) and more effective (4.41 QALYs vs. 4.54 QALYs). The incremental cost-utility ratio (ICUR) was 802389.27 CNY per QALY. One-way sensitivity analysis revealed that cardiovascular mortality in the two groups was the parameter that had the greatest impact on the results. The GDP per capita in 2022 in China was 85,700 CNY. The probability sensitivity analysis (PSA) showed that the probability of vericiguat being cost-effective was only 41.7% at the willingness-to-pay (WTP) threshold of 3 times GDP per capita (257,100 CNY).

CONCLUSIONS

In China, the treatment of CHF with vericiguat is not cost-effective. The drug price could decrease to 145.8 CNY, which could be considered cost-effective.

Sponsorship bias in published pharmacoeconomic evaluations of national reimbursement negotiation drugs in China: a systematic review

BACKGROUND

China's National Reimbursement Drug List (NRDL) has become the primary route for drug reimbursement in China. More recently, the authority has made pharmacoeconomic evaluation an integral part of the application for NRDL inclusion. The underlying financial conflict of interests (FCOI) of pharmacoeconomic evaluations, however, has the potential to influence evidence generated and thus subsequent decision-making yet remains poorly understood.

METHODS

We searched for studies published between January 2012 and January 2022 on the 174 drugs added to the 2017-2020 NRDLs after successful negotiation. We categorised the study's FCOI status into no funding, industry funding, non-profit funding and multiple fundings based on authors' disclosure and assessed the reporting quality of included studies using the Consolidated Health Economic Evaluation Reporting Standards 2022 checklist. We compiled descriptive statistics of funding types and study outcomes using t-tests and χ2 tests and conducted multivariate regression analysis.

RESULTS

We identified 378 records and our final sample included 92 pharmacoeconomic evaluations, among which 69.6% were conducted with at least one funding source. More than half (57.6%) of the evaluations reached favourable conclusions towards the intervention drug and 12.6% reached a dominant result of the intervention drug over the comparison from model simulation. The reporting quality of included studies ranged from 19 to 25 (on a scale of 28), with an average of 22.3. The statistical tests indicated that industry-funded studies were significantly more likely to conclude that the intervention therapy was economical (p<0.01) and had a significantly higher proportion of resulting target drug economically dominated the comparison drug (p<0.05).

CONCLUSION

The study revealed that FCOI bias is common in published pharmacoeconomic evaluations conducted in Chinese settings and could significantly influence the study's economical results and conclusions through various mechanisms. Multifaceted efforts are needed to improve transparency, comparability and reporting standardisation.

Frameworks for Health Technology Assessment at an Early Stage of Product Development: A Review and Roadmap to Guide Applications

OBJECTIVES

Early health technology assessment (eHTA) can be used to evaluate and optimize a medical product's value proposition and to inform go/no-go decisions by using health economic modeling, literature scanning, and stakeholder preference studies at an early stage of development. eHTA frameworks offer high-level guidance on conducting this complex, iterative, and multidisciplinary process. The objective of this study was to review and summarize existing eHTA frameworks, understood as systematic approaches to guide early evidence generation and decision making.

METHODS

Using a rapid review methodology, we identified all relevant studies published in English, French, and Spanish from PubMed/MEDLINE and Embase until February 2022. We only included frameworks relevant to the preclinical and early clinical (phase I) stages of medical product development.

RESULTS

From 737 reviewed abstracts, 53 publications describing 46 frameworks were selected for inclusion and classified into categories based on their scope: (1) criteria frameworks, which provide an overview of eHTA; (2) process frameworks, which offer stepwise guidance for conducting eHTA, including preferred methods; and (3) methods frameworks, which provide detailed descriptions of specific eHTA methods. Most of the frameworks did not specify their target users or the specific stage of technology development.

CONCLUSIONS

Despite some variability and gaps found across existing frameworks, the structure provided by this review helps inform eHTA applications. Remaining challenges are the frameworks' limited accessibility to users without a background in health economics, poor distinctions being made among early lifecycle stages and technology types, and the inconsistent terminology used to describe eHTA in different contexts.

Methods for Extrapolating Survival Analyses for the Economic Evaluation of Advanced Therapy Medicinal Products

There are two significant challenges for analysts conducting economic evaluations of advanced therapy medicinal products (ATMPs): (i) estimating long-term treatment effects in the absence of mature clinical data, and (ii) capturing potentially complex hazard functions. This review identifies and critiques a variety of methods that can be used to overcome these challenges. The narrative review is informed by a rapid literature review of methods used for the extrapolation of survival analyses in the economic evaluation of ATMPs. There are several methods that are more suitable than traditional parametric survival modelling approaches for capturing complex hazard functions, including, cure-mixture models and restricted cubic spline models. In the absence of mature clinical data, analysts may augment clinical trial data with data from other sources to aid extrapolation, however, the relative merits of employing methods for including data from different sources is not well understood. Given the high and potentially irrecoverable costs of making incorrect decisions concerning the reimbursement or commissioning of ATMPs, it is important that economic evaluations are correctly specified, and that both parameter and structural uncertainty associated with survival extrapolations are considered. Value of information analyses allow for this uncertainty to be expressed explicitly, and in monetary terms.

An Integrated Pharmacokinetic-Pharmacodynamic-Pharmacoeconomic Modeling Method to Evaluate Treatments for Adults with Schizophrenia

INTRODUCTION

Schizophrenia is a chronic mental disorder that worsens with each relapse. Long-acting injectable (LAI) antipsychotics may prevent the exacerbation of symptoms and occurrence of relapses through improved continuity of care. Different dose regimens are available for the LAIs aripiprazole monohydrate (AM) and aripiprazole lauroxil (AL), but their cost effectiveness is unclear.

OBJECTIVES

The study aim was to compare costs and effects (relapses) of the different aripiprazole LAI dose regimens to inform clinical and US payer decisions.

METHODS

A state-transition model calculated the outcomes of eight LAI dose regimens based on their relapse rates. As effectiveness data from randomized controlled trials were unavailable, relapse rates were modeled using pharmacokinetic and pharmacodynamic evidence. These described blood plasma levels of aripiprazole as a function of AM and AL dose regimens and described the probability of relapse as a function of aripiprazole blood plasma levels. The analysis had a time horizon of 1 year and took the US healthcare payer perspective. The incremental cost per relapse avoided and the probability of cost effectiveness were calculated in deterministic and probabilistic analyses. Scenario analyses explored the model's main assumptions, and results were validated against external data and other cost-effectiveness analyses.

RESULTS

Monthly administration of AM 400 mg consistently yielded the lowest predicted number of relapses across deterministic, probabilistic, and scenario analyses. The costs of treatment and relapses were projected to be the lowest with a monthly administration of AL 441 mg. The incremental cost per relapse avoided with AM 400 mg ranged from AM 400 mg being dominant to $US83,300. From willingness-to-pay thresholds of $US30,000 per relapse avoided, the probability of cost effectiveness was highest for AM 400 mg. The validation showed alignment with external data.

CONCLUSION

The analysis highlighted the robustness of the novel framework based on pharmacokinetic and pharmacodynamic evidence and demonstrated an application in a postmarketing setting.

Population pharmacokinetic-pharmacodynamic model-based exploration of alternative ustekinumab dosage regimens for patients with Crohn's disease

AIMS

In the UNITI endoscopy sub-study, only 17.4% of patients with Crohn's disease (CD) on ustekinumab achieved endoscopic response and 10.9% of patients achieved endoscopic remission at week (w)44. We aimed to evaluate the impact of alternative ustekinumab dosage regimens on endoscopic outcomes based on population pharmacokinetic-pharmacodynamic (popPK-PD) modelling and simulation analysis.

METHODS

Real-world data were obtained from 83 patients with moderate-to-severe CD (95% biological-refractory) enrolled in a prospective cohort study receiving intravenous ustekinumab (~6 mg/kg) followed by every eight-week (q8w) subcutaneous maintenance therapy (90 mg). Three sequential models were developed: a two-compartment popPK model linking ustekinumab dose to ustekinumab exposure, an indirect response popPK-PD model describing the effect of ustekinumab exposure on fecal calprotectin (fCal), and a logistic regression outcome model linking fCal to endoscopic outcomes.

RESULTS

Ustekinumab clearance increased with decreasing serum albumin and increasing bodyweight. fCal decreased with increasing ustekinumab exposure. The probability of endoscopic response at w24 increased from 10.0% to 17.9% with fCal at w8 decreasing from 1800 μg/g to 694 μg/g (EC₅₀ ). The probability of endoscopic remission at w24 increased from 2.1% to 10.0% with fCal at w8 decreasing from 1800 μg/g to 214 μg/g (EC₅₀ ). Simulation-based comparison of q8w and q4w maintenance dosing regimens predicted 16.7% and 22.2% endoscopic response rates, respectively. Endoscopic remission rates were estimated to be 4.2% on q8w dosing and 6.7% on q4w dosing.

CONCLUSIONS

The developed models can guide clinical trial design and support model-informed dose optimization (stratified or individualized dosing) to improve endoscopic outcomes.