Health state utilities for metastatic breast cancer in Taiwan

Differences in Preferences for Drug Therapy Between Patients with Metastatic Versus Early-Stage Breast Cancer: A Systematic Literature Review

INTRODUCTION

Compared with early stages (eBC) metastatic BC (mBC) is incurable. In mBC, aggressive treatment may increase the duration of survival but may also cause severe treatment side effects. A better understanding how patients with BC value different aspects of drug therapy might improve treatment effectiveness, satisfaction and adherence. This systematic review aims to identify and summarise studies evaluating patient preferences for drug therapy of BC and to compare preferences of patients with eBC and mBC.

METHODS

The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The electronic databases PubMed and Web of Science were searched on 22 June 2023. All studies published to this point were considered. Original studies reporting patient preferences on BC drug therapy determined by any type of choice experiment were eligible. A narrative synthesis of the effect measures presented as relative importance ratings, trade-offs (required benefit to make a therapy worthwhile) or monetary values of the treatment attributes was reported for each study. Risk of bias assessment for individual studies was performed using the checklist for observational studies from the STROBE Statement and the checklist from 'Conducting Discrete Choice Experiments to Inform Healthcare Decision Making: A User's Guide'. The study protocol was registered at the PROSPERO database (CRD42022377031).

RESULTS

A total of 34 studies met the inclusion criteria were included in the analysis evaluating the preferences of patients with eBC (n = 18), mBC (n = 10) or any stage BC (n = 6) on, for example, chemotherapy, endocrine therapy, hormonal therapy or CKD4/6-inhibitors using different types of choice experiments. Regardless of the stage, most patients valued treatment effectiveness in terms of survival gains higher than potential adverse drug reactions (ADRs). Treatment cost, mode of administration, treatment regimen and monitoring aspects were considered as least important treatment attributes. In addition, preferences concerning 16 different types of ADRs were described, showing high heterogeneity within BC stages. Yet, comparable results across BC stages were observed.

CONCLUSIONS

Regardless of the stage, patients with BC consistently valued survival gains as the most important attribute and were willing to accept the risk of potential ADRs. Incorporating patient preferences in shared decision making may improve the effectiveness of interventions by enhancing adherence to drug therapy in patients suffering from BC.

Cost-effectiveness analysis of pembrolizumab plus chemotherapy for patients with recurrent or metastatic cervical cancer in China

OBJECTIVE

To evaluate the cost-effectiveness of adding pembrolizumab to various therapy combinations in patients with recurrent or metastatic cervical cancer from the Chinese perspective.

MATERIALS AND METHODS

The clinical data for our model was taken from the KEYNOTE-826 trial. The direct costs and utilities were collected from local price databases or previously published literature. A three-state partitioned survival model was designed to simulate the disease process of patients with recurrent or metastatic cervical cancer. All costs were estimated in US dollars, with an annual RMB exchange rate of $1 to 6.45 Yuan in 2021. The willingness to pay threshold (WTP) was set at US$37,663.26/QALY. One-way sensitivity analyses and probabilistic sensitivity analyses were performed to evaluate the influence of variables on the model parameters.

RESULTS

For patients with a programmed death-ligand 1 combined positive score greater than 1,compared to the chemotherapy group, pembrolizumab plus chemotherapy contributed an incremental 1.12 Quality-adjusted Life Years (QALYs) with an incremental cost of US$71,884.42, resulting in an incremental cost-effectiveness ratio (ICER) of US$64,338.19, which is beyond the willingness-to-pay (WTP) threshold of China. According to sensitivity analyses, the ICERs were most sensitive to the utility of progressive disease and the cost of pembrolizumab. However, those parameters had no significant impact on the model's outcomes.

CONCLUSIONS

The addition of pembrolizumab to various therapy combinations chemotherapy is exorbitant and may not be cost-effective for patients with recurrent or metastatic cervical cancer in China.

Trastuzumab deruxtecan versus trastuzumab emtansine for patients with human epidermal growth factor receptor 2-positive metastatic breast cancer: A cost-effectiveness analysis

BACKGROUND

DESTINY-Breast03 (NCT03529110) was the first global phase III study to assess the antitumor activity of trastuzumab deruxtecan (T-DXd) compared to trastuzumab emtansine (T-DM1) in 2022. However, the balance between efficacy and cost of T-DXd remains unclear. As a result, the present study's goal is to investigate the cost-effectiveness of T-DXd vs T-DM1 as a second-line treatment for patients with HER2-positive MBC from the US and Chinese payer's perspectives.

METHODS

A Markov model with a 20-year time horizon was developed to evaluate the overall cost of patient treatment, incremental cost-effectiveness ratio (ICER), quality-adjusted life-years (QALYs), and life-years (LYs) in the US and China at WTP levels of 150,000/QALY and 37,653/QALY, respectively (3 times GDP per capita in 2021). Key data were gathered from the US government's official website, the Xiangya Hospital of Central South University, and published literature. To determine the model's stability, a sensitivity analysis was performed. A subgroup analysis was also implemented.

RESULTS

Compared with T-DM1, treatment with T-DXd generated an additional 1.672 QALYs (2.796 LYs), resulting in an ICER of $13,342/QALY (US) and $186,017/QALY (China). The cost of drugs is the most influential factor in the American and Chinese models. Subgroup analysis revealed that the T-DXd and T-DM1 regimens were more cost-effective at reducing the risk of death in the US and Chinese HER2-positive MBC patients.

CONCLUSION

T-DXd as second-line treatment could gain more health benefits for HER2-positive MBC patients in comparison with T-DM1, which is considered to be cost-effective in the US but not in China.

Cost-effectiveness analysis of lenvatinib plus pembrolizumab compared with chemotherapy for patients with previously treated mismatch repair proficient advanced endometrial cancer in China

Aims: This study aimed to evaluate the cost-effectiveness of lenvatinib plus pembrolizumab (LP) vs. chemotherapy for patients with previously treated mismatch repair proficient advanced endometrial cancer in China. Methods: A lifetime of partitioned survival Markov was used to evaluate the overall lifetime, total costs, quality adjusted life years (QALYs), and incremental cost effectiveness ratio (ICER) across a 10-years time horizon in the study 309-KEYNOTE-775 clinical trial. Direct costs and utility values were gathered from available literature. The willingness to pay (WTP) was defined at $37,663.26 per QALY. Sensitivity analyses were carried out to determine the model's uncertainty. Results: According to the baseline analysis, the LP group gained 4.02 total life years and 3.13 QALYs for $93,496.69, whereas the chemotherapy group gained 2.86 total life years and 2.24 QALYs for $30,578.04. LP versus chemotherapy resulted in an incremental cost of $62,918.65, with an ICER of $70,962.09/QALY, which was higher than China's WTP threshold ($37,663.26/QALY). The ICERs were most sensitive to the cost of pembrolizumab and the cycle of LP delivered, according to the sensitivity analysis. However, changing the range of those parameters has no influence on the model's results. Conclusion: Our present analysis suggests that LP treatment is not cost-effective for patients with previously treated mismatch repair proficient advanced endometrial cancer. However, LP treatment may be a cost-effective treatment option if the price is reduced.

Validation of the predictive accuracy of health-state utility values based on the Lloyd model for metastatic or recurrent breast cancer in Japan

INTRODUCTION

Although there is a lack of data on health-state utility values (HSUVs) for calculating quality-adjusted life-years in Japan, cost-utility analysis has been introduced by the Japanese government to inform decision making in the medical field since 2016.

OBJECTIVES

This study aimed to determine whether the Lloyd model which was a predictive model of HSUVs for metastatic breast cancer (MBC) patients in the UK can accurately predict actual HSUVs for Japanese patients with MBC.

DESIGN

The prospective observational study followed by the validation study of the clinical predictive model.

SETTING AND PARTICIPANTS

Forty-four Japanese patients with MBC were studied at 336 survey points.

METHODS

This study consisted of two phases. In the first phase, we constructed a database of clinical data prospectively and HSUVs for Japanese patients with MBC to evaluate the predictive accuracy of HSUVs calculated using the Lloyd model. In the second phase, Bland-Altman analysis was used to determine how accurately predicted HSUVs (based on the Lloyd model) correlated with actual HSUVs obtained using the EuroQol 5-Dimension 5-Level questionnaire, a preference-based measure of HSUVs in patients with MBC.

RESULTS

In the Bland-Altman analysis, the mean difference between HSUVs estimated by the Lloyd model and actual HSUVs, or systematic error, was -0.106. The precision was 0.165. The 95% limits of agreement ranged from -0.436 to 0.225. The t value was 4.6972, which was greater than the t value with 2 degrees of freedom at the 5% significance level (p=0.425).

CONCLUSIONS

There were acceptable degrees of fixed and proportional errors associated with the prediction of HSUVs based on the Lloyd model for Japanese patients with MBC. We recommend that sensitivity analysis be performed when conducting cost-effectiveness analyses with HSUVs calculated using the Lloyd model.

Changes in Health State Utility Values in Japanese Patients with End-Stage Breast Cancer

We aimed to determine the dynamic trends in health state utility values (HSUVs) in patients with end-stage breast cancer. We selected 181 patients comprising 137 with primary breast cancer (PBC) and 44 with metastatic breast cancer (MBC) (28 survivors and 16 patients with MBC death). HSUVs were 0.90 and 0.89 in patients with PBC and 0.83 and 0.80 in those with MBC (survivors) at 6 and 3 months, respectively, before the end of the observation period; these values were 0.73 and 0.66, respectively, in those with MBC (deceased) during the aforementioned period. The root-mean-squared error (RMSE) for the decrease in HSUVs over 3 months was 0.10, 0.096, and 0.175 for patients with PBC, MBC (survivors), and MBC (deceased), respectively. One-way analysis of variance for differences in absolute error among the groups was significant (p = 0.0102). Multiple comparisons indicated a difference of 0.068 in absolute error between patients with PBC and those with MBC (deceased) (p = 0.0082). Patients with end-stage breast cancer had well-controlled HSUVs 3 months before death, with a sharp decline in HSUVs in the 3 months leading up to death.