Regulatory Approval, Reimbursement, and Clinical Use of Cyclin-Dependent Kinase 4/6 Inhibitors in Metastatic Breast Cancer in the Netherlands

CONCLUSIONS AND RELEVANCE

This study found that CDK4/6 inhibitors rapidly reached many eligible patients with metastatic breast cancer and were adopted gradually over time in the Netherlands. Adoption of innovative medicines may be further optimized, and better transparency of the availability of new medicines during different phases of the postapproval access pathway is needed.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study reviewed approval and reimbursement decisions of the CDK4/6 inhibitors palbociclib, ribociclib, and abemaciclib and estimated the number of patients with metastatic breast cancer who were eligible for these medicines compared with the actual use in clinical practice. The study used nationwide claims data that were obtained from the Dutch Hospital Data. Claims and early access data for patients with hormone receptor-positive and ERBB2 (formerly HER2)-negative metastatic breast cancer who were treated with CDK4/6 inhibitors from November 1, 2016, to December 31, 2021, were included.

IMPORTANCE

The number of new cancer medicines that are being approved by regulatory agents is increasing exponentially. Yet little is known about the pace at which these medicines reach eligible patients in daily clinical practice during different phases of the postapproval access pathway.

MAIN OUTCOMES AND MEASURES

Description of the postapproval access pathway, monthly number of patients who were treated with CDK4/6 inhibitors in clinical practice, and estimated number of patients who were eligible for treatment. Aggregated claims data were used, and patient characteristics and outcomes data were not collected.

OBJECTIVE

To describe the entire postapproval access pathway of cyclin-dependent kinase 4/6 (CDK4/6) inhibitors in the Netherlands, from regulatory approval to reimbursement and to investigate the adoption of these medicines in clinical practice among patients with metastatic breast cancer.

RESULTS

Three CDK4/6 inhibitors have received European Union-wide regulatory approval for the treatment of HR-positive and ERBB2-negative metastatic breast cancer since November 2016. In the Netherlands, the number of patients who have been treated with these medicines increased to approximately 1847 (based on 1 624 665 claims over the entire study period) from approval to the end of 2021. Reimbursement for these medicines was granted between 9 and 11 months after approval. While awaiting reimbursement decisions, 492 patients received palbociclib, the first approved medicine of this class, via an expanded access program. By the end of the study period, 1616 patients (87%) were treated with palbociclib, whereas 157 patients (7%) received ribociclib, and 74 patients (4%) received abemaciclib. The CKD4/6 inhibitor was combined with an aromatase inhibitor in 708 patients (38%) and with fulvestrant in 1139 patients (62%). The pattern of use over time appeared to be somewhat lower compared with the estimated number of eligible patients (1847 vs 1915 in December 2021), especially in the first 2.5 years after approval.

Estimating Quality of Life Decrements in Oncology Using Time to Death

OBJECTIVES

The estimation of lifetime quality-adjusted life-years (QALYs) requires the extrapolation of both length and quality of life (QoL). The extrapolation of QoL has received little attention in the literature. Here we explore the predictive value of "time to death" (TTD) for extrapolating QoL in oncology.

METHODS

We used QoL and survival data from the Patient Reported Outcomes Following Initial Treatment and Long-Term Evaluation of Survivorship registry, which is linked to The Netherlands Cancer Registry. QoL was assessed with EQ-5D and SF-6D. We tested the relationship between TTD and QoL using linear, 2-part, and beta regression models. Incremental QALYs were compared using the TTD approach and an annual age-related disutility approach using artificial survival data with varying mortality rates.

RESULTS

A total of 6 samples with >100 patients each were used for the analysis. A declining pattern in QoL was observed when patients were closer to death, confirming the predictive value of TTD for QoL. The declining pattern in QoL was most pronounced when QoL was measured with SF-6D. Proximity to death had a larger impact on QoL than age. Incremental QALYs were higher using the TTD approach than annual age-related disutility, ranging from +0.139 to +0.00003 depending on mortality rates.

CONCLUSIONS

TTD is a predictor variable for QoL. Using TTD allows cost-effectiveness models that lack QoL data to extrapolate morbidity using overall survival estimates. The TTD approach generates more incremental QALYs than an annual age-related disutility, most notably for longer survival periods.

Real-world evidence in health technology assessment of high-risk medical devices: Fit for purpose?

Health technology assessment (HTA) of medical devices (MDs) increasingly rely on real-world evidence (RWE). The aim of this study was to evaluate the type and the quality of the evidence used to assess the (cost-)effectiveness of high risk MDs (Class III) by HTA agencies in Europe (four European HTA agencies and EUnetHTA), with particular focus on RWE. Data were extracted from HTA reports on the type of evidence demonstrating (cost-)effectiveness, and the quality of observational studies of comparative effectiveness using the Good Research for Comparative Effectiveness principles. 25 HTA reports were included that incorporated 28 observational studies of comparative effectiveness. Half of the studies (46%) took important confounding and/or effect modifying variables into account in the design and/or analyses. The most common way of including confounders and/or effect modifiers was through multivariable regression analysis. Other methods, such as propensity score matching, were rarely employed. Furthermore, meaningful analyses to test key assumptions were largely omitted. Resulting recommendations from HTA agencies on MDs is therefore (partially) based on evidence which is riddled with uncertainty. Considering the increasing importance of RWE it is important that the quality of observational studies of comparative effectiveness are systematically assessed when used in decision-making.

Variation in the utilization of medical devices across Germany, Italy, and the Netherlands: A multilevel approach

Variation in healthcare utilization has been discussed extensively, with many studies showing that variation exists, but fewer studies investigating the underlying factors. In our study, we used a logistic multilevel-model at the patient, hospital, and regional levels to investigate (i) the levels to which variation could be attributed and (ii) the hospital and regional factors associated with treatment decisions. To do so, we used hospital discharge records for the years 2012-2016 in Germany and Italy and for 2014-2016 in the Netherlands combined with hospital and regional characteristics in nine case studies. We used a theoretical framework to categorize these case studies into effective, preference-sensitive, and supply-sensitive care. Our results suggest that most variation in the treatment decision can be attributed to the hospital level (e.g., case volume), whereas only a minor part is explained by regional characteristics. Italy had the highest share attributable to the regional level, whereas the Netherlands had the lowest. We observed less variation for procedures in the effective-care category compared to the preference- and supply-sensitive categories. Although our results were heterogeneous, we identified patterns in line with the theoretical framework for treatment categories, underlining the need to address variation differently depending on the category in question.

Abstract P1-18-31: Accessibility of CDK4/6 inhibitors for breast cancer patients in the Netherlands

Background: Before new cancer drugs are available to patients, they must obtain regulatory approval by international authorities. In many countries new drugs are also subject to health technology assessment procedures to decide on the reimbursement. When these procedures are completed, new drugs need to be adopted into clinical practice. All these processes take time and may delay or hamper patient access. In this study we investigated the access to CDK4/6 inhibitors for HR+Her2- metastatic breast cancer patients in daily practice in the Netherlands and explored whether certain policy procedures may have influenced accessibility. Method: For this study we used a mixed method approach. For our qualitative analysis, we used publicly available documents describing drug approval and reimbursement decisions and clinical practice recommendations. Information from these documents were used to provide a timeline of procedures involved and decisions made to make CDK4/6 inhibitors available to patients in the Netherlands. For our quantitative analysis we used monthly prescription data to calculate the number of patients treated with CDK4/6 inhibitors each month, to describe the trends over time and to calculate annual drug expenses. The monthly number of patients treated were compared to an estimated number of patients eligible for the drugs as per European Medicine Association (EMA) label. The trends were compared to the decision timeline in order to identify as to whether certain procedures and/or decisions may have been associated with accessibility to CDK4/6 inhibitors in the Netherlands. Results: In June 2017, the first approved CDK4/6 inhibitor - palbociclib - was prescribed for breast cancer for the first time in the Netherlands. This was approximately 7 months after the EMA gave a positive opinion for marketing authorization. This delay was caused by pricing and reimbursement procedures which involved a thorough evaluation of the costs and effects of the drug and negotiations with the manufacturer. After prescribing palbociclib for the first time, the utilization of CDK4/6 inhibitors in clinical practice increased rapidly with a gradual increase from zero to approximately 1400 patients over a period of 30 months. The majority of patients were treated with palbociclib even after the approval of other drugs of this class (i.e. in December 2019: palbociclib 94% ribociclib 6% and abemaciclib <1%). In addition, approximately 63% of patients were treated with a CKD4/6 inhibitor combined with fulvestrant. The pattern of utilization over time appeared to correspond quite well to the estimated number of patients eligible but these estimates were surrounded by a substantial amount of uncertainty. The total expenses of the CDK4/6 inhibitors from 2017 to 2019 were approximately 3.5 times smaller than the estimates made by the health authorities in the Netherlands prior to the decision to reimburse the drugs. Conclusion: Pricing and reimbursement decisions caused a significant delay in access to the newest drugs for HR+/HER2- metastatic breast cancer. Nevertheless, after palbociclib - the first approved CDK4/6 inhibitor - received a positive reimbursement decision, the prescription in daily practice increased rapidly, a pattern not seen in the other drugs of this class. Though the number of patients treated appeared to be in line with the projected number of patients eligible for these drugs, detailed information regarding metastatic breast cancer patients, their treatments and the decision making process in daily practice is needed to fully understand access to the newest drugs.

Citation Format: Marianne Luyendijk, Hedwig Blommestein, Agnes Jager, Sabine Siesling, Carin Uyl-de Groot. Accessibility of CDK4/6 inhibitors for breast cancer patients in the Netherlands [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-18-31.

Validity of Surrogate Endpoints and Their Impact on Coverage Recommendations: A Retrospective Analysis across International Health Technology Assessment Agencies

BACKGROUND

Surrogate endpoints (i.e., intermediate endpoints intended to predict for patient-centered outcomes) are increasingly common. However, little is known about how surrogate evidence is handled in the context of health technology assessment (HTA).

OBJECTIVES

1) To map methodologies for the validation of surrogate endpoints and 2) to determine their impact on acceptability of surrogates and coverage decisions made by HTA agencies.

METHODS

We sought HTA reports where evaluation relied on a surrogate from 8 HTA agencies. We extracted data on the methods applied for surrogate validation. We assessed the level of agreement between agencies and fitted mixed-effects logistic regression models to test the impact of validation approaches on the agency's acceptability of the surrogate endpoint and their coverage recommendation.

RESULTS

Of the 124 included reports, 61 (49%) discussed the level of evidence to support the relationship between the surrogate and the patient-centered endpoint, 27 (22%) reported a correlation coefficient/association measure, and 40 (32%) quantified the expected effect on the patient-centered outcome. Overall, the surrogate endpoint was deemed acceptable in 49 (40%) reports (k-coefficient 0.10, P = 0.004). Any consideration of the level of evidence was associated with accepting the surrogate endpoint as valid (odds ratio [OR], 4.60; 95% confidence interval [CI], 1.60-13.18, P = 0.005). However, we did not find strong evidence of an association between accepting the surrogate endpoint and agency coverage recommendation (OR, 0.71; 95% CI, 0.23-2.20; P = 0.55).

CONCLUSIONS

Handling of surrogate endpoint evidence in reports varied greatly across HTA agencies, with inconsistent consideration of the level of evidence and statistical validation. Our findings call for careful reconsideration of the issue of surrogacy and the need for harmonization of practices across international HTA agencies.

Abstract P2-08-02: Trends in survival and the introduction of novel systemic therapies for locoregional and metastatic breast cancer in the Netherlands, 1989-2017

Objective:The introduction of innovations in breast cancer care such as screening and new systemic treatments may influence the proportions of patients with metastatic and locoregional disease as well as their survival outcomes. Aim of this study is to provide insight in trends in relative survival for locoregional versus metastatic breast cancer over the period 1989-2017 in relation to innovations introduced in the Netherlands.

Methods: We used data from the population-based Netherlands Cancer Registry (NCR) which contains demographic and tumor information (e.g. stage at diagnosis, initial treatment) which is abstracted from the medical records by trained data managers. Information on patient’s last available vital status was retrieved by merging the NCR with the Municipal Personal Records Database (last update 31-01-2019). All patients with breast cancer were selected from the NCR and stratified into locoregional (TNM stage I-III) or metastatic disease (TNM stage IV) at time of diagnosis. 1-year and 5-year relative survival rates were calculated for the entire population and for patients with locoregional and metastatic disease separately. Relative survival rates were estimated by using the Ederer II method and plotted over time. Along with the annual survival rates the introduction of innovations were projected. The date of introduction of screening and the registration of new medicines was obtained from the literature, the medicines evaluation board the Netherlands (CBG) and the European Medicines Association.

Results: In total 342.017 breast cancer patients were included in the study. The number of newly diagnosed patients increased from 7.741 in 1989 to 14.958 in 2017. Meanwhile, the proportion of patients with metastatic breast cancer at diagnosis decreased from 7.0% in 1989 to 5.4% in 2017. One year relative survival increased from 94% to 98% for all patients, from 97% to 99% for locoregional disease and from 60% to 76% for metastatic disease. Five year relative survival increased from 75% to 89% for all patients, from 80% to 92% for locoregional disease and from 16% to 33% for metastatic disease. The survival increase in metastatic disease was most prominent after 2010. Over the past three decades, several systemic therapies were introduced including taxanes, monoclonal antibodies and CDK 4/6 inhibitors. Taxanes were introduced for metastatic breast cancer in the 1990s. Trastuzumab was introduced for metastatic breast cancer in 2000 and for locoregional breast cancer in 2006. CDK 4/6 inhibitors were introduced for metastatic breast cancer from 2016 onwards.

Conclusion: Breast cancer survival gradually improved during 1989-2017, both for patients with locoregional and metastatic disease. Nevertheless, a large though slightly shrinking gap in survival between the two groups was observed over the entire period. During the study period, many innovative systemic therapies were introduced. These are likely to have contributed to the increase in breast cancer survival, especially in metastatic disease after 2010. However, other innovations such as in surgery and radiotherapy may also have contributed to the higher survival rates, especially in locoregional disease. The most recent introductions of new drugs are not yet visible in our results, but might result in a further reduction in the gap in survival rates between locoregional and metastatic breast cancer.

Citation Format: Marianne Luyendijk, Otto Visser, Hedwig Blommestein, Carin Uyl- de Groot, Sabine Siesling. Trends in survival and the introduction of novel systemic therapies for locoregional and metastatic breast cancer in the Netherlands, 1989-2017 [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-08-02.