Cost-effectiveness of 3-years of adjuvant imatinib in gastrointestinal stromal tumors (GIST) in the United States

Cost-Effectiveness Analysis of Tyrosine Kinase Inhibitors in Gastrointestinal Stromal Tumor: A Systematic Review

Background: The introduction of tyrosine kinase inhibitor (TKI) therapy has dramatically improved the clinical effectiveness of patients with locally advanced and/or metastatic gastrointestinal stromal tumors (GIST), and this systematic review was conducted aiming at the cost-effectiveness analysis of TKIs in GIST.

Methods: A thorough literature search of online databases was performed, using appropriate terms such as “gastrointestinal stromal tumor or GIST,” “cost-effectiveness,” and “economic evaluation.” Data extraction was conducted independently by two authors, and completeness of reporting and quality of the evaluation were assessed. The systematic review was conducted following the PRISMA statement.

Results: Published between 2005 and 2020, 15 articles were incorporated into the systematic review. For advanced GIST, imatinib followed by sunitinib was considered cost-effective, and regorafenib was cost-effective compared with imatinib re-challenge therapy in the third-line treatment. For resectable GIST, 3-year adjuvant imatinib therapy represented a cost-effective treatment option. The precision medicine-assisted imatinib treatment was cost-effective compared with empirical treatment.

Conclusion: Although identified studies varied in predicted costs and quality-adjusted life years, there was general agreement in study conclusions. More cost-effectiveness analysis should be conducted regarding more TKIs that have been approved for the treatment of GIST.

Systematic Review Registration:https://www.crd.york.ac.uk/, PROSPERO: CRD42021225253.

Cost-Effectiveness Analysis of Fourth- or Further-Line Ripretinib in Advanced Gastrointestinal Stromal Tumors

Background

The INVICTUS trial assessed the efficacy and safety of ripretinib compared with placebo in the management of advanced gastrointestinal stromal tumors.

Method

We used a Markov model with three health states: progression-free disease, progression disease and death. We parameterized the model from time-to-event data (progression-free survival, overall survival) of ripretinib and placebo arms in the INVICTUS trial and extrapolated to a patient’s lifetime horizon. Estimates of health state utilities and costs were based on clinical trial data and the published literature. The outcomes of this model were measured in quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs). Uncertainty was tested via univariate and probabilistic sensitivity analyses.

Results

The base-case model projected improved outcomes (by 0.29 QALYs) and additional costs (by $70,251) and yielded an ICER of $244,010/QALY gained for ripretinib versus placebo. The results were most sensitive to progression rates, the price of ripretinib, and health state utilities. The ICER was most sensitive to overall survival. When overall survival in the placebo group was lower, the ICER dropped to $127,399/QALY. The ICER dropped to $150,000/QALY when the monthly cost of ripretinib decreased to $14,057. Probabilistic sensitivity analyses revealed that ripretinib was the cost-effective therapy in 41.1% of simulations at the willingness-to-pay (WTP) threshold of $150,000.

Conclusion

As the fourth- or further-line therapy in advanced gastrointestinal stromal tumors, ripretinib is not cost-effective in the US. Ripretinib would achieve its cost-effectiveness with a price discount of 56% given the present effectiveness.

National Utilization of Imatinib in the Management of Resected Gastrointestinal Stromal Tumors

BACKGROUND

Imatinib decreases recurrence risk and improves overall survival (OS) in localized gastrointestinal stromal tumors (GISTs); however, the extent to which patients receive appropriate treatment in the US has not been well characterized.

METHODS

Patients with non-metastatic, resectable GIST were included in this study (National Cancer Database, 2010-2015). Those with a low-risk of recurrence were classified as receiving overtreatment or guideline-concordant treatment, while those with a high-risk of recurrence were classified as receiving undertreatment or guideline-concordant treatment. Multivariable logistic regression was used to determine factors associated with non-concordant treatment. The association between non-concordant treatment and OS was evaluated using multivariable Cox regression and propensity score matching.

RESULTS

Among 3088 patients with high-risk GIST, 41% were undertreated, and among 3908 patients with low-risk GIST, 18.8% were overtreated. For patients with high-risk GIST, age > 60 years, African American race, and treatment at a community or comprehensive cancer program were associated with undertreatment. Among low-risk patients, small bowel primary, tumor size > 2 cm, and tumors with > 1 mitotic figure per 50 high-power fields were more likely to be overtreated. After propensity score matching, guideline-concordant therapy was associated with an 8.8% improvement in 5-year OS (81.9% vs. 73.1%, p = 0.002) for those with high-risk GIST and decreased risk of death (hazard ratio 0.63, 95% confidence interval 0.47-0.84). There was no statistically significant difference in survival for patients with low-risk GIST with the addition of imatinib overtreatment (overtreatment 93.9% vs. 89.6%, p = 0.053).

CONCLUSIONS

Nearly 30% of GIST patients do not receive guideline-concordant treatment and future work is needed to understand the factors driving non-concordant treatment.

Indirect Treatment Comparison of Nivolumab Versus Observation or Ipilimumab as Adjuvant Therapy in Resected Melanoma Using Pooled Clinical Trial Data

INTRODUCTION

Nivolumab has been approved in patients with melanoma with lymph node involvement or metastatic disease who have undergone complete resection, in the adjuvant setting. A pivotal trial compared nivolumab with ipilimumab; however, no head-to-head trial exists comparing nivolumab to observation, a common comparator in the adjuvant setting. Here, we compared the efficacy and cost-effectiveness of nivolumab with observation or ipilimumab as adjuvant therapies in resected stage IIIB/C melanoma.

METHODS

Patient data were pooled from the EORTC 18071 and CheckMate 238 trials using propensity score weighting and adjusting for cross-trial differences. Number needed to treat (NNT) and costs per recurrence-free life-month (RFLM) at 12, 16, 18, and 24 months (as data allowed) were estimated. Costs included drug acquisition, administration costs, and direct medical costs. Sensitivity analyses including patients with stage IIIB/C and resected stage IV melanoma were conducted.

RESULTS

A total of 1287 patients (278 nivolumab, 365 observation, and 644 ipilimumab) with resected stage IIIB/C melanoma were pooled. NNTs to achieve one additional recurrence-free survivor with nivolumab versus observation were 3.93 at 12 months and 3.42 at 24 months; NNTs for nivolumab versus ipilimumab were 7.97 at 12 months and 6.43 at 24 months. Mean drug costs per RFLM were lower for nivolumab at 12, 18, and 24 months, respectively (nivolumab: $13,447, $9462, and $7370; ipilimumab: $52,734, $40,484, and $33,875). Mean medical costs per RFLM were the lowest for nivolumab versus observation or ipilimumab at 12 months ($449 versus $674 or $1531) and 16 months ($383 versus $808 or $1316). The sensitivity analysis results were consistent with the base case.

CONCLUSION

For resected melanoma, adjuvant nivolumab is both clinically effective and cost-effective compared with observation or ipilimumab. Adjuvant nivolumab was associated with a lower drug cost per RFLM compared with ipilimumab, and a lower medical cost compared with observation. Future analyses incorporating long-term follow-up data may help increase understanding of the economic impact of nivolumab in the adjuvant setting.

FUNDING

Bristol-Myers Squibb Company.

Cost-utility analysis of adjuvant imatinib treatment in patients with high risk of recurrence after gastrointestinal stromal tumour (GIST) resection in Thailand

Background

Many patients develop tumour recurrence within a few years after undergoing surgical resection of gastrointestinal stromal tumours (GIST). Adjuvant imatinib treatment is recommended for patients with high risk of GIST recurrence as it can improve recurrence-free survival and overall survival of patients. This study aims to assess the cost-utility of adjuvant imatinib in patients with high risk of GIST recurrence after surgery compared with no adjuvant therapy in Thailand.

Methods

A Markov model was developed to estimate lifetime costs and outcomes of using adjuvant imatinib treatment and other treatment alternatives if recurrence occurred compared with the current situation of no adjuvant therapy in high-risk patients after surgery. A 1-month cycle length was deployed in the model. Transition probabilities were derived from literature review. Costs were collected and calculated for the year 2014 from a societal perspective. Future costs and outcomes were discounted at 3% per year. One-way and probabilistic sensitivity analyses were conducted to assess parameter uncertainties.

Results

Three years of adjuvant imatinib treatment followed by imatinib treatment and best supportive care if recurrence occurred after or during adjuvant therapy, respectively, was the best option as it produced more health outcomes (1.23 life years (LYs) and 1.16 quality-adjusted life years (QALYs)) compared to no adjuvant therapy while yielding the lowest incremental cost-effectiveness ratio (ICER) of 1,648,801 Thai Baht (THB) per QALY gained. Three years of adjuvant imatinib treatment followed by sunitinib treatment if recurrence occurred had an ICER of 2,608,264 THB per QALY gained compared to the best option, while other options were dominated. A one-way sensitivity analysis showed that the utility of patients receiving adjuvant imatinib had the greatest effect on the model, followed by the discount rate and probability of GIST recurrence.

Conclusions

Adjuvant imatinib treatment improved the health benefits of patients with high risk of GIST recurrence. However, in the Thai context, it was not cost-effective at the current price.

Cost-effectiveness of precision medicine in gastrointestinal stromal tumor and gastric adenocarcinoma

Over the past 20 years, with the incorporation of genetic sequencing and improved understanding regarding the mechanisms of cancer growth/metastasis, novel targets and their associated treatments have emerged in oncology and are now regularly incorporated into the clinical care of patients in the US. Novel, more tumor-specific, non-chemotherapy agents, including agents that are commonly used in the treatment of patients with gastric adenocarcinoma (GA) and gastrointestinal stromal tumor (GIST), fall under a broader treatment strategy, termed "precision medicine". While diagnostic testing and associated treatments in metastatic GA (mGA) are costly and may produce marginal benefit, those associated with GIST, despite being costly, produce significant improvements in patient outcomes. Despite the significant difference in impact, the agents associated with these cancers have similar acquisition costs. In this paper, we will review the current literature regarding cost and cost-effectiveness associated with precision medicine diagnosis and treatment strategies for GA and GIST.

Current status of publicly available sarcoma cell lines for use in proteomic studies

Cell lines are valuable resources for proteomic studies and can be used as tools to verify the significance of proteomic findings. Here, the authors overview the current status of the publicly available sarcoma cell lines. The authors surveyed seven major cell banks and found that the diversity observed in the sarcoma cell banks was largely insufficient; sarcoma cell lines are available for only a limited histological subtype. They also observed a number of issues with the pathological diagnosis of the cell lines, limitations in their behavioral diversity, and various unmet needs. Well characterized cell lines with accurate diagnosis based on modern diagnosis criteria should be available from public cell banks. The authors conclude that additional cell lines, along with detailed genetic and pathological analyses, should be prepared and deposited in order to promote sarcoma-specific proteomic research. The authors focused on sarcoma cell lines, but their discussion can be applied to the other cancers.

Cost-effectiveness analyses of targeted oral anti-cancer drugs: a systematic review

BACKGROUND

Over the last 15 years, a paradigm shift in oncology has led to the approval of dozens of targeted oral anti-cancer medications (OAMs), which have become the standard of care for certain cancers. While more convenient for patients than infused drugs, the possibility of non-adherence and the frequently high costs of targeted OAMs have proven controversial.

OBJECTIVE

Our objective was to perform the first comprehensive review of cost-effectiveness analyses (CEAs) of targeted OAMs.

METHODS

A literature search in PubMed, The Cochrane Library, and the Health Technology Assessment (HTA) reports published by the National Institute for Health Research HTA Programme in the UK was performed, covering articles published in the 5 years prior to 30 September 2013. Our inclusion criteria were peer-reviewed English-language full-text original research articles with a primary focus on CEA related to targeted OAMs. We categorized these articles by treatment setting (i.e. cancer site/type, line of therapy, and treatment and comparator) and synthesized information from the articles into summary tables.

RESULTS

We identified 41 CEAs covering nine of the 18 targeted OAMs approved by the US FDA as of December 2012. These medications were studied in seven cancers, most often as second-line therapy for advanced-stage patients. In over half of treatment settings where a targeted OAM was compared with treatment that was not a targeted OAM, targeted OAMs were considered cost effective. Limitations in interpreting these findings include the risk of bias due to author conflicts of interest, cross-country variation, and difficulties in generalizing clinical trial evidence to community practice.

CONCLUSIONS

Several types of cost-effectiveness studies remain under-represented in the literature on targeted OAMs, including those for follow-on indications approved after the initial indication for a drug and for off-label indications, head-to-head comparisons of targeted OAMs with other targeted OAMs and targeted intravenous therapies, and studies that adopt a perspective other than the payer's. Keeping up with the increasing number of approved targeted OAMs will also prove an important challenge for economic evaluation.

Effect of a structured, active, home-based cancer-treatment program for the management of patients on oral chemotherapy

INTRODUCTION

The advent of oral chemotherapy agents has had a strong impact on several aspects of the management of cancer patients, including survival rates, health-care expenditure, and health-related quality of life. However, access to care and adherence to oral chemotherapy are central to optimal outcomes.

PATIENTS AND METHODS

In this multicenter observational study, we assessed the effect of the "Active Home Care" initiative - a structured, active, home-based cancer-treatment program - on quality of life, health-care utilization, and patient adherence and satisfaction using self-administered questionnaires. Sixty-two patients treated with oral chemotherapy (capecitabine, vinorelbine, imatinib, sunitinib, sorafenib, temozolomide, ibandronate) were enrolled in the program. Weekly home visits were scheduled, each one with a trained nurse who delivered the home-based chemotherapy and reviewed patients' compliance and treatment toxicity. An oncologist evaluated patients and modified the dosage of oral chemotherapy based on toxicity reported during the previous cycle at bi-weekly visits.

RESULTS

A total of 460 home visits were performed between April 2012 and February 2013. The Active Home Care initiative was associated with significant improvements in physical functioning and symptoms, and reductions in the access to cancer facilities. Satisfaction with oral chemotherapy and care received was high. All patients reported having taken their medications according to their prescription, and no patient reported difficulties in managing the oral chemotherapy regimen.

CONCLUSION

The Active Home Care program was associated with improvements in the quality of life of patients and caregivers, better adherence to treatment, and the effective management of therapy and cancer-related symptoms. Home-based cancer treatment may also optimize the utilization of health-care resources.

Efficacy and economic value of adjuvant imatinib for gastrointestinal stromal tumors

OBJECTIVE

This article presents the clinical effectiveness and cost-effectiveness of the use of adjuvant imatinib mesylate for treating patients with localized primary gastrointestinal stromal tumors (GISTs) and discusses the impact of prolonged treatment with adjuvant imatinib on health care costs.

METHODS

A systematic review of the medical literature was conducted to explore recently reported clinical trials demonstrating the clinical benefit of adjuvant imatinib in GISTs, along with analyses discussing the economic impact of adjuvant imatinib.

RESULTS

Two phase III trials have demonstrated a significant clinical benefit of adjuvant imatinib treatment in GIST patients at risk of recurrence after tumor resection. Guidelines now suggest adjuvant treatment for at least 3 years in patients at high risk of recurrence. Despite this clinical effectiveness, prolonged use of adjuvant imatinib can lead to an increase in the risk for adverse events and to increased costs for both patients and health care systems. However, the increased cost is partially offset by cost reductions associated with delayed or avoided GIST recurrences. Three years of adjuvant treatment in high-risk patients was concluded to be cost-effective. Therefore, the careful selection of patients who are most likely to benefit from treatment can lead to improved clinical outcomes and significant cost savings.

CONCLUSION

Although introducing adjuvant imatinib has an economic impact on health plans, this effect seems to be limited. Several analyses have demonstrated that adjuvant imatinib is more cost-effective for treating localized primary GISTs than surgery alone. In addition, 3 years of adjuvant imatinib is more cost-effective than 1 year of adjuvant therapy.