Disease-free survival as a surrogate for overall survival in HR+/HER2- early breast cancer: A correlation analysis

BACKGROUND

Overall survival (OS) is a universally accepted measure of clinical benefit; however, prolonged follow-up is needed to observe sufficient events. Disease-free survival (DFS) has been widely adopted as a primary endpoint for early breast cancer (EBC) trials, as follow-up is comparatively shorter. Here, we present an analysis evaluating DFS as a surrogate for OS for adjuvant treatment of hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) EBC.

METHODS

A systematic literature review which included randomized controlled trials (RCTs) with ≥80% of adult patients with HR+/HER2- EBC was conducted. The RCTs evaluated various systemic therapeutic categories; key inclusion criteria included reporting of DFS and OS hazard ratios (HRs) and mature OS data. Spearman rank correlation and weighted linear regression analyses evaluated DFS and OS HR correlation. A scenario analysis tested base-case analysis robustness, and a parallel analysis using patient-level data was conducted.

RESULTS

The base case (N = 14 RCTs) showed an unweighted Spearman coefficient of 0.81 between OS and DFS (weighted: 0.81), with 84% of the variability in OS explained by DFS differences (R2 from weighted regression). The surrogate threshold effect (Burzykowski T, Buyse M. Pharm Stat. 2006;5:173-186) was 0.82 for DFS/OS HR. Scenario analysis (n = 9 RCTs), which excluded chemotherapy trials, and patient-level analysis using FACE trial data were consistent with the base-case analysis.

CONCLUSIONS

These analyses support DFS as a reliable surrogate endpoint for OS in adjuvant HR+/HER2- EBC trials. Using DFS as a surrogate measure will permit timelier access to novel treatments for patients with HR+/HER2- EBC.

Real-world effectiveness of voxelotor for treating sickle cell disease in the US: a large claims data analysis

BACKGROUND

Sickle cell disease (SCD) is a genetic disease that impacts patients' quality of life, healthcare costs, and life expectancy. Elevated sickle hemoglobin (HbS), which readily polymerizes, causes red blood cell sickling, leading to chronic hemolytic anemia and complications often requiring hospitalization and transfusions. In 2019, voxelotor, which inhibits HbS polymerization, was approved for SCD treatment.

OBJECTIVES

This study uses real-world evidence to assess voxelotor's effectiveness in SCD patients in typical clinical practice from 2019 to 2021 using a national medical claims database (N = 3128).

RESULTS

After initiating voxelotor, 60.8% of patients with available hemoglobin (Hb) laboratory data (n = 74) showed a Hb increase >1 g/dL. Mean transfusion rate per patient-year dropped 52% in patients with ≥1 transfusion before treatment (n = 190). In patients with ≥1 of the corresponding events (n = 1065), decreases were observed in mean vaso-occlusive crisis (VOC) frequency (-23%); mean VOC-related hospitalizations and length of stay (LOS) time (-34% and -30%, respectively); mean all-cause hospitalization and LOS time (-37% and -23%, respectively); outpatient visits (-10%); iron chelation use (-46%); and prescribed opioids (-13%).

CONCLUSION

These data align with randomized controlled trial results showing voxelotor improvements and support that voxelotor may lower transfusion and VOC rates in clinical practice.

Economic burden of disease progression among multiple myeloma patients who have received transplant and at least one line of therapy in the US

Effects of disease progression on healthcare resource utilization (HRU) and costs among multiple myeloma (MM) patients with ≥1 line of therapy (LOT) who received their first stem cell transplant (SCT) within 1 year of initial MM diagnosis were estimated using a large US claims database. Disease progression was defined as advancement to the next LOT, bone metastasis, hypercalcemia, soft tissue plasmacytoma, skeletal related events, acute kidney disease, or death within 12 months of LOT initiation. Annual HRU and costs in the first three LOTs (L1-L3) were compared for patients with versus without disease progression using inverse probability of treatment weighting to adjust for differences between groups in baseline characteristics. In all LOTs, mean annual hospitalizations and healthcare costs were greater for patients with versus without progression. Total incremental annual costs among patients with versus without progression in L1-L3 were $18,359, $87,055, and $71,917, respectively, among LOTs initiated between 2006 and 2018. In LOTs initiated between 2013 and 2018, the figures were $46,024, $100,329, and $101,942 in L1-L3, respectively. The economic burden of disease progression is substantial in this population of MM patients who underwent SCT and received systemic anti-myeloma therapy.

Cost-Effectiveness of Adding Zoledronic Acid to Endocrine Therapy in Premenopausal Women with Hormone-Responsive Early Breast Cancer in Sweden, Norway, Denmark, and Finland, Based on the ABCSG-12 Study

Background: The ABCSG-12 trial demonstrated that adding zoledronic acid 4 mg IV q 6 months (ZOL) to endocrine therapy with goserelin 3.6 mg sc q 28 days plus tamoxifen 20 mg oral qd or anastrozole 1mg oral qd (ET) in premenopausal women with hormone receptor positive (HR+) early breast cancer (EBC) improves disease free survival versus ET alone. The objective of this study was to estimate the cost-effectiveness of ZOL in this setting from the perspectives of the healthcare systems in Sweden, Norway, Denmark, and Finland.Material and Methods: A Markov model was used to project lifetime outcomes and costs of breast cancer care for premenopausal women with HR+ EBC receiving 3 yrs of ET or 3 yrs of ET plus ZOL. Cost-effectiveness was measured as the incremental cost per quality adjusted life year (QALY) gained. Probabilities of breast cancer recurrence were based on ABCSG-12 (median [maximum] follow-up 48 [84] months). Probabilities and costs were from the published literature. Results were generated under 2 scenarios: (1) benefits of ZOL persist to the maximum follow-up in ABCSG-12 (trial benefits); (2) benefits persist until recurrence or death (lifetime benefits). Local currencies were converted to Euros to facilitate cross-country comparisons.Results: Expected costs of 3 yrs of ZOL q6m (medication and administration) were €1,869 for Sweden, €1,947 for Norway, €2,647 for Finland, and €2,824 for Denmark. Under the trial benefits scenario, these costs were partially offset by savings in the expected lifetime costs of treatment of breast cancer recurrence of €1,105 for Sweden, €1,422 for Norway, €1,400 for Finland, and €1,585 for Denmark. ZOL was therefore projected to increase total costs by €800 for Sweden, €559 for Norway, €1,247 for Finland, and €1,293 for Denmark. QALYs gained with ZOL were 0.37 in all settings. Cost per QALY gained was therefore €2,162 for Sweden, €1,510 for Norway, €3,369 for Finland, and €3,494 for Denmark. Assuming lifetime benefits, savings from preventing breast cancer exceeded additional costs of ZOL for all four countries, with net savings of €3,364 for Sweden, €4,736 for Norway, €3,753 for Finland, and €4,644 for Denmark. QALYs gained with ZOL were similar across countries, ranging from 1.22 to 1.24. ZOL was therefore a “dominant” strategy (more effective and less costly) in all settings under this assumption.Conclusion: Adding ZOL to ET in premenopausal women with HR+ EBC may be highly cost-effective (<€50,000 per QALY gained) from the healthcare system perspectives of Sweden, Norway, Finland, and Denmark even under conservative assumptions of the duration of ZOL benefit. Adding ZOL to ET leads to cost savings in all four Nordic countries if benefits observed in ABCSG-12 are assumed to persist until disease progression or death.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4088.

Cost-effectiveness of zoledronic (ZOL) acid plus endocrine therapy (ET) in premenopausal women with early breast cancer (EBC) from a Canadian perspective

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Background: The Austrian Breast and Colorectal Cancer Study Group Trial 12 (ABCSG-12) examined the efficacy of 3 years (yrs) of treatment with goserelin in combination with ET (anastrozole or tamoxifen) with or without ZOL 4 mg q6 mos in 1,803 premenopausal women with EBC (median age 45 yrs). After a median follow-up of 47.8 mos (max 84 mos), risk of disease-free survival (DFS) events was reduced by 36% (HR = 0.64; p = 0.01) in patients (pts) who received ZOL (ZOL+ET) compared with those who did not (ET). Methods: A Markov model was used to estimate the cost per quality adjusted life years (QALYs) gained of 3 years treatment duration of ZOL+ET versus ET-only in premenopausal women with EBC based on results of the ABCSG-12. A Canadian healthcare system perspective and a lifetime timeframe were used. Outcomes and cost of breast cancer recurrence were based on recent published studies. Results were generated under 2 scenarios regarding duration of benefit (reduction in risk of recurrence) with ZOL: (1) Benefits persist to maximum follow-up in ABCSG-12 (trial benefit); (2) Benefits persist until death (lifetime benefit). Results: The cost of 3 years of ZOL (medication and administration) is 4 191 $CDN. Under the lifetime benefit scenario, 73% of these costs are offset by savings in the cost of recurrences. Under the trial benefit scenario, 12% are offset. QALYs gained are 1.63 yrs and 0.52 yrs under the lifetime and trial benefit scenarios respectively; cost-effectiveness is 1 122 $CDN and 3 675 $CDN per QALY gained respectively, which is well below the 50 000 $CDN per QALY threshold frequently used to assess whether therapies are cost-effective. Conclusions: The combination of ZOL + ET is a cost-effective use of healthcare resources from a Canadian healthcare system perspective.

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Cost utility analysis of early adjuvant letrozole or anastrozole versus tamoxifen in postmenopausal women with early invasive breast cancer: the UK perspective

Five years with the aromatase inhibitors letrozole or anastrozole is clinically superior to 5 years tamoxifen in postmenopausal women with early breast cancer. This paper analyses the cost-effectiveness of the aromatase inhibitors compared to tamoxifen using the same health economic model. A Markov model describes lifetime incidence of breast cancer events and treatment-related adverse events. Probabilities of disease progression, adverse events, and utility values were estimated using secondary sources; costs of breast-cancer care were obtained from a primary costing study. The incremental cost per QALY gained of letrozole vs. tamoxifen is 10,379pounds (95% CI 6,705-23,574pounds), and of anastrozole versus tamoxifen is 11,428pounds (95% CI 6,211-48,795pounds). If a 5-year carry over effect for the reduction in breast cancer events is assumed, the incremental costs per QALY gained compared to tamoxifen are 6,253pounds (95% CI 3,675-14,766pounds) for letrozole and 7,015pounds (95% CI 3,316-31,997pounds) for anastrozole. Five years of letrozole or anastrozole therapy is cost-effective in postmenopausal women with early breast cancer. Though the respective confidence intervals show significant overlap, letrozole has a 95% probability of being more cost-effective than tamoxifen at a 20,000pounds QALY value, whilst anastrozole has an 85% probability.

Cost-Effectiveness of Letrozole in the Extended Adjuvant Treatment of Women with Early Breast Cancer

Adjuvant tamoxifen therapy for 5 years reduces recurrence in hormone receptor positive, post-menopausal women with early breast cancer, but offers no advantage when prolonged to another 5 years, during which the risk of recurrence remains high. Treating patients, who remain disease-free after 5 years of tamoxifen, with letrozole significantly reduces recurrence, regardless of nodal status. This study evaluated the life-time cost-utility of extended adjuvant letrozole therapy in 62-year-old patients from a third-party payer perspective. A Markov model incorporated locoregional, contralateral, and metastatic recurrences. The comparator was placebo. Event rates were based on published trials. Utility values were taken from a clinical trial and published literature. Costs were obtained from published literature, provincial payment schedules, cancer agencies, and drug plans formularies. Resource use reflected Canadian treatment patterns. Robustness of the model was tested using deterministic and probabilistic sensitivity analyses. Extended adjuvant letrozole therapy of a cohort consisting of 50% node-negative and 50% node-positive patients prolonged their lives on average by 0.466 years or 0.267 quality-adjusted life years (QALYs) at an additional cost of Can$8,031 per patient, yielding an incremental cost-utility ratio (ICUR) of $34,058 per QALY. Letrozole was more cost-effective in node-positive than in node-negative patients (Can$26,553 vs Can$46,049 per QALY). Results were robust to variations in age, healthcare costs, and utilities. The degree of confidence that the cost per QALY would be below Can$50,000 reached 100% for node-positive and 77% for node-negative patients. Extended adjuvant letrozole is cost-effective in both node-negative and node-positive patients having ICURs below Can$50,000/QALY.

Retrospective study of the effect of skeletal complications on total medical care costs in patients with bone metastases of breast cancer seen in typical clinical practice

Intravenous bisphosphonates are effective in reducing the incidence of skeletal-related events (SREs) in women with bone metastases of breast cancer. The cost-effectiveness of such therapy depends in part on the potential cost savings achieved by preventing these events. However, estimates of the costs of SREs in women with bone metastases of breast cancer in typical US clinical practice are unavailable. The purpose of this study was to estimate the treatment costs of clinically significant SREs and the impact of these events on total medical care costs in patients with bone metastases of breast cancer. Data were gathered from a large US health insurance claims database. Patients with bone metastases of breast cancer who experienced one or more clinically significant SREs in typical clinical practice were matched to similar patients without SREs based on propensity scores. Kaplan-Meier estimated total medical care costs were compared over 60 months for propensity-matched samples of patients with SREs and without SREs. We identified 617 patients with breast cancer and bone metastases, including 321 (52%) with > or = 1 clinically significant SRE. After matching, there were 201 patients each in the SRE and no-SRE groups, with mean follow-up of 13.8 and 11.0 months, respectively. In the SRE group, costs of treatment of SREs were $13,940 (95% CI, $11,240-$16,856) per patient. Total medical care costs were $48,173 (95% CI, $19,068-$77,684) greater in SRE versus no-SRE patients (P = 0.001). The costs of clinically significant SREs in patients with breast cancer and bone metastases seen in typical clinical practice are substantial. Treatments that reduce the incidence of SREs, such as intravenous bisphosphonates, should reduce these costs.

Cost effectiveness of extended adjuvant letrozole in postmenopausal women after adjuvant tamoxifen therapy: the UK perspective

BACKGROUND

MA17 was a randomised placebo-controlled trial of letrozole 2.5 mg/day in 5187 estrogen receptor-positive, 50% node-negative, postmenopausal women (median age 62 years at enrollment) with early breast cancer, post-5 years' adjuvant tamoxifen therapy. The objective of this evaluation was to extrapolate the findings from the MA17 trial to estimate the lifetime cost effectiveness of letrozole in this setting.

METHODS

A Markov model was used to estimate the incremental cost per QALY gained with extended adjuvant letrozole versus no therapy. Probabilities of disease progression and death were estimated using data from the MA17 study and other secondary sources. Costs of breast cancer care (letrozole therapy, surveillance, recurrences, terminal care) and treatment of osteoporosis and utilities were derived from literature. A full probabilistic sensitivity analysis was undertaken. The analysis was conducted from the perspective of the UK National Health Service (NHS) and cost estimates reflect 2004 values. All costs and outcomes were discounted at 3.5%.

RESULTS

Extended adjuvant letrozole resulted in a gain of 0.36 QALYs per patient (13.66 vs 13.30 with no therapy). These benefits were obtained at an additional expected lifetime cost of 3732 pounds per patient (10,833 pounds letrozole vs 7101 pounds with no therapy). Cost effectiveness was estimated at 10,338 pounds per QALY gained (95% CI 5276, 43,828). The results were robust to sensitivity analyses.

CONCLUSION

Five years of letrozole therapy appears to be cost effective from the NHS perspective and should be considered in women with early breast cancer, following tamoxifen adjuvant therapy.

The Cost of Treatment of Skeletal-Related Events in Patients with Bone Metastases from Lung Cancer

PURPOSE

Patients with bone metastases from lung cancer often experience skeletal-related events (SREs) including pathological fracture, spinal cord compression, hypercalcemia or pain requiring surgery, radiotherapy or opioid analgesics. These complications result in impaired mobility and reduced quality of life and have a significant negative impact on survival. The economic consequences of SREs in patients with lung cancer have not been examined.

METHODS

We conducted a retrospective analysis using a large US health insurance claims database to estimate the incidence and costs of treatment of SREs in patients with bone metastases of lung cancer treated in a naturalistic setting. Study subjects had >/=2 encounters with a diagnosis of primary lung cancer and >/=2 encounters with a diagnosis of metastases to bone. SREs were identified based on the occurrence on or after the date of first diagnosis of bone metastases, of (1) >/=1 encounter with a diagnosis of pathological fracture, spinal cord compression or hypercalcemia, (2) >/=1 bone surgery or radiotherapy procedure, or (3) the initiation of opioid analgesic therapy. Survival and costs of SRE-related care in patients with SREs were estimated using Kaplan-Meier methods.

RESULTS

We identified 534 patients with lung cancer and bone metastases, including 295 (55%) with >/=1 SRE. Radiotherapy (68%) and fracture (35%) were the most common SREs. Median survival after the first identified SRE was 4.1 months (95% confidence interval: 3.6-5.5 months). The estimated lifetime SRE-related cost per patient was USD 11,979 (95% confidence interval: USD 10,193-13,766). Radiotherapy accounted for the greatest proportion of cost (61%) by SRE type.

CONCLUSION

The economic burden of SREs in patients with bone metastases of lung cancer is substantial. Intravenous bisphosphonates, such as zoledronic acid, which have been shown to prevent these events, may reduce these costs.