Health state utilities associated with treatment for transfusion-dependent β-thalassemia

Cost-Effectiveness of Lovotibeglogene Autotemcel (Lovo-Cel) Gene Therapy for Patients with Sickle Cell Disease and Recurrent Vaso-Occlusive Events in the United States

BACKGROUND AND OBJECTIVE

Gene therapies for sickle cell disease (SCD) may offer meaningful benefits for patients and society. This study evaluated the cost-effectiveness of lovotibeglogene autotemcel (lovo-cel), a one-time gene therapy administered via autologous hematopoietic stem cell transplantation, compared with common care for patients in the United States (US) with SCD aged ≥ 12 years with ≥ 4 vaso-occlusive events (VOEs) in the past 24 months.

METHODS

We developed a patient-level simulation model accounting for lovo-cel and SCD-related events, complications, and mortality over a lifetime time horizon. The pivotal phase 1/2 HGB-206 clinical trial (NCT02140554) served as the basis for lovo-cel efficacy and safety. Cost, quality-of-life, and other clinical data were sourced from HGB-206 data and the literature. Analyses were conducted from US societal and third-party payer perspectives. Uncertainty was assessed through probabilistic sensitivity analysis and extensive scenario analyses.

RESULTS

Patients treated with lovo-cel were predicted to survive 23.84 years longer on average (standard deviation [SD], 12.80) versus common care (life expectancy, 62.24 versus 38.40 years), with associated discounted patient quality-adjusted life-year (QALY) gains of 10.20 (SD, 4.10) and direct costs avoided of $1,329,201 (SD, $1,346,446) per patient. Predicted societal benefits included discounted caregiver QALY losses avoided of 1.19 (SD, 1.38) and indirect costs avoided of $540,416 (SD, $262,353) per patient. Including lovo-cel costs ($3,282,009 [SD, $29,690] per patient) resulted in incremental cost-effectiveness ratios of $191,519 and $124,051 per QALY gained from third-party payer and societal perspectives, respectively. In scenario analyses, the predicted cost-effectiveness of lovo-cel also was sensitive to baseline age and VOE frequency and to the proportion of patients achieving and maintaining complete resolution of VOEs.

CONCLUSIONS

Our analysis of lovo-cel gene therapy compared with common care for patients in the US with SCD with recurrent VOEs estimated meaningful improvements in survival, quality of life, and other clinical outcomes accompanied by increased overall costs for the health care system and for broader society. The predicted economic value of lovo-cel gene therapy was influenced by uncertainty in long-term clinical effects and by positive spillover effects on patient productivity and caregiver burden.

Health State Utilities Associated with False-Positive Cancer Screening Results

INTRODUCTION

Early cancer detection can significantly improve patient outcomes and reduce mortality rates. Novel cancer screening approaches, including multi-cancer early detection tests, have been developed. Cost-utility analyses will be needed to examine their value, and these models require health state utilities. The purpose of this study was to estimate the disutility (i.e., decrease in health state utility) associated with false-positive cancer screening results.

METHODS

In composite time trade-off interviews using a 1-year time horizon, UK general population participants valued 10 health state vignettes describing cancer screening with true-negative or false-positive results. Each false-positive vignette described a common diagnostic pathway following a false-positive result suggesting lung, colorectal, breast, or pancreatic cancer. Every pathway ended with a negative result (no cancer detected). The disutility of each false positive was calculated as the difference between the true-negative and each false-positive health state, and because of the 1-year time horizon, each disutility can be interpreted as a quality-adjusted life-year decrement associated with each type of false-positive experience.

RESULTS

A total of 203 participants completed interviews (49.8% male; mean age = 42.0 years). The mean (SD) utility for the health state describing a true-negative result was 0.958 (0.065). Utilities for false-positive health states ranged from 0.847 (0.145) to 0.932 (0.059). Disutilities for false positives ranged from - 0.031 to - 0.111 (- 0.041 to - 0.111 for lung cancer; - 0.079 for colorectal cancer; - 0.031 to - 0.067 for breast cancer; - 0.048 to - 0.088 for pancreatic cancer).

CONCLUSION

All false-positive results were associated with a disutility. Greater disutility was associated with more invasive follow-up diagnostic procedures, longer duration of uncertainty regarding the eventual diagnosis, and perceived severity of the suspected cancer type. Utility values estimated in this study would be useful for economic modeling examining the value of cancer screening procedures.

Assessment of health state utilities associated with adult and pediatric acid sphingomyelinase deficiency (ASMD)

INTRODUCTION

Acid sphingomyelinase deficiency (ASMD) type B is a rare genetic disorder leading to enlargement of the spleen and liver, pulmonary dysfunction, and other symptoms. Cost-utility analyses are often conducted to quantify the value of new treatments, and these analyses require health state utilities. Therefore, the purpose of this study was to estimate utilities associated with varying levels of severity of adult and pediatric ASMD type B.

METHODS

Seven adult and seven child health state vignettes describing ASMD were developed based on published literature, clinical trial results, and interviews with clinicians, patients with ASMD, and parents of children with ASMD. The health states were valued in time trade-off interviews with adult general population respondents in the UK.

RESULTS

Interviews were completed with 202 participants (50.0% female; mean age = 41.3 years). The health state representing ASMD without impairment had the highest mean utility for both the adult and child health states (0.92/0.94), and severe ASMD had the lowest mean utility (0.33/0.45). Every child health state had a significantly greater utility than the corresponding adult health state. Differences between adult/child paired states ranged from 0.02 to 0.13. Subgroup analyses explored the impact of parenting status on valuation of child health states.

DISCUSSION

Greater severity of ASMD was associated with lower mean utility. Results have implications for valuation of pediatric health states. The resulting utilities may be useful in cost-utility modeling estimating the value of treatment for ASMD.

Gene Therapy Versus Common Care for Eligible Individuals With Sickle Cell Disease in the United States : A Cost-Effectiveness Analysis

BACKGROUND

Sickle cell disease (SCD) and its complications contribute to high rates of morbidity and early mortality and high cost in the United States and African heritage community.

OBJECTIVE

To evaluate the cost-effectiveness of gene therapy for SCD and its value-based prices (VBPs).

DESIGN

Comparative modeling analysis across 2 independently developed simulation models (University of Washington Model for Economic Analysis of Sickle Cell Cure [UW-MEASURE] and Fred Hutchinson Institute Sickle Cell Disease Outcomes Research and Economics Model [FH-HISCORE]) using the same databases.

DATA SOURCES

Centers for Medicare & Medicaid Services claims data, 2008 to 2016; published literature.

TARGET POPULATION

Persons eligible for gene therapy.

TIME HORIZON

Lifetime.

PERSPECTIVE

U.S. health care sector and societal.

INTERVENTION

Gene therapy versus common care.

OUTCOME MEASURES

Incremental cost-effectiveness ratios (ICERs), equity-informed VBPs, and price acceptability curves.

RESULTS OF BASE-CASE ANALYSIS

At an assumed $2 million price for gene therapy, UW-MEASURE and FH-HISCORE estimated ICERs of $193 000 per QALY and $427 000 per QALY, respectively, under the health care sector perspective. Corresponding estimates from the societal perspective were $126 000 per QALY and $281 000 per QALY. The difference in results between models stemmed primarily from considering a slightly different target population and incorporating the quality-of-life (QOL) effects of splenic sequestration, priapism, and acute chest syndrome in the UW model. From a societal perspective, acceptable (>90% confidence) VBPs ranged from $1 million to $2.5 million depending on the use of alternative effective metrics or equity-informed threshold values.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to the costs of myeloablative conditioning before gene therapy, effect on caregiver QOL, and effect of gene therapy on long-term survival.

LIMITATION

The short-term effects of gene therapy on vaso-occlusive events were extrapolated from 1 study.

CONCLUSION

Gene therapy for SCD below a $2 million price tag is likely to be cost-effective when applying a societal perspective at an equity-informed threshold for cost-effectiveness analysis.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute.

Disutilities Associated with Intravenous Iron Infusions: Results from a Time Trade-off Survey and Diminishing Marginal Utility Model for Treatment Attributes in China

Purpose

Treatment process attributes can affect health state utilities associated with therapy. For intravenous iron, used to treat iron deficiency and iron deficiency anemia, research into process attributes is still lacking. This study estimated utilities associated with process attributes for intravenous iron infusions.

Methods

An online survey including seven health state vignettes and time trade-off tasks was administered to participants, who were not patients living with iron deficiency or iron deficiency anemia, from a Chinese online panel. Vignettes used an identical description of iron deficiency and iron deficiency anemia but differed in the annual number of infusions, infusion duration, and infusion-associated risk of hypophosphatemic osteomalacia. Disutilities and their rate of change as the number of infusions increased were examined using a power model.

Results

The survey was completed by 1091 participants. The highest utilities were observed for one annual infusion of 15-30 minutes or 30-60 minutes, without risk of hypophosphatemic osteomalacia (0.754 and 0.746, respectively). In comparison, more infusions and infusions with a risk of hypophosphatemic osteomalacia were associated with lower utilities. Utility continued to decrease, but at a diminishing rate, as the annual number of infusions increased, with utility decrements of 0.006 and 0.002, respectively, when going from zero to one and from four to five infusions per year. All marginal disutilities were small (values <0.01).

Conclusion

This study suggested that treatment attributes of intravenous iron infusions affect health state utilities. Using intravenous iron formulations that allow for fewer and shorter infusions without the risk of hypophosphatemic osteomalacia can reduce the number of visits required and increase patients' quality of life.

Health state utilities for beta-thalassemia: a time trade-off study

BACKGROUND

Beta-thalassemia (BT) is an inherited blood disorder characterized by reduced levels of functional hemoglobin resulting in phenotypes ranging from clinically asymptomatic to severely anemic. Patients with BT may require lifelong regular blood transfusions supported by appropriate iron chelation therapy (ICT). This study aimed to determine how the UK general population values BT health states associated with differing transfusion burden and ICT.

METHODS

Composite time trade-off (cTTO) methodology was employed to elicit health state utilities in BT. Relevant BT literature related to symptom and quality-of-life impact, including physical, functional, and emotional well-being, and safety profiles of BT treatments were considered when drafting health state descriptions. Eleven health state descriptions were developed and validated by hematologists and patient advocates for clinical accuracy and completeness. 200 individuals from the UK general population participated in the cTTO interviews.

RESULTS

The mean age of participants was 41.50 years (SD 16.01, range 18-81); 88 (46.8%) were female. Utility values ranged from 0.78 (SD 0.34) for non-transfusion dependent BT with oral ICT to 0.37 (SD 0.50) for high transfusion burden with subcutaneous ICT in transfusion-dependent BT.

CONCLUSIONS

This study provides health utilities for a range of BT health states from the UK general population perspective. Importantly, lower transfusion burden and lower burden of anemia were associated with higher utilities. To a lesser extent, differential modes of ICT were found to impact utility valuations in patients with BT. The utilities obtained in this study can be employed as inputs in cost-effectiveness analyses of BT therapies.

Health State Utilities for Adverse Events Associated with Chimeric Antigen Receptor T-Cell Therapy in Large B-Cell Lymphoma

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy provides effective treatment for large B-cell lymphoma (LBCL). Cost-utility analyses examining and comparing the value of these treatments require health state utilities representing key characteristics to differentiate among therapies. This study estimated utilities for adverse events (AEs) associated with CAR T-cell therapy, including cytokine release syndrome (CRS) and neurological events (NEs).

METHODS

Health state vignettes were drafted based on literature review, AE reports from a trial of CAR T-cell therapy, and clinician input. Health states were valued in time trade-off interviews with general population participants in the UK. The first vignette described relapsed/refractory LBCL treated with CAR T-cell therapy without AEs. Five other vignettes had the same LBCL and treatment description, with the addition of an AE. Disutilities (i.e., utility decrease) associated with these AEs were calculated by subtracting the utility of the health state without AEs from those of the other health states.

RESULTS

Interviews were completed with 218 participants (50% male; mean age 49 years). Mean (standard deviation [SD]) utility for CAR T-cell therapy without AEs was 0.73 (0.30). Mean (SD) disutilities associated with CRS were -0.01 (0.04) for grade 1, -0.05 (0.09) for grade 2, and -0.23 (0.24) for grade 3/4. Mean (SD) disutilities associated with NEs were -0.04 (0.07) for grade 1/2 and -0.18 (0.22) for grade 3/4.

CONCLUSIONS

More severe AEs were associated with greater disutilities. Health state utilities estimated in this study may be useful in cost-effectiveness models examining the value of CAR T-cell therapy in patients with LBCL.

Cost Utility of Lifelong Immunoglobulin Replacement Therapy vs Hematopoietic Stem Cell Transplant to Treat Agammaglobulinemia

IMPORTANCE

Lifelong immunoglobulin replacement therapy (IRT) is standard-of-care treatment for congenital agammaglobulinemia but accrues high annual costs ($30 000-$90 000 per year) and decrements to quality of life over patients' life spans. Hematopoietic stem cell transplant (HSCT) offers an alternative 1-time therapy, but has high morbidity and mortality.

OBJECTIVE

To evaluate the cost utility of IRT vs matched sibling donor (MSD) and matched unrelated donor (MUD) HSCT to treat patients with agammaglobulinemia in the US.

DESIGN, SETTING, AND PARTICIPANTS

This economic evaluation used Markov analysis to model the base-case scenario of a patient aged 12 months with congenital agammaglobulinemia receiving lifelong IRT vs MSD or MUD HSCT. Costs, probabilities, and quality-of-life measures were derived from the literature. Microsimulations estimated premature deaths for each strategy in a virtual cohort. One-way sensitivity and probabilistic sensitivity analyses evaluated uncertainty around parameter estimates performed from a societal perspective over a 100-year time horizon. The threshold for cost-effective care was set at $100 000 per quality-adjusted life-year (QALY). This study was conducted from 2020 across a 100-year time horizon.

EXPOSURES

Immunoglobulin replacement therapy vs MSD or MUD HSCT for treatment of congenital agammaglobulinemia.

MAIN OUTCOMES AND MEASURES

The primary outcomes were incremental cost-effectiveness ratio (ICER) expressed in 2020 US dollars per QALY gained and premature deaths associated with each strategy.

RESULTS

In this economic evaluation of patients with congenital agammaglobulinemia, lifelong IRT cost more than HSCT ($1 512 946 compared with $563 776 [MSD] and $637 036 [MUD]) and generated similar QALYs (20.61 vs 17.25 [MSD] and 17.18 [MUD]). Choosing IRT over MSD or MUD HSCT yielded ICERs of $282 166 per QALY gained over MSD and $255 633 per QALY gained over MUD HSCT, exceeding the US willingness-to-pay threshold of $100 000/QALY. However, IRT prevented at least 2488 premature deaths per 10 000 microsimulations compared with HSCT. When annual IRT price was reduced from $60 145 to below $29 469, IRT became the cost-effective strategy. Findings remained robust in sensitivity and probabilistic sensitivity analyses.

CONCLUSIONS AND RELEVANCE

In the US, IRT is more expensive than HSCT for agammaglobulinemia treatment. The findings of this study suggest that IRT prevents more premature deaths but does not substantially increase quality of life relative to HSCT. Reducing US IRT cost by 51% to a value similar to IRT prices in countries implementing value-based pricing may render it the more cost-effective strategy.

Economic evaluation of betibeglogene autotemcel (Beti-cel) gene addition therapy in transfusion-dependent β-thalassemia

Background: Standard of care (SoC) for transfusion-dependent β-thalassemia (TDT) requires lifelong, regular blood transfusions as well as chelation to reduce iron accumulation. Objective: This study investigates the cost-effectiveness of betibeglogene autotemcel ('beti-cel'; LentiGlobin for β-thalassemia) one-time, gene addition therapy compared to lifelong SoC for TDT. Study design: Microsimulation model simulated the lifetime course of TDT based on a causal sequence in which transfusion requirements determine tissue iron levels, which in turn determine risk of iron overload complications that increase mortality. Clinical trial data informed beti-cel clinical parameters; effects of SoC on iron levels came from real-world studies; iron overload complication rates and mortality were based on published literature. Setting: USA; commercial payer perspective Participants: TDT patients age 2-50 Interventions: Beti-cel is compared to SoC. Main outcome measure: Incremental cost-effectiveness ratio (ICER) utilizing quality-adjusted life-years (QALYs) Results: The model predicts beti-cel adds 3.8 discounted life years (LYs) or 6.9 QALYs versus SoC. Discounted lifetime costs were $2.28 M for beti-cel ($572,107 if excluding beti-cel cost) and $2.04 M for SoC, with a resulting ICER of $34,833 per QALY gained. Conclusion: Beti-cel is cost-effective for TDT patients compared to SoC. This is due to longer survival and cost offset of lifelong SoC.

Vignette-Based Utilities: Usefulness, Limitations, and Methodological Recommendations

Health technology assessment agencies often prefer that utilities used to calculate quality-adjusted life years in cost-utility analyses (CUAs) are derived using standardized methods, such as generic preference-based measures completed by patients in clinical trials. However, there are situations when no standardized approach is feasible or appropriate for a specific medical condition or treatment that must be represented in a CUA. When this occurs, vignette-based methods are often used to estimate utilities. A vignette (sometimes called a "scenario," "health state description," "health state vignette," or "health state") is a description of a health state that is valued in a preference elicitation task to obtain a utility estimate. This method is sometimes the only feasible way to estimate utilities representing a concept that is important for a CUA. Consequently, vignette-based studies continue to be conducted and published, with the resulting utilities used in economic models to inform decision making about healthcare resource allocation. Despite the potential impact of vignette-based utilities on medical decision making, there is no published guidance or review of this methodology. This article provides recommendations for researchers, health technology assessment reviewers, and policymakers who may be deciding whether to use vignette-based methods, designing a vignette study, using vignette-based utilities in a CUA, or evaluating a CUA that includes vignette-based utilities. Recommendations are provided on: (A) when to use vignette-based utilities, (B) methods for developing vignettes, (C) valuing vignettes, (D) use of vignette-based utilities in models, and (E) limitations of vignette methods.