Burden of illness among Medicare and non-Medicare US populations with acquired thrombotic thrombocytopenic purpura

A Systematic Review of the Epidemiology and Disease Burden of Congenital and Immune-Mediated Thrombotic Thrombocytopenic Purpura

Congenital (cTTP) and immune-mediated (iTTP) thrombotic thrombocytopenic purpura are serious and rare clotting disorders resulting from a deficiency in the ADAMTS13 enzyme. A systematic review was conducted using the Ovid® MEDLINE & Embase databases to synthesize the epidemiology and burden of cTTP and iTTP worldwide (from January 1, 2010, to February 6, 2020, with an update that covered the period January 1, 2020-February 11, 2022). Outcomes of interest were incidence and prevalence of TTP, incidence of acute episodes, mortality, burden of illness (eg complications, healthcare utilization, patient-reported outcomes) and disease management. A total of 221 eligible observational studies were included. The incidence rate of acute episodes ranged from 0.19-0.35 person-years in adult patients with cTTP, and 1.81-3.93 per million persons per year for iTTP in the general population. Triggers of acute episodes were similar for cTTP and iTTP, with pregnancy and infection the most commonly observed. Exacerbation in patients with iTTP varied widely, ranging from 2.4-63.1%. All-cause mortality was observed in 0-13.4% of patients with cTTP, across studies and follow-up periods, and in 1.1% (median follow-up: 0.4 years) to 18.8% (1 year) of patients with iTTP during acute episodes. Cardiovascular, renal, and neurological disease were common complications. TTP also led to work disturbances, feelings of anxiety and depression, and general activity impairment. TTP treatment regimens used were generally reflective of current treatment guidelines. The evidence identified describes a high patient burden, highlighting the need for effective treatment regimens leading to improvements in outcomes. Considerable evidence gaps exist, particularly for disease epidemiology, patient-reported outcomes, costs of disease management, and associated healthcare resource utilization. This review may help increase disease awareness and highlights the need for additional real-world studies, particularly in geographical regions outside the United States and Western Europe.

Background incidence rates of health outcomes of interest for COVID-19 vaccine safety monitoring in a US population: a claims database analysis

OBJECTIVE

To evaluate background incidence rates of 59 health outcomes of interest (HOI) in a diverse population, including important subpopulations, during the pre-COVID-19 era (1 January 2017-31 December 2019) and the COVID-19 era (1 March 2020-31 December 2020), before the introduction of COVID-19 vaccines.

DESIGN

Observational retrospective cohort study. Annual incidence rates and 95% confidence intervals (CIs) of HOIs were estimated for each population of interest, stratified by: age, sex, age and sex and seasonality.

DATA SOURCE

Optum's de-identified Clinformatics Data Mart Database (CDM).

PARTICIPANTS

Individuals from the US general population and four subgroups of interest: influenza-vaccinated, paediatric (<18 years of age), elderly (≥65 years of age) and pregnant women.

RESULTS

During the COVID-19 era, the incidence of several cardiac conditions, coagulation disorders and acute liver injury increased across all populations assessed while the rates of some dermatological and neurological HOIs decreased relative to the pre-COVID-19 era. The incidence of acute respiratory distress syndrome (ARDS) varied considerably by subgroup: among the elderly, it decreased annually during the pre-COVID-19 era but peaked during the COVID-19 era; among pregnant women, it slightly increased annually during the pre-COVID-19 era and substantially increased during the COVID-19 era; among paediatrics, it decreased annually over the entire study. The incidence of the majority of HOIs increased with age, but were generally comparable between sexes with few exceptions. Cardiac, gastrointestinal, neurological and haematological HOIs, along with acute kidney injury and ARDS, were more common in males, whereas several immunological HOIs and chilblain-like lesions were more common in females. Pregnancy-related HOIs did not increase during the COVID-19 era, except for spontaneous abortions which increased annually over the entire study.

CONCLUSION

These observations help contextualise fluctuations in background rates of adverse events noted during the COVID-19 era, and provide insight on how their use may impact safety surveillance for other vaccines.

Should we consider caplacizumab as routine treatment for acute thrombotic thrombocytopenic purpura? An expert perspective on the pros and cons

INTRODUCTION

Immune thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening disorder. Caplacizumab has been the latest drug incorporated into the initial treatment of acute episodes, allowing for faster platelet recovery and a decrease in refractoriness, exacerbation, thromboembolic events, and mortality. However, caplacizumab is also associated with a bleeding risk and higher treatment costs, which prevent many centers from using it universally.

AREAS COVERED

Studies that included iTTP and/or caplacizumab to date were selected for this review using PubMed and MEDLINE platforms. We describe outcomes in the pre-caplacizumab era and after it, highlighting the benefits and risks of its use early in frontline, and also pointing out special situations that require careful management.

EXPERT OPINION

It is clear that the availability of caplacizumab has significantly and favorably impacted the management of iTTP patients. Whether this improvement is cost-effective still remains uncertain, and data on long-term sequelae and different healthcare systems will help to clarify this point. In addition, evidence of the bleeding/thrombotic risk of iTTP patients under this drug needs to be better addressed in future studies.

Global Health Resource Utilization and Cost-Effectiveness of Therapeutics and Diagnostics in Immune Thrombotic Thrombocytopenic Purpura (TTP)

In this review, we examine the current landscape of health resource utilization and cost-effectiveness data in the care of patient populations with immune thrombotic thrombocytopenic purpura. We focus on the therapeutic (therapeutic plasma exchange, glucocorticoids, rituximab, caplacizumab) and diagnostic (ADAMTS13 assay) health technologies employed in the care of patients with this rare disease. Health resource utilization and cost-effectiveness data are limited to the high-income country context. Measurement of TTP-specific utility weights in the high-income country context and collection of health resource utilization data in the low- and middle-income country settings would enable an evaluation of country-specific quality-adjusted life expectancy and cost-effectiveness of these therapeutic and diagnostic health technologies. This quantification of value is one way to mitigate cost concerns where they exist.

Effectiveness and safety of caplacizumab in acquired thrombotic thrombocytopenic purpura: health technology assessment and classification according to the methodology established in Colombia

OBJECTIVES

Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare hematological disease whose clinical management includes caplacizumab along with plasma exchange and immunosuppression, according to international guidelines. Caplacizumab has been available in Colombia since 2022. This study seeks to determine the therapeutic classification of caplacizumab according to the methodology of the Instituto de Evaluación Tecnológica en Salud.

METHODS

The classification was carried out through a deliberative process following the modified Delphi technique, with a panel of experts, made up of four hemato-oncologists, a pharmaceutical chemist, and a patient. The results of effectiveness and safety obtained through a systematic review, therapeutic thresholds (clinical significance), and degree of acceptability (willingness to use the technology) were used for the classification.

RESULTS

Fourteen effectiveness and safety outcomes were submitted for the classification process. Caplacizumab showed clinical significance for some effectiveness outcomes, was not considered inferior in terms of safety, and displayed acceptability of use. Through consensus, the panel determined that caplacizumab plus the standard regimen is superior to the standard regimen in terms of treatment response and composite outcome, and no different for the other effectiveness and safety outcomes. Likewise, in overall terms, the panel determined that caplacizumab together with the standard regimen is superior to the standard regimen.

CONCLUSION

Treatment with caplacizumab together with the standard regimen was considered superior to the standard regimen for the treatment of patients with aTTP, as it showed clinically significant benefits in critical outcomes for decision making, and a safety profile no different to its comparator.

Cost-consequence analysis of diagnosis and early treatment of acquired thrombotic thrombocytopenic purpura in Colombia

INTRODUCTION

The objective of the study was to evaluate the costs and benefits of early identification and treatment (within 24 hours of admission) of patients with aTTP in Colombia.

METHODS

A cost-consequence analysis was conducted to evaluate the costs and health outcomes of diagnosis and early treament versus no treatment (scenario 1) and late treatment (scenario 2) in a hypothetical cohort of 100 patients with aTTP. The analysis perspective was that of the third-party payer.

RESULTS

In scenario 1, he total cost of early treatment was USD$515,157 compared to USD$293,265 for no treatment. Early treatment avoided 65 deaths in the hypothetical cohort. The cost per death avoided was USD$3,414. In scenario 2, the cost of early treatment was USD$935,507 compared to USD$809,103 in the late start of treatment. By treating patients early, 33 deaths were avoided, 23 patients were estimated to be alive without exacerbations and 16 without relapses. The cost per death avoided was USD$3,879 and the cost per patient alive without exacerbations and relapses was USD$5,611 and USD$7,858, respectively.

CONCLUSIONS

The early identification and treatment of patients with aTTP are associated with benefits in survival and recurrence-free survival, and an incremental cost in the process of care compared to no treatment or late treatment.

Cost analysis of the impact of caplacizumab in the treatment of acquired thrombotic thrombocytopenic purpura from a US hospital perspective

AIM

This study aimed to model the financial impact of caplacizumab with therapeutic plasma exchange (TPE) + immunosuppression for patients experiencing an acute acquired thrombotic thrombocytopenic purpura (aTTP) episode versus TPE + immunosuppression, from a US hospital's perspective.

METHODS AND MATERIALS

We developed an economic model to estimate the impact of caplacizumab on a US hospital's budget. Cost offsets from caplacizumab utilization targeted inpatient general ward days, intensive care unit (ICU) days, and TPE utilization. Costs and event probabilities were estimated from primary data analyses of the phase 3 HERCULES trial and peer-reviewed literature or other public sources. Plan reimbursement was obtained from 2019 Medicare Fee Schedules and adjusted to represent reimbursement from different US payers. Cost of ICU and general ward utilization were estimated from Medicare Provider Analysis and Review data analyses capturing hospital discharges.

RESULTS

The model results indicate that caplacizumab leads to hospitalization cost savings of over $8,000 ($23,148 versus $14,904) along with TPE cost savings of over $14,000 ($37,150 versus $23,033) per patient. When the cost of caplacizumab and plan reimbursement are incorporated into the results, the per-patient cost of TPE + immunosuppression is $23,120 versus $70,068 for caplacizumab with TPE + immunosuppression, an incremental cost of $46,948. The model was robust to several scenario analyses; however, when limited to Medicare fee-for-service (FFS), the incremental cost of caplacizumab per patient was reduced to $4,852 due to add-on payments.

CONCLUSIONS

Caplacizumab with TPE + immunosuppression is associated with an increase in costs; however, the increase is nominal among payers who provide an add-on payment consistent with that of Medicare FFS.