French Retrospective Database Analysis of Patient Characteristics and Treatment Patterns in Patients with R/R FLT3-Mutated AML: A Registry-Based Cohort Study.

INTRODUCTION: There is a dearth of evidence to document treatment of FMS-like tyrosine kinase 3 (FLT3)-mutated acute myeloid leukemia (AML) in real-world settings before the introduction of FLT3 inhibitors. A retrospective cohort study was conducted to understand treatment practices prior to the availability of FLT3 inhibitors in patients with FLT3-mutated AML from two registries in France. METHODS: Patient data from January 1, 2009 to December 31, 2017 were collected from the Hauts-de-France and Midi-Pyrénées registries. Patients aged ≥ 18 years at diagnosis with FLT3-mutated AML were included. Demographic and disease characteristics of patients with FLT3-mutated AML and relapsed or refractory (R/R) FLT3-mutated AML were documented. Treatment regimens, overall survival (OS), and event-free survival were assessed in patients with R/R FLT3-mutated AML who did not participate in clinical trials. RESULTS: Overall, 819 and 1244 adult patients with AML from the Midi-Pyrénées and Hauts-de-France cohorts, respectively, underwent FLT3 mutation testing; 172 (21.0%) and 263 (21.1%) patients, respectively, had a FLT3 mutation. Primary R/R status was identified in 41.3% (n = 71/172) of the Midi-Pyrénées and 34.6% (n = 91/263) of the Hauts-de-France cohorts. Before R/R AML diagnosis, 82.0% and 97.5% of patients in the Midi-Pyrénées and Hauts-de-France cohorts, respectively, achieved complete remission (CR) or CR with incomplete hematologic recovery (CRi) following induction chemotherapy; after diagnosis of R/R AML, CR/CRi rates with salvage therapy were 33.3% and 28.1%, respectively. Median OS (interquartile range) in patients receiving salvage therapy (n = 49, n = 78) was 5.2 (2.3-11.1) and 6.1 (2.5-35.2) months, in the Midi-Pyrénées and Hauts-de-France cohorts, respectively. Across both cohorts, patients with R/R FLT3-mutated AML had low rates of CR/CRi with salvage therapy and a median OS of approximately 6 months. CONCLUSION: Before FLT3 inhibitor availability, real-world treatment patterns and outcomes in French patients with R/R FLT3-mutated AML were consistent with clinical trial data, highlighting a poor prognosis and unmet need for effective treatment.

Acute myeloid leukemia is a cancer affecting the blood and bone marrow. The presence of specific mutations in the FMS-like tyrosine kinase 3 (FLT3) gene in patients with acute myeloid leukemia can negatively impact response to standard chemotherapy. Patients with these mutations may not respond to chemotherapy or have a shortened duration of response causing a return of the disease, which in turn substantially decreases their life span. In the era prior to the availability of drugs specifically designed to counteract the negative effects of FLT3 mutations, evidence related to patient characteristics and treatment effects in individuals with acute myeloid leukemia harboring FLT3 mutations was mainly derived from clinical studies, with little evidence based on real-world experience. To better understand real-world patient characteristics and treatment effects in patients with acute myeloid leukemia and FLT3 mutations, we analyzed patients from two French registries, Midi-Pyrénées and Hauts-de-France, with a focus on patients who did not respond to or whose disease returned after initial chemotherapy. Patient data from between January 2009 and December 2017 included patients with FLT3-mutated acute myeloid leukemia from Midi-Pyrénées and Hauts-de-France who did not respond to or had recurrent disease after responding to initial chemotherapy, had low response to salvage chemotherapy, and a survival duration of 6 months or less. Our real-world observations in patients with relapsed or refractory FLT3-mutated acute myeloid leukemia from these two registries were consistent with results reported in clinical trials. Our results highlight the bleak forecast for these patients in the absence of effective drugs.

Cost-effectiveness of gilteritinib for relapsed/refractory FLT3mut+ acute myeloid leukemia.

BACKGROUND: Patients with relapsed or refractory (R/R) acute myeloid leukemia (AML) and confirmed feline McDonough sarcoma (FMS)-like tyrosine kinase 3 gene mutations (FLT3mut+) have a poor prognosis and limited effective treatment options. Gilteritinib is the first targeted therapy approved in the United States and Europe for R/R FLT3mut+ AML with significantly improved efficacy compared with existing treatments. OBJECTIVE: To evaluate gilteritinib against salvage chemotherapy (SC) and best supportive care (BSC) over a lifetime horizon among adult patients with R/R FLT3mut+ AML from a US third-party payer's perspective. METHODS: The model structure of this cost-effectiveness analysis included a decision tree to stratify patients based on their hematopoietic stem cell transplantation (HSCT) status, followed by 2 separate 3-state partitioned survival models to predict the long-term health status conditional on HSCT status. The ADMIRAL trial data and literature were used to predict probabilities of patients being in different health states until a conservative cure point at year 3. Afterwards, living patients followed the survival outcomes of long-term survivors with AML. Model inputs for utilities, medical resource use, and costs were based on the ADMIRAL trial, published literature, and public sources. All costs were inflated to 2019 US dollars (USD). Total incremental costs (in 2019 USD), life-years (LYs), quality-adjusted LYs (QALYs), and incremental cost-effectiveness ratios (ICERs) were calculated. Deterministic sensitivity analyses and probabilistic sensitivity analyses were performed. RESULTS: Over a lifetime horizon with a 3.0% annual discount rate, the base-case model estimated that gilteritinib led to an increase of 1.29 discounted QALYs at an additional cost of $148,106 vs SC, corresponding to an ICER of $115,192 per QALY; for BSC, results were an increase of 2.32 discounted QALYs, $249,674, and $107,435, respectively. The base-case findings were robust in sensitivity analyses. The estimated probabilities of gilteritinib being cost-effective vs SC and BSC were 90.5% and 99.8%, respectively, in the probabilistic sensitivity analyses, based on a willingness-to-pay threshold of $150,000 per QALY. CONCLUSIONS: Gilteritinib is a cost-effective novel treatment for patients with R/R FLT3mut+ AML in the United States. DISCLOSURES: This work was supported by Astellas Pharma, Inc., which was involved in all stages of the research and manuscript development. Garnham, Pandya, and Shah are employees of Astellas and hold stock/stock options. Zeidan consulted and received personal fees/honoraria and research funding from Astellas. Zeidan also has received research funding from Celgene/BMS, Abbvie, Astex, Pfizer, Medimmune/AstraZeneca, Boehringer-Ingelheim, Trovagene/Cardiff Oncology, Incyte, Takeda, Novartis, Amgen, Aprea, and ADC Therapeutics; has participated in advisory boards; has consulted with and/or received honoraria from AbbVie, Otsuka, Pfizer, Celgene/BMS, Jazz, Incyte, Agios, Boehringer-Ingelheim, Novartis, Acceleron, Daiichi Sankyo, Taiho, Seattle Genetics, BeyondSpring, Cardiff Oncology, Takeda, Ionis, Amgen, Janssen, Syndax, Gilead, Kura, Aprea, Lox Oncology, Genentech, Servier, Jasper, Tyme, and Epizyme; has served on clinical trial committees for Novartis, Abbvie, Geron, Gilead, Kura, Lox Oncology, BioCryst, and Celgene/BMS; and has received travel support for meetings from Pfizer, Novartis, and Cardiff Oncology. Qi and Yang are employees of Analysis Group, Inc., which received consulting fees from Astellas for work on this study. Part of this material was presented at the American Society of Hematology (ASH) Annual Meeting; December 7-10, 2019; Orlando, FL.

Cost-Effectiveness of Mirabegron Compared with Antimuscarinic Agents for the Treatment of Adults with Overactive Bladder in the United Kingdom.

BACKGROUND: Mirabegron, a first-in-class selective oral ß3-adrenoceptor agonist, has similar efficacy to most antimuscarinic agents and a lower incidence of dry mouth in patients with overactive bladder (OAB). OBJECTIVES: To evaluate the cost-effectiveness of mirabegron 50 mg compared with oral antimuscarinic agents in adults with OAB from a UK National Health Service perspective. METHODS: A Markov model including health states for symptom severity, treatment status, and adverse events was developed. Cycle length was 1 month, and the time horizon was 5 years. Antimuscarinic comparators were tolterodine extended release, solifenacin, fesoterodine, oxybutynin extended release and immediate release (IR), darifenacin, and trospium chloride modified release. Transition probabilities for symptom severity levels and adverse events were estimated from a mirabegron trial and a mixed treatment comparison. Estimates for other inputs were obtained from published literature or expert opinion. Quality-adjusted life-years (QALYs) and total health care costs, including costs of drug acquisition, physician visits, incontinence pad use, and botox injections, were modeled. Deterministic and probabilistic sensitivity analyses were performed. RESULTS: Base-case incremental cost-effectiveness ratios ranged from £367 (vs. solifenacin 10 mg) to £15,593 (vs. oxybutynin IR 10 mg) per QALY gained. Probabilistic sensitivity analyses showed that at a willingness-to-pay threshold of £20,000/QALY gained, the probability of mirabegron 50 mg being cost-effective ranged from 70.2% versus oxybutynin IR 10 mg to 97.8% versus darifenacin 15 mg. A limitation of our analysis is the uncertainty due to the lack of direct comparisons of mirabegron with other agents; a mixed treatment comparison using rigorous methodology provided the data for the analysis, but the studies involved showed heterogeneity. CONCLUSIONS: Mirabegron 50 mg appears to be cost-effective compared with standard oral antimuscarinic agents for the treatment of adults with OAB from a UK National Health Service perspective.

Economic Evaluation of Fidaxomicin for the Treatment of Clostridium Difficile Infection (C. difficile-associated diarrhoea) in Ireland.

Background: Clostridium difficile is associated with 20-30% of cases of antibiotic-associated diarrhoea. The incidence of C. difficile infection (CDI) is higher in Ireland than in other countries in Europe, and it is associated with considerable morbidity. Previously recommended standard therapeutic options were vancomycin and metronidazole, but the macrocyclic antibiotic fidaxomicin has recently been recommended for use in adults with CDI in Ireland. Objectives: To perform a cost-utility analysis of fidaxomicin compared to oral metronidazole (used to treat initial non-severe disease and first non-severe recurrence) and oral vancomycin (used to treat severe disease and any non-severe recurrence beyond the first) for the treatment of CDI. Methods: A Markov model was used to determine the cost-utility of fidaxomicin in the treatment of all adult CDI patients (base case), patients with severe CDI and patients with initial CDI recurrences, respectively. Patients enter the model in the CDI health state and are treated either with fidaxomicin or current standard of care (oral metronidazole for non-severe CDI; vancomycin for severe CDI) for 10 days. The time horizon was 1 year. Deterministic and probabilistic sensitivity analyses were performed. Health state utilities were derived from the literature. The perspective was that of the Irish Health Service Executive (HSE). Results: In the base case, fidaxomicin was dominant to current standard-of-care therapy, with cost savings of €2,904 and incremental quality-adjusted life year (QALY) gain of 0.031. The main drivers of costeffectiveness were recurrence rates and cost of hospitalization. Fidaxomicin was also dominant for all patient subgroups. The probability of fidaxomicin being cost-effective in all patients with CDI at a willingness to pay threshold of €45,000 per QALY gained was 82%. Conclusion: Fidaxomicin was dominant to the current standard-of-care therapy for CDI. Based on this analysis, fidaxomicin has received reimbursement for CDI treatment under the High Tech Drug Scheme in Ireland.

Cost effectiveness of mirabegron compared with tolterodine extended release for the treatment of adults with overactive bladder in the United Kingdom.

BACKGROUND: Overactive bladder (OAB) is highly prevalent and is associated with considerable morbidity and reduced health-related quality of life. ß3-adrenergic receptor (ß3-AR) stimulation is a novel alternative to antimuscarinic therapy for OAB. OBJECTIVE: The objective of this analysis was to assess the cost effectiveness of the ß3-AR agonist mirabegron relative to tolterodine extended release (ER) in patients with OAB from a UK National Health Service (NHS) perspective. METHODS: A Markov model was developed to simulate the management, course of disease, and effect of complications in OAB patients over a period of 5 years. Transition probabilities for symptom severity levels and probabilities of adverse events were estimated from the results of the randomised, double-blind SCORPIO trial in 1,987 patients with OAB. Other model inputs were derived from the literature and on assumptions based on clinical experience. RESULTS: Total 5-year costs per patient were £1,645.62 for mirabegron 50 mg/day and £1,607.75 for tolterodine ER 4 mg/day. Mirabegron was associated with a gain of 0.009 quality-adjusted life-years (QALYs) with an additional cost of £37.88. The resulting incremental cost-effectiveness ratio (ICER) was £4,386/QALY gained. In deterministic sensitivity analyses in the general OAB population and several subgroups, ICERs remained below the generally accepted willingness-to-pay (WTP) threshold of £20,000/QALY gained. The probability of mirabegron 50 mg being cost effective relative to tolterodine ER 4 mg was 89.4 % at the same WTP threshold. CONCLUSIONS: Mirabegron 50 mg/day is likely to be cost effective compared with tolterodine ER 4 mg/day for adult patients with OAB from a UK NHS perspective.