Modelling the resource implications of managing adults with Fabry disease in Italy

A systematic literature review on the health-related quality of life and economic burden of Fabry disease

BACKGROUND

Fabry disease (FD) is a rare lysosomal storage disease associated with glycolipid accumulation that impacts multiple physiological systems. We conducted a systematic literature review (SLR) to characterize the humanistic (quality of life [QoL]) and economic burden of FD.

METHODS

Searches were conducted in the Embase, MEDLINE®, and MEDLINE® In-Process databases from inception to January 19, 2022. Conference abstracts of specified congresses were manually searched. Additional searches were performed in the Cochrane and ProQuest databases for the humanistic SLR and the National Health Service Economic Evaluations Database for the economic SLR. Studies of patients with FD of any sex, race, and age, and published in the English language were included. There was no restriction on intervention or comparator. For the humanistic SLR, studies that reported utility data, database/registry-based studies, questionnaires/surveys, and cohort studies were included. For the economic SLR, studies reporting economic evaluations or assessing the cost of illness and resource use were included.

RESULTS

Of the 1363 records identified in the humanistic search, 36 studies were included. The most commonly used QoL assessments were the 36-item Short-Form Health Survey (n = 16), EQ-5D questionnaire descriptive system or visual analog scale (n = 9), and the Brief Pain Inventory (n = 8). Reduced QoL was reported in patients with FD compared with healthy populations across multiple domains, including pain, physical functioning, and depressive symptoms. Multiple variables-including sex, age, disease severity, and treatment status-impacted QoL. Of the 711 records identified in the economic burden search, 18 studies were included. FD was associated with high cost and healthcare resource use. Contributors to the cost burden included enzyme replacement therapy, healthcare, and social care. In the seven studies that reported health utility values, lower utility scores were generally associated with more complications (including cardiac, renal, and cerebrovascular morbidities) and with classical disease in males.

CONCLUSION

FD remains associated with a high cost and healthcare resource use burden, and reduced QoL compared with healthy populations. Integrating information from QoL and economic assessments may help to identify interventions that are likely to be of most value to patients with FD.

In vitro characterization of cells derived from a patient with the GLA variant c.376A>G (p.S126G) highlights a non-pathogenic role in Fabry disease

Fabry disease (FD) is a life-limiting disorder characterized by intracellular globotriaosylceramide (Gb3) accumulations. The underlying α-galactosidase A (α-GAL A) deficiency is caused by variants in the gene GLA. Variants of unknown significance (VUS) are frequently found in GLA and challenge clinical management. Here, we investigated a 49-year old man with cryptogenic lacunar cerebral stroke and the chance finding of the VUS S126G, who was sent to our center for diagnosis and initiation of a costly and life-long FD-specific treatment. We combined clinical examination with in vitro investigations of dermal fibroblasts (HDF), induced pluripotent stem cells (iPSC), and iPSC-derived sensory neurons. We analyzed α-GAL A activity in iPSC, Gb3 accumulation in all three cell types, and action potential firing in sensory neurons. Neurological examination and small nerve fiber assessment was normal except for reduced distal skin innervation. S126G iPSC showed normal α-GAL A activity compared to controls and no Gb3 deposits were found in all three cell types. Baseline electrophysiological characteristics of S126G neurons showed no difference compared to healthy controls as investigated by patch-clamp recordings. We pioneer multi-level cellular characterization of the VUS S126G using three cell types derived from a patient and provide further evidence for the benign nature of S126G in GLA, which is of great importance in the management of such cases in clinical practice.

Safety and tolerability of agalsidase beta infusions shorter than 90 min in patients with Fabry disease: post-hoc analysis of a Japanese post-marketing study

BACKGROUND

Agalsidase beta, an enzyme replacement therapy for Fabry disease, is dosed biweekly at 1 mg/kg body weight, with increasing infusion rates based on tolerability. The US label specifies ≥ 90-min infusions for all patients; the US and EU labels require ≤ 15 mg/hr infusions in patients < 30 kg. The Japanese label allows infusions up to 30 mg/hr, allowing < 90-min dosing for some patients weighing < 45 kg. Japanese post-marketing data were analyzed for rate of infusion-associated reactions (IARs), adverse events (AEs), and serious AEs (SAEs) based on infusion rate and patient attributes (weight, antibody status).

RESULTS

Data were available for 436 reduced-duration infusions (< 90 min) and 2242 standard infusions (≥ 90 min). SAEs were rare (0.6%), and the frequency of all safety events decreased over the treatment course. Little impact of infusion duration on safety outcomes was observed: IARs and AEs were numerically more common when infusion duration was ≥ 90 min compared to < 90 min (IARs: 2.0% vs 0.9%; AEs: 2.9% vs 1.4%), while the rate of SAEs was similar (0.4% vs 0.5%). IAR, AE, and SAE frequencies decreased significantly with increasing infusion rates, and this trend was consistent in patients < 30 kg. Safety events tended to be less frequent in patients < 30 kg vs those ≥ 30 kg (IARs: 1.8% vs 2.1%; AEs: 2.3% vs 3.6%; SAEs: 0.0% vs 0.6%), although the differences were not statistically significant. IARs occurred in < 1% of all infusions in the < 30 kg group, 84% of which were < 90 min. More anti-agalsidase beta antibody-positive patients experienced IARs (41.9% vs 30.7%; P = 0.0445) and AEs (61.1% vs 49.3%; P = 0.0497) vs antibody-negative patients; however, there was no significant difference in the frequency of SAEs. In patients with available data, no changes in antibody status were observed after infusion durations were reduced to < 90 min.

CONCLUSIONS

The results of this post-hoc analysis demonstrated no significant impact of infusion duration on safety outcomes, and no significant difference in outcomes between patients of different weights. These findings suggest that infusion times in patients who are tolerating treatment can, with careful monitoring, be gradually decreased.

Budget impact analysis of medicines: updated systematic review and implications

This evaluation determines whether published studies to date meet the key characteristics identified for budget impact analyses (BIA) for medicines, accomplished through a systematic review and assessment against identified key characteristics. Studies from 2001-2015 on 'budget impact analysis' with 'drug' interventions were assessed, selected based on their titles/abstracts and full texts, and their characteristics checked according to key criteria. Out of 1,984 studies, 92 were subsequently identified for review. Of these, 95% were published in Europe and the USA. 2012 saw the largest number of publications (16%) with a decline thereafter. 48% met up to 7 out of the 9 key characteristics. Only 22% stated no conflict of interest. The results indicate low adherence to the key characteristics that should be considered for BIAs and strong conflict of interest. This is an issue since BIAs can be of fundamental importance in managing the entry of new medicines including reimbursement decisions.

A critical systematic review of budget impact analyses on drugs in the EU countries

BACKGROUND

Budget impact analysis (BIA) is a relatively recent technique that is supposed to be complementary to more established economic evaluations (EEs).

OBJECTIVE

We reviewed the BIAs published on drugs in the EU since December 2008, to assess whether these studies have improved in quality in the last few years.

METHODS

We conducted a literature search on the international databases PubMed and EMBASE. The selected articles were screened using a two-step approach to assess (1) their main methodological characteristics and (2) the level of adherence to the latest BIA definition. The assessment was made by two independent reviewers and any disagreement was resolved through discussion.

RESULTS

Eventually, 17 articles were reviewed. Thirteen referred to a stand-alone BIA not accompanying a full EE, only nine focussed on a new treatment, 15 were sponsored by the manufacturer of the drug of reference, all but one claiming savings for healthcare budgets. The quality of methods was poor in many of the studies, and only a few of them attempted to estimate real local costs in a credible way. Therefore, the crucial items that in theory make a BIA different from other types of EEs were often the major points of weakness of the studies reviewed.

CONCLUSIONS

Our review confirmed that the BIA is not yet a well-established technique in the literature and many published studies still fail to reach an acceptable quality. In particular, BIAs funded by pharmaceutical companies appear to be tailored to show short-term savings induced by new, highly priced products.

Cost effectiveness of first-line treatment with doxorubicin/ifosfamide compared to trabectedin monotherapy in the management of advanced soft tissue sarcoma in Italy, Spain, and sweden

Background. Doxorubicin/ifosfamide is a first-line systemic chemotherapy for the majority of advanced soft tissue sarcoma (ASTS) subtypes. Trabectedin is indicated for the treatment of ASTS after failure of anthracyclines and/or ifosfamide; however it is being increasingly used off-label as a first-line treatment. This study estimated the cost effectiveness of these two treatments in the first-line management of ASTS in Italy, Spain, and Sweden. Methods. A Markov model was constructed to estimate the cost effectiveness of doxorubicin/ifosfamide compared to trabectedin monotherapy, defined as the cost per QALY gained, in each country. Results. First-line treatment with doxorubicin/ifosfamide resulted in lower two-year healthcare costs and more QALYs than first-line treatment with trabectedin monotherapy in all three countries. Probabilistic sensitivity analysis showed that at a cost per QALY threshold of €35,000, >90% of a cohort would be cost effectively treated with doxorubicin/ifosfamide compared to trabectedin monotherapy in all three countries. Conclusion. Within the model's limitations, first-line treatment of patients with ASTS with doxorubicin/ifosfamide instead of trabectedin monotherapy affords a cost-effective use of publicly funded healthcare resources in Italy, Spain, and Sweden and is therefore the preferred treatment in all three countries. These findings support the recommendation that trabectedin should remain a second-line treatment.

A revised home treatment algorithm for Fabry disease: influence of antibody formation

BACKGROUND

Enzyme replacement therapy for Fabry disease, consisting of biweekly infusions, interferes daily life. Home treatment proved beneficial. We evaluated a previously reported home treatment algorithm aiming to shorten the period of in-hospital infusions, while ascertaining patient safety.

METHODS

Retrospective analysis on clinical records of treated Fabry patients. Potentially predictive factors for infusion associated reactions (IARs) were studied: agalsidase antibodies, agalsidase product and dose, FOS-SSI scores, and GLA activity and mutation. A questionnaire evaluated patient satisfaction and compliance.

RESULTS

Seventy-nine patients were included (41 males, 46% agalsidase antibody positive (AB+)). 85% received home treatment. Home treatment complications were erroneous fast infusion rates (n=4) causing IARs and, rarely, venous access problems. The single SAE was unrelated to home treatment. IgG antibody status was significantly associated with IARs (89% vs. 26% p-value<0.01). Negative antibody status did not preclude IARs. Except for three AB+ patients, all first IARs occurred within 13 infusions. IARs occurred more frequently in patients using agalsidase beta 1.0 mg/kg/eow than agalsidase alpha or beta 0.2 mg/kg/eow, but the time to first IAR did not differ between groups. Four AB+ males experienced IARs after a dose increase. Compliance between home and in-hospital treatment was similar. Most patients preferred home treatment.

CONCLUSION

In this study home therapy for Fabry disease was safe and improved patient satisfaction. We propose a revised algorithm which allows safe home-treatment in all male patients after 13 instead of 26 infusions, irrespective of ERT preparation or dose. Furthermore, AB+ patients with dosage increase may experience new or increased IARs, necessitating in-hospital observations.