Consensus français sur la prise en charge de l’acromégalie

Cost-Utility of Acromegaly Pharmacological Treatments in a French Context

Objective

Efficacy of pharmacological treatments for acromegaly has been assessed in many clinical or real-world studies but no study was interested in economics evaluation of these treatments in France. Therefore, the objective of this study was to estimate the cost-utility of second-line pharmacological treatments in acromegaly patients.

Methods

A Markov model was developed to follow a cohort of 1,000 patients for a lifetime horizon. First-generation somatostatin analogues (FGSA), pegvisomant, pasireotide and pegvisomant combined with FGSA (off label) were compared. Efficacy was defined as the normalization of insulin-like growth factor-1 (IGF-1) concentration and was obtained from pivotal trials and adjusted by a network meta-analysis. Costs data were obtained from French databases and literature. Utilities from the literature were used to estimate quality-adjusted life year (QALY).

Results

The incremental cost-utility ratios (ICUR) of treatments compared to FGSA were estimated to be 562,463 € per QALY gained for pasireotide, 171,332 € per QALY gained for pegvisomant, and 186,242 € per QALY gained for pegvisomant + FGSA. Pasireotide seems to be the least cost-efficient treatment. Sensitivity analyses showed the robustness of the results.

Conclusion

FGSA, pegvisomant and pegvisomant + FGSA were on the cost-effective frontier, therefore, depending on the willingness-to-pay for an additional QALY, they are the most cost-effective treatments. This medico-economic analysis highlighted the consistency of the efficiency results with the efficacy results assessed in the pivotal trials. However, most recent treatment guidelines recommend an individualized treatment strategy based on the patient and disease profile.

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Acromegaly is characterized by increased release of growth hormone (GH) and, consequently, Insulin-Like Growth Factor I (IGF-I), most often by a pituitary adenoma. Prolonged exposure to excess hormone leads to progressive somatic disfigurement and a wide range of systemic manifestations that are associated with increased mortality. Transsphenoidal adenomectomy is the treatment of choice of GH-secreting pituitary tumors but surgical cure is not achieved in around 50% of patients, then adjuvant treatment is necessary. Mortality in acromegaly is normalized with biochemical control and has decreased in the last decade with the increased use of adjuvant therapy. Both GH and IGF-I are currently biomarkers for assessing disease activity in patients with acromegaly. However, discordance between GH and IGF-I results is encountered in a quarter of treated patients. The impacts of such a discrepancy over mortality and morbidity and the risk of biochemical and/or clinical recurrence are unclear. Moreover, despite a good biochemical control, some symptoms persist, leading to a decreased quality of life. Back pain due to vertebral fractures seem to be frequent in these patients and underdiagnosed. In patients with acromegaly, bone mineral density is not a reliable predictor of fracture risk. A more accurate evaluation of bone microstructural alterations associated with GH hypersecretion and vertebral fractures may be provided by new radiological devices analyzing alteration of trabecular microarchitecture, leading to a better prevention. © 2019 Published by Elsevier Masson SAS. All rights reserved. Cet article fait partie du numéro supplément Les Must de l'Endocrinologie 2019 réalisé avec le soutien institutionnel de Ipsen-Pharma.

Pegvisomant treatment in patients with acromegaly in clinical practice: The French ACROSTUDY

OBJECTIVE

To monitor long-term pegvisomant treatment of patients with acromegaly in routine clinical practice.

PATIENTS AND METHODS

The French ACROSTUDY is part of the global ACROSTUDY, an observational post-authorization safety surveillance study of acromegaly treatment with pegvisomant.

RESULTS

The median duration of follow-up of the 292 included patients was 5.2 years. Overall 272 (93%) patients received somatostatin analogues before initiation of pegvisomant. The most prescribed initial dose of pegvisomant (after possible administration of a loading dose) was 10mg/day and, starting from the 2nd year, the median dose was 20mg/day. Serum IGF-1 concentration decreased as soon as pegvisomant was started and after 5 years there was a 62% mean decrease in serum IGF-1 concentration. The percentage of patients with serum IGF-1 concentration within normal ranges (for age and sex) of the local laboratory shifted from 11% at start of pegvisomant to 43% at 6 months and 63% after 5 years. The last available imaging (242 patients) showed an increased or decreased tumor size in 4 and 10% of patients, respectively. Mean weight increased by 3 kg over the 5-year period (P<10(-3)). Mean fasting blood glucose significantly decreased over time (P<0.05), while HbA1c level remained unchanged. Tolerance profile was generally good and similar to that described in clinical studies.

CONCLUSION

This analysis showed a significant decrease in IGF-1 levels throughout the follow-up period, and confirmed that pegvisomant treatment is safe in acromegaly. The results of this interim analysis remain to be confirmed by the final analysis.