Immunotherapies & stability: a costly race against time

Introduction
Immunotherapies have revolutionized oncology care, however their increasing use leads to considerable health expenses. In a hospital subcontracting the activity of reconstitution of anti-cancer drugs, the prescription is made 48 hours in advance. This study aims to assess the impact of the stability of immunotherapy bags on losses and associated costs.

Matériel et Méthodes
A retrospective analysis was carried out on the prescriptions of immunotherapies in oncology departments between January 2020 and April 2023. The most commonly prescribed were compared according to the criteria: number of bags prepared, bags returned due to non-administration, bags destroyed due to expiry, stability data from the Summary of Product Characteristics. Finally, the costs associated with the losses of the destroyed bags were calculated.

Résultats
Over this period, 5452 immunotherapy preparations were produced including: Pembrolizumab (49%), Nivolumab (30%), Atezolizumab (7%), Durvalumab (5%). Of all the immunothrapy bags prepared, there are on average 3% of bags that are destroyed for Pembrolizumab, 0.02% for Nivolumab, 0.16% for Atezolizumab and 0.44% for Durvalumab. Destroyed bags are bags reaching its expiry date and returned by the service because the patient has not received his treatment.
The stability of a bag of Pembrolizumab is 96 hours, while the 3 other immunotherapies had an initial stability of 24 hours, extended to 30 days. For these three immunotherapies (Nivolumab, Atezolizumab and Durvalumad) a significant decrease in the rate of destroyed bags following a return to service after the extension of their duration of stability was noticed, falling from approximately 80% to 10%. The rate of Pembrolizumab remains stable around 36%. Costs associated with losses amount is approximately €300,000 per year for Pembrolizumab, while the others cost less than €40,000.

Discussion-Conclusion
Pembrolizumab stands out with a high rate of destroyed bags due to its short duration of stability. Extending stability is fundamental to provide durable and economically viable solutions, especially for pembrolizumab, which has currently the largest cost among health insurance drugs. It is therefore imperative that pharmaceutical companies finance stability studies.

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