Analysis of the pharmacoeconomic effectiveness of the tyrosine kinase inhibitors therapy in patients with chronic myeloid leukemia in a Single Hematology Center in Plovdiv, Bulgaria
Authors: Goranova-Marinova Veselina , Grekova-Kafalova Daniela , Andreevska Kalina , Georgieva Vania , Gvozdeva Yana , Kassarova Margarita , Grudeva-Popova Zhanet , Gavazova Evelina , Petkova Valentina 
Published: June 2024

Summary: Chronic myelogenous leukemia (CML) is a pluripotent hemopoietic stem cell malignancy characterized by the presence of a BCR-ABL1 fusion gene derived from a balanced translocation between the long arms of chromosomes 9 and 22 [t(9;22) (q34; q11)] known as the Philadelphia (Ph) chromosome. CML is an acquired hematopoietic stem cell disease common to myelo- and lymphopoiesis, characterized by uncontrolled proliferation of granulopoiesis (Shuvaev et al. 2015; Yordanov and Varbanova 2019).

Relevance and goals: Second-generation tyrosine kinase inhibitors (TKIs) (nilotinib, dasatinib, and bosutinib) have an advantage over imatinib (first-generation) in the frequency and speed of achieving cytogenetic and molecular responses in the treatment of chronic myelogenous leukemia (CML), but they cause severe adverse effects and are much more expensive than imatinib, especially if we compare them to the prices of the registered generic products of Imatinib and Dasatinib. “Novartis Tasigna® trial shows superior results to Glivec® in patients with early-stage chronic myeloid leukemia”, reported on 10/20/2021 by Pierre Perrin-Montlouis. In the first direct comparison of these two oral therapies back in 2009 (Тasigna (nilotinib) 2009), as first-line treatment for CML, the results of Tasigna showed statistically significant improvement over Glivec in every measure of efficacy, including major molecular response (MMR), complete cytogenetic response (CCyR) and prevention of progression to accelerated or blast phase, with responses achieved faster in the Tasigna group than in the Glivec group. Furthermore, in the last ten years, CML patients who have achieved a stable deep molecular response for at least 2 years have been included in clinical trials for the management of treatment-free remission (TFR) (Kim et al. 2013; Saußele et al. 2016).

On the other hand, the ever-increasing costs of diagnosis, treatment and monitoring of the response of CML to the various therapeutic strategies require conducting pharmacoeconomic analyses of the cost-effectiveness and cost-utility types in order to evaluate which are the cost-effective strategies with a view to introducing them into therapeutic practice. The present study aims to analyze the pharmacoeconomic efficiency of the TKI inhibitors used by the patients with CML-CP in the first and second lines, treated in the hematology clinic at UMHAT “St. George”, MU- Plovdiv during the period 2018–2022.

Methods: An economic analysis of the medicinal use of TKIs for a 5-year period (2018–2022) was performed at the national level according to data from the National Health Insurance Fund and the availability, accessibility, and usability of original and generic TKIs in Bulgaria were evaluated. The direct medical costs for the therapy of all patients were calculated, including the costs of the TKI therapy, laboratory tests, and monitoring of the molecular response for the entire treatment period from the appointment of the TKI therapy until the end of 2022. A comparative analysis was conducted to assess the cost-effectiveness of the different therapeutic strategies with TKIs on the first and second lines of treatment of patients with CML-CP in the hematology clinic at UMHAT “St. George” Medical University, Plovdiv, using the decision analysis method and conducting one-way and probalistic sensitivity analyses.

Results: The sensitivity analyzes of all pharmacoeconomic models showed the robustness and reliability of the obtained results. The threshold limits of medical costs and the frequency of achieving a deep molecular response determining the choice of first- and second-generation tyrosine kinase inhibitors as first- and second-line therapy for patients with chronic myeloid leukemia in the chronic phase have been determined. Prescribing doctors prefer the original MPs to generic analogues, which is also assumed by the current regulations, according to which even for expensive MPs dispensing by protocols, the prescription is by trade and not by international non-proprietary names (INN), which is why the use of the much cheaper generic MPs is negligibly low compared to original MPs. A personalized approach to the patient’s therapy and monitoring the patient’s molecular response to it, as well as stopping therapy in 25–30% of patients suitable to stop it safely when in TFR phase with a probability of more than 50% of not having a relapse will save additional costs that, by improving the cost-effectiveness of therapy for patients with CML, will be directed towards the treatment of new patients with this or other diseases.

Conclusion: These pharmacoeconomic models can be applied to improve diagnostic and therapeutic standards in clinical practice and for the efficient use of the very limited resources for health care in countries like Bulgaria. The conducted cost-effectiveness analyses confirmed that the hematologists at the University Center in Plovdiv adhere to the recommendations of Leukemia Net and the Bulgarian Medical Society of Hematology and achieve not only good therapeutic but also pharmacoeconomic efficiency in the treatment of CML-СР patients in first- and second- line therapy.