Pharmacoeconomic Analysis of the Real World Treatment of Chronic Myeloid Leukemia in Chronic Phase of a Brazilian Private Institution Considering the Use of Generic Drugs and Eventual Discontinuation of Treatment

INTRODUCTION In Brazil, Chronic Myeloid Leukemia patients receive almost exclusively first-line imatinib ;since 2013, only generic drugs and copies of imatinib mesylate have been used in first-line treatments throughout the whole Public Health System (Sistema Único de Saúde - SUS) and, in several institutions within the private system.. However, in the public system, which corresponds to 75% of the health assistance in the country, there is no funding for such exams, which are performed exclusively by the donation of vouchers from pharmaceutical industries. Within the private healthcare system, there is an average coverage of 04 PCR exams per annum, which allows for adequate monitoring, but is not sufficient for the implementation of treatment discontinuation in eligible patients.

AIMS

To analyse real world data related to 140 patients from a Brazilian private institution and determine, using epidemiological and treatment characteristics, the cost of branded imatinib mesylate, generic imatinib mesylate and nilotinib chloride first-line treatment, under the context where the discontinuation of treatment is unfeasible, and, as a secondary aim, to determine the financial impact from an eventual discontinuation of patients that achieved MR 4.0

METHODS

Retrospective data from 140 patients with Chronic Myeloid Leukemia in chronic phase treated solely with first-line imatinib mesylate were analysed, including 95% of patients treated with generic imatinib and 5% with branded imatinib mesylate .

Median treatment : 07 years. Median age of diagnosis of the studied population was 47 years .Life expectancy is 76.8 years (IBGE-2018). In order to facilitate , 14 patients that had overcome life expectancy of 76.8 years of age were excluded (Source: IBGE), resulting in a total of 126 patients.

The cost of treatment was estimated for the following first-line treatments: branded imatinib mesylate, generic imatinib mesylate, nilotinib chloride, in a scenario with or without discontinuation, including the cost of all PCR exams necessary in order to achieve adequate monitoring.It was evidenced, within that group, 26 patients with a criterial stable response of MR4.0 (80%) and MR4.5 (20%), confirmed by 04 PCR exams performed from a two years minimum period of ongoing treatment.

Concerning discontinuation, the calculation included: 12 exams within treatment year 1, 06 exams in year 2, trimestral exams from year 3 to year 5, and semestral from year 6 on, even for those who resumed treatment.

Projection of the financial impact from treatment with or without discontinuation in the studied population - 26 patients including follow-up PCR exams post-discontinuation for 29 years

RESULTS

STUDY OF THE REAL COST OF TREATMENTS

Without descontinuation :

Branded IMATINIB - total cost : US$ 173.773.130 / cost per patient: US$ 1.241.237

GENERIC IMATINIB US$ 113.297.014 / cost per patient: US$ 809,264

NILOTINIB US$ 168.231.166 / cost per patient: US$ 1.201.651

PROJECTION OF BUDGET IMPACT OF DISCONTINUATION

BRANDED IMATINIB AND GENERIC IMATINIB, it was considered a rate of 20% eligible patients for discontinuation, and that 50% of such patients needed to resume the treatment within 12 months.

BRANDED IMATINIB : US$ 17.206.022 total economy / US$682.779 per patient .

GENERIC IMATINIB US$ 11.141.59 total economy and US$ 442.127 per patient.

Regarding the drug NILOTINIB, the analysis used 45% of eligible patients for discontinuation and considered 50% of patients resuming the treatment, resulting in an economy of US$ 37.463.140.

DISCUSSION We present, based on Brasíndice data, real cost projection for the available lines of treatment for first line and, lastly, that the financial impact from treatment discontinuation of 15% of the total study population would fund :

Branded imatinib :146.422 exams ;Imatinib copies- 94.827 ; Nilotinib- 318.853 .

The data shows that the non coverage of such exams deprives patients of the possibility to maintain stable molecular response in the absence of treatment and makes both the discontinuation practice and the chance to significantly reduce costs to the health system, whether public or private, unfeasable.

CONCLUSION

The analysis and projections performed in the study suggest economically viable solution to conduct systematic molecular tests in order to monitor patients therapeutic response, under a treatment discontinuation scenario for eligible patients.