Comparative Cost for Required Monitoring to Detect Adverse Events or Laboratory Abnormalities: Dasatinib Versus Nilotinib.
Authors: Simons W. Robert , Maclean Ross , Cairns Jessica 
Published: October 2019

Abstract
Abstract 4524
Adverse event (AE) profiles and laboratory abnormalities are different amongst TKIs used as second line therapy in chronic myeloid leukemia. These differences are apparent between nilotinib and dasatinib, as evidenced by the required monitoring parameters that are contained within the products' labeling.

AIM
Ancillary costs often accrue beyond drug acquisition costs; this assessment translates required monitoring as per FDA approved product labeling for AEs and laboratory abnormalities into annual ancillary costs for dasatinib and nilotinib in the treatment of CML.

METHODS
Prescribing Informations (PI) of dasatinib and nilotinib were carefully reviewed to tabulate the required monitoring parameters and their recommended periodic timing during the initial one-year course of treatment. For example, due to the risk of myelosuppression with these agents, a complete blood count (CBC) is required for patients treated with either dasatinib or nilotinib at 2 weeks, 4 weeks and monthly thereafter, or 13 times in year one. Nilotinib also requires an ECG at baseline, 1 week, and periodically thereafter (assessed as every other month) throughout treatment due to the risk of QT prolongation. QT intervals should also be closely monitored in patients with hepatic impairment. Also with Nilotinib treatment, the following are recommended: blood tests periodically due to the risk of serum lipase elevation; hepatic function tests due to the risk of liver function abnormalities; and screening for electrolyte abnormalities. While fluid retention is associated with dasatinib therapy, it requires only careful observation. Patients who develop symptoms suggestive of pleural effusion such as dyspnea or dry cough should be evaluated by chest X-ray. A large, commercial managed care database based on more than 4 million records was used to assess the mean costs for each required test; those costs were multiplied by the required frequencies for the first year.

RESULTS
The average cost and standard deviations for CBC is $30.46±73.75. The average costs for an ECG, electrolyte panel and hepatic panel are $174.40±74.71, $13.60±15.91, and $21.20±17.30. Cost data are skewed to the right inflating the standard deviations. First year annual costs associated with required monitoring for myelosuppression is $426.44 for both dasatinib and nilotinib. Additional monitoring costs for nilotinib in the first year included $81.60 for electrolyte panels, $2,092.80 for ECGs and $275.60 for hepatic panels. Total costs are $2,721.29 and $426.44 for monitoring parameters for nilotinib and dasatinib, respectively.

CONCLUSION
Drug acquisition cost rarely provides a complete picture of treatment cost. Nilotinib requires nearly $500 a month just for required monitoring due to greater risks for adverse events and laboratory abnormalities.

Disclosures:
Simons: Bristol-Myers Squibb: Consultancy. Maclean:Bristol-Myers Squibb: Employment. Cairns:Bristol-Myers Squibb: Employment.