Identification of non-adherence to adjuvant letrozole using a population pharmacokinetics approach in hormone receptor-positive breast cancer patients.
Eur J Pharm Sci
; 199: 106809, 2024 Aug 01.
Article
en En
| MEDLINE
| ID: mdl-38788907
ABSTRACT
BACKGROUND:
Letrozole, an aromatase inhibitor metabolised via CYP2A6 and CYP3A4/5 enzymes, is used as adjuvant therapy for women with hormone receptor (HR)-positive early breast cancer. The objective of this study was to quantify the impact of CYP2A6 genotype on letrozole pharmacokinetics (PK), to identify non-adherent patients using a population approach and explore the possibility of a relationship between non-adherence and early relapse.METHODS:
Breast cancer patients enrolled in the prospective PHACS study (ClinicalTrials.gov NCT01127295) and treated with adjuvant letrozole 2.5 mg/day were included. Trough letrozole concentrations (Css,trough) were measured every 6 months for 3 years by a validated LC-MS/MS method. Concentration-time data were analysed using non-linear mixed effects modelling. Three methods were evaluated for identification of non-adherent subjects using the base PK model.RESULTS:
617 patients contributing 2534 plasma concentrations were included and led to a one-compartment PK model with linear absorption and elimination. Model-based methods identified 28 % of patients as non-adherent based on high fluctuations of their Css,trough compared to 3 % based on patient declarations. The covariate analysis performed in adherent subjects revealed that CYP2A6 intermediate (IM) and slow metabolisers (SM) had 21 % (CI95 % = 12 - 30 %) and 46 % (CI95 % = 41 - 51 %) lower apparent clearance, respectively, compared to normal and ultrarapid metabolisers (NM+UM). Early relapse (19 patients) was not associated with model-estimated, concentration-based or declared adherence in the total population (p = 0.41, p = 0.37 and p = 0.45, respectively).CONCLUSIONS:
These findings will help future investigations focusing on the exposure-efficacy relationship for letrozole in adjuvant setting.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Neoplasias de la Mama
/
Inhibidores de la Aromatasa
/
Cumplimiento de la Medicación
/
Letrozol
Límite:
Adult
/
Aged
/
Aged80
/
Female
/
Humans
/
Middle aged
Idioma:
En
Revista:
Eur J Pharm Sci
Asunto de la revista:
FARMACIA
/
FARMACOLOGIA
/
QUIMICA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Francia