Pharmacogénétique des médicaments antidépresseurs : état des connaissances et des pratiques – recommandations du Réseau national de pharmacogénétique (RNPGx)

[Optimal pain management for cancer patients with chronic renal failure]

The management of multimorphic cancer pain is a major supportive care in oncology, for which many national and international recommendations have recently been updated. Any cancer patient must benefit from access to supportive care from the diagnosis, throughout the entire care pathway. Chronic renal failure, from any etiology, requires special attention and constant attention to details from interdisciplinary caregivers' teams to propose the best analgesic therapeutic strategy, combining complementary and interventional approaches to treatments. Analgesic therapies, in particular opioids and antineuropathics, require specific precautions. A therapeutic alliance integrating clinical pharmacy as a supportive care in its own right, is a major asset allowing the optimization and securing of analgesic drug treatments, conditioning both their efficacy, their tolerance and therapeutic observance, in the goal of improving the patient's quality of life.

Experience and expectations of pharmacogenetic tests in France

Although French genomic medicine is reaching a turning point in its history and the implementation of genome sequencing in routine is being implemented as part of the France Genomic Medicine 2025 Plan (FGMP), many questions about secondary data management remain to be addressed. In particular, the use of pharmacogenetic (PGx) information that can be extracted from genome data is a concern. We sought to analyze the opinion of French health professionals on their desire to have access to this information. For this purpose, we created a 22-item questionnaire on the experiences, attitudes, expectations, and knowledge of French physicians and pharmacists about PGx. We collected the responses in different groups and determined a knowledge score with the last 3 questions of the questionnaire. Then, we built a prediction model for this score and determined which factors may influence it. Half of the responders were physicians (158/311) and the other half were pharmacists (153/311), and the majority of them worked in a hospital (265/311). Almost two third (62.7%, 195/311) of the responders thought that pharmacogenetic data should be communicated with genomic results for the primary indication within the framework of FGMP, and 89.1% (277/311) of them that PGx tests could be an interesting tool to optimize patients' drug therapy in the future. Only 11.2% (35/311) of the responders reached the maximum knowledge score, while 25.4% (76/311) had already prescribed or recommended a PGx test. This study identified a need for training for French physicians and pharmacists in PGx, particularly given the interest of health professionals in it.

Therapeutic Drug Monitoring and Pharmacogenetic Testing as Guides to Psychotropic Drug Dose Adjustment: An Observational Study

To avoid the failures in therapy with psychotropic drugs, treatments can be personalized by applying the results of therapeutic drug monitoring and pharmacogenetic testing. The objective of the present single-center observational study was to describe the changes in psychotropic drug management prompted by therapeutic drug monitoring and pharmacogenetic testing, and to compare the effective drug concentration based on metabolic status with the dose predicted using an in silico decision tool for drug-drug interactions. The study was conducted in psychiatry wards at Lille University Hospital (Lille, France) between 2016 and 2020. Patients with data for at least one therapeutic drug monitoring session or pharmacogenetic test were included. Blood tests were performed for 490 inpatients (mainly indicated by treatment monitoring or failure) and mainly concerned clozapine (21.4%) and quetiapine (13.7%). Of the 617 initial therapeutic drug monitoring tests, 245 (40%) complied with good sampling practice. Of the patients, 51% had a drug concentration within the therapeutic range. Regardless of the drug concentration, the drug management did not change in 83% of cases. Thirty patients underwent pharmacogenetic testing (twenty-seven had also undergone therapeutic drug monitoring) for treatment failure; the plasma drug concentration was outside the reference range in 93% of cases. The patient's metabolic status explained the treatment failure in 12 cases (40%), and prompted a switch to a drug metabolized by another CYP450 pathway in 5 cases (42%). Of the six tests that could be analyzed with the in silico decision tool, all of the drug concentrations after adjustment were included in the range estimated by the tool. Knowledge of a patient's drug concentration and metabolic status (for CYD2D6 and CYP2C19) can help clinicians to optimize psychotropic drug adjustment. Drug management can be optimized with good sampling practice, support from a multidisciplinary team (a physician, a geneticist, and clinical pharmacist), and decision support tools.

[Pharmacoresistance to psychotropic drugs in children and adolescents: Pharmacogenetic anomalies of cytochrome P450 2D6]

OBJECTIVES

Some patients in child and adolescent psychiatry present resistance to psychotropic drugs, often resulting in polytherapy, an increased risk of adverse events, and more frequent and longer hospitalisation. Psychotropic drugs are mainly metabolised in the liver, in particular by the CYP2D6 subunit of cytochrome P450. Anomalies such as a duplication of the CYP2D6 gene related to an ultra-rapid metaboliser phenotype has been described to be linked to clinical efficacy. However, little research has been done in child and adolescent psychiatry.

METHODS

A multi-centric cross-sectional study in the southeast of France explored the relation between pharmaco-resistance to psychotropic drugs and the prevalence of duplications or polymorphisms of CYP2D6 associated with an ultra-rapid phenotype in children and adolescents with severe mental health disease.

RESULTS

Twenty-two patients have been included. The presence of an ultra-rapid phenotype concerns one patient in our study. A second patient presents a slow metaboliser phenotype.

CONCLUSIONS

This study allows a clinical characterisation of the population of pediatric drug-resistant patients whose severity and the impact of their pathology are major and require long-term care associated with repeated hospitalisations, multiple drug prescriptions and numerous side effects. However, a link between drug resistance to psychotropic drugs and CYP2D6 UFM abnormalities could not be confirmed. An additional pharmacogenetic analysis by a panel of genes applied in the metabolism, transport and action of psychotropic drugs should be considered to answer questions about the resistance and independent effects of CYP2D6.