Impact of sex on antidepressant discontinuation in groups of similar cytochrome P450 phenotypes

Introduction

Although there are studies assessing reasons for antidepressant discontinuation, little is known about the impact of sex differences or cytochrome P450 phenotypes. Our objective is to assess discontinuation rates between males and females and whether CYP450 phenotype influences discontinuation.

Methods

This is a retrospective review of patients previously enrolled in the Right Drug, Right Dose, Right Time: Using Genomic Data to Individualize Treatment database with major depressive disorder. Patients were evaluated for antidepressants trialed between January 1, 2009, and September 30, 2019. Survival analyses with competing risks were used to analyze discontinuation reasons. A Kaplan-Meier estimation method was used to assess the time to discontinuation and discontinuation rates. Analyses were also completed to assess discontinuation between men and women by phenotypic groups. All tests were two-sided, and p-values ≤ .05 were considered statistically significant.

Results

There were 620 antidepressant discontinuation events discovered from 1015 antidepressant trials included. Overall, the median time to discontinuation for males was 2.6 years and 1.9 years for females (hazard ratio [HR] 0.97 [95% confidence interval (CI): 0.80, 1.19], p = .77). The risk of discontinuation was not different between males and females in any of the phenotype groups, which was consistent in the multivariable analyses. Concomitant use of medications that inhibited or induced antidepressant metabolism increased the overall risk of discontinuation (HR 1.45, 95% CI [1.06, 1.99], p = .020) in a time-dependent analysis.

Discussion

We did not detect a significant difference in risk of antidepressant discontinuation rates between males and females even when accounting for cytochrome P450 phenotype. Future studies should account for whether medications that inhibit or induce antidepressant metabolism may be a crucial factor in antidepressant discontinuation.

Implementation of preemptive DNA sequence-based pharmacogenomics testing across a large academic medical center: The Mayo-Baylor RIGHT 10K Study

PURPOSE

The Mayo-Baylor RIGHT 10K Study enabled preemptive, sequence-based pharmacogenomics (PGx)-driven drug prescribing practices in routine clinical care within a large cohort. We also generated the tools and resources necessary for clinical PGx implementation and identified challenges that need to be overcome. Furthermore, we measured the frequency of both common genetic variation for which clinical guidelines already exist and rare variation that could be detected by DNA sequencing, rather than genotyping.

METHODS

Targeted oligonucleotide-capture sequencing of 77 pharmacogenes was performed using DNA from 10,077 consented Mayo Clinic Biobank volunteers. The resulting predicted drug response-related phenotypes for 13 genes, including CYP2D6 and HLA, affecting 21 drug-gene pairs, were deposited preemptively in the Mayo electronic health record.

RESULTS

For the 13 pharmacogenes of interest, the genomes of 79% of participants carried clinically actionable variants in 3 or more genes, and DNA sequencing identified an average of 3.3 additional conservatively predicted deleterious variants that would not have been evident using genotyping.

CONCLUSION

Implementation of preemptive rather than reactive and sequence-based rather than genotype-based PGx prescribing revealed nearly universal patient applicability and required integrated institution-wide resources to fully realize individualized drug therapy and to show more efficient use of health care resources.

Pharmacogenomics testing in patients with liver transplant and potential impact on prospective management

Aim: Pharmacogenomics (PGx) tests are performed on whole-blood or saliva specimens. In patients with a transplanted liver, PGx results may be discordant with hepatic drug metabolizing enzyme activity. We evaluate the incidence and impact of PGx testing in liver transplant recipients, detail potential errors and describe clinical decision support (CDS) solution implemented. Materials & methods: A retrospective cohort study of liver transplant recipients at Mayo Clinic who underwent PGx testing between 1 January 1996 and 7 October 2019 were characterized. Impact of a CDS solution was evaluated. Results: There were 129 PGx tests in 117 patients. PGx testing incidence increased before (per year incidence rate ratio = 1.45, 95% CI: 1.20-1.74, p < 0.001) and after transplant (incidence rate ratio = 1.48, 95% CI: 1.27-1.72, p < 0.001). Three erroneous PGx tests were avoided 6 months following CDS implementation. Conclusion: Incidence of PGx testing in liver transplant recipients is increasing, leading to erroneous therapeutic decisions. CDS interventions and education are needed to prevent errors.