Pharmacogenetic considerations for late life depression therapy

Pharmacogenetic guidelines and decision support tools for depression treatment: application to late-life

Late-life depression (LLD) is a major depressive disorder that affects someone after the age of 60 years. LLD is frequently associated with inadequate response and remission from antidepressants, in addition to polypharmacy. Pharmacogenetics offers a promising approach to improve clinical outcomes in LLD via new discoveries determining the genetic basis of response rates and side effects, as well as the development of tailored pharmacogenetic-based decision support tools. This invited review evaluates the LLD pharmacogenetic evidence base and the extent to which this was incorporated into existing commercial decision support tools and clinical pharmacogenetic guidelines.

Efficacy of light therapy on nonseasonal depression among elderly adults: a systematic review and meta-analysis

OBJECTIVE

The aim of this study was to examine the effectiveness of light therapy in the treatment of geriatric depression.

METHODS

A systematic review and meta-analysis were carried out. Data sources for the literature search were PubMed, Cochrane Collaboration's Central Register of Controlled Clinical Trials, Cochrane Systematic Reviews, and ClinicalTrials.gov. Controlled trials of light therapy on older patients with nonseasonal depression and depression rating scales were eligible. Studies were pooled using a random-effect model for comparisons with light therapy. We used effect size (ES), which expresses changes in depression severity, in each selected meta-analysis to calculate the standardized mean difference on the basis of Hedges' adjusted g; positive values indicated that the depression severity improved after light therapy. All results were presented with 95% CIs. Statistical heterogeneity was explored through visual inspection of funnel plots and the I2 statistic. Moderators of effects were explored using meta-regression.

RESULTS

We identified eight trials involving 395 participants that met the inclusion criteria. Light therapy was significantly more effective than comparative treatments, including placebo or dim light, with an ES of 0.422 (95% CI: 0.174-0.709, P=0.001). In addition, six of the eight trials used bright (white) light, resulting in significantly reduced severity of geriatric depression (N=273, ES: 0.460, 95% CI: 0.085-0.836, P=0.016). Furthermore, pale blue light therapy reduced the severity of geriatric depression (N=89, ES: 0.464, 95% CI: 0.046-0.882, P=0.030).

CONCLUSION

Our results highlighted the significant efficacy of light therapy in the treatment of geriatric depression. Additional well-designed, controlled studies are necessary to adopt standard parameters, adequate group sizes, and randomized assignment to evaluate more thoroughly the efficacy of light therapy for treating geriatric depression.

Optimization of Antidepressant use with Pharmacogenetic Strategies

BACKGROUND

The response rate in the pharmacological treatment of depression has been estimated to be around 50%, achieving a remission in symptomatology in only one third of the patients. Suboptimal prescription of antidepressants has been proposed as a significant explanatory factor for this therapeutic inefficacy. The use of pharmacogenetic testing might favor the optimization of pharmacotherapy in emotional disorders. However, its implementation in the clinical routine requires studies which prove its efficacy.

OBJECTIVE

The aim is to explore the clinical effects obtained by means of the personalization of antidepressant treatment derived from the pharmacogenetic profile of the individual.

METHOD

A sample of 291 patients under antidepressant treatment was selected, and these patients were genotyped for the most common polymorphisms of the CYP2D6, CYP2C9, CYP2C19 and CYP3A4/5 genes using RT-PCR and TaqMan® technology. 30 of them were subjected to psycho-affective assessment using the HDRS scale before and after a process of individualization of their psychopharmacological treatment in accordance with the genotype obtained.

RESULTS

70% of the individuals treated using the traditional criterion of trial-and-error were not taking the active ingredient most suited to their pharmacogenetic profile. The inclusion of this genetic information in the choice of drug and its dosage entailed a significant, progressive reduction in depressive symptomatology, with an efficacy ratio of 80% and a remission of the pathology in almost 30% of the cases.

CONCLUSION

These results suggest that the prescription of pharmacogenetic profile-based strategies has a positive effect on the therapeutic response to antidepressants.

Optimization of Antidepressant use with Pharmacogenetic Strategies

Background:

The response rate in the pharmacological treatment of depression has been estimated to be around 50%, achieving a remission in symptomatology in only one third of the patients. Suboptimal prescription of antidepressants has been proposed as a significant explanatory factor for this therapeutic inefficacy. The use of pharmacogenetic testing might favor the optimization of pharmacotherapy in emotional disorders. However, its implementation in the clinical routine requires studies which prove its efficacy.

Objective:

The aim is to explore the clinical effects obtained by means of the personalization of antidepressant treatment derived from the pharmacogenetic profile of the individual.

Method:

A sample of 291 patients under antidepressant treatment was selected, and these patients were genotyped for the most common polymorphisms of the CYP2D6, CYP2C9, CYP2C19 and CYP3A4/5 genes using RT-PCR and TaqMan® technology. 30 of them were subjected to psycho-affective assessment using the HDRS scale before and after a process of individualization of their psychopharmacological treatment in accordance with the genotype obtained.

Results:

70% of the individuals treated using the traditional criterion of trial-and-error were not taking the active ingredient most suited to their pharmacogenetic profile. The inclusion of this genetic information in the choice of drug and its dosage entailed a significant, progressive reduction in depressive symptomatology, with an efficacy ratio of 80% and a remission of the pathology in almost 30% of the cases.

Conclusion:

These results suggest that the prescription of pharmacogenetic profile-based strategies has a positive effect on the therapeutic response to antidepressants.

Falls: the adverse drug reaction of the elderly and the impact of pharmacogenetics

Falls is a frequent type of adverse drug reactions causing significant morbidity and mortality in the elderly. We reviewed, with which drugs the risk of falls is relevant and might depend on genomic variation. Pharmacogenetic variability may contribute to drug-induced falls for instance mediated by impaired drug elimination due to inherited deficiency in enzymes like CYP2C9, CYP2C19 and CYP2D6. The relative role of specific genes and polymorphisms in old age may differ from younger people. Biomarkers for frailty, but also genomic biomarkers might help identifying patients at high risk for drug-induced falls. Many other factors including disease and drug-drug interactions also contribute to risk of falls. Further studies analyzing the impact of genomic variation on the medication-related fall risk in the older adult are urgently needed.

Cyr NM, Siddarth P, Baune BT, Lavretsky H. Genomic predictors of remission to antidepressant treatment in geriatric depression using genome-wide expression analyses: a pilot study

OBJECTIVE

This first pilot study of genome-wide expression as predictor of antidepressant response in late-life depression examined genome-wide transcriptional profiles in a randomized placebo-controlled trial of combined methylphenidate and citalopram.

METHODS

Genome-wide transcriptional profiles were examined in peripheral blood leukocytes sampled at baseline and 16 weeks from 35 older adults with major depression, who were randomized to methylphenidate + citalopram, citalopram + placebo, or methylphenidate + placebo. Methylphenidate doses ranged between 10 and 40 mg/day, and citalopram doses ranged between 20 and 60 mg/day. Remission was defined as Hamilton Depression Rating Scale score of 6 or below. Early remission was achieved in the first 4 weeks of treatment. We hypothesized that differential gene expression at baseline can predict antidepressant response.

RESULTS

We analyzed gene expression in 24 remitters and 11 non-remitters. At baseline, we found three genes showing higher expression in all remitters versus non-remitters that satisfied the established level of significance: a fold change of 2 and p-value of 0.05 that included HLA-DRB5, SELENBP1, and LOC388588. Two gene transcripts showed higher expression in early remitters at baseline compared with non-remitters. The first gene was CA1 carbonic anhydrase gene, on chromosome 8 involved in respiratory function (fold change 2.54; p = 0.03). The second gene was the SNCA-α-synuclein gene, implicated, which binds to dopamine transporter (fold change 2.1; p = 0.03).

CONCLUSIONS

Remission to antidepressants in geriatric depression may be associated with a particular gene expression profile in monoaminergic and metabolic pathways and needs to be replicated in a larger sample.

Klotho Gene and Selective Serotonin Reuptake Inhibitors: Response to Treatment in Late-Life Major Depressive Disorder

Klotho protein, encoded by the Klotho gene (KL) at locus 13q12, is an antiaging hormone-like protein playing a pivotal role in cell metabolism homeostasis and associated to longevity and age-related diseases. In particular, altered cell metabolism in central nervous system may influence the behavior of serotoninergic neurons. The role of KL in the response to treatment with selective serotonin reuptake inhibitors (SSRIs) in late-life depressive syndromes and late-life major depressive disorder (MDD) is unclear. We genotyped three single-nucleotide polymorphisms (SNPs) of KL in 329 older patients with diagnosis of late-life MDD, treated with SSRIs and evaluated with the Hamilton Rating Scale for Depression 21-items (HRSD-21) at baseline and after 6 months. A reduction ≥50 and <10 % in HDRS-21 score was considered as response or nonresponse to therapy, respectively, and the values of reduction between 10 and 49 % as poor responders. After 6 months of SSRI treatment, 176 patients responded, 54 patients did not respond and 99 patients showed a poor response. Ordinal logistic models showed a significant association between mutation of SNP rs1207568 and responders and, similarly, for each unitary risk allele increase overlapping results were found. Conversely, a significantly higher frequency of the minor genotype of SNP rs9536314 was found in nonresponders. Considering the pre-post differences of HRSD-21 scores as a continue variable, we confirmed a significant improvement of depressive symptoms after treatment in patients carrying at least one minor allele at rs1207568 and a worse response in patients homozygous for the minor allele at rs9536314. Our results were the first that suggested a possible role of KL in the complex pathway of SSRI response in late-life MDD.