Powerpoint presentation

Association of Genetic Polymorphisms with Response
to Placebo Treatment in Patients with Osteoarthritis Knee Pain
Richard H. Gracely,1 Shad B. Smith,1 Gary Slade,1 Luda Diatchenko,1 Roger B. Fillingim,1 Bonnie Fijal,2 Eli Frakes,2 Samuel A. McLean,1 Kevin Piezer,2 Alexandra N. Heinloth,3 William Maixner,1 John P. Houston2
1Algynomics Inc., Chapel Hill, NC, USA; 2Eli Lilly and Company and/or any of its subsidiaries, Indianapolis, IN, USA; 3i3 Statprobe, Ann Arbor, MI, USA
METHODS (continued)
Results Summary
ABSTRACT
Figure 1. LS Mean Changes in BDI-II Total Score and
Depression Factor Stratified by HTR3A SNP
• The Depression and Pain Factors explained >75% of variance in the 25 endpoint Aim of investigation: Identification of genetic polymorphisms associated with therapeutic
• Statistical Analysis
rs1176752 Genotype in the Placebo Group
response to placebo or duloxetine in patients with painful osteoarthritis of the knee.
– Factor analysis with Maximum Likelihood Extraction and Oblique (oblimin) Rotation was used to • A total of 3 SNPs in 2 genes, COMT and HTR3A, were statistically significantly associated with change in the Depression Factor in the placebo group.
Methods used: Used were data from patients who consented to genetic testing in 2
capture the highest proportion of variance among 25 variables measuring symptom, function, placebo-controlled, 13-week studies examining the efficacy of duloxetine 60 to 120 mg/day • At the end of treatment in the placebo-treated group and comorbidity related to osteoarthritis.
in treatment of knee osteoarthritis. Factor analysis using Maximum Likelihood Extraction – BDI-II was significantly decreased from baseline for HTR3A major homozygotes but not – Associations were evaluated separately in duloxetine and placebo groups using analysis of and Oblique (oblimin) Rotation identified factors (Depression and Pain Factors) that covariance with adjustment for the baseline factor (Depression or Pain Factor). For these captured the highest proportion of variance among 25 variables measuring symptom, analyses, the difference between week 13 and baseline values were evaluated using last – BDI-II was not significantly decreased from baseline within individual COMT genotypes, function, and comorbidity related to osteoarthritis. Forty-four single nucleotide observation carried forward (LOCF) methodology.
although baseline BDI-II appeared greater for patients with the minor allele for each of polymorphisms (SNPs) in 12 candidate genes (prioritized for analysis from a larger set of genes selected for exploratory analysis) were analyzed for associations with post-treatment – The Spectral Decomposition Method of Nyholt6 was used to estimate the effective number of independent SNPs tested, accounting for linkage disequilibrium between neighboring SNPs.
change in factor scores. Associations were evaluated separately in duloxetine (N=82) and • No statistically significant associations between candidate SNPs and change in the placebo (N=83) groups using analysis of covariance with adjustment for baseline factor. – The threshold for statistical significance (p=0.0018) was determined by applying a Bonferroni Depression Factor were detected in the duloxetine group.
correction based on testing 28 independent SNPs.
Results: Two factors, one reflecting depression (Depression Factor) and the other reflecting
• None of the examined SNPs were statistically significantly associated with change in the pain (Pain Factor), accounted for >75% of variance in measured variables. In the placebo SNPs in Candidate Genes
Baseline BDI-II Total Score
group, change in the Depression Factor was statistically significantly associated with 2 – Associations of 44 SNPs in 12 candidate genes with improvement in measures of pain and HTR3A SNPs (rs1176752, p<0.001; rs1150226, p<0.001) and 1 COMT SNP (rs174696, depression were examined. The 12 candidate genes are critical elements of the Limitations
p<0.001). Genetic associations were not significant (p>0.0018) for the Depression Factor in norepinephrine/serotonin pathways, which are known to strongly contribute to pain and the duloxetine group, nor for the Pain Factor in either treatment group.
• Overall, patients in this study had very low depression scores – similar to a healthy depression. The genes included ADRA2A, ADRA2B, ADRA2C, ADRB2, COMT, DRD2, GCH1, Conclusions: Genetic polymorphisms in HTR3A and COMT may influence placebo
HTR2A, HTR3A, SLC6A2, SLC6A4, and TPH1. Abbreviations: BDI-II=Beck Depression Inventory II; LS Mean=least squared mean; n=number of patients; NA=not available; response of depression symptoms in patients with osteoarthritis knee pain.
SNP=single nucleotide polymorphism. A is minor allele, C is major allele. Error bars indicate standard error; * p<0.05 for BDI-II – Within a chosen gene locus, SNPs situated in potentially functional regions (promoters, exons, • Only white patients were included in the current analyses (too few study participants of change from baseline. LS Mean refers to least-squares means for endpoints from analysis of covariance model. areas of conservation) were examined.
Figure 2. LS Mean Changes in BDI-II Total Score and
• Power to detect associations was limited.
INTRODUCTION
• Limited coverage was present for some candidate genes.
Depression Factor Stratified by HTR3A SNP
rs1150226 Genotype in the Placebo Group
• An epidemiological study with data from North Carolina suggests that the life-time risk for symptomatic knee osteoarthritis is 44.7% in the general population, with an increase to 56.8% Table 1. Factor Loading
in patients with a history of a knee injury.1 • The efficacy of duloxetine, a dual norepinephrine/serotonin reuptake inhibitor, in the treatment Depression Factor
Pain Factor
CONCLUSIONS
of osteoarthritis knee pain has been demonstrated in 2 double-blind, placebo-controlled • Change in the Depression Factor was statistically significantly associated • Genetic risk factors for the development of knee osteoarthritis have been identified,4 but no HADS Anxiety Subscale Score – Odd numbered items (0.72) with rs1176752 and rs1150226 in HTR3A and with rs174696 in COMT in studies have examined how genetic factors might influence treatment outcome in patients patients with osteoarthritis knee pain treated with placebo.
HADS Anxiety Subscale Score – Even numbered items (0.73) • Genetic associations were not significant (p>0.0018) for the Depression SF-36 Mental Health Transformed Score (-0.81) Factor in the duloxetine group, nor for the Pain Factor in either treatment OBJECTIVE
• A prior study in clinically depressed patients showed significant associations Abbreviations: BDI-II=Beck Depression Inventory II; BPI=Brief Pain Inventory; HADS=Hospital Anxiety Depression Scale; Baseline BDI-II Total Score
between COMT SNP rs174696 and decreases in depression scores during To test the association of potentially functional single nucleotide polymorphisms (SNPs) in SF-36=36-item Short-Form Health Survey. treatment with duloxetine, with the strongest decreases observed in carriers select candidate genes with response to treatment with duloxetine and placebo in patients Values in parentheses indicate standard regression coefficients from the rotated factor pattern. of the minor homozygote genotype.7 Here, we observed higher baseline Table 2. Patient Baseline Characteristics
depression (BDI-II) scores in carriers of the minor homozygote genotype of COMT SNPs rs174696 in patients with osteoarthritis knee pain but no Placebo (N=83)
Duloxetine (N=82)
Abbreviations: BDI-II=Beck Depression Inventory II; LS Mean=least squared mean; n=number of patients; SNP=single nucleotide polymorphism. T is minor allele, C is major allele. Error bars indicate standard error; * p<0.05 for BDI-II change from significant changes in BDI-II within any of the COMT genotypes at the end baseline. LS Mean refers to least-squares means for endpoints from analysis of covariance model. • Due to the very low level of depression observed in the current population, • Patients and Study Design
Figure 3. LS Mean Changes in BDI-II Total Score and
the clinical significance of these results require further investigation.
– Used were data from white patients who consented to genetic testing while participating Depression Factor Stratified by COMT SNP
in either one of 2 clinical trials examining the efficacy and safety of treatment with rs174696 Genotype in the Placebo Group
duloxetine in patients with osteoarthritis knee pain.
References:
– Patients with Major Depressive Disorder were excluded from both studies.
– Both clinical trials were double-blind and placebo-controlled; patients received treatment 1. Murphy L, et al. Arthritis Rheum 2008;59(9):1207-1213 2. Chappell AS, et al. Pain 2009;146(3):253-260 • Measures Used to Assess Changes in Pain
3. Chappell AS, et al. Pain Pract 2010 Jul 5 [Epub ahead of print] Abbreviations: BDI-II=Beck Depression Inventory II; BMI=body mass index; n=number of patients affected; N=total number of self-identified white patients who agreed to genetic testing; SD=standard deviation. 4. Valdes AM and Spector TD. Curr Opin Rheumatol 2010;22(2):139-143 Table 3. SNPs Associated with Change in Depression Factor
5. Nicolini H, et al. Psychol Med 2009;39(2):267-276 • Measures Used to Assess Changes in Depression
in the Placebo Group
6. Nyholt DR. Am J Hum Genet 2004;74(4):765-769 – Beck Depression Inventory II (BDI-II) 7. Perlis RH, et al. Biol Psychiatry 2009;65(9):785-791 – Hospital Anxiety Depression Scale (HADS) Unadjusted p-Value
– 36-item Short-Form Health Survey (SF-36) Placebo Group Duloxetine Group
Disclosures
• Genotyping
0.001
Baseline BDI-II Total Score
This study was sponsored by Eli Lilly and Company and/or any of its subsidiaries. Drs. – Genotyping was performed by Beckman-Coulter Genomics (Morrisville, NC) on the Fijal, Frakes, Gray, Piezer, Liu, and Houston are fulltime employees of Eli Lilly and/or any Algynomics Pain Research Panel, a proprietary candidate gene SNP array using 0.001
of its subsidiaries, and minor stockholders of Eli Lilly and Company. Drs. Maixner, Affymetrix MegAllele technology. Additional SNPs were genotyped with the Sequenom 0.001
Fillingim, Smith, Diatchenko, Gracely, McLean, and Slade are consultants and MassArray platform as previously described.5 Abbreviation: SNP=single nucleotide polymorphism. Results from generalized linear model, where the dependent variable was Abbreviations: BDI-II=Beck Depression Inventory II; LS Mean=least squared mean; n=number of patients; SNP=single nucleotide – All SNPs used in the current analysis had ≥95% usable calls across patients, and only change in depression factor from baseline (Week 0) to Week 13. polymorphism. C is minor allele, T is major allele. Error bars indicate standard error; * p<0.05 for BDI-II change from baseline. Dr. Heinloth is a fulltime employee of i3 Statprobe, a division of Ingenix, which is a SNPs with minor allele frequencies of ≥1% were examined.
Italic and Bold indicates p-values that reached statistical significance. LS Mean refers to least-squares means for endpoints from analysis of covariance model. International Association for the Study of Pain (IASP) 13th World Congress; Montreal, QC, Canada; August 29 – September 2, 2010
Sponsored by Eli Lilly and Company and/or any of its subsidiaries

Source: http://www.algynomics.com/pdf/2010IASPCymbaltaPoster.pdf