1. 1 Pharmacogenetics of Antipsychotic Drug Response Anil K. Malhotra, MD The Zucker Hillside Hospital Glen Oaks, New York The Albert Einstein College of Medicine Bronx, New York

2. 2 Dissecting the Heterogeneity of Antipsychotic Drug Response Marked inter-individual variation in response to antipsychotic drugs Biologic predictors of drug response (plasma HVA, prolactin, CSF metabolites) have been inconsistent Need for molecular correlates of drug efficacy and drug-induced adverse events Molecular correlates may suggest new targets for future drug development

3. 3 Pharmacogenetics of Clozapine Response CandidateFrequency ofAssociation With ReceptorPolymorphismRare AlleleClozapine Response? D 3 Ser 9 Gly35%Yes (Shaikh et al, 1996) 1 No (Malhotra et al, 1998) 2 D 4 16 amino acid repeatmultiple allelesNo (Rao et al, 1994) 3 in exon III 5HT 2A His 452 Tyr 45%Yes (Arranz et al, 1996) 4 No (Malhotra et al, 1996) 5 T 102 C9%No (Malhotra et al, 1996) 5 5HT 2C Cys 23 Ser13% (males)Yes (Sodhi et al, 1995) 6 24% (females)No (Malhotra et al, 1996) 7 5HTT20-34 bp repeat in40%No (Tsai SJ et al, 2000) 8 5 regulatory region 1. Shaikh S et al. Hum Genet. 1996;97:714-719; 2. Malhotra AK et al. Mol Psychiatry. 1998;3:72-75; 3. Rao PA et al. Arch Gen Psychiatry. 1994;51:912-917; 4. Arranaz MJ et al. Neurosci Lett. 1996;217:177-178; 5. Malhotra AK et al. Am J Psychiatry. 1996;153:1092-1094; 6. Sodhi MS et al. Neuroreport. 1995;29:169-172; 7. Malhotra AK et al. Neuroreport. 1996;7:2100-2102; 8. Tsai SJ et al. Schizophr Res. 2000;44:177-181;

4. 4 Dopamine D2 Receptor Blockade and Antipsychotic Potency Seeman et al 1975

5. 5 5’ 1 -141C Ins/Del 254368 Taq1 B 7 Ser 311 Cys 0.91 Kb 0.2 Kb 0.14 Kb -50 Kb -10 Kb 25.5 Kb A-241G Taq1 D TaqI A 3’ DRD2 (11q22-q23): Candidate Gene for Antipsychotic Drug Response

6. 6 P <0.02P <0.01 Transient expression of luciferase enzymatic activity driven by the DRD2 5’-flanking 304 bp containing the A-241 and -141C Del alleles, the A-241 and -141C Ins alleles in Y79 (A) and 293 (B) cells From Arinami et al, 1997. Functional Effects of the DRD2 - 141C Ins/Del Polymorphism Percentage

7. 7 Del- Del+ BPRS total 18 BaselineWeek 10 Clozapine 25 30 35 40 45 DRD2 -141C Ins/Del and Clozapine Response BPRS=Brief Psychiatric Rating Scale.

8. 8 Dopamine D2 Receptor Upregulation after Antipsychotic Treatment Silvestri et al. 2000

9. 9 DRD2 Promoter Region Polymorphisms in First-episode Schizophrenia 61 first-episode patients (schizophrenia/schizoaffective disorder/schizophreniform disorder) – 74% male; mean age 24±5 years, range 16-38 years Random assignment to medication – Risperidone (1-6 mg, n=33) or olanzapine (2.5-20 mg, n=28) Raters blind to medication and genotype – Weekly (first 4 weeks), then biweekly ratings up to 16 weeks Response: absence of delusions, hallucinations, and substantial thought disorder – Mild (3) or less on SADS-C positive symptom items – “Much Improved” or “Very Much Improved” on CGI change item – Sustained for two or more consecutive ratings CGI=Clinical Global Impression; SADS-C=Schedule for Affective Disorders and Schizophrenia – Change Version. Lencz T et al. Am J Psychiatry. 2006;163:529-531.

10. 10 DRD2 -141C Ins/Del and Response to Atypical Antipsychotics Del+ (n=30) Del- (n=31) Log rank=5.0, df=1, P=.025. Time (wk) 1614121086420 Initiating sustained response (%) Modified from Lencz T et al. Am J Psychiatry. 2006;163:529-531. 100 90 80 70 60 50 40 30 20 10 0

11. 11 DRD2 -141C Ins/Del and Antipsychotic Response: Meta – Analytic Results

12. 12 DRD2 -141C Ins/Del and Antipsychotic Response: Meta – Analytic Results

13. 13 DRD2 Predicts Acute Weight Gain

14. 14 Affymetrix 500K Platform: Specifications and Quality Control Marker spacing: 2.5kb (median); 5.8kb (mean) Mean Call Rate = 97% (range: 90-99) Mean heterozygosity = 27% 22 samples repeated; all SNPs > 1 error dropped Concordance across 454,699 SNPs > 99% SNPs with <85% calls excluded: 1,526 SNPs not in HWE (p<.001) in controls: 13,662 Total SNPs analyzed: 439,511

15. 15 Assessing Treatment Responsivity in Schizophrenia Clozapine usually reserved for patients who failed two prior antipsychotic drug trials or have severe side effects. Clozapine – treated patients are more severely ill and treatment nonresponsive. – McEvoy et al. 2006: Patients entering CATIE CLZ trial (N=99) : 58% with > 4 prior hosps vs 48% for others (N=444) (p=0.03) PANSS total: CLZ trial subjects: 87.6 + 20.2; Others: 77.0 +18.6 (p<0.001).

16. 16 Treatment Response Phenotype in Phase I Whole Genome Analyses Clozapine (n = 62) Non-Clozapine (n = 110) P Value Age37.10 ± 10.3838.47 ± 10.620.41 % Female29.03%39.10%0.19 Age of Onset20.89 ± 5.4120.69 ± 6.490.84 % Positive Family History 31.58%20.21%0.12

17. 17 Treatment Responsive vs. Treatment Nonresponsive: Phase I Results P = 5*10 -6

18. 18 Genes Associated with Treatment Response: Affy 500K Phase I Results ChromGene (Function)P value 3pAxonal cell adhesion4.6*10 -7 19pSNARE-related9.4*10 -7 8qNeuroreceptor (cannabinoid) 2.2*10 -6 5qLipid transport3.0*10 -6 8pProtein phosphatase subunit 3.2*10 -6

19. 19 Pharmacogenetics of Antipsychotic Drug Response: Conclusions Multiple candidate genes have been investigated in relatively small samples with inconsistent results DRD2: Candidate genes and meta-analytic support for role in antipsychotic efficacy Adverse events may be more amenable for pharmacogenetic targeting New genomic tools will markedly expand the opportunity for pharmacogenetic studies over the next few years