Association of NR1I2, CYP3A5 and ABCB1 genetic polymorphisms with variability of temsirolimus pharmacokinetics and toxicity in patients with metastatic bladder cancer Litaty MBATCHI, Matthieu GASSIOT, Philippe POURQUIER, Alejando GOBERNA, Hakim MAHAMMEDI, Loic MOUREY, Florence JOLY, Serge LUMBROSO, Alexandre EVRARD, Nadine HOUEDE Montpellier and Nimes University Hospital 2nd International Workshop on Clinical Pharmacology of Anticancer Drugs Madrid, September the 13th and 14th
TEMSIROLIMUS, Torisel Ester of Sirolimus Inhibitor of mtor (mammalian target of rapamycin) => G1 growth arrest in treated tumor cells Approval (2 nd line) : o Metastatic renal carcinoma o Mantle lymphoma Studied in clinical trials for various cancers : glioma, sarcoma, thyroid, etc. o Phase II clinical Trial: patients with relapsed urothelial carcinoma of the bladder who were refractory to first-line chemotherapy Unpredictible inter-individual variability of response and adverse reactions (rash, edema, mucositis, lymphopenia, asthenia, anorexia etc)
Temsirolimus metabolism and disposition TEMSIROLIMUS CYP3A4 CYP3A5 Esterases SIROLIMUS Active metabolite CYP3A4 CYP3A5 ABCB1 Metabolites with no or low activity Metabolites with no or low activity Metabolism similar to calcineurin inhibitors Substrate of ABCB1 (P-gp, MDR1) Elimination => metabolism (CYP3A4 and CYP3A5) and biliary excretion
Variability of temsirolimus/sirolimus metabolism : Inhibition of CYP3A activity Temsirolimus + Strong CYP3A4 inhibitor (ketoconazole) Temsirolimus : No significant variation of Cmax and AUC Sirolimus : AUC by 3.2 fold and Cmax by 2.2 British Journal of Cancer (2008) 98, 1797 1802
Variability of temsirolimus/sirolimus metabolism : Induction of CYP3A activity and ABCB1 expression Temsirolimus + rifampicine S T John Wort Temsirolimus : No significant changes Ligands: xenobiotics NR1I2 (PXR) RXR Coactivators TARGET GENE Sirolimus : AUC by 56% CYP3A4/5, ABCB1, SLC01B3, UGT1A1, ABCG2 Journal of Clinical Pharmacology, 2007;47:1430-1439
Goal of the study CYP3A5 and ABCB1 polymorphisms are critical factors that affect the pharmacokinetic of calcineurin inhibitors Goal: Identify genetic determinants of the inter-individual variability of temsirolimus pharmacokinetics and toxicity. Ancillary study of a Phase II clinical Trial: 54 patients with urothelial carcinoma of the bladder; PK samples available for 15 patients 25 mg of temsirolimus weekly infusion
Patients and Methods PHARMACOKINETICS HPLC-MS/MS temsirolimus (TS), sirolimus (S) GENOTYPES 7 candidate SNPs Single Nucleotide Polymorphisms CYP3A5*3 (rs1045642) ABCB1 (rs1045642, rs1128503, rs20322582) NR1I2 (rs3814055, rs2472677, rs6785049) Non compartmental analysis AUC (Area Under curve), AUC SUM (AUC TS +AUC S ), AUC RATIO (AUC S /AUC TS ) CL, t 1/2, Cmax TOXICITY Most observed toxicities (CTAE v3, and SOC classification) Bone marrow disorders Gastro-intestinal disorders Athenia, pyrexia rash Data split into 2 categories: grade 3/4 versus grade 1/2 Non-parametric Kruskal Wallis test and Fisher s exact test was performed to assess the association between pharmacokinetics, genetics, toxicity and demographics data
CYP3A5*3 allele is associated with sirolimus PK CYP3A5 CYP3A5*3 (rs776746) Non functional allele Non-expressor status Guidelines for tacrolimus dosing p=0.020 p=0.037 Sirolimus Cmax (ng/ml) Sirolimus CL/fm (ml/h) (n=5) (n=10) (n=5) (n=10)
SNPs of ABCB1 are associated with sirolimus PK ABCB1 Rs1045642, rs1128503, (synonymes) ; rs2032582 ( missens) Low expression ABCB1 Cyclosporin PK variability Sirolimus AUC rs1128503 p=0.037 Sirolimus t 1/2 rs1128503 p=0.010 Sirolimus t 1/2 rs2032582 p=0.033 (ng/ml) (h) (h) (n=7) (n=6) (n=2) (n=7) (n=6) (n=2) (n=5) (n=7) (n=3)
SNPs of NR1I2 are associated with temsirolimus PK NR1I2-rs3814055 NR1I2-rs2472677 NR1I2-rs6785049 In vitro functionality T allele: down regulation of PXR and target genes expression level T allele: basal NR1I2 mrna level and CYP3A4 activity CYP3A4 induction Pharmacokinetics of calcineurin inhibitors T allele is associated with decreased apparent clearance of tacrolimus Cyclosporine interindividual pharmacokinetic variability in children AUC SUM (temsirolimus + sirolimus) (ng.h/ml) rs6785049 p=0.049 Temsirolimus t 1/2 (h) rs3814055 p=0.017 (n=5) (n=7) (n=3) (n=6) (n=6) (n=3) AUC SUM = AUC TEMSIROLIMUS + AUC SIROLIMUS Globale exposure on active entity
Does temsirolimus PK affect its toxicity? Population PK-safety-genomics in CCI-779 treated patients Boni et al, 2005 CLINICAL PHARMACOLOGY & THERAPEUTICS, 2005;77(1):76-89 AUC SUM = AUC TEMSIROLIMUS + AUC SIROLIMUS Globale exposure on active entity
Does temsirolimus PK affect its toxicity? Severity of toxicity p= 0.034 AUC RATIO (temsirolimus+sirolimus) G1/G2 (n=9) G3/G4 (n=6)
SNPs of NR1I2 are associated with temsirolimus toxicity Genotype Effectif No toxicity or G1/G2 Severe toxicity* G3/G4 Fisher's Exact Test (n) (n) OR** p-value NR1I2-rs3814055 CC 6 1 6 CT 6 6 0 TT 4 2 1-0.0057 CC 7 1 6 CT_TT 9 8 1 0.032 [4.1*10-4 8.9*10-1 ] 0.0087 NR1I2-rs6785049 AA 6 1 5 AG 7 6 1 GG 3 2 1-0.040 AA 6 1 5 AG_GG 10 8 2 Total 9 7 *Most observed toxicity: bone marrow disorders, gastro-intestinal disorders, thenia, pyrexia, rash **OR, odds ratio 0.065 [9.5*10-4 5.7*10-1 ] 0.034
Summary CYP3A5*3 ABCB1-rs1128503 ABCB1-rs2032582 Sirolimus half-time Sirolimus AUC Sirolimus CL/fm (apparent clearance) AUC RATIO (AUC SIROLIMUS /AUC TEMSIROLIMUS ) NR1I2-rs3814055 NR1I2-rs6785049 Temsirolimus half-time Globale exposure on active entity (AUC SUM ) Severity of the toxicity
Discussion First pharmacogenetic study about temsirolimus Small size of the cohort o Lack of power o Obligation to group the toxicity whatever the organs o Confirmation needed on a larger cohort: patients with metastatic renal cancer? Mechanism of genotype / toxicity association? o Which is the most toxic entity o Change in temsirolimus and sirolimus global exposure? o Change in local metabolisms in target tissus
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