Helen Ambrose

Rosuvastatin pharmacokinetics and pharmacogenetics in white and Asian subjects residing in the same environment

Systemic exposure to rosuvastatin had been observed to be approximately 2‐fold higher in Japanese subjects living in Japan compared with white subjects in Western Europe or the United States. The organic anion transporting polypeptide 1B1 contributes to the hepatic uptake of rosuvastatin. Polymorphisms in the SLCO1B1 gene can lead to reduced transport function in vitro (T521>C). This study was conducted to determine whether the pharmacokinetic differences between Japanese and white subjects extended to other Asian ethnic groups and to determine whether polymorphisms in the SLCO1B1 gene contribute to any pharmacokinetic differences observed.

Effect of ADRB2 polymorphisms on response to longacting β2-agonist therapy: a pharmacogenetic analysis of two randomised studies

BACKGROUND New evidence has suggested that people with asthma who are homozygous for arginine at aminoacid 16 of the beta2-adrenergic receptor (ADRB2) might not benefit from longacting beta2-agonist therapy. We, therefore, investigated whether ADRB2 polymorphisms affect response to longacting beta2-agonists in combination with inhaled corticosteroids. METHODS Asthmatics were stratified by ADRB2 genotype in two studies to assess the effects of inhaled corticosteroids plus longacting beta2-agonists on asthma exacerbations. In study 1 (double-blind), 2250 asthmatics were randomly assigned to budesonide plus formoterol maintenance and reliever therapy, fixed-dose budesonide plus formoterol, or fixed-dose fluticasone plus salmeterol for 6 months. Study 2 (open-label) consisted of 405 asthmatics and compared an adjustable regimen of budesonide plus formoterol with fixed-dose budesonide plus formoterol and fixed-dose fluticasone plus salmeterol for 7 months. The relation between ADRB2 polymorphism, severe asthma exacerbations, and other asthma outcomes was analysed. Primary endpoints for studies 1 and 2 were severe asthma exacerbation and asthma control as assessed by measures of exacerbations, respectively. FINDINGS In study 1, Gly16Arg genotype had no effect on the percentage of participants with severe exacerbations across all treatment groups (99 [12%] of 833 Gly/Gly, 110 [11%] of 1028 Gly/Arg, and 32 [9%] of 361 Arg/Arg participants). Secondary endpoints, including forced expiratory volume in 1 s, peak expiratory flow, use of as-needed medication, and number of nights with awakenings were similar between genotype groups. No relation was recorded between ADRB2 haplotype and primary and secondary endpoints. In study 2, the frequency of asthma exacerbations (15 [9%] of 168 Gly/Gly, 13 [8%] of 169 Gly/Arg, and 6 [9%] of 67 Arg/Arg participants) and other study endpoints were closely similar for all ADRB2 genotypes. INTERPRETATION Since we showed no pharmacogenetic effect of ADRB2 variation on therapeutic response in asthma, patients, irrespective of their genotype, can continue to receive inhaled corticosteroids plus longacting beta2-agonists.

AKT Inhibition in Solid Tumors With AKT1 Mutations

Purpose AKT1 E17K mutations are oncogenic and occur in many cancers at a low prevalence. We performed a multihistology basket study of AZD5363, an ATP-competitive pan-AKT kinase inhibitor, to determine the preliminary activity of AKT inhibition in AKT-mutant cancers. Patients and Methods Fifty-eight patients with advanced solid tumors were treated. The primary end point was safety; secondary end points were progression-free survival (PFS) and response according to Response Evaluation Criteria in Solid Tumors (RECIST). Tumor biopsies and plasma cell-free DNA (cfDNA) were collected in the majority of patients to identify predictive biomarkers of response. Results In patients with AKT1 E17K-mutant tumors (n = 52) and a median of five lines of prior therapy, the median PFS was 5.5 months (95% CI, 2.9 to 6.9 months), 6.6 months (95% CI, 1.5 to 8.3 months), and 4.2 months (95% CI, 2.1 to 12.8 months) in patients with estrogen receptor-positive breast, gynecologic, and other solid tumors, respectively. In an exploratory biomarker analysis, imbalance of the AKT1 E17K-mutant allele, most frequently caused by copy-neutral loss-of-heterozygosity targeting the wild-type allele, was associated with longer PFS (hazard ratio [HR], 0.41; P = .04), as was the presence of coincident PI3K pathway hotspot mutations (HR, 0.21; P = .045). Persistent declines in AKT1 E17K in cfDNA were associated with improved PFS (HR, 0.18; P = .004) and response ( P = .025). Responses were not restricted to patients with detectable AKT1 E17K in pretreatment cfDNA. The most common grade ≥ 3 adverse events were hyperglycemia (24%), diarrhea (17%), and rash (15.5%). Conclusion This study provides the first clinical data that AKT1 E17K is a therapeutic target in human cancer. The genomic context of the AKT1 E17K mutation further conditioned response to AZD5363.

Effect of β2-adrenergic receptor gene (ADRB2) 3′ untranslated region polymorphisms on inhaled corticosteroid/long-acting β2-adrenergic agonist response

BackgroundEvidence suggests that variation in the length of the poly-C repeat in the 3′ untranslated region (3′UTR) of the β2-adrenergic receptor gene (ADRB2) may contribute to interindividual variation in β-agonist response. However, methodology in previous studies limited the assessment of the effect of sequence variation in the context of poly-C repeat length. The objectives of this study were to design a novel genotyping method to fully characterize sequence variation in the ADRB2 3′UTR poly-C repeat in asthma patients treated with inhaled corticosteroid and long-acting β2-adrenergic agonist (ICS/LABA) combination therapy, and to analyze the effect of the poly-C repeat polymorphism on clinical response.MethodsIn 2,250 asthma patients randomized to treatment with budesonide/formoterol or fluticasone/salmeterol in a six-month study (AstraZeneca study code: SD-039-0735), sequence diversity in the ADRB2 poly-C repeat region was determined using a novel sequencing-based genotyping method. The relationship between the poly-C repeat polymorphism and the incidence of severe asthma exacerbations, and changes in pulmonary function and asthma symptoms from baseline to the average during the treatment period, were analyzed.ResultsPoly-C repeat genotypes were assigned in 97% (2,192/2,250) of patients. Of the 13 different poly-C repeat alleles identified, six alleles occurred at a frequency of >5% in one or more population in this study. The repeat length of these six common alleles ranged from 10 to 14 nucleotides. Twelve poly-C repeat genotypes were observed at a frequency of >1%. No evidence of an association between poly-C repeat genotype and the incidence of severe asthma exacerbations was observed. Patients’ pulmonary function measurements improved and asthma symptoms declined when treated with ICS/LABA combination therapy regardless of poly-C repeat genotype.ConclusionsThe extensive sequence diversity present in the poly-C repeat region of the ADRB2 3′UTR did not predict therapeutic response to ICS/LABA therapy.

SNPs and Pharmacogenomics

Pharmacogenomics, the study of the association between genetics and drug response, is a rapidly growing field in human genetics. At a recent IBC Life Sciences conference in London, ‘SNPs and Pharmacogenomics,’ speakers emphasized the potential of pharmacogenomics to revolutionize traditional drug discovery and development processes. Common themes of the conference were the ability of pharmacogenomics to lead to an increased understanding of the molecular basis of disease and enable the discovery, development and delivery of safer and more effective treatments. Inherited differences in drug targets, as well as polymorphisms in genes with a role in drug metabolism and disposition, each have an influence on the efficacy and safety of therapeutics. Speakers also described the opportunities and challenges facing pharmacogenomics and the technical and educational obstacles that must be overcome in order to realize the promise of personalized medicine. Systematic identification of SNPs, the most common type of human genetic variation, is providing the markers that may be used to elucidate the basis of inter-individual variation in drug response. The conference presented an opportunity for providers of highthroughput SNP genotyping technologies to describe how their platforms, in combination with gene expression and population studies, are facilitating the molecular characterization of complex diseases. SNPs have a prominent role in the progress of pharmacogenomics due to their high prevalence rate and ease of analysis [1]. Dr Arthur Holden (Chairman, The SNP Consortium [TSC] [101]), addressing the conference from the US, summarized the current status and activities of the consortium. To date, the TSC has contributed ~ 1.8 million publicly available SNPs towards the goal of defining a high quality SNP map for full genome association and haplotyping studies. Dr Holden believes that the next challenges are to:

Abstract B109: AZD5363, a catalytic pan-Akt inhibitor, in Akt1 E17K mutation positive advanced solid tumors

This abstract has been withheld from publication due to its inclusion in the AACR-NCI-EORTC Molecular Targets Conference 2015 Official Press Program. It will be posted online at the time of its presentation in a press conference or in a session: 10:00 AM ET Saturday, November 7. Citation Format: David M. Hyman, Lillian Smyth, Philippe L. Bedard, Amit Oza, Emma Dean, Anne Armstrong, Joao Lima, Hideaki Bando, Peter Kabos, J. Alejandro Perez-Fidalgo, Kathleen Moore, Shannon N. Westin, Benoit You, Sarat Chandarlapaty, Leila Alland, Helen Ambrose, Andrew Foxley, Justin Lindemann, Martin Pass, Paul Rugman, Shaista Salim, Gaia Schiavon, Kenji Tamura, Jose Baselga, Udai Banerji. AZD5363, a catalytic pan-Akt inhibitor, in Akt1 E17K mutation positive advanced solid tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B109.

A Phase I Open-Label Study to Identify a Dosing Regimen of the Pan-AKT Inhibitor AZD5363 for Evaluation in Solid Tumors and in PIK3CA-Mutated Breast and Gynecologic Cancers

Purpose: This phase I, open-label study (Study 1, D3610C00001; NCT01226316) was the first-in-human evaluation of oral AZD5363, a selective pan-AKT inhibitor, in patients with advanced solid malignancies. The objectives were to investigate the safety, tolerability, and pharmacokinetics of AZD5363, define a recommended dosing schedule, and evaluate preliminary clinical activity. Experimental Design: Patients were aged ≥18 years with World Health Organization (WHO) performance status of 0 to 1. Dose escalation was conducted within separate continuous and intermittent [4 days/week (4/7) or 2 days/week (2/7)] schedules with safety, pharmacokinetic, and pharmacodynamic analyses. Expansion cohorts of approximately 20 patients each explored AZD5363 activity in PIK3CA-mutant breast and gynecologic cancers. Results: MTDs were 320, 480, and 640 mg for continuous (n = 47), 4/7 (n = 21), and 2/7 (n = 22) schedules, respectively. Dose-limiting toxicities were rash and diarrhea for continuous, hyperglycemia for 2/7, and none for 4/7. Common adverse events were diarrhea (78%) and nausea (49%) and, for Common Terminology Criteria for Adverse Events grade ≥3 events, hyperglycemia (20%). The recommended phase II dose (480 mg bid, 4/7 intermittent) was assessed in PIK3CA-mutant breast and gynecologic expansion cohorts: 46% and 56% of patients, respectively, showed a reduction in tumor size, with RECIST responses of 4% and 8%. These responses were less than the prespecified 20% response rate; therefore, the criteria to stop further recruitment to the PIK3CA-mutant cohort were met. Conclusions: At the recommended phase II dose, AZD5363 was well tolerated and achieved plasma levels and robust target modulation in tumors. Proof-of-concept responses were observed in patients with PIK3CA-mutant cancers treated with AZD5363. Clin Cancer Res; 24(9); 2050–9. ©2017 AACR. See related commentary by Costa and Bosch, p. 2029

Accurate detection of low prevalence AKT1 E17K mutation in tissue or plasma from advanced cancer patients

Personalized healthcare relies on accurate companion diagnostic assays that enable the most appropriate treatment decision for cancer patients. Extensive assay validation prior to use in a clinical setting is essential for providing a reliable test result. This poses a challenge for low prevalence mutations with limited availability of appropriate clinical samples harboring the mutation. To enable prospective screening for the low prevalence AKT1 E17K mutation, we have developed and validated a competitive allele-specific TaqMan® PCR (castPCR™) assay for mutation detection in formalin-fixed paraffin-embedded (FFPE) tumor tissue. Analysis parameters of the castPCR™ assay were established using an FFPE DNA reference standard and its analytical performance was assessed using 338 breast cancer and gynecological cancer FFPE samples. With recent technical advances for minimally invasive mutation detection in circulating tumor DNA (ctDNA), we subsequently also evaluated the OncoBEAM™ assay to enable plasma specimens as additional diagnostic opportunity for AKT1 E17K mutation testing. The analysis performance of the OncoBEAM™ test was evaluated using a novel AKT1 E17K ctDNA reference standard consisting of sheared genomic DNA spiked into human plasma. Both assays are employed at centralized testing laboratories operating according to quality standards for prospective identification of the AKT1 E17K mutation in ER+ breast cancer patients in the context of a clinical trial evaluating the AKT inhibitor AZD5363 in combination with endocrine (fulvestrant) therapy.