Clonal haemopoiesis and therapy-related myeloid malignancies in elderly patients: a proof-of-concept, case-control study.

BACKGROUND: Clonal haemopoiesis of indeterminate potential (CHIP) is an age-associated genetic event linked to increased risk of primary haematological malignancies and increased all-cause mortality, but the prevalence of CHIP in patients who develop therapy-related myeloid neoplasms is unknown. We did this study to investigate whether chemotherapy-treated patients with cancer who have CHIP are at increased risk of developing therapy-related myeloid neoplasms. METHODS: We did a nested, case-control, proof-of-concept study to compare the prevalence of CHIP between patients with cancer who later developed therapy-related myeloid neoplasms (cases) and patients who did not develop these neoplasms (controls). We identified cases from our internal biorepository of 123 357 patients who consented to participate in the Total Cancer Care biobanking protocol at Moffitt Cancer Center (Tampa, FL, USA) between Jan 1, 2006, and June 1, 2016. We included all individuals who were diagnosed with a primary malignancy, were treated with chemotherapy, subsequently developed a therapy-related myeloid neoplasm, and were 70 years or older at either diagnosis. For inclusion in this study, individuals must have had a peripheral blood or mononuclear cell sample collected before the diagnosis of therapy-related myeloid neoplasm. Controls were individuals who were diagnosed with a primary malignancy at age 70 years or older and were treated with chemotherapy but did not develop therapy-related myeloid neoplasms. Controls were matched to cases in at least a 4:1 ratio on the basis of sex, primary tumour type, age at diagnosis, smoking status, chemotherapy drug class, and duration of follow-up. We used sequential targeted and whole-exome sequencing and described clonal evolution in cases for whom paired CHIP and therapy-related myeloid neoplasm samples were available. The primary endpoint of this study was the development of therapy-related myeloid neoplasm and the primary exposure was CHIP. FINDINGS: We identified 13 cases and 56 case-matched controls. The prevalence of CHIP in all patients (23 [33%] of 69 patients) was higher than has previously been reported in elderly individuals without cancer (about 10%). Cases had a significantly higher prevalence of CHIP than did matched controls (eight [62%] of 13 cases vs 15 [27%] of 56 controls, p=0·024; odds ratio 5·75, 95% CI 1·52-25·09, p=0·013). The most commonly mutated genes in cases with CHIP were TET2 (three [38%] of eight patients) and TP53(three [38%] of eight patients), whereas controls most often had TET2 mutations (six [40%] of 15 patients). In most (four [67%] of six patients) cases for whom paired CHIP and therapy-related myeloid neoplasm samples were available, the mean allele frequency of CHIP mutations had expanded by the time of the therapy-related myeloid neoplasm diagnosis. However, a subset of paired samples (two [33%] of six patients) had CHIP mutations that decreased in allele frequency, giving way to expansion of a distinct mutant clone. INTERPRETATION: Patients with cancer who have CHIP are at increased risk of developing therapy-related myeloid neoplasms. The distribution of CHIP-related gene mutations differs between individuals with therapy-related myeloid neoplasm and those without, suggesting that mutation-specific differences might exist in therapy-related myeloid neoplasm risk. FUNDING: Moffitt Cancer Center.

Key Lessons Learned from Moffitt's Molecular Tumor Board: The Clinical Genomics Action Committee Experience.

BACKGROUND: The increasing practicality of genomic sequencing technology has led to its incorporation into routine clinical practice. Successful identification and targeting of driver genomic alterations that provide proliferative and survival advantages to tumor cells have led to approval and ongoing development of several targeted cancer therapies. Within many major cancer centers, molecular tumor boards are constituted to shepherd precision medicine into clinical practice. MATERIALS AND METHODS: In July 2014, the Clinical Genomics Action Committee (CGAC) was established as the molecular tumor board companion to the Personalized Medicine Clinical Service (PMCS) at Moffitt Cancer Center in Tampa, Florida. The processes and outcomes of the program were assessed in order to help others move into the practice of precision medicine. RESULTS: Through the establishment and initial 1,400 patients of the PMCS and its associated molecular tumor board at a major cancer center, five practical lessons of broad applicability have been learned: transdisciplinary engagement, the use of the molecular report as an aid to clinical management, clinical actionability, getting therapeutic options to patients, and financial considerations. Value to patients includes access to cutting-edge practice merged with individualized preferences in treatment and care. CONCLUSIONS: Genomic-driven cancer medicine is increasingly becoming a part of routine clinical practice. For successful implementation of precision cancer medicine, strategically organized molecular tumor boards are critical to provide objective evidence-based translation of observed molecular alterations into patient-centered clinical action. Molecular tumor board implementation models along with clinical and economic outcomes will define future treatment standards. The Oncologist 2017;22:144-151Implications for Practice: It is clear that the increasing practicality of genetic tumor sequencing technology has led to its incorporation as part of routine clinical practice. Subsequently, many cancer centers are seeking to develop a personalized medicine services and/or molecular tumor board to shepherd precision medicine into clinical practice. This article discusses the key lessons learned through the establishment and development of a molecular tumor board and personalized medicine clinical service. This article highlights practical issues and can serve as an important guide to other centers as they conceive and develop their own personalized medicine services and molecular tumor boards.

The pharmacogenomics of drug resistance to protein kinase inhibitors.

Dysregulation of growth factor cell signaling is a major driver of most human cancers. This has led to development of numerous drugs targeting protein kinases, with demonstrated efficacy in the treatment of a wide spectrum of cancers. Despite their high initial response rates and survival benefits, the majority of patients eventually develop resistance to these targeted therapies. This review article discusses examples of established mechanisms of drug resistance to anticancer therapies, including drug target mutations or gene amplifications, emergence of alternate signaling pathways, and pharmacokinetic variation. This reveals a role for pharmacogenomic analysis to identify and monitor for resistance, with possible therapeutic strategies to combat chemoresistance.

Identification of Clonal Hematopoiesis Mutations in Solid Tumor Patients Undergoing Unpaired Next-Generation Sequencing Assays.

PURPOSE: In this era of precision-based medicine, for optimal patient care, results reported from commercial next-generation sequencing (NGS) assays should adequately reflect the burden of somatic mutations in the tumor being sequenced. Here, we sought to determine the prevalence of clonal hematopoiesis leading to possible misattribution of tumor mutation calls on unpaired Foundation Medicine NGS assays. EXPERIMENTAL DESIGN: This was a retrospective cohort study of individuals undergoing NGS of solid tumors from two large cancer centers. We identified and quantified mutations in genes known to be frequently altered in clonal hematopoiesis (DNMT3A, TET2, ASXL1, TP53, ATM, CHEK2, SF3B1, CBL, JAK2) that were returned to physicians on clinical Foundation Medicine reports. For a subset of patients, we explored the frequency of true clonal hematopoiesis by comparing mutations on Foundation Medicine reports with matched blood sequencing. RESULTS: Mutations in genes that are frequently altered in clonal hematopoiesis were identified in 65% (1,139/1,757) of patients undergoing NGS. When excluding TP53, which is often mutated in solid tumors, these events were still seen in 35% (619/1,757) of patients. Utilizing paired blood specimens, we were able to confirm that 8% (18/226) of mutations reported in these genes were true clonal hematopoiesis events. The majority of DNMT3A mutations (64%, 7/11) and minority of TP53 mutations (4%, 2/50) were clonal hematopoiesis. CONCLUSIONS: Clonal hematopoiesis mutations are commonly reported on unpaired NGS testing. It is important to recognize clonal hematopoiesis as a possible cause of misattribution of mutation origin when applying NGS findings to a patient's care.See related commentary by Pollyea, p. 5790.

Quantitation of Targetable Somatic Mutations Among Patients Evaluated by a Personalized Medicine Clinical Service: Considerations for Off-Label Drug Use.

INTRODUCTION: Moffitt Cancer Center's Personalized Medicine Clinical Service (PMCS) reviews somatic next-generation sequencing (NGS) assay results, provides interpretations, and identifies potential therapeutic options. The number of individuals reviewed by our clinical service who are eligible for on-label or off-label drug therapy based on genetic test results has previously not been quantitated. We determined the number of patients harboring an actionable mutation that would qualify a patient for an on-label drug or consideration for off-label drug treatment. METHODS: The Food and Drug Administration (FDA) Table of Pharmacogenomic Biomarkers in Drug Labeling was utilized to identify anticancer agents containing genomic markers in the Indications and Usage section of the drug label. A database containing discrete NGS patient data was queried retrospectively for those drugs and associated genomic mutations included in this study. On-label was defined as those patients who were eligible for a drug based on harboring a targetable mutation in the FDA-approved cancer type. Off-label was defined as those patients who may be considered for a drug based on harboring a targetable mutation in a non-FDA-approved cancer type. RESULTS: A total of 1072 patients and 1131 NGS results were eligible for study inclusion. Fifty-two patients (4.9%) had results for more than one NGS assay. Seventeen drugs targeting ALK, BRAF, BRCA1/BRCA2, EGFR, or ERBB2 mutations met the study inclusion criteria. Of the entire patient population, 92 (8.6%) unique patients were eligible for at least one on-label drug; off-label use of at least one drug could be considered in 103 (9.6%) unique patients. CONCLUSION: Combining both on-label and off-label opportunities, 175 (16.3%) unique patients had actionable mutations in six genes. Because most patients reviewed by our PMCS have previously treated advanced disease with limited treatment options, identifying additional lines of therapy is of clinical utility.

Tumor exome sequencing and copy number alterations reveal potential predictors of intrinsic resistance to multi-targeted tyrosine kinase inhibitors.

Multi-targeted tyrosine kinase inhibitors (TKIs) have broad efficacy and similar FDA-approved indications, suggesting shared molecular drug targets across cancer types. Irrespective of tumor type, 20-30% of patients treated with multi-targeted TKIs demonstrate intrinsic resistance, with progressive disease as a best response. We conducted a retrospective cohort study to identify tumor (somatic) point mutations, insertion/deletions, and copy number alterations (CNA) associated with intrinsic resistance to multi-targeted TKIs. Using a candidate gene approach (n=243), tumor next-generation sequencing and CNA data was associated with resistant and non-resistant outcomes. Resistant individuals (n=11) more commonly harbored somatic point mutations in NTRK1, KDR, TGFBR2, and PTPN11 and CNA in CDK4, CDKN2B, and ERBB2 compared to non-resistant (n=26, p<0.01). Using a random forest classification model for variable reduction and a decision tree classification model, we were able to differentiate intrinsically resistant from non-resistant patients. CNA in CDK4 and CDKN2B were the most important analytical features, implicating the cyclin D pathway as a potentially important factor in resistance to multi-targeted TKIs. Replication of these results in a larger, independent patient cohort has potential to inform personalized prescribing of these widely utilized agents.

Atenolol induced HDL-C change in the pharmacogenomic evaluation of antihypertensive responses (PEAR) study.

We sought to identify novel pharmacogenomic markers for HDL-C response to atenolol in participants with mild to moderate hypertension. We genotyped 768 hypertensive participants from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) study on the Illumina HumanCVD Beadchip. During PEAR, participants were randomized to receive atenolol or hydrochlorothiazide. Blood pressure and cholesterol levels were evaluated at baseline and after treatment. This study focused on participants treated with atenolol monotherapy. Association with atenolol induced HDL-C change was evaluated in 232 whites and 152 African Americans using linear regression. No SNPs achieved a Bonferroni corrected P-value. However, we identified 13 regions with consistent association across whites and African Americans. The most interesting of these regions were seven with prior associations with HDL-C, other metabolic traits, or functional implications in the lipid pathway: GALNT2, FTO, ABCB1, LRP5, STARD3NL, ESR1, and LIPC. Examples are rs2144300 in GALNT2 in whites (P=2.29x10(-4), ß=-1.85 mg/dL) and rs12595985 in FTO in African Americans (P=2.90x10(-4), ß=4.52 mg/dL), both with consistent regional association (P<0.05) in the other race group. Additionally, baseline GALNT2 expression differed by rs2144300 genotype in whites (P=0.0279). In conclusion, we identified multiple gene regions associated with atenolol induced HDL-C change that were consistent across race groups, several with functional implications or prior associations with HDL-C.

An in vitro evaluation of guanfacine as a substrate for P-glycoprotein.

BACKGROUND: With a US Food and Drug Administration-labeled indication to treat attention-deficit/hyperactivity disorder (ADHD), the nonstimulant guanfacine has become the preferred α(2)-agonist for ADHD treatment. However, significant interindividual variability has been observed in response to guanfacine. Consequently, hypotheses of a contributing interaction with the ubiquitously expressed drug transporter, P-glycoprotein (P-gp), have arisen. We performed an in vitro study to determine if guanfacine is indeed a substrate of P-gp. METHODS: Intracellular accumulation of guanfacine was compared between P-gp expressing LLC-PK1/MDR1 cells and P-gp-negative LLC-PK1 cells to evaluate the potential interaction between P-gp and guanfacine. Cellular retention of guanfacine was analyzed using a high-performance liquid chromatographic-ultraviolet method. Rhodamine6G, a known P-gp substrate, was included in the study as a positive control. RESULTS: At guanfacine concentrations of 50 µM and 5 µM, intracellular accumulation of guanfacine in LLC-PK1/MDR1 cells was, 35.9% ± 4.8% and 49.0% ± 28.3% respectively, of that in LLC-PK1 cells. In comparison, the concentration of rhodamine6G, the positive P-gp substrate, in LLC-PK1/MDR1 cells was only 5% of that in LLC-PK1 cells. CONCLUSION: The results of the intracellular accumulation study suggest that guanfacine is, at best, a weak P-gp substrate. Therefore, it is unlikely that P-gp, or any genetic variants thereof, are a determining factor in the interindividual variability of response observed with guanfacine therapy.