Pharmacogenomics: Use of genomic medicine in CF and Oncology Quiz

Pharmacogenomics

• Genomics is the study of the genome and related techniques
• A genome is a complete set of DNA
• Pharmacogenomics studies how genes affect a person's response to medicine
• Pharmacogenetics studies how variations in a single gene affects response to specific medicine
• Pharmacogenomics examines how a patient's entire genome influences their response to many drugs

Applications of Genomics in Practice

• Rare Diseases: Genomics can help identify patterns in patients with the same condition, leading to personalized diagnostics and targeted therapies
• Cancer: Identifying cancer-related mutations (somatic and germline) aids in preventative and targeted treatments
• Cystic Fibrosis: The CF gene was discovered in the 1980s. Therapy now targets dysfunctional genes.

Pharmacogenetics vs. Pharmacogenomics

• Pharmacogenetics focuses on how a single gene impacts medicine variability
• Pharmacogenomics studies a patient's entire genome and how it affects their response to multiple drugs.

Pharmacogenomics in CF and Oncology

• Cystic Fibrosis (CF) is an inherited disorder affecting cells that produce mucus, sweat, and digestive juices. CF damages the lungs, digestive system, and other organs.
• 7,000 people worldwide have CF
• CF primarily affects Caucasians
• Median survival age is increasing due to advances in research
• CFTR gene discovery has been impactful

Pathophysiology of Cystic Fibrosis

• CTFR is a phosphorylation-regulated chloride channel
• Composed of 1480 amino acids organized into 5 functional domains
• Proper function of these five domains is critical to control channel activity

Pharmacology and Life Expectancy

• A graph shows an increasing life expectancy for individuals with CF over time, correlating with advancements in medicine
• Key milestones, including the discovery of the CF gene in 1989, are noted on the graph

CFTR Modulator Therapies

• Kalydeco® (ivacaftor), Orkambi® (lumicaftor/ivacaftor), Symkevi® (tezacaftor/ivacaftor), and Kaftrio® (elexacafor/tezacaftor/ivacaftor) are CFTR modulator therapies
• Strict criteria are needed for eligibility for certain mutations, such as F508del
• Kalydeco targets the CTFR protein to open the channel

Interactions

• Avoid CYP3A inducers like rifampicin and inhibitors like grapefruit, which affect drug metabolism
• Monitor liver function tests (LFTs) and watch for cataracts, conditions that cloud the lens in the eye

Pharmacogenomics Oncology

• Traditional prescription methods involve a standard dose for most patients
• However, some patients need higher or lower doses based on their specific needs
• Pharmacogenomic testing tailored to a patient's response to the specific drug.

DPD Pharmacogenetic Testing

• Dihydropyridine dehydrogenase (DPYD) is an enzyme involved in metabolizing certain chemotherapy drugs (fluorouracil, capecitabine, tegafur) mainly used for GI, breast and neck cancers
• Deficiency (variants) in the DPYD gene, due to an inherited mutation, increase the risk of serious side effects such as mouth sores, inflammation of mucous membranes, and harmful effects on the immune system.
• Testing for DPYD can help predict a patient's response and tailor treatment to reduce severe toxicity risk

Other Pharmacogenetic Testing

• Testing can identify variations in genes that affect responses to other drugs like TPMT (6-mercaptopurine/thioguanine) or UGT1A1 (irinotecan).
• Identifying variant types or "drivers" can determine proper dosage, to minimize harm and maximize effectiveness.