Pharmacogenetics and Pharmacogenomics

As part of the Doctor of Nursing Practice curriculum we must take a class in advanced pharmacotherapy. I’m currently going through this course, and we are learning the importance of our genetic makeup and our response to the various medicines. Advances are being accomplished in the field of pharmacogenetics so pharmacological therapies are becoming more personalized. The following article and post relates to pharmacogenomics and pharmacogenetics.

Weng, L., Zhang, L., Yan, P., Huang, R.S., (2013). Pharmacogenetics and pharmacogenomics: a bridge to individualized cancer therapy. Pharmacogenomics 14(3): 315-324.

The drug Cetuximab belongs to the class of drugs known as monoclonal antibodies. It is considered a target therapy. This drug is currently used in anticancer treatment regimens specifically, head, neck, lung, and colon cancer. 

The drug targets the overexpressed epidermal growth factor receptor (EGFR) in tumor cells and thereby prevents the proliferation of tumor cells and promotes apoptosis.

The drug is beneficial to individuals who do not have mutations with the oncogene KRAS, but rather have what is considered (wild type) oncogene. About 35-45 % of colon cancer patients have a mutation in the KRAS oncogene and this drug does not seem to benefit such cases.

The patient needs to be screened as the diagnosis of cancer is made and this may be an option for therapy. It may be administered in conjunction with other antineoplastic regimens or on its own. It is administered intravenously and the patient needs observation after, since it may cause anaphylaxis. The patient is to be premedicated with an antihistamine. It may cause an acne like rash, dry cracked swollen skin, sore throat, headache, upset stomach, nausea, vomiting, diarrhea.

Patients who do not benefit from this drug need alternative treatments with other antineoplastic agents.

The article addressed the importance of pharmacogenetics and pharmacogenomics with different lines of therapy. Great discoveries have occurred in the last ten years which give light to pharmacogenomics and pharmacogenetics in treatment, specially after the identification of the genome. There is great genetic variability that can be identified as it relates to drug metabolism, transport or molecular targets/pathways. 

There are more than 120 drugs identified by the US FDA with relationships to greater than 50 genes. These drugs may be indicated in cancer treatments, cardiovascular, infectious, and psychiatric diseases. In oncology genetic variations are looked at in the context of germlike genome, tumor genome or somatic variations.

The utilization of incorporating genetics into cancer treatment will improve our understanding of the differences in response to cancer therapy.  IMG_1787

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