Children should have a future, not cancer. But, just before her first birthday, Rory was fighting for her future. Born with a teratoma, a type of tumour in the germ cells, she underwent surgery and fought through related complications. As if cancer surgery wasn’t enough for any child to face, the potentially devastating side effects of chemotherapy treatment would also put Rory’s future at risk.
We now know that our genetic differences can cause some patients to react differently to the same drug, with some patients experiencing the intended effect while some experience an adverse drug reaction (ADR). Rory was fortunate to be part of a pharmacogenetic study. (Pharmacogenomics is the science that studies the role of the genome related to an individual’s response to a drug.) Sequencing her genome revealed she was at significant risk of hearing loss based on the combination of her genetics and the prescribed therapeutic treatment.
Based on this information, Dr. Bruce Carelton, a clinical pharmacologist at the University of British Columbia (UBC), searched for an alternative treatment that would be more likely to preserve hearing. He found a less toxic drug which promised to be as effective to treat Rory’s cancer, but presented less chance of causing hearing impairment.
“Often, parents say to me that the adverse effects of cancer chemotherapy were harder for them to manage and deal with than the survival questions because they’re not prepared for it.”
— Dr. Bruce Carleton
ADRs are a major problem in modern medicine, leading to withdrawal of treatment, non-compliance with medication, permanent disability and death. This is particularly true for cancer treatment, with its potent medications. Carelton has made it his life’s mission to reduce and prevent the incidence of ADRs among children being treated for cancer. Building upon the success of his ongoing pharmacogenomics research, Carelton is working with his colleague Dr. Colin J. Ross, also at UBC, to prevent ADRs by developing lab tests to predict the likelihood of a childhood cancer patient developing an ADR.
The vision of their Go-PGx project is to save lives and improve the quality of life of children with cancer, by using genomics to reduce the most common and serious ADRs in these children. Starting with five of the most severe ADRs in childhood cancer, they will analyze more than 6,125 DNA samples along with corresponding medication use and ADR outcome data to discover biomarkers that reveal genetic susceptibility to ADRs. With the data they generate, they will develop tools to educate and inform physicians and patients as they begin providing testing at 10 pediatric cancer centres across Canada.
Today, Rory is cancer free. She finished her chemotherapy without experiencing an adverse reaction to her treatment. Her mom proudly reports “she is able to communicate (sometimes non-stop) and her hearing hasn’t been impaired (although it’s sometimes selective.)”