What Good is Targeted Cancer Treatment without the Test?
A review of precision medicine companion diagnostics in Canada
The Canadian Cancer Survivor Network (CCSN) commissioned a review of precision medicine companion diagnostic testing in Canada through a literature review and a series of stakeholder interviews to determine if there were any challenges or barriers that would ultimately impact patient access to companion diagnostics and then issue a series of recommendations to help inform thoughtful change to address those concerns.
The rise of precision medicine in Canada has generated a desire to have reliable and accurate methods of identifying patients who will benefit from oncology drug therapies in clinical practice. Precision medicine is directed at delivering the right drug to the right patient at the right time, promising more efficient use of healthcare resources by targeting those patients most likely to respond to the therapy. Precision medicines can identify biological information (genes, RNA/DNA, or proteins) to target those patients most likely to respond to a specific treatment. In precision medicine, diagnosis and treatment are intrinsically linked.
Clinicians prescribing cancer drug therapies have departed from the age of one-size-fits-all drugs to the age of precision therapeutics, characterized by higher rates of effective therapies and lower rates of adverse events. Previously, the anti-cancer therapy drugs prescribed typically depended upon the type of cancer, size, and stage, along with patient preferences. With precision medicine, information about genetic changes in the tumour is used to determine the best management strategy for each patient. Although there is still a great deal to learn, the hope is that precision medicine will result in cancer patients achieving both better treatment outcomes and fewer side effects.
Companion diagnostics are so named because these assays or tests are specifically developed for use as a companion to a particular drug therapy. In addition to identifying the correct patient population, companion diagnostics may also help avoid adverse drug reactions by allowing clinicians to identify patients who are at increased risk for serious side effects from certain therapies. Our understanding of oncology and response to therapies has evolved over the years due to a better understanding of the molecular drivers of disease. Subsequently, the treatments that target these processes have shown improved health outcomes, most notably, with extensions in overall survival. These benefits are extremely important to cancer patients and their families.
This review has been undertaken by the Canadian Cancer Survivor Network as part of an awareness campaign about the state of companion diagnostics in Canada. A robust literature review was conducted to identify key articles about the gaps and challenges presented in this paper as well as proposed recommendations to help foster a homogeneous health system surrounding access to companion diagnostic testing for patients in Canada. In addition, stakeholders were interviewed for the purposes of capturing their valuable perspectives on the use of companion diagnostic testing in Canada. Their perspectives were incorporated throughout the paper to help inform and guide recommendations.
Read the full report, A Review of Precision Medicine Companion Diagnostics in Canada