Pharmacogenomics — providing the right drug to the right patient at the right dose, at the right time

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By Catalina-Lopez Correa

Affordability makes precision health more accessible

The ‘one-size-fits-all’ approach to health care is nearing an end ushering in the era of precision. The future of health care lies in harnessing the power of molecular approaches embodied in modern genomics. Today, sequencing the human genome costs around $1000 and it can be done in just a couple of days. It is predicted that advancements in the technology over the next few years will enable our genome to be sequenced in a matter of hours for $100. — a feat that was unimaginable just ten years ago.

The lower cost and increased access to genome sequencing is already helping to improve diagnosis, treatment and disease management for patients touched by cancer, heart disease, autism, epilepsy, rare diseases and other debilitating diseases. Societal attitudes toward genomics in clinical care are also shifting. We are no longer asking ‘if’ genomics should be integrated with clinical care. Instead we are asking ‘when’ and ‘how’ genomics can be applied to benefit as many people as possible.

When patients are matched with diagnosis and treatment specific to their individual disease or “omic” information, medical practice becomes much more precise. Individual patients are provided a greater chance of better health outcomes than if they were subjected to diagnoses and treatment strategies based on the generalized data collected through observation of patient populations.

Pharmacogenomics is a gamechanger

We know that the use of medication in modern medicine has revolutionized health care and made a significant impact on patient longevity and quality of life. We know there can be individual variability in a patient’s response to drug treatment — the same treatment doesn’t always work in patients with similar conditions. And we also know that many medications can cause unintended side effects, known as adverse drug reactions (ADRs).

What is now becoming much clearer is the role our genes and genetics play in predicting drug response. The discipline of pharmacogenomics uses an individual’s genetic profile to understand whether a person will benefit from a particular medication or suffer serious side effects.

While science has yet to discover all there is to know about the workings of human DNA, some of the specific genes that determine a person’s response to drug therapy are well documented. Now that sequencing DNA is no longer cost-prohibitive, analyzing the genes that impact how a patient will either react or respond to treatment has become much more accessible.

MORE: OPTIMIZING DRUG THERAPY FOR PATIENTS WITH CANCER

The stakes are high

In Canada, patients experience significant preventable ADRs, which account for approximately 1.6 million (12%) of emergency departments and 25 per cent of all hospital and emergency room admissions to medication-related illnesses according to the Canadian Institute for Health Information (CIHI). CIHI also reports that, people over the age of 65 are five times as likely to be hospitalized due to an adverse drug reaction. It is estimated that ADRs cost Canadians upwards of $14 billion annually, placing a significant burden on health care system.

Furthermore, these numbers don’t account for costly and inefficient prescribing for people who simply aren’t benefiting from a drug therapy. The lack of efficacy for a drug may not always lead to severe ADRs, but prescribing treatments for patients who will not benefit is a waste of limited health care dollars. A recent economic evaluation indicated that ‘pharmacogenomics guided treatment can be a cost-effective and even a cost-saving strategy. Having genetic information readily available in the clinical health record is a realistic future prospect and would make more genetic tests economically worthwhile.’

Pharmacogenomics can also play an important role in prescreening for efficacy of a patient’s response to a drug therapy where high cost drugs are the prescribed treatment. Considering the extremely high cost of some drug treatments (e.g. a 12-week therapy for Hepatitis C can cost as much as $68,000 US per patient), pre-screening can save millions of dollars by avoiding treatments that would have no benefit to the patient.

Moving toward clinical application

The time seems right to move toward the adoption of pharmacogenomics as a standard of care. Toward this goal, Genome BC, in cooperation with BC’s Ministry of Health, is exploring opportunities to illustrate the effectiveness of pharmacogenomics within BC’s public health care system. This three-phase initiative seeks to advance the clinical implementation of pharmacogenomics in British Columbia. Phase I and II will outline the anticipated resources and infrastructure while developing a robust business case and a detailed study design. Phase Ill would initiate a project focused on evaluating the potential pharmacogenomics has to improve health outcomes for mental health patients in British Columbia and improve cost-effectiveness within the health care system.

Pharmacogenomics clearly has a role to play in most disease areas. The expertise, infrastructure and economic analysis developed through this pharmacogenomics initiative should help to advance the broader clinical implementation of genomics in other areas of importance, such as oncology, rare diseases and infectious diseases. The potential for improving health care delivery in Canada is enormous, but more importantly, patients will benefit.

Catalina-Lopez Correa is Chief Scientific Officer and Vice President, Sectors at Genome British Columbia.