What is personalised medicine?

Kusha Kalideen explains personalised medicine, its benefits and limitations.

Quite simply, personalised medicine is an emerging medical approach which aims to deliver the right drug to the right patient, at the right time, at the right dose, and through the right route of administration.  This approach is transforming medical care and moves from the conventional one-size-fits-all approach treatment of patients to tailoring the treatment to the patient’s specific characteristics.

Often referred to as precision medicine, personalised medicine has become increasingly important in the field of oncology.

Cancer is a complex and heterogeneous disease where even tumours from the same anatomical site, can be different. It’s therefore no surprise that there is limited success in the conventional medicine one-size-fits-all approach which treats all cancer patients with the same treatment.

Advances in cancer research have provided greater understanding of the pathogenesis (biological process of how a disease develops) of cancer. Tumours have unique characteristics that can drive their growth, influence treatment response and clinical outcomes. By identifying these tumour-specific characteristics, known as biomarkers, of a patient and their tumour, oncologists can more effectively tailor a treatment plan for effective treatment and improved clinical outcomes.

Biomarkers

Biomarker testing, which is used to identify the unique characteristics, is a cornerstone of personalised medicine. The presence or absence of biomarkers can play a critical role in selecting appropriate treatment strategies.

Usually, biomarker testing is performed on tumour tissue or blood, however, other bodily fluids may also be evaluated.

Several technologies are used for biomarker testing (sometimes referred to as molecular diagnostics) which include genetic studies (next generation sequencing), immunohistochemistry, or immunoassays.

Tailored treatment plans

As a result of biomarker testing in personalised medicine, tailored treatment plans can include targeted therapy or optimal use of existing therapies.

Targeted therapies are designed to interfere with specific biomarkers that promote cancer growth. By focusing on abnormalities present primarily in cancer cells, these treatments are more effective in treating the tumour and may improve the quality of life during treatment as well as reduce damage to healthy tissues.

While targeted therapies for some cancers are widely used, there are more therapies that are receiving tumour-agnostic approval (where the therapy is approved based on the biomarkers of that cancer, not the site of the cancer).

Biomarker testing can be beneficial in traditional treatments (chemotherapy) as well, as these can help identify patients who are more likely to benefit from these treatments, optimising dose, improving outcomes, and avoiding ineffective therapy.

Limitation of personalised medicine

While there are several benefits to the personalised medicine approach, particularly in cancer care, there are limitations which need to be highlighted.

First, testing and targeted treatments can be costly (and may not always be reimbursed by medical insurers). Second, both testing and targeted treatments may not be widely available or accessible in SA. Third, not all patients will have tumours with identifiable biomarkers, and tumours can evolve over time which can lead to resistance to treatment.

Furthermore, the interpretation of genetic and molecular test results can be complex and often requires expertise from multi-disciplinary care teams.

Considering the limitations, personalised medicine does represent a significant step forward in cancer treatment. While not all malignancies currently have identifiable or actionable biomarkers, ongoing research continues to expand the range of targeted treatment options available to patients.

Kusha Kalideen is a medical scientist specialising in molecular testing of solid tumours to aid in diagnosis, prognosis, and therapeutic options in cancer patients. She currently works at Lancet Laboratories.

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