Precision Medicine and Companion Diagnostics in Stroke Patients
Posted 11th April 2018 by Jane Williams
A stroke is a clinical condition that could benefit greatly from personalized medicine. Strokes remain a leading cause of mortality and morbidity in the United States, affecting over 800,000 adults annually, leaving many with a permanent disability. The current stroke population are approximately 195,000 recurrent strokes, which are often more severe, debilitating, and costly than first-time strokes.
A strokes presentation and clinical workup present unique challenges that can be addressed by a personalised medicine strategy where up to 40% of patients never have a cause determined, which are diagnosed as “cryptogenic”. The difficulty in determining a cause in the hospital may lead to an increased cost of patient care and suboptimal management of patients. In many cases, if the cause is not determined in hospital, it is difficult for guideline directed patient management strategies that are cause based to be adopted. The above figure provides a very simple overview of downstream patient management to prevent recurrence.
Ischemic Strokes in Younger Populations
A stroke is often considered an older person’s disease, but an estimated 10% of stroke patients are younger than 50. Reports show an apparent increasing trend in ischemic strokes among young adults, a figure that is particularly concerning when compared to the overall decrease in stroke incidence and mortality. Although certain rare risk factors have been suggested as possible causes, reports show that traditional risk factors for stroke may be overlooked in this population. The face of a stroke is not necessarily an 80 year old with hypertension and diabetes, it also includes the 40-year-old with no risk factors such as diabetes, hypertension, hyperlipidemia or atrial fibrillation.
Stroke Clinical Trials & Improved Stratification
The challenge in treating these cryptogenic patients is a “one size fits all” approach has not been proven effective as demonstrated by the recent Xarelto Phase III ESUS trial. “ESUS” is a term used to describe patients with “embolic strokes of unknown source”. Xarelto is a class of NOACs, or novel oral anticoagulants, that may be used to manage stroke patients to prevent recurrent stroke, in cases of cardioembolic stroke caused by atrial fibrillation.
Strokes & Biomarkers
Parallels can be drawn between stroke care today and the care of cardiac patients in the 1950’s. Heart attacks were once thought to be unpredictable, untreatable, and once an individual had a heart attack, the long-term prognosis was not very good. Today, there are many treatment modalities available to effectively manage patients at risk for cardiac conditions, as well as those that have suffered from heart attack. In particular, a blood-based biomarker, Troponin, is the biomarker of choice for the detection of cardiac injury. There are no such biomarkers for stroke.
Here is a summary of challenges in companion diagnostics and stroke patients:
- A stroke represents a very large market, spanning ages, and comprised of a diverse patient population.
- A stroke cause is difficult to diagnose during hospitalisation, where up to 40% of these patients are diagnosed as “cryptogenic” or unknown cause, making adoption of secondary prevention difficult.
- Therapeutic clinical trials are yet to produce a safe and effective treatment option for secondary prevention in cases where the cause is determined to be “embolic strokes of unknown source”.
- Unlike other disease states, there are no biomarkers for the cause of strokes.
Blood Biomarkers & Ischemic Stroke Patients
While there are challenges in the field of stroke, a recent development may lead to a personalized medicine approach to better treat stroke patients. Edward C. Jauch, MD, Professor and Chair of Emergency Medicine at the Medical University of South Carolina, recently presented positive clinical data demonstrating the ability of biomarkers from blood to identify the cause of an ischemic stroke. Dr Jauch is a 2013 author on the stroke guidelines, former Chair of the Stroke Committee for the American Heart Association and lead Principal Investigator for the Biomarkers of Acute Stroke Etiology (BASE) clinical trial.
The potential of using blood biomarkers to stratify ischemic stroke patients will one day lead to breakthroughs in advancing diagnosis and treatment of stroke, resulting in fewer “unknown” events, and leading to advancements in applying existing treatment modalities, but ultimately leading to new innovations in the understanding cause to prevent these events in the future.
Jeff June is the CEO and founder of Ischemia Care, the molecular diagnostic company commercializing blood tests for cause of stroke.
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