Working towards a brighter future in giant cell arteritis
Neil Collinson, PhD, Senior Clinical Development Scientist is part of a team at Roche focused on research that will increase our understanding of giant cell artertis, a rare inflammatory autoimmune condition with challenging diagnosis.
Giant cell arteritis (GCA, temporal arteritis) is an inflammatory disease that affects medium- and large-sized arteries, primarily those supplying the temple, scalp, face and eyes and the aorta and its branches that supply the neck and arms. The hallmark sign of GCA is when immune cells invade the walls of affected arteries leading to inflammation and erosion resulting in partial or complete blockage of the vessels. What triggers this immune attack is not well understood.
GCA has a predilection for Caucasians over 50 years old, hitting its peak incidence in the eighth decade of life and favouring women three to one. GCA presents in many different ways, depending on affected arteries. Classical symptoms include excruciating head pain that can initially be difficult to tell apart from migraine or cluster headaches. Head pain can also be felt in the neck, scalp, cheek, and in the jaw when chewing or speaking, even extending to the tongue. Visual complications are also common – including blurring, double or obscured vision. The most feared manifestation of GCA, permanent vision loss, still occurs in some patients.
There are other forms of GCA characterised by debilitating pain in the arms, aching in the hips and shoulders or even as unpronounced as a non-productive cough. Weight loss, fever and night sweats are also common symptoms. In either case there is a real risk that timely diagnosis is delayed as symptoms can be confused, first by the patient and then by the medical practitioner, with other common conditions particularly those related to aging. Swift diagnosis is essential as untreated GCA can lead to irreversible vision loss, stroke or aneurysms.
Evolving standards of care
Over the course of the last half century, the use of steroids transformed inflammatory disease and brought immediate relief to people living with GCA. In high doses, their rapid effect on the acute symptoms such as headache, jaw pain and debilitating limb pain along with the ability to prevent vision loss, one of the most devastating effects of untreated GCA, were proof points of their efficacy and they soon became the mainstay of therapy.
However, as with many treatments, there are pitfalls. There is no ‘one size fits all’ approach and for at least half of patients a relapse occurs - meaning that their symptoms come back - as the high dose steroids are gradually weaned to mitigate the toxic effects unleashed by chronic steroid treatment, or because they are unable to take steroids due to other complications. The hope is to bring new therapies that break the inflammatory response cycle and thereby help patients maintain remission in the absence of steroids.
Understanding the pitfalls of the current standard of care is ultimately driving innovation for the future of GCA treatment. Research academia is interested in GCA because of the opportunity to address patient needs with the new understanding of immunopathology. Scientists and clinicians need to collaborate to understand why GCA develops and more importantly, how it can be stopped. Characterising the role of all the different immune cells and biological pathways within immune-mediated disease is complex, but we are making progress. Published research across the world is increasingly corroborating a key role of a cytokine called interleukin-6 (IL-6) in the development of GCA, and through my work at Roche and that of the broader team, I am inspired to potentially deliver the opportunity to bring a new standard of care to people living with GCA.