Image-Derived Enzymatic Adrenal Lateralisation of Patients with Primary Aldosteronism: A Phase 2 Clinical Trial with [18F]AldoView PET/CT (IDEAL 2)

High blood pressure (known as hypertension) affects one quarter of all adults and over one billion people globally. Left untreated, high blood pressure reduces life expectancy by causing heart attack, stroke, kidney disease and dementia. The health consequences of hypertension are among the most burdensome in Europe, costing the NHS £2 billion per year. Hypertension can be effectively treated in most people by lifestyle changes and life-long drug therapy. However, in around 1 in 10 patients (over 500,000 in the UK), hypertension is caused by overproduction of the hormone aldosterone. This increase in aldosterone is known as primary aldosteronism (PA). PA increases the severity of hypertension and risk of heart disease and stroke, as well as reducing quality and duration of life.

Making the diagnosis of PA is vital because more than a third of patients can potentially be cured of hypertension by surgery to remove the gland overproducing aldosterone. For those, who cannot be surgically treated, the detection of PA allows doctors to prescribe more effective and better targeted medications.

Unfortunately, very few patients with PA (only about 300 per year in the UK) are surgically treated due to the complexity of current diagnostic tests for PA. Typically, to diagnose PA, patients undergo a multi-stage series of specialist tests, that are rarely performed and often produce inconclusive results. Consequently, PA is rarely diagnosed, with estimates suggesting that more than 99 out of every 100 cases of PA are undetected world-wide. Thus, most patients with PA are destined to lifelong, poorly targeted treatment, with a high risk of complications and reduced quality of life. There is a clear need for a more practical and clear-cut test to diagnose PA to enable appropriate treatment for these patients.

PA is caused by benign tumours that overproduce aldosterone in either one or both adrenal glands, which are located on top of the kidneys. We have developed a highly selective 'tracer' (AldoView) to be used with a medical imaging test, known as a PET scan, which we call the AldoView-PET scan. The AldoView-PET scan promises to revolutionise the diagnosis and treatment of PA by showing if there is overproduction of aldosterone and where the overproduction is coming from (in one or both adrenal glands). This one stop test will allow physicians to identify which patients are suitable for potential surgical cure of their hypertension, and which patients would benefit from better targeted drug therapy, if surgery is not an option. Thus, the AldoView-PET scan would transform care, allowing many more PA patients to be accurately diagnosed and receive optimal treatment, with a quick scan, which provides immediate results. This is in stark contrast to the current cumbersome diagnostic process, which is often not performed at all, and is costly, invasive and requires highly specialised health facilities.

Results from our recently completed first-in-human study are very promising in showing that the AldoView-PET scan clearly detects aldosterone producing tumours in patients with PA. We now want to conduct a more extensive second phase clinical trial, to further evaluate AldoView-PET as a definitive diagnostic test for PA when compared to the current diagnostic process. Our hypothesis is that the AldoView-PET scan will transform the current diagnostic process in predicting the optimal treatment for individual patients.