A stroke occurs when blood flow leading to, or in, the brain is blocked (ischaemic stroke) or a blood vessel in the brain ruptures (haemorrhagic stroke), which can result in damage to the nerve cells in the brain and a loss of bodily functions. Stroke is the single largest cause of adult disability in the developed world. Over 150,000 people suffer a stroke each year in the UK, and approximately 800,000 in the US. The vast majority of these strokes are ischaemic in nature. Our CTX stem cell therapy candidate seeks initially to treat those patients who have suffered an ischaemic stroke and have been left disabled by it. These patients constitute approximately one half of stroke survivors.

The annual health and social costs of caring for disabled stroke patients is estimated to be in excess of £5 billion in the UK, with stroke patients occupying 25 per cent of long term hospital beds. In the US, the annual direct and indirect costs of stroke are estimated to be in excess of US$70 billion. The type of stroke treatment a patient should receive depends on the stage of disease. Generally there are three treatment stages of stroke:

Prevention – treatments to prevent a first or recurrent stroke are based on treating associated risk factors, e.g. high cholesterol, smoking and diabetes;

Treatment immediately after the stroke; acute-phase stroke treatments attempt to arrest a stroke whilst it is happening by dissolving the blood clot that has caused the infarct; and

Post stroke rehabilitation – the aim of post stroke rehabilitation is to improve both functional and cognitive recovery in the patient some weeks or months after the stroke event.

It is this third treatment stage that our CTX stem cell therapy candidate seeks to address. A number of treatments exist or are in development to treat stroke patients in the acute phase. However, there are currently no therapies available for patients who have a stable and fixed neurological deficit following a stroke.

ReNeuron’s CTX stem cell therapy candidate for stroke disability consists of a neural stem cell line which has been generated using our proprietary cell expansion and cell selection technologies and then taken through a full manufacturing scale-up and quality-testing process.  As such, CTX is a cryopreserved, clinical and commercial-grade cell therapy product capable of treating all eligible patients presenting.

CTX has been shown to be safe and well-tolerated in a first-in-man UK clinical trial (PISCES I) in eleven disabled stroke patients who were followed up for at least two years post-treatment.  The data from this study were recently published in The Lancet (click here to view).  We recently announced positive efficacy data from a single arm, follow on Phase II clinical trial (PISCES II) of our CTX therapy in disabled stroke patients.  In this study, patients were monitored on a number of efficacy measures of limb motor function, disability and dependence and performance in activities of daily living.  At the time of reporting, all 21 patients treated in the study had completed three-month follow-up, with ten patients followed for six months and three for twelve months.  In total, 15 out of the 21 patients had a clinically significant response on at least one efficacy measure and these improvements were sustained throughout the follow up period.

As a result of the positive data from the PISCES II study, we intend to apply to the US and European regulatory authorities to commence a randomised, placebo controlled, pivotal clinical trial in patients who are living with disability post-stroke.  If ultimately successful in late clinical development, our CTX cell therapy candidate will represent a ground-breaking new treatment option for stroke survivors.  The therapy offers the potential for a degree of recovery of function in disabled stroke patients, resulting in greater independence and quality of life for these patients and reduced reliance on health and social care systems.

The CTX cells that were used in the both the PISCES I and PISCES II clinical trials were taken from the existing manufactured cell banks that will form the basis of the eventual marketed product.  There will therefore be no need to re-derive and test new CTX cell lines for subsequent clinical trials or for the market – all such cells can simply be expanded from the existing banked and tested product.

For further information please refer to the clinical trials page.