Frequently Asked Questions (FAQs)

Hydromethylthionine mesylate (HMTM) is a novel chemical compound being investigated for potential early intervention that aims to influence the underlying disease process in Alzheimer’s disease (AD). If approved, it has the potential to be the world’s first oral, anti-tau therapy. In clinical trials to date it has required only standard monitoring and care, and it has the potential to fit into the existing healthcare systems and reach a large number of patients who meet the diagnostic criteria.

The Phase 3 LUCIDITY clinical study investigated HMTM in individuals with mild cognitive impairment due to AD (MCI-AD) and mild to moderate AD.

HMTM is currently being assessed by the UK Medicines and Healthcare products Regulatory Agency (MHRA) as a potential new treatment for people living with AD.

The LUCIDITY clinical study was designed to explore whether earlier intervention at the MCI stage of the disease may offer greater benefit.

HMTM is formulated as a small film-coated tablet that will be administered orally. It is hoped that this  tablet dosage-form could offer patients the opportunity of a convenient treatment without the need for regular clinic visits.

In the LUCIDITY study (TRx-237-039), HMTM 16 mg/day reduced the blood biomarker of neurodegeneration (NfL) by 95% at 52 weeks (the prespecified primary exploratory biomarker outcome). A reduction in the tau biomarker pTau217 was also seen in the MCI-AD subgroup at 104 weeks.

In a separate analysis comparing HMTM-treated participants with matched placebo controls (TRx-237-080), HMTM was associated with a 35% reduction in brain shrinkage across participants ranging from MCI to mild-to-moderate AD¹.

To date, approximately 3,000 patients have participated in our clinical trials and expanded access programmes, with some individuals having taken HMTM for over 10 years. Trials reported that headache (1.5%) and diarrhoea (1.2%) were the most frequent adverse events with the 16 mg/day dose. 

In these studies, HMTM did not require expensive tests nor scans as part of routine safety monitoring¹. 

Currently approved oral treatments for AD fall into two classes: cholinesterase inhibitors (such as donepezil, rivastigmine and galantamine) and the NMDA-receptor antagonist memantine. These treatments help manage the symptoms of AD but are not understood to modify the underlying disease process.

More recently approved anti-amyloid therapies are given by intravenous infusion, target the amyloid protein, and can carry a risk of amyloid-related imaging abnormalities (ARIA).

HMTM is being investigated as an oral treatment that targets the tau protein. In clinical trials to date it has not shown an increased risk of ARIA and has not required infusions or intensive monitoring, which may mean the administrative burden of delivering and receiving the treatment is minimal. This, in turn, suggests HMTM could be integrated into existing health and social care systems and made accessible to a greater number of patients.

Every country’s regulatory body will carefully and fairly scrutinise every drug seeking market approval. Of necessity, the standards are very high, and we will look to satisfy those within the regulatory processes. TauRx is currently engaged with regulators in several territories. In the UK, HMTM was granted an Innovation Passport by the MHRA in 2022, recognising it as an innovative medicine addressing the unmet need that is AD.

TauRx remains engaged with the MHRA, with a final decision on our Marketing Authorisation Application (MAA) expected in 2026. The company is committed to working with regulatory bodies as necessary in order to help bring the drug to market.

HMTM is an investigational medicine. It is not currently approved or licensed by any medicines regulator and is not yet available to be prescribed. A marketing authorisation application for HMTM is under review by the MHRA, and TauRx is engaged with regulators in a number of other territories. Any future availability will depend on the outcome of these regulatory reviews. 

Should we receive MHRA approval, the UK National Institute for Health and Care Excellence (NICE) will assess whether HMTM can be recommended for NHS use. Timelines vary, but TauRx will work to support a rapid appraisal process and look to build on previous conversations with NICE at the earliest opportunity. The company has been working in parallel with NICE for a significant period following the granting of an Innovative Licensing and Access Pathway (ILAP) and looks forward to continuing should we receive marketing approval from the MHRA.