Focus on pre-clinical investigations
The planning, design, approval, recruitment, implementation and reporting of clinical trials all require significant input from a number of niche specialists in these areas, as well as in others such as pharmacodynamics / pharmacokinetics (how a drug affects the body and how the body affects a drug) and biomarkers.
Consulting support, design and planning
Since January, we completed a search and recruitment initiative for the services of a clinical trials consultant. We have received advice that a phase I trial to test the safety of the candidate drug in healthy people should not be needed by the regulatory authorities as there is a good safety record for the drug over a long period, even though its use has been for a different purpose to date. This is very welcome news as it represents significant savings of both time and money.
Design ideas and plans to calculate drug dosages for use in the trials have been produced by Prof. Alan Mackay-Sim working in conjunction with the consultant, and range from computer modelling studies to testing in mice.
Measuring treatment effectiveness
The biggest challenge in testing the effectiveness of a drug for HSP is measuring if progression of the condition has been slowed down or stopped, as it can remain unchanged for years at a time – way beyond the time frame for a cost-effective clinical trial. This is why a biomarker for HSP progression would be so valuable to have, and why its establishment is such a high priority.
Prof. Carolyn Sue has recently appointed Dr. Sue-Faye Siow* to investigate a brain imaging biomarker** for HSP employing a technology called DTI (diffusion tensor imaging) which is a type of MRI that quantifies important aspects of both the structure and function of brain white matter, including neuronal axons. There is also an HSP biomarker initiative in the early stages in Germany that is investigating the potential for levels of a particular protein in the urine to be an accurate and effective measure of HSP progression.
Where to start?
Data now needs to be assembled on the feasibility and cost/benefit of conducting a small, ‘proof-of-concept in humans’ trial to gauge the effectiveness of the candidate drug on HSP in the absence of an established biomarker.
On the upside, if there is measurable improvement in symptoms/mobility of HSPers taking the drug, that would be a huge boost and support for a larger clinical trial. However, without significant improvement, the results would be inconclusive – did the drug not work or was it, in fact, effective in slowing or stopping HSP progression? Without a biomarker, we just would not know.
Work is also continuing on legal, logistical and organisational aspects of clinical trials planning. Clinical trial team member Gautam Wali made a presentation in Germany at the well-regarded annual Tom Wahlig symposium, on the drug validation studies completed last December using induced pluripotent stem cells to create HSP neurons with long axons. The talk stimulated significant interest amongst the HSP researchers in attendance, with questions following the talk from some of the leading global players in HSP research.
*Dr. Sue-Faye Siow
We welcome Sue-Faye to the clinical trials team. Sue-Faye is a neurologist who will be undertaking a Ph.D. study to investigate diffusion tensor imaging as a potential biomarker for HSP.
Here is an outline of the study:
**There needs to be a standardised biomarker to monitor disease severity in order to assess the effect of therapeutic drugs on the disease process. Motor evoked potentials (MEP) have been used to demonstrate damage to nerves in HSP. Diffusion tensor imaging (DTI) is a form of magnetic resonance imaging (MRI) which reveals damage to nerves affected in HSP which cannot be seen on conventional MRI. Previous studies have shown correlation between abnormal MEPs and DTI abnormalities with disease severity and duration.
However, these studies have not been performed over a period of time to demonstrate the expected changes in MEP and DTI measures over time in HSP patients who are not receiving treatment. This information is required to compare the MEP and DTI changes in HSP patients with and without treatment in order to show stability or a reduction in changes.
We will study MEP and DTI measures in a group of HSP patients without treatment to establish the expected changes. We will also investigate any possible correlation between the MEP and DTI findings.