Drug dose modelling study initiated
Whenever research moves from stem cells or experimental animals in a laboratory to thinking about giving a drug to humans, there are questions that need an answer:
* Is the drug safe for people? Up to what dose levels is it safe?
* What are the potential side-effects?
*How can the most effective dose levels in the laboratory be translated into the most effective dose levels for people?
For drugs that are already approved for one use or another, there is generally a lot of information available from studies of its pharmacodynamics and pharmacokinetics – or put simply, studies of what a drug does to the body and what the body does to a drug.
However, when a drug is considered for a very different use, such as is the case with HSP, the challenge is to achieve the optimal concentration of the drug at the site where it needs to act. In the case of HSP, we are talking about those brain cells known as neurons, which have the long arm or axon travelling the length of, and making up, the spinal cord.
An oral dose needs to be calculated that will translate to maximum effectiveness at the site of action. That is, the drug concentration that is most effective in reversing impairment and restoring function in human HSP stem cells in the laboratory needs to be translated so that an oral dose can be estimated that will result in the desired concentration of the drug in the neurons of someone with HSP.
Further questions get raised:
* What happens to the drug, and the drug taker, when they take the oral dose?
* What happens in the stomach?
* How much finishes up in the bloodstream?
* How much of that successfully crosses the blood-brain barrier so that it can reach the neurons?
* Is there any change in the active ingredient caused by mixing with stomach acid or blood?
* How much is lost along the way or breaks down?
These questions and others have been addressed over the last three months by Prof Alan Mackay-Sim working with a clinical trials consultant and an external research organisation who specialise in drug dose modelling. The result is the creation of detailed and specific plans for a study where all the relevant factors will be modelled and an answer or estimate derived. Such an estimate is a starting point, perhaps the mid-range of an eventual dosing regime to test drug effectiveness for HSP.
When available, the data from drug trials with HSPers will be fed back into the model so as to refine and improve the model and provide greater accuracy. The implementation of the modelling study by the specialist external research organisation has now commenced, at a total cost of around $50,000 to the Foundation.