Trial details


Screening questionnaire

This will involve a series of questions to which you will assign a score from a choice of 0-4. It should not take more than 10 minutes to complete. You will then post it back to us and should the score meet our criteria we will invite you to visit us at the Wellcome Trust Research Facility in Manchester.

In-depth Assessment

At the first visit you will be asked to bring your child. Siblings are also welcome. The day will consist of interviewing you, while your child separately undergoes a couple of structured play assessments. Lunch will be provided. At then end of the day we will let you know if your child will be eligible for the trial. If they are we will obtain your consent for the trial. You will be free to withdraw from the trial at any point.

Study Assessments and Details

Study visits

There will be 3 further visits, at week 0, 4 and 12. They will randomly allocated either Simvastatin or placebo (inactive syrup). Your child will have a blood test at each visit. They will also have a brain scan (Magnetic Resonance Imaging - MRI) at week 0 and week 12. We will also need to ask you questions. Lunch and refreshments will be provided at each visit and your child will receive a gift for taking part. Travel expenses will be reinbursed. 

We will also contact you by telephone at 16 weeks to get some feedback which will take about 30 minutes.

Length of trial

The trial will last 16 weeks. 


Simvastatin is not licensed for use in children under 10 years but our extensive clinical experience of using this medication with younger children aged birth - 8 years suggests that it is safe and well tolerated. Nevertheless, simvastatin has not been used in children of this age with neurofibromatosis type 1 before, and thus we will carefully watch for any side-effects associated with the drug.  

Blood tests

Our staff from the Children's Hospital taking the blood tests are expert and very experienced in doing this with young children. We use techniques that prepare the child, minimise any pain by using anaesthetic creams on the skin and use effective distraction techniques. The tests are needed to ensure there are no unwanted effects of the medication, and they will also help us with our research.

Brain Scan

The Children's Hospital routinely does brain scans on young children. They are completely safe. They involve the child spending about half an hour in a large tunnel-like structure and for some of this time they need to be still. There are always staff around to reassure the child and we work with families to create the best experience possible for the child. The staff are very experienced in preparing children and families for this experience. Nevertheless, some children can have difficulty in being in the confined space of the scanner, or the noise of it or the need to keep still for a period of time.  For this reason we will be doing careful preparation with both child and family for this experience. Our extensive experience is that, with this preparation, discomfort is minimised.