Once a candidate drug has been selected and preclinical tests in disease models have been conducted, it is necessary to perform rigorous tests in clinical trials to build an evidence base for off-label use or to achieve marketing authorisation. This section details important considerations when undertaking clinical trials in a repurposed drug. For more information on clinical trials, please see Findacure’s “Developing and conducting clinical trials” course on our E-learning portal.
To exemplify some of the important considerations when undertaking clinical trials for repurposed drugs, information from the MCDS-Therapy Project is included throughout this section. This case study outlines an academic-led approach to repurposing the generic drug, carbamazepine, for metaphyseal chondrodysplasia type Schmid (MCDS); a rare condition that leads to short stature, short limbs, bowed legs and joint pain. Having established through research that endoplasmic reticulum (ER) stress is a primary cause of MCDS, academic researchers screened several drugs that act to reduce this process, to identify a candidate that could be repurposed to treat MCDS. Carbamazepine demonstrated the largest reduction in ER stress and so was taken forward to be tested in an MCDS mouse model. Mice with MCDS are generally shorter in length and have a distorted pelvis, with analysis of the growth plate of the long bones under a microscope demonstrating that collagen X is abnormally retained in the cells. Carbamazepine treatment was shown to improve growth and reduce pelvic distortion, with less collagen X retained in the cells. These results are now being taken forward into a clinical trial which is being organised by 11 international partners and funded by the European Union’s Horizon 2020 research and innovation programme, to test if carbamazepine could ultimately be used as a MCDS treatment. Whilst MCDS-Therapy is an academic-led project, where researchers have independently taken a repurposed drug from bench to bedside, the learnings for testing in clinical trials described below are applicable to any repurposing project, including ones driven primarily by patient groups.
If the clinical trial research for your repurposed drug is being conducted by a separate organisation, it is important to remember that contract negotiations can take a substantial amount of time and resources. Close follow-up with the contracted organisation at each stage of the project is also necessary, to ensure the research is being conducted as expected and to evaluate successes and challenges periodically.
Prior to commencing clinical studies, it is necessary to write a protocol that establishes all details of the tests that will be performed during the trials. This should include how the drug(s) will be administered (frequency, dosage etc.) and the clinical endpoints that will be measured to determine the efficacy/safety of the treatment. It is important to get in touch with regulatory/reimbursement bodies such as the EMA and National Institute for Health and Care Excellence (NICE) as early as possible, to understand what clinical endpoints they would need to be met in the trials, in order to be granted regulatory/reimbursement approval.