6.1 A number of ongoing or proposed research studies have been noted in the evaluation of burosumab. Burosumab has a conditional marketing authorisation for the treatment of X‑linked hypophosphataemia (XLH). The marketing authorisation is conditional on further data collection in 3 of the clinical studies considered in this evaluation: CL205; CL201; and CL301. Further to this, the company noted that it is developing a European registry and running disease-monitoring programmes in the United States and Japan to generate more data in young people aged 13 years and over. It also explained that there was a planned long-term real-world-data collection programme for burosumab.
6.2 In its evaluation of burosumab, the committee noted substantial uncertainty in several areas, and agreed that further research into the treatment benefit of burosumab in young people aged 13 years and over would relieve some of the clinical uncertainty in an age group covered by the marketing authorisation. The committee also noted that the additional evidence exploring the relationship between radiological measures of bone defects (that is, the Rickets Severity Score and the Radiographic Global Impression of Change) and health-related quality of life would help to address several key uncertainties in the economic analysis. Evidence on the progression of XLH over time and the long-term benefits of burosumab would also be valuable.