Parent and professional experiences of a clinical trial of prenatal and postnatal stem cell therapy for severe osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a rare genetic disorder characterised by bone fragility and frequent fractures. While current treatments aim to preserve bone mass, there is no cure. Boost Brittle Bones Before Birth (BOOSTB4) is an international clinical trial investigating postnatal (n = 15) and prenatal plus postnatal (n = 3) infusions of fetal mesenchymal stem cells as a potential treatment for severe OI. Each BOOSTB4 participant received four stem cell doses at four-month intervals. Here we explore the experiences of parents and of healthcare professionals involved in BOOSTB4. In this qualitative study, one or both parents of children participating in BOOSTB4 took part after the second dose (T1: 16 families, 22 participants) and at least 6 months after the final dose (T2: 12 families, 16 participants). Professionals delivering BOOSTB4 participated in one interview (n = 13). Data were analysed using codebook thematic analysis. Decisions to participate in the trial were influenced by the potential for improved prognosis and limited alternative therapies. Parents felt reassurance because they were taking action and gratitude for access to expertise in OI. Balancing hope, expectations and uncertainty around treatment efficacy was challenging. Parents also expressed disappointment and uncertainty about treatment ending. Practical challenges included travel for treatment with a child with OI or late in pregnancy. Professionals noted the difficulty in managing parental expectations and the regulatory and logistical barriers of an international trial. Findings emphasised the need for clear communication before, during and after the trial, transparent information and trial designs that accommodate the needs of individual families.