The effects of garetosmab in people with fibrodysplasia ossificans progressiva (FOP): a plain language summary of the LUMINA-1 study

What is this summary about? This is a plain language summary of a clinical research study called LUMINA-1. This study investigated a medicine called garetosmab in adults with fibrodysplasia ossificans progressiva, or FOP. FOP is a very rare disease that causes new bone to form in places where it does not usually develop (also known as heterotopic ossification). In FOP, when bone is formed in areas it is not supposed to, it results in mature heterotopic bone. The build-up of new bone makes it difficult for people with FOP to move, which means they often require the use of a wheelchair or other mobility aid. People with FOP who took part in the study were experiencing bone formation in areas where new bone should not form, flare-ups (episodes of localized swelling, pain, and/or warmth), and worsening joint movement. What were the results? People with FOP were given garetosmab or placebo every 4 weeks as a liquid infusion through a vein for 28 weeks. After 28 weeks, those who were receiving placebo were switched to garetosmab and treated for 28 weeks. This part was known as the open-label portion of the trial, which is when all people received garetosmab treatment. Treatment with garetosmab did not change the mature heterotopic bone in people with FOP, but it did stop new bone lesions from forming in areas where they should not. Treatment with garetosmab also reduced the number of flare-ups. During the trial, common side effects were nosebleeds, loss of eyebrows or eyelashes, and skin and soft tissue infections. Five people died during the open-label portion of the trial, when all were on garetosmab. Their deaths appeared consistent with the known causes of death and life expectancy of people with FOP who were of a similar age and severity of disease. There was no clear pattern that linked the deaths with how garetosmab works. However, a causal relationship between deaths and garetosmab could not be ruled out. What do the results of the study mean? The LUMINA-1 study showed that in people with FOP, garetosmab stopped new heterotopic bone from developing in areas that it should not and also reduced flare-ups. This shows that garetosmab may be a useful treatment for people with FOP. More testing is needed to better understand the benefits and risks of garetosmab. Clinical Trial Registration: NCT03188666 ( ClinicalTrials.gov ) (LUMINA-1)