Successful alemtuzumab retreatment in multiple sclerosis following previous diffuse alveolar haemorrhage.

Alemtuzumab-induced diffuse alveolar haemorrhage (DAH) is a rare but serious complication in people with relapsing-remitting multiple sclerosis (RRMS). Evidence supporting retreatment despite adverse events remains limited. We report a 29-year-old female who developed DAH during the first alemtuzumab cycle and was subsequently retreated 1 year later following interdisciplinary advice from respiratory. There was no recurrence of DAH. This case report provides evidence towards retreatment feasibility with regular monitoring and low thresholds for laboratory and radiological investigations.