Two successful pregnancies -in patients taking Volanesorsen for familial chylomicronemia syndrome.

Familial chylomicronemia syndrome (FCS) is a rare inherited disorder characterized by severe hypertriglyceridemia, posing a heightened risk of acute pancreatitis. Recently, Volanesorsen, an APOC3 antisense oligonucleotide, gained approval for FCS treatment in the UK. Caution is advised during pregnancy due to limited safety data, although animal studies show no toxicity/teratogenicity. Two case scenarios are presented: In the first case, a patient with FCS continued Volanesorsen injections without having thrombocytopenia during an unplanned pregnancy until third trimester, maintaining triglyceride control. Upon discovering the pregnancy at 38 weeks, Volanesorsen was ceased, and a low-fat diet reinstated. Despite a heightened risk of pancreatitis, no episodes of pancreatitis occurred during the pregnancy. In the second case, stopping Volanesorsen before conception led to elevated triglycerides, and an episode of acute pancreatitis at 22 weeks, despite strict very low-fat diet and fibrate therapy from 14 weeks. At 23 weeks, Volanesorsen was reintroduced concurrently with regular therapeutic plasma exchange. No further episodes of pancreatitis occurred. In both case, fetal health was maintained throughout pregnancy, fetal scans revealed no anomalies, and planned C-sections delivered healthy babies without congenital issues. Both babies are well and developing normally at 24 and 19 months.