D1.312 - Acquired C1-inhibitor deficiency angioedema treated with lanadelumab: a case series

Acquired angioedema is a rare condition characterized by severe and unpredictable episodes of swelling in the extremities, face, airways and gastrointestinal tract. Currently, evidence regarding optimal management is lacking, and available treatments are the same as those used for the hereditary form of bradykinin-mediated angioedema.

We describe six patients with acquired C1-inhibitor deficiency angioedema and their clinical responses to lanadelumab.

This series included four males and two females, all French-Canadian Caucasians, aged 58 to 82 years at onset of symptoms, started on lanadelumab for recurrent and/or severe episodes of angioedema. Four patients had an underlying monoclonal gammopathy of undetermined significance (MGUS), one had a lymphoproliferative disorder, and one had a history of solid lung neoplasm without evidence of recurrence. Four patients had antibodies against C1-inhibitor. All six had significantly low levels of C1q, C4 and functional C1-inhibitor (<50% of normal values). Before lanadelumab, three patients received a rituximab cycle with variable results, one was on long-term tranexamic acid with partial clinical remission, and two started lanadelumab as their first prophylactic treatment. Among all six patients, four of whom were treated for more than a year, there was no reported episode of angioedema under lanadelumab monotherapy prophylaxis. No significant adverse events were reported.

Lanadelumab effectively prevented angioedema episodes in all six patients with acquired C1-inhibitor deficiency angioedema.