Cobimetinib-induced "dropped head syndrome" and subsequent disease management in an Erdheim-Chester patient.

Our rechallenge of cobimetinib in an Erdheim-Chester Disease (ECD) patient for the rare adverse effect, "dropped head syndrome," with a previously unexplored cobimetinib regimen was successful. Similar to other experiences with targeted agents in ECD, dosing of cobimetinib may vary to mitigate toxicity without impairing efficacy.