Original sentence: According to the US Food and Drug Administration, the drug may cause rare and possibly fatal skin reactions such as Stevens–Johnson syndrome and toxic epidermal necrolysis, Rechallenge tests and an analysis of American but not French pharmacovigilance databases indicated a risk of these reactions
Edited sentence: According to the US Food and Drug Administration, the drug may cause rare and possibly fatal skin reactions such as Stevens–Johnson syndrome and toxic epidermal necrolysis, although an analysis of the French Pharmacovigilance Database indicated no obvious risk of these reactions