Associated Press (09.10.07) - Tuesday, September 11, 2007
On Monday, the Food and Drug Administration (FDA) announced
that Pfizer Inc. has notified health care professionals that
its HIV drug Viracept contains traces of ethyl
methanesulfonate (EMS), a potential human carcinogen.
FDA has asked Pfizer to limit the presence of EMS, a process-
related impurity, in Viracept. Animal studies have indicated
EMS is carcinogenic; however, no human-based data are
Drug maker Roche in June recalled all packs of Viracept in
Europe. Pfizer, which sells the drug in the United States, has
not issued a recall here. Pfizer said testing has found EMS
levels in its Viracept substantially lower than the levels
that prompted the European recall by Roche.
Pediatric patients on stable HIV treatment plans may continue
taking Viracept, but treatment-na�ve patients should not begin
regimens including Viracept until further notice. Pregnant
women are advised not to start taking Viracept; those
currently taking it should be switched to an alternative.
Pfizer is working with FDA on measures to keep EMS at
substantially lower levels. For more information, visit