Complex sentence: Its cardiovascular safety profile compares favorably with rosiglitazone (Avandia), which was withdrawn after concerns about an increased risk of cardiac events, but pioglitazone has subsequently been found to be associated with bladder tumors and has been withdrawn in some countries.
Split into simpler sentences: Its cardiovascular safety profile compares favorably with rosiglitazone (Avandia), which was withdrawn after concerns about an increased risk of cardiac events. However, pioglitazone has subsequently been found to be associated with bladder tumors and has been withdrawn in some countries.