Thomas A. Abrams, MD: Clinical deterioration that is not related to obvious AEs of sorafenib has to be regarded as a progression or sorafenib failure, especially if there's corroborating evidence such as biochemical worsening, AFPs going up, worsening liver function, or ascites. Those could be used as a surrogate to progression. If radiological data suggest that the disease is getting worse with new or enlarged lesions, worsening portal venous thrombus, or worsening liver function due to increas...