FDA MedWatch

07/15/2008 - Genentech, Inc. informed healthcare professionals of reports of several cases of microangiopathic hemolytic anemia (MAHA) in patients with solid tumors receiving Avastin in combination with sunitinib malate. Avastin is not approved for use in combination with sunitinib malate and this combination is not recommended. Twenty-five patients were enrolled in a Phase I dose-escalation study combining Avastin and sunitinib malate. The study consisted of 3 cohorts using a fixed dose of Avastin at 10mg/kg/IV every 2 weeks and escalating doses of sunitinib that included 25, 37.5, and 50 mg orally daily given in a 4 weeks on/ 2 weeks off schedule. Five of 12 patients at the highest sunitinib dose level exhibited laboratory findings consistent with MAHA. Two of these cases were considered severe with evidence of thrombocytopenia, anemia, reticulocytosis, reductions in serum haptoglobin, schistocytes on peripheral smear, modest increases in serum creatinine levels, and severe hypertension, reversible posterior leukoencephalopathy syndrome, and proteinuria. The findings in these two cases were reversible within three weeks upon discontinuation of both drugs without additional interventions. Healthcare professionals should report cases of MAHA or any serious adverse events suspected to be associated with the use of Avastin.

Read the entire 2008 MedWatch Safety Summary, including a link to the manufacturer's Dear Healthcare Provider Letter regarding this issue at: http://www.fda.gov/medwatch/safety/2008/safety08.htm#Avastin