The first study, performed in the US, is evaluating MVA-BN-HER2 treatment following chemotherapy and Herceptin treatment. In the second study, performed in Serbia and Poland, MVA-BN-HER2 is being evaluated following only chemotherapy or in combination with single-agent taxane chemotherapy.
Both studies evaluate treatment of metastatic breast cancer patients, whose tumors overexpress HER2. Patients are vaccinated three times, at three-week intervals, with the MVA-BN viral vector which has been engineered to express the extracellular fragment of human HER2.
With 27 out of 30 patients vaccinated, enrollment in the studies is nearly completed. No drug-related severe adverse events have been reported thus far. The vaccine has been shown to be well tolerated and immunogenic. Immune evaluation of samples from 18 patients treated with MVA-BN-HER2 revealed that 12 patients developed an immune response (humoral and/or cellular response).
These preliminary data show that MVA-BN-based HER2 directed vaccination is a biologically active treatment for patients with HER2 positive breast cancer. The final study data are expected around the turn of the year 2008/2009.