Cancer immunotherapy drugs take longer to benefit patients and may not result in the rapid tumor shrinkage often seen with chemotherapy or targeted therapies even though they can prolong survival, experts say. This was evident in the Yervoy study, where patients treated with the drug reported a median time to tumor progression of 2.8 months compared to 2.6 months for the chemotherapy arm. The rate of tumor shrinkage attributed to Yervoy-dacabazine was 15% compared to 10% for dacarbazine alone. --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein. >To submit a news tip, send an email to: email@example.com.