"Fundamental research -- much of it done in Boston -- has led to a shift in the scientific strategy for fighting some cancers, toward using drugs to activate a patient’s own immune system. An approach that was on the fringes of cancer therapy is suddenly the hottest trend in cancer drug development. On Monday, for example, Boston researchers presented data showing that nearly half of patients with advanced melanoma lived for two years after getting an experimental immune therapy called nivolumab, though multiple other therapies hadn’t worked for them. And drug companies have announced several deals recently to acquire companies developing immunotherapies. The frenzy of activity is an abrupt change for a field that had made big promises but failed to deliver for years."