At this week's American Society of Clinical Oncology meeting in Chicago, cancer immunotherapies are all the rage. Using the body's immune system to battle cancer is significantly extending survival times for a variety of cancers and has created the next frontier for blockbusters. Bristol-Myers Squibb (BMY), Merck (MRK), Roche (RHHBY) and AstraZeneca (AZN) are all racing to bring their offerings to market.
Some caution is warranted, however. The drugs work for only a minority of patients and they frequently have significant side effects, especially when a combination of therapies is used. For example, in a trial of BMY's Yervoy for advanced lung cancer, half of the 46 patients in the trial suffered serious side effects and three died from the drugs themselves.