Talk about a double whammy: Two big cancer drugs failed late-stage trials that could have broadened their use considerably. Roche’s Avastin didn’t make the grade against prostate cancer, failing to improve overall survival in combo with chemotherapy and prednisone. And Pfizer’s kidney and gastric cancer drug Sutent flopped against breast cancer in two separate studies. For Roche, this latest Avastin failure makes it two out of three of the big studies expected this year. The drug performed well in an ovarian cancer study, but failed to meet its endpoint in a gastric-cancer trial. Had the drug beat prostate cancer in this latest study, it was expected to add somewhere between 500 million and 1 billion swiss francs, or $471 million to $943 million. The setback means that sales forecasts for the company may need cutting by up to 2 percent, analysts tell Reuters . In Pfizer’s case, this was the second type of cancer Sutent has failed to beat over the past year; earlier, Pfizer stopped a trial of