A large-scale clinical trial combining two popular lung cancer drugs Tarceva and Avastin has showed no increase in survival rates.

However, the combination treatment kept the disease from progressing for a longer period than Tarceva alone, the study found. Tarceva is marketed by Genentech and Avastin by Roche. Roche Holding AG sells both drugs in Europe.

Both drugs that belong to a series of drugs under targeted therapies called innovative drugs are already widely available in U.S. and Europe as lung cancer treatment. However, the two drugs together would cost $12,000 a month.

The trial results can be successfully used in further studies examining lung cancer treatments. The findings will be presented in detail at a cancer meeting in Chicago next month.