New drugs often loom as a last hope for terminal-cancer patients who have exhausted without success all forms of conventional treatment available. Sometimes, though, drugs cause serious side effects and completely betray patients' expectations. Two such incidents have occurred recently, giving us reason to think again about this problem.

The cases involve a new drug, Iressa, which is used to treat lung cancer, and an old drug, Thalidomide, which has quietly re-emerged even though it is not authorized by the Ministry of Health, Welfare and Labor and was proven in the past to have been responsible for limb deformities in human fetuses.

In the roughly six months since the oral drug Iressa went on sale, it has been used by an estimated 20,000 people. For 124 of the users who have died during this period, the suspected cause of death is the drug's side effects, which include pneumonia. This figure may increase as the investigation develops further. It would be extremely problematic if so many people were found to have died from the side effects of a new drug. Given the speedy approval of the drug by the Health Ministry and its rapid, widespread use, one cannot help but feel that insufficient caution has been taken.