Every medical intervention, even a very positive one, has unfortunately very often a negative offset. In other words, every benefit is counterbalanced by a risk.
It is then very difficult for those who have to decide the commercialization of a new drug (EMA in Europe and FDA in the US) to conciliate two legitimate but opposite necessities: to make a new drug available for patients as soon as possible and at the same time to be sure not to harm those same patients because of the possible toxic effects.