Not sure what you are asking, do you mean can the IGF1 expressing gene or the IGF1 receptor be switched off? If so, then yes they can but this would most likely require genetic manipulation which as a therapy for humans doesn't exist (to my knowledge). An alternative would be to produce an IGF1 antagonist (it blocks the receptor preventing the IGF1 from activating it) or an inhibitor which kills the IGF1 such as an antibody - like the myostatin antibody.