Sure, the (non-drug) fillers have an impact and no one should underestimate the placebo effect* - not relevant for the approval, but the human body is a curious machine (see also the different anecdotes in the MSG thread).
*) short psychiatry story: a patient was accustomed to one sort of placebo/sugar pills with a very distinct form. the pharmacy was not able to provide the pills any longer and the replacement just did not work; the patient explained vehemently and violently that the new medication is harmful
