Blind

The essence of drug development is the clinical trial betwixt your Fabulous New Thing and something else. That something else is, mostly, a placebo, aka inert somethingorother, less often the predominant current drug. And the essence of a 'good' clinical trial is that it is double-blind, placebo controlled, and randomized. The former characteristic attempts to ensure that no one involved (drug company, administering doctors, patients, data collectors, and such) knows who is getting what. The latter's purpose is to ensure, more or less, that both known and unknown patient characteristics are equally distributed between the groups; it's pretty much impossible to know (even after years of approved use) what all of the patient characteristics are that affect efficacy. If such were typically known, good drugs would work 100% in 100% of administered patients 100% of the time. Not so much.

So, we find out that a drug for a rare disease, Rett Syndrome, just got approved. There is currently no direct therapy for Rett. It's a pediatric disease that's 100% fatal for boys within mnnths of birth and nearly so for girls who live a shortened time, who are almost all patients. The price tag? Lowest 'estimate' is $575,000 per year; for life, it appears. Some remarkable results: the company stock dropped after the announcement and it turns out that during the clinical trial 82% of the patients getting the drug had diarrhea. Oh, and the measures used to assess the drug were all subjective observations of the patient. So: shits like a chicken - on the drug or shits like a kid - not on the drug. FDA approved this cash cow on no hard data (I'll assume that no physical measure has been found, and not that the company chose to duck it). Certainly, with no existing therapy, and significantly reduced life time and quality of life during that time, we have to do something!, is clearly the marching orders. What if, and I'm betting if, the girls don't live any better or longer? The two companies will have hauled in a boatload of cash for snake oil.

That link includes the following

The mechanism by which trofinetide exerts therapeutic effects in patients with Rett syndrome is unknown. In animal studies, trofinetide has been shown to increase branching of dendrites and synaptic plasticity signals.

FDA is a mess.