Ann: Notification of investor webinar, page-14

After reviewing the data, I sent the following questions to Jon. His reply was very fast.

What is the dosage used in the Phase III trial and how does it compare to that used in the Rett Phase II trial?

A weight-banded dosing regimen is being used in the Phase 3 trial, designed to mimic the exposure in the blood that was achieved by the effective 200mg/kg dose in the Phase 2 trial, but with the exposure in the lightest subjects (i.e. the lowest weight band) increased a little. We ran simulations of many different potential weight bands and doses to arrive at the optimum regimen.

Have there been any long term studies of trofinetide usage? I know of some neurological medicines (i.e. Levodopa) whose effectiveness decreases with time.

The Phase 3 trial program includes an open label extension after the 12 week placebo controlled study, so there will be data for 12 months treatment in some girls. As you probably know we were only able to treat for 6 weeks in the Phase 2 study. Our expectation is the opposite of the waning of effectiveness over time. We are trying to improve the physical connections and signaling between neurons and we think there will be a “learning” process to enable the positive impacts of that to emerge over time.

Kind regards, Jon