The way I would interpret it is the first cohort did not have significant enough efficacy (thus the dose escalation).
Also, the wording is they had this info early April and so presumably sat on it (granted for just a week or two). Considering this is their ONLY program that seems material doesn't the three day rule apply? At the least, it puts little confidence in management (not that I had much).
I am in the shock the stock was not down to below cash (where it should have been once they cut all their AAV10 programs).