That's not quite true. The MHRA did allow the PIP trial design to be the same as the final SAP for DCVax-L phase III. That would not have happened if they had not felt that the trial design was acceptable for approval. You are somewhat right that we have yet to hear from other 3 RA's, though the FDA has signaled that ECA's is the way forward for these kind of trials.
Misleading. MHRA explicitly approved the trial protocol by green lighting a pediatric trial using the same SAP and the FDA implicitly approved the design by Finalizing their guidance on ECAs.