inglês para português Medicina Medicina: farmacêutica Clinical Research

The protocol states that if the DSMB recommends graduation for the xxx agent a small, **firewalled** group of investigators, representatives from yyy and xxx will review the phase 2 data to determine which dose of the agent should move to phase 3.

Encontrei nesse material (https://www.fda.gov/media/75398/download) do FDA a seguinte frase:
In such circumstances it may be very advantageous for the sponsor to set up a "firewall" to ensure that those who would be proposing interim protocol changes based on external data are insulated from knowledge of interim comparative results.

Alguém com experiência em tradução de pesquisa clínica saberia me dizer o termo usado nesse contexto?