Shallue, formerly an account director at Medical Action Communications (MAC), will join next month and help the agency's five-strong management team 'consolidate and grow' its cross-border business.
The agency's principal international work is currently with GlaxoSmithKline, for which it promotes migraine treatment Imigran.
Shallue started her career as a sales representative for AstraZeneca in her native New Zealand.
Prior to MAC she worked for companies such as Thomson Gardiner-Caldwell Communications.
The appointment of Shallue takes the independent, South-West London-based healthcare specialist agency to 31 staff.