Aún no tenemos significados para "prove inefficacious".
1As this proved inefficacious, he resorted to other means.
2Their poison proved inefficacious, and so shall their love!
3When even this remedy proves inefficacious, and the patient survives it, the illness is pronounced incurable!
4"Simply if it should prove inefficacious in the form of a request."
5Unhappily it proved inefficacious.