Enzalutamide was not effective as a single agent to inhibit the proliferation of AR+ TNBC cells...inhibition of cell cycle progression using the CDK7 inhibitor UD-017 showed the most synergistic anti-proliferation effect with enzalutamide in AR+ LAR MDA-MB-453 (50.61% reduction in proliferation compared with enzalutamide alone, P < 0.001; and 48.98% reduction in proliferation compared with UD-017 alone, P < 0.001) and SUM185 (40.41% reduction in proliferation compared with enzalutamide alone, P < 0.05; and 42.76% reduction in proliferation compared with UD-017 alone, P < 0.05) TNBC cells....Our results suggest that enzalutamide synergizes with UD-017 by inhibiting c- MYC–mediated oncogenic activity.