Running title : Pharmacology of SERD inhibitor in breast cancer models

Title: AZD9496: An oral estrogen receptor inhibitor that blocks the growth of ER1 positive and ESR1 mutant breast tumours in preclinical models. 2 3 Running title: Pharmacology of SERD inhibitor in breast cancer models 4 5 Hazel M. Weir, Robert H. Bradbury, Mandy Lawson, Alfred A. Rabow, David Buttar, 6 Rowena J. Callis, Jon O. Curwen, Camila de Almeida, Peter Ballard, a Michael Hulse, 7 Craig S. Donald, Lyman J. L. Feron, Galith Karoutchi, Philip MacFaul, Thomas Moss, 8 Richard A. Norman, Stuart E. Pearson, Michael Tonge, Gareth Davies, Graeme E. 9 Walker, Zena Wilson, Rachel Rowlinson, Steve Powell, Claire Sadler, Graham 10 Richmond, Brendon Ladd, d Ermira Pazolli, Anne Marie Mazzola, Celina D’Cruz, Chris 11 De Savi. 12 13 Authors’ Affiliations: 14 Oncology iMed, AstraZeneca, Mereside, Alderley Park, Macclesfield SK10 4TG, UK; 15 Discovery Sciences, AstraZeneca, Mereside, Alderley Park, Macclesfield SK10 4TG UK; c 16 H3 Biomedicine, Technology Sq, Cambridge, MA 02139,Oncology iMed, AstraZeneca R&D 17 Boston, Gatehouse Drive, Waltham, MA 02451, U.S. 18 19