Best overall response (BoR) of Partial Response (PR) by RECIST 1.1 was observed in 5 patients, with duration of up to 13 months, and 22 patients experienced stable disease (SD), for a Clinical Benefit Rate (CBR) of 39.7%. Responders included patients with refractory lung and breast cancer, whose tumors expressed HER2 1+ to 3+ by IHC....DF1001 monotherapy demonstrates promising anti-tumor activity in treatment refractory patients with a spectrum of HER2 expression...