Zhejiang Medicine, NovoCodex and Ambrx announced positive interim topline data from the ongoing "111" trial (CTR20171162) evaluating ARX788, a novel anti-HER2 ADC, in heavily pretreated patients with metastatic HER2 positive breast cancer. All patients enrolled had failed prior therapy with trastuzumab and 47% had failed therapy with trastuzumab and lapatinib. ARX788 was well tolerated at all dose levels with just two = Grade 3 drug related reversible adverse events observed amongst 51 enrolled patients. ARX788 showed an excellent safety profile with dose escalation continuing. No DLT or MTD was observed as of the November 20, 2019 cut-off date. Response rates correlated with increased dose levels. As of the cut-off date, the highest dose tested was 1.5mg/kg every three weeks. This cohort, which continues dosing and remains under observation, had already achieved a 63% overall response rate. Prior cohorts at 0.88, 1.1 and 1.3 mg/kg demonstrated overall response rates of 14%, 36% and 56% respectively. Further, the substantial increases in efficacy observed at higher doses was achieved with only mild increases in toxicity. These data originate from the Fudan University Shanghai Cancer Center in China and are part of a broader global ARX788 development program (NCT03255070 and CTR20171162) that includes clinical sites in China, USA and Australia.