1042 Background: LZM005 is a novel anti-HER2 antibody that binds with elevated affinity to the domain II of HER2. This phase I study assessed the safety, tolerability, pharmacokinetics (PK) and activity of LZM005, as monotherapy or combined with trastuzumab and docetaxel in patients with HER2-positive metastatic breast cancer. Methods: The phase I trial included phase Ia and Ib. Phase Ia was the monotherapy dosage escalation design. LZM005 was administered intravenously with 5mg/kg, 10mg/kg, 15mg/kg and 20mg/kg. The endpoints were dose limited toxicity (DLT) and maximum-tolerated dose (MTD), safety, tolerability and PK analysis. In phase Ib, LZM005 was combined with trastuzumab and docetaxel with MTD. The endpoints included safety and tolerability, response, PK and biomarker analysis. Results: From Jan 2017 to Feb 2020, 35 patients received LZM005 (15 monotherapy, 20 combination). No DLT was observed from 5mg/kg to 20mg/kg. In phase Ib two arms were set: 420mg arm and 525mg arm. The pharmacokinetics of LZM005 were similar to pertuzumab (Table). Common adverse events included increased transaminases, diarrhea and anemia in monotherapy and combination therapy. The common AE in phase Ia trial included diarrhea (21.4%), anemia (14.3%), elevated transaminase (14.3%). The common AE in phase Ib trial included anemia (44.1%), diarrhea (41.2%), fatigue (26.5%), elevated transaminases (23.5%), nausea (20.6%), rash (17.6%) and asymptomatic urinary tract infection (11.7%). All adverse events were manageable. No treatment-related death occurred. The clinical benefit rate and objective response rate was respectively 42.90% (6/14) and 7.14% (1/14) with monotherapy, with combination cohort was 100% (8/8) and 62.5% (5/8) in trastuzumab-naive, 83.3% (11/12) and 41.7% (5/12) in trastuzumab-pretreated patients. The median progression free survival was 22.5 weeks. Conclusions: LZM005 was well tolerated and showed potent activity in patients with HER2-positive metastatic breast cancer. Further evaluation was warranted. Clinical trial information: CTR20191921 .[Table: see text]
Preliminary Results of Phase I Combination Study of Eribulin Mesylate with Trastuzumab in Patients with Human Epidermal Growth Factor 2 (HER2) Positive Advanced or Metastatic Breast Cancer
