Abstract 312P
Background
Human epidermal growth factor receptor 2 (HER2) overexpression or amplification is found in 10-20% of biliary tract cancers (BTCs). We aimed to evaluate the combination of trastuzumab and lapatinib as a second-line treatment option in HER2+ advanced BTCs.
Methods
In this single-center retrospective study, clinical information of consecutive adult patients with HER2-positive (defined as immunohistochemistry [IHC] 3+ or IHC 2+ and fluorescent in situ hybridization positive) advanced BTC who received second-line trastuzumab plus lapatinib after progressing on first-line chemotherapy or chemo-immunotherapy was included. Appropriate survival and descriptive statistics were used to estimate six-month progression-free survival (PFS), objective response rate (ORR), and adverse events.
Results
Twenty-one patients (n=21) with a gall bladder carcinoma majority (95.2%) received trastuzumab plus lapatinib. The first-line treatment was gemcitabine and cisplatin in 71.4%, gemcitabine and oxaliplatin in 19%, and durvalumab added to gemcitabine-platinum combination in 9.5%. With a median follow-up of 7.5 months, the 6-month PFS rate was 42.9% (95% CI 28.6-57.1). A complete response was seen in 4.8% of cases, and 38.1% had a partial response as the best response to treatment, making an ORR of 42.9%. The most frequent AEs were diarrhoea and rash, with grades≥3 AEs seen in 14.3%.
Conclusions
This study demonstrated trastuzumab plus lapatinib as a chemotherapy-free treatment option with encouraging efficacy in second-line treatment of advanced HER2-positive BTCs. This combination merits further evaluation in prospective studies.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.