Abstract 450P
Background
Pyrotinib, an irreversible pan-Human epidermal growth factor receptor (HER）tyrosine kinase inhibitor, has shown its antineoplastic activity in HER2-positive metastatic breast cancer and HER2 mutation lung cancer. This retrospective study was designed to analyze the efficacy of pyrotinib-based therapy in HER2-positive metastatic colorectal and gastric cancer.
Methods
Patients with HER2 positive advanced colorectal and gastric cancer received pyrotinib-based therapy were collected from December 2018 to January 2021 in Fudan University Zhongshan Hospital. The primary endpoint was objective response rate (ORR). Secondary endpoints were disease control rate (DCR), duration of treatment (DOT), progression-free survival (PFS) and adverse events (AE).
Results
15 patients with colorectal cancer (CRC) and 11 gastric cancer (GC) were enrolled. In patients with CRC, 12 (80%) showed HER2 overexpression and 3 (20%) were HER2 mutation with or without HER2 overexpression. In GC, 10 (90.9%) patients showed HER2 overexpression, and 1 (9.1%) showed HER2 mutation. 20% CRC patients and 90.9% GC patients had undergone anti-HER2 therapy, previously.The ORR and DCR were 26.9% (7/26) and 61.5% (16/26) in all enrolled patients with a median DOT of 6.1 months (range 0.8-13.2 months) and a median PFS of 5.7 months (95% CI 3.6-7.8 months). In the subgroup analysis, ORR and DCR were 33.3% (5/15) and 66.7% (10/15) in CRC, 18.2% (2/11) and 54.5% (6/11) in GC, respectively. The median DOT was similar in CRC (6.3 months) and GC (5.8 months). While median PFS was 5.7 months in CRC and 4.3 months in GC. Grouped by different previous therapies, patients receiving ≤ 2 lines had a numerically longer median PFS than those receiving ＞2 lines: 7.3 vs 4.3 months (HR 0.740, 95% CI 0.294-1.847, P = 0.519). The most frequent AE were diarrhea (14, 53.8%) and rash (5, 19.2%). Pyrotinib reduction was observed in 2 patients, no treatment-related deaths and administration delay were recorded.
Conclusions
Pyrotinib-based therapy demonstrates promising effects in HER2-positive metastatic colorectal and gastric cancer and prospective clinical trial is warranted to confirm its activity in patients failed to first-line therapy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Qian Li.
Funding
Special Clinical Research Program of Shanghai Municipal Health Commission Health Industry 202040222.
Disclosure
All authors have declared no conflicts of interest.