This trial was initiated to evaluate the efficacy and safety of pyrotinib in combination with trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive recurrent/metastatic colorectal cancer (CRC). In this single-arm, open-label, multicenter, phase 2 trial patients with HER2-positive recurrent/metastatic CRC were enrolled and received oral pyrotinib 400 mg once a day plus intravenous trastuzumab 8 mg/kg loading dose followed by 6 mg/kg once every 3 weeks. The primary endpoint was the objective response rate (ORR). Disease control rate (DCR), progression-free survival (PFS), duration of response, and safety were assessed as secondary endpoints. From December 2019 to October 2021, a total of 20 patients were enrolled and 18 of them were evaluable for response. All patients were B-rapidly accelerated fibrosarcoma (BRAF) wild type. Four patients achieved partial response, with an ORR of 22.2% (4/18, 95% confidence interval [CI] 6.4-47.6) and DCR of 61.1% (11/18, 95% CI 35.8-82.7), while the ORR and DCR were 33.3% (4/12, 95% CI 13.8-60.9) and 83.3% (10/12, 95% CI 51.6-97.9), respectively, in RAS wild-type patients. At the time of cut-off day, median follow-up was 10.7 months (range 3.8-13.8). The median PFS was 3.4 months (95% CI 1.8-4.3) in the overall population and 4.3 months (95% CI 3.2-8.5) in the RAS wild-type group. The most common adverse event of grade ≥3 was diarrhea (13/20, 65.0%). Pyrotinib combined with trastuzumab showed promising antitumor activity and a manageable safety profile in patients with RAS/BRAF wild-type HER2-positive advanced CRC.
Keywords: RAS mutation; colorectal cancer; human epidermal growth factor receptor 2; pyrotinib; trastuzumab.
© 2022 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.