Case Report: Durable Clinical Response to Third-Line Pyrotinib After Resistance to Trastuzumab in a Gastric Cancer Patient

Abstract

BackgroundTrastuzumab plus chemotherapy remains the standard first-line treatment strategy for HER2-positive gastric cancer (GC). Trastuzumab resistance, on the other hand, remains a significant issue. There are a few effective anti-HER2 agents for patients who develop resistance to trastuzumab.Case PresentationA 49-year-old female was diagnosed with stage IV GC with liver and lung metastasis in July 2017. She underwent gastrostomy, and the immunohistochemistry (IHC) result of postoperative tissue demonstrated HER2 (3+). She received first-line treatment of trastuzumab (440 mg), oxaliplatin (200 mg), and S-1 (40 mg). After treatment for 6 months, the patient achieved complete response (CR) with PFS up to 21 months. After progression, she subsequently received trastuzumab (440 mg) plus oxaliplatin (200 mg) as second-line treatment. However, the patient developed resistance to trastuzumab after 12 months of treatment. She started to receive third-line treatment of irinotecan (200 mg d1) and capecitabine (60 mg bid) plus pyrotinib (400 mg/day). After 2 months of treatment, the tumor is evaluated as partial response with PFS of 12 months.ConclusionsWe presented a patient with HER2-positive GC who benefited from the pyrotinib-based treatment after two lines of trastuzumab-based therapies failed. Further research is required to validate such conclusions.

Pyrotinib alone or in combination with docetaxel in refractory HER2‐positive gastric cancer: A dose‐escalation phase I study

“…Pyrotinib is an irreversible pan‐ErbB small‐molecular TKI, which has been approved in HER2‐positive BC. While the safety and efficacy data were limited in HER2‐positive GC, only several small‐sample retrospective studies and case reports involved it 13,14 . And the effect of chemotherapy combined with pyrotinib in GC was unknown.…”

“…While the safety and efficacy data were limited in HER2‐positive GC, only several small‐sample retrospective studies and case reports involved it. 13 , 14 And the effect of chemotherapy combined with pyrotinib in GC was unknown. A study was necessary to prospectively explore the safety and antitumor activity in HER2‐positive GC.…”

HER2+ advanced gastric cancer: Current state and opportunities (Review)

“…The patient has survived for >30 months after postoperative recurrence and is currently receiving combination therapy with pyrotinib and capecitabine, with a PFS >8.5 months. Furthermore, several analogous cases have shown a favorable outcome following pyrotinib administration as a later-line treatment (128)(129)(130). Pyrotinib may be another promising targeted drug for the treatment of HER2 + AGC.…”