Objective:To investigate the efficacy and safety of chemotherapy combined with inetetamab and pyrotinib (triplet therapy group), and capecitabine combined with pyrotinib (doublet therapy group) in second-line treatment for HER2-positive metastatic breast cancer patients who have failed on trastuzumab.Methods:A retrospective analysis was conducted on 30 HER2-positive metastatic breast cancer patients who underwent second-line treatment with a regimen of chemotherapy plus inetetamab and pyrotinib at Fujian Provincial Tumor Hospital between Jan. 1, 2020 and Dec. 31, 2023, and on 28 HER2-positive metastatic breast cancer patients treated with capecitabine plus pyrotinib during the same period. The study analyzed the differences in ORR (objective response rate), CBR (clinical benefit rate), PFS (progression free survival), and OS (overall survival) between the two groups and documented any adverse reactions observed during treatment.Results:The three-drug group exhibited a higher ORR rate than the two-drug group (60.0% vs. 39.2%, P>0.05), and a higher CBR rate (83.3% vs. 57.1%, P<0.05). Univariate analysis and multivariate Logistic regression analysis showed that group (three drug group compared to two drug group) was the only independent prognostic factor affecting median PFS in patients ( P<0.05). The median PFS of the three drug group was higher than that of the two drug group (19 months vs. 11 months, P<0.05), but by the end of follow-up, neither group had reached the median OS ( P>0.05) .The three-drug group and the two-drug group demonstrated 1-year OS rates of 85% and 85%, 2-year OS rates of 74% and 63%, and 3-year OS rates of 56% and 52%, respectively. The most frequent hematological toxicities in the three-drug group were leukopenia, neutropenia, and anemia, with diarrhea being the most common non-hematological toxicity. No significant differences were observed in adverse reaction profiles between the two groups ( P>0.05) . Conclusion:In the second-line treatment of HER2 positive metastatic breast cancer, chemotherapy + inetetamab + pyrotinib significantly prolonged the median PFS and increased the CBR compared with the current domestic standard capecitabine + pyrotinib regimen, and did not increase the incidence of adverse reactions, demonstrating higher efficacy and safety.

Objective:To investigate the efficacy and safety of chemotherapy combined with inetetamab and pyrotinib (triplet therapy group), and capecitabine combined with pyrotinib (doublet therapy group) in second-line treatment for HER2-positive metastatic breast cancer patients who have failed on trastuzumab.Methods:A retrospective analysis was conducted on 30 HER2-positive metastatic breast cancer patients who underwent second-line treatment with a regimen of chemotherapy plus inetetamab and pyrotinib at Fujian Provincial Tumor Hospital between Jan. 1, 2020 and Dec. 31, 2023, and on 28 HER2-positive metastatic breast cancer patients treated with capecitabine plus pyrotinib during the same period. The study analyzed the differences in ORR (objective response rate), CBR (clinical benefit rate), PFS (progression free survival), and OS (overall survival) between the two groups and documented any adverse reactions observed during treatment.Results:The three-drug group exhibited a higher ORR rate than the two-drug group (60.0% vs. 39.2%, P>0.05), and a higher CBR rate (83.3% vs. 57.1%, P<0.05). Univariate analysis and multivariate Logistic regression analysis showed that group (three drug group compared to two drug group) was the only independent prognostic factor affecting median PFS in patients ( P<0.05). The median PFS of the three drug group was higher than that of the two drug group (19 months vs. 11 months, P<0.05), but by the end of follow-up, neither group had reached the median OS ( P>0.05) .The three-drug group and the two-drug group demonstrated 1-year OS rates of 85% and 85%, 2-year OS rates of 74% and 63%, and 3-year OS rates of 56% and 52%, respectively. The most frequent hematological toxicities in the three-drug group were leukopenia, neutropenia, and anemia, with diarrhea being the most common non-hematological toxicity. No significant differences were observed in adverse reaction profiles between the two groups ( P>0.05) . Conclusion:In the second-line treatment of HER2 positive metastatic breast cancer, chemotherapy + inetetamab + pyrotinib significantly prolonged the median PFS and increased the CBR compared with the current domestic standard capecitabine + pyrotinib regimen, and did not increase the incidence of adverse reactions, demonstrating higher efficacy and safety.

Purpose: We aimed to evaluate whether the addition of pemetrexed is effective in improving progression-free survival (PFS) in epidermal growth factor receptor (EGFR)–mutated patients with or without concomitant alterations. Materials and Methods: This multicenter clinical trial was conducted in China from June 15, 2018, to May 31, 2019. A total of 92 non–small cell lung cancer (NSCLC) patients harboring EGFR-sensitive mutations were included and divided into concomitant and non-concomitant groups. Patients in each group were randomly treated with EGFR–tyrosine kinase inhibitor (TKI) monotherapy or EGFR-TKI combined with pemetrexed in a ratio of 1:1. PFS was recorded as the primary endpoint. Results: The overall median PFS of this cohort was 10.1 months. There were no significant differences in PFS between patients with and without concomitant and between patients received TKI monotherapy and TKI combined with pemetrexed (p=0.210 and p=0.085, respectively). Stratification analysis indicated that patients received TKI monotherapy had a significantly longer PFS in non-concomitant group than that in concomitant group (p=0.002). In concomitant group, patients received TKI combined with pemetrexed had a significantly longer PFS than patients received TKI monotherapy (p=0.013). Molecular dynamic analysis showed rapidly emerging EGFR T790M in patients received TKI monotherapy. EGFR mutation abundance decreased in patients received TKI combined chemotherapy, which supports better efficacy for a TKI combined chemotherapy as compared to TKI monotherapy. A good correlation between therapeutic efficacy and a change in circulating tumor DNA (ctDNA) status was found in 66% of patients, supporting the guiding role of ctDNA minimal residual disease (MRD) in NSCLC treatment. Conclusion EGFR-TKI monotherapy is applicable to EGFR-sensitive patients without concomitant alterations, while a TKI combined chemotherapy is applicable to EGFR-sensitive patients with concomitant alterations. CtDNA MRD may be a potential biomarker for predicting therapeutic efficacy.