To evaluate the efficacy and safety of lapatinib ( L ) and trastuzumab ( T ) combination in HER2-positive metastatic breast cancer ( MBC ) patients previously treated with T and/or L.
A retrospective, multicenter study of the efficacy of lapatinib plus trastuzumab in HER2-positive metastatic breast cancer patients previously treated with trastuzumab, lapatinib, or both: the Trastyvere study.  To evaluate the efficacy and safety of lapatinib ( L ) and trastuzumab ( T ) combination in HER2-positive metastatic breast cancer ( MBC ) patients previously treated with T and/or L. ### Materials And Methods We conducted a retrospective, post-authorized, multicenter study including patients with HER2-positive MBC or locally advanced breast cancer (ABC) treated with the combination of L-T. Concomitant endocrine therapy, as well as brain metastasis and/or prior exposure to L, were allowed. ### results One hundred and fifteen patients from 14 institutions were included. The median age was 59.8 years. The median number of prior T regimens in the advanced setting was 3 and 73 patients had received a prior L regimen. The clinical benefit rate (CBR) was 34.8% (95% CI 26.1-43.5). Among other efficacy endpoints, the overall response rate was 21.7%, and median progression-free survival (PFS) and overall survival were 3.9 and 21.6 months, respectively. Heavily pretreated and ≥ 3 metastatic organ patients showed lower CBR and PFS than patients with a low number of previous regimens and < 3 metastatic organs. Moreover, CBR did not significantly change in L-pretreated compared with L-naïve patients (31.5% versus 40.5% for L-pretreated versus L-naïve). Grade 3/4 adverse events were reported in 19 patients (16.5%). ### conclusion The combination of L-T is an effective and well-tolerated regimen in heavily pretreated patients and remains active among patients progressing on prior L-based therapy. Our study suggests that the L-T regimen is a safe and active chemotherapy-free option for MBC patients previously treated with T and/or L.
### Instruction:
            Given the context about compound efficacy for the given treatment mentioned within the input, mentioned the compounds 
            that can co-occur for the mentioned treatment

            ### Input:
            A retrospective, multicenter study of the efficacy of lapatinib plus trastuzumab in HER2-positive metastatic breast cancer patients previously treated with trastuzumab, lapatinib, or both: the Trastyvere study.  To evaluate the efficacy and safety of lapatinib ( L ) and trastuzumab ( T ) combination in HER2-positive metastatic breast cancer ( MBC ) patients previously treated with T and/or L. ### Materials And Methods We conducted a retrospective, post-authorized, multicenter study including patients with HER2-positive MBC or locally advanced breast cancer (ABC) treated with the combination of L-T. Concomitant endocrine therapy, as well as brain metastasis and/or prior exposure to L, were allowed. ### results One hundred and fifteen patients from 14 institutions were included. The median age was 59.8 years. The median number of prior T regimens in the advanced setting was 3 and 73 patients had received a prior L regimen. The clinical benefit rate (CBR) was 34.8% (95% CI 26.1-43.5). Among other efficacy endpoints, the overall response rate was 21.7%, and median progression-free survival (PFS) and overall survival were 3.9 and 21.6 months, respectively. Heavily pretreated and ≥ 3 metastatic organ patients showed lower CBR and PFS than patients with a low number of previous regimens and < 3 metastatic organs. Moreover, CBR did not significantly change in L-pretreated compared with L-naïve patients (31.5% versus 40.5% for L-pretreated versus L-naïve). Grade 3/4 adverse events were reported in 19 patients (16.5%). ### conclusion The combination of L-T is an effective and well-tolerated regimen in heavily pretreated patients and remains active among patients progressing on prior L-based therapy. Our study suggests that the L-T regimen is a safe and active chemotherapy-free option for MBC patients previously treated with T and/or L.

            ### Response:
            lapatinib, trastuzumab
            