Abstract 46P
Background
Real-world (rw) data on the management of pts with HER2+ u/mBC is lacking. The HER2 REAL (NCT04857619) retrospective study explored treatment (Tx) practices and survival outcomes in pts with HER2+ u/mBC from 4 Asian countries (HK, KR, SG, TW).
Methods
Adult pts diagnosed with HER2+ u/mBC since wider access to trastuzumab emtansine (T-DM1) from Jan 2015 (SG) or 01/01/17 (HK, KR, TW), with ≥12 months (mo) follow-up (FU) data from index date, having ≥1 line of therapy (LOT) were enrolled per medical chart review (data cut-off 31/10/22). We present median (m) rwPFS and mrwOS based on Tx patterns for LOT1 and LOT2 with 95% CI.
Results
Of the 502 pts analyzed (99.6% females; 69.7% postmenopausal), 501 (99.8%) received LOT1, and 468 (93.2%) LOT2; 1 pt in LOT1 excluded because LOT1 start date >30 days before index date. Tx attrition rates increased from 3.3% (3/92) after LOT1 to 18.2% (16/88) after LOT2 for HK, 5.7% (9/157) to 15.5% (23/148) for KR, 3.8% (4/105) to 14.9% (15/101) for SG, and 9.5% (14/147) to 10.7% (14/131) for TW. Overall, the mrwOS was 40.9 mo (35.2, 43.8; HK: 37.3 mo [29.3, 43.6]; KR: 39.8 mo [31.5, 49.3]; SG: 49.1 mo [36.3, not evaluable]; TW: 37.4 mo [31.4, 43.6]) with a 2-year survival rate of 73.5%. The mrwOS was 46.8 mo and the mrwPFS was 10.9 mo for the TRA+PTZ+CT-based regimen in LOT1 with a mFU duration of 28.9 mo. The mrwOS was 23.9 mo and the mrwPFS was 6.3 mo for the T-DM1-based regimen in LOT2 with mFU duration of 29.3 mo Table: 46P
| FU duration (mo) median (range) | rwPFS (mo) median (95% CI) | PFS rate at 2 years (%) | rwOS (mo) median (95% CI) | OS rate at 2 years (%) | |
| LOT1 | |||||
| TRA+PTZ+CT | 28.9 (0.6–73.8) | 10.9 (9.1–12.4) | 15.5 | 46.8 (37.0–49.5) | 74.8 |
| LOT2 | |||||
| T-DM1 | 29.3 (7.2–73.8) | 6.3 (4.9–7.2) | 12.3 | 23.9 (19.2–31.6) | 48.3 |
CI, confidence interval; CT, chemotherapy; rwPFS, real-world progression-free survival; PTZ, pertuzumab; rwOS, real-world overall survival; TRA, trastuzumab
.Conclusions
This retrospective study from Asia showed suboptimal usage of guideline-recommended therapies in LOT1 (TRA+PTZ+CT) and LOT2 (T-DM1) at the time of study enrolment for pts with HER2+ u/mBC. The shorter PFS in LOT1 for TRA+PTZ+CT compared with the global population emphasizes the need for better adherence to guideline-recommended therapies. Additionally, the poor survival outcomes in LOT2 with T-DM1 highlight the need for optimization of standard of care practices in earlier LOTs to improve in this population.
Clinical trial identification
NCT04857619.
Editorial acknowledgement
Medical writing and editorial support were provided by Dr. Soma Santra and Dr. Debasri Mukherjee from Fortrea Scientific Pvt Ltd funded by AstraZeneca.
Legal entity responsible for the study
AstraZeneca International.
Funding
AstraZeneca International.
Disclosure
S.C. Lee: Financial Interests, Personal, Advisory Board: Pfizer, Novartis, AstraZeneca, Eli Lilly, MSD, Roche, ACT Genomics; Financial Interests, Personal and Institutional, Research Grant: Pfizer, Eisai, Taiho, ACT Genomics, Bayer, Karyopharm, MSD, Epizyme, Adagene; Financial Interests, Personal, Speaker, Consultant, Advisor: Pfizer, Novartis, AstraZeneca, Eli Lilly, MSD, Roche, Sanofi, Daiichi Sankyo. R. K.c. Ngan: Financial Interests, Institutional, Speaker, Consultant, Advisor: Novartis; Financial Interests, Personal, Speaker, Consultant, Advisor: AstraZeneca, Sanofi, Pfizer, ZaiLab, Eisai, Eli Lilly, Fosun Pharma, Roche, Nuance (China), Bristol Myers Squibb, Astellas; Financial Interests, Personal, Advisory Board: Merck Sharp & Dohme, Gilead. S. Im: Financial Interests, Institutional, Research Grant: AstraZeneca, Daewoong Pharm, Eisai, Roche, Pfizer; Financial Interests, Personal, Speaker, Consultant, Advisor: AstraZeneca, Eisai, GSK, Hanmi, Eli Lilly, MSD, Idience, Novartis, Roche, Pfizer; Financial Interests, Personal, Advisory Role: Amgen, AstraZeneca, Daiichi Sankyo, Eisai, GSK, Hanmi, Eli Lilly, MSD, Novartis, Pfizer Inc., Roche/Genentech. R. Hui: Financial Interests, Personal, Advisory Board: Amgen, AstraZeneca, BMS, Eisai, Eli Lilly, Janssen, Merck Sereno, MSD, Novartis, Oncosec, Pfizer, Roche, Seagen, Takeda, Zai Lab; Financial Interests, Personal, Speaker, Consultant, Advisor: AstraZeneca, Eli Lilly, Janssen, MSD, Novartis; Financial Interests, Institutional, Research Grant: AstraZeneca, BMS, Corvus, Eisai, Eli Lilly, Janssen, MSD, Novartis, Oncosec, Roche, Seagen. C. Huang: Financial Interests, Institutional, Invited Speaker, Speakers bureaus: Daiichi Sankyo; Financial Interests, Institutional, Invited Speaker, speakers bureaus: AstraZeneca, Pfizer, Novartis, Roche, Eli Lilly, Gilead; Financial Interests, Institutional, Research Grant, research grants to institution: Daiichi Sankyo; Financial Interests, Institutional, Research Grant, Research grants to institution: AstraZeneca, EirGenix, Eli Lilly, MSD, OBI Pharma, Pfizer, Roche, Novartis, Seagen, Gilead, Aston Sci; Non-Financial Interests, Personal, Advisory Role, Advisory boards: Daiichi Sankyo, AstraZeneca, Eli Lilly, Pfizer, Novartis, Roche. T. Tung: Financial Interests, Personal, Full or part-time Employment: AstraZeneca. All other authors have declared no conflicts of interest.