125MO - Long-term outcomes of neoadjuvant trastuzumab emtansine + pertuzumab (T-DM1+P) and docetaxel + carboplatin + trastuzumab + pertuzumab (TCbHP) for HER2-positive primary breast cancer: JBCRG20 study (Neo-peaks)

Background

The randomized phase II Neo-peaks study examined usefulness of neoadjuvant trastuzumab emtansine + pertuzumab (T-DM1+P) following docetaxel + carboplatin + trastuzumab + pertuzumab (TCbHP) vs the standard TCbHP regimen. Pathological complete response (pCR) rate was numerically higher with T-DM1+P following TCbHP (Masuda N et al Breast Cancer Res Treat 2020;180:135–46).

Methods

Patients received TCbHP (6 cycles, group A), TCbHP followed by T-DM1+P (4 cycles each, group B) or T-DM1+P (4 cycles, group C). In group C, non-responders after 4 cycles were switched to an anthracycline (A)-based regimen. We evaluated 5-yr disease-free survival (DFS), distant DFS (DDFS) and overall survival (OS).

Results

From Aug 2014 to Feb 2016, 204 patients (51, 52, 101 in groups A–C, respectively) were enrolled; 129 (63.2%) had cN0, 118 (57.8%) had ER-positive disease, median age was 53 (25–70) yrs, and median diameter of the primary tumor was 26 (11–70) mm. During follow-up, 1 patient withdrew consent. The table shows 5-yr DFS, DDFS and OS rates. Of 181 patients who received A-free neoadjuvant therapy, 116 achieved pCR. Of these, 111 did not receive A after surgery and achieved 5-yr DDFS of 97.3% (91.7%–99.1%) with 3 events.

Table: 125MO

Values: % or % (95% CI)^aIncl. those who withdrew during the study treatment^bAfter neoadjuvant therapy

Conclusions

Patients with pCR after neoadjuvant therapy had favorable long-term prognosis, and omission of A may be a reasonable option. Treatment needs to be adjusted in case of residual disease.

Legal entity responsible for the study

Japan Breast Cancer Research Group.

Funding

The Neo-peaks study was funded by Chugai Pharmaceutical, and the present follow-up study was funded by Japan Breast Cancer Research Group.

Disclosure

K. Inoue: Financial Interests, Institutional, Research Grant: AstraZeneca, Chugai, Daiichi Sankyo, MSD, Ono, Gilead, Takeda, Eisai , Novartis, Astellas. N. Masuda: Financial Interests, Personal and Institutional, Speaker’s Bureau: AstraZeneca, Chugai, Eli Lilly, Pfizer; Financial Interests, Institutional, Research Grant: AstraZeneca, Chugai, Daiichi Sankyo, Eisai, Eli Lilly, Kyowa Kirin, MSD, Novartis, Pfizer, Ono; Non-Financial Interests, Personal, Member of the Board of Directors: Japanese Breast Cancer Society, Japan Breast Cancer Research Group Association. T. Takano: Financial Interests, Personal, Invited Speaker: Daiichi Sankyo, Chugai, Eli Lilly. K. Kawaguchi: Financial Interests, Personal, Speaker’s Bureau: Chugai , Daiichi Sankyo, Takeda, Eisai; Financial Interests, Institutional, Research Grant: Eli Lilly, KBCRN. H. Yasojima: Financial Interests, Institutional, Research Grant: Chugai. H. Bando: Financial Interests, Personal, Invited Speaker: AstraZeneca, Chugai, Eisai, Kyowa Kirin, Pfizer, Daiichi Sankyo, Eli Lilly, MSD. R. Nakamura: Financial Interests, Personal, Speaker’s Bureau: Eli Lilly, AstraZeneca, Chugai, Novartis. T. Yamanaka: Financial Interests, Personal, Invited Speaker: AstraZeneca, Chugai, Daiichi Sankyo, Eisai, Eli Lilly, Kyowa Kirin, Novartis, Pfizer. T. Argua: Financial Interests, Personal, Speaker’s Bureau: Pfizer, Chugai, AstraZeneca. E. Tokunaga: Financial Interests, Personal, Speaker’s Bureau: Eli Lilly, AstraZeneca, Daiichi Sankyo. K. Aogi: Financial Interests, Personal, Invited Speaker: Chugai, Eisai, Taiho, AstraZeneca , Daiichi Sankyo, Pfizer, Eli Lilly; Financial Interests, Personal, Advisory Board: Taiho. S. Ohno: Financial Interests, Personal, Speaker’s Bureau: Chugai, AstraZeneca, Eli Lilly, Pfizer, Eisai; Financial Interests, Institutional, Research Grant: Eisai. S. Morita: Financial Interests, Personal, Invited Speaker: AstraZeneca, Bristol Myers Squibb , Chugai, Eisai, Eli Lilly, MSD, Pfizer , Taiho. M. Toi: Financial Interests, Personal, Invited Speaker: Chugai, Takeda, Pfizer, Kyowa Kirin, Taiho, Eisai, Daiichi Sankyo, AstraZeneca, Eli Lilly, Exact Science, Novartis, Shimadzu, Yakult, Nippon Kayaku; Financial Interests, Institutional, Research Grant: Chugai, Takeda, Kyowa Kirin, Taiho, JBCRG association, Eisai, Daiichi Sankyo, AstraZeneca, Astellas, Shimadzu, Yakult, Nippon Kayaku, AFI technologies, Luxonus, Shionogi, GL Science; Financial Interests, Institutional, Principal Investigator: Pfizer; Financial Interests, Institutional, Funding: Pfizer; Financial Interests, Personal, Advisory Board: Kyowa Kirin, Daiichi Sankyo, AstraZeneca, Eli Lilly, Konica Minolta, Bristol Myers Squibb, Athenex Oncology, Bertis, Terumo, Luxonus, Kansai Medical Net; Non-Financial Interests, Personal, Member of the Board of Directors: JBCRG association; Non-Financial Interests, Institutional, Member of the Board of Directors: KBCRN, OOTR. All other authors have declared no conflicts of interest.