1846 - Pertuzumab, trastuzumab, and docetaxel for HER2-positive metastatic breast cancer: results of single arm phase IV COMACHI study

Background

CLEOPATRA study demonstrated the efficacy and safety of pertuzumab (P) + trastuzumab (T) + docetaxel (D) but efficacy results of Japanese subgroup weren’t consistent with the whole study results. A phase IV, multicenter, prospective, COMACHI study was conducted in Japan to re-confirm the efficacy and safety of P+T+D demonstrated in the CLEOPATRA study.

Methods

Patients (pts) with HER2-positive breast cancer who were diagnosed as Stage IV or recurred more than a year after (neo)adjuvant taxane chemotherapy completion were enrolled. Pts were administered study drugs intravenously every 3 weeks. Discontinuation of D was allowed after cycle 6. After discontinuation of D, pts were given maintenance by T+P, however not allowed to receive hormonal therapy for HR positive pts. We defined PFS as the primary endpoint. To demonstrate a median PFS of 12.4 months (mos) or more, which was observed in the placebo arm in the CLEOPATRA study.

Results

From November 2013 to September 2015, 132 pts were enrolled and all pts were treated with T+P at least once. The median age was 56.5 years old and 102 pts (77.3%) had not received prior HER2 therapy. Median cycles of T and P were both 24.0 (range 2.0-71.0) and that of D was 6.0 (range 0.0-65.0). Pts characteristics and subgroup analysis results are shown in the Table below.Table:

353P

Median PFS was 22.8 mos [95% CI, 16.9-34.8], and thereby a median PFS of 12.4 mos or more was confirmed. The incidence of typical Grade 3/4 adverse events were febrile neutropenia (31.1%), neutropenia (24.2%), leukopenia (10.6%), and diarrhea (4.5%), and these findings are consistent with the CLEOPATRA study except for febrile neutropenia. Febrile neutropenia lead to only one case of treatment discontinuation and it was manageable.

Conclusions

The efficacy and safety of P+T+D in Japanese pts were consistent with those of the CLEOPATRA study and we confirmed this treatment as a standard care at 1st line therapy for HER2-positive metastatic breast cancer.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Chugai Pharmaceutical Co., Ltd.

Funding

Chugai Pharmaceutical Co., Ltd.

Disclosure

N. Masuda: Speaker Bureau / Expert testimony, Research grant / Funding (institution): Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony, Research grant / Funding (institution): AstraZeneca; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Pfizer; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Eli-Lilly; Speaker Bureau / Expert testimony: Takeda; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Eisai; Research grant / Funding (institution): Kyowa-Kirin; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Daiichi Sankyo; Officer / Board of Directors: Japan Breast Cancer Research Group Association. S. Ohtani: Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony: Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: Eisai; Speaker Bureau / Expert testimony: AstraZeneca. S. Nagai: Advisory / Consultancy, Speaker Bureau / Expert testimony: Eli-Lilly; Advisory / Consultancy, Speaker Bureau / Expert testimony: Chugai Pharmaceutical Co., Ltd. Y. Komoike: Speaker Bureau / Expert testimony, Research grant / Funding (institution): Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: AstraZeneca; Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony: Eli-Lilly; Research grant / Funding (institution): Daiichi Sankyo; Research grant / Funding (institution): Takeda; Research grant / Funding (institution): Taiho; Speaker Bureau / Expert testimony, the publisher, for writing atricle: Nikkei Business Publications, Inc. Y. Ito: Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Novartis; Speaker Bureau / Expert testimony, Research grant / Funding (self): Taiho; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Eli-Lilly; Speaker Bureau / Expert testimony, Research grant / Funding (self): Eisai; Research grant / Funding (institution): Covance; Research grant / Funding (institution): IQVIA; Research grant / Funding (institution): MSD; Research grant / Funding (institution): AstraZeneca; Research grant / Funding (institution): A2healthcare; Research grant / Funding (institution): Parexel; Research grant / Funding (institution): Kyowa-Kirin. M. Ikeda: Advisory / Consultancy, Speaker Bureau / Expert testimony: Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony: Eisai; Speaker Bureau / Expert testimony: Novartis; Speaker Bureau / Expert testimony: Daiichi Sankyo; Speaker Bureau / Expert testimony: Asahi Kasei Pharma Corporation; Speaker Bureau / Expert testimony: Kyowa-Kirin; Speaker Bureau / Expert testimony: Ono; Speaker Bureau / Expert testimony: Mundipharma; Speaker Bureau / Expert testimony: Taiho; Speaker Bureau / Expert testimony: Bayer; Speaker Bureau / Expert testimony: Nippon Kayaku; Research grant / Funding (institution): Hisamitsu; Officer / Board of Directors, engaged in the project of medical practice guidline: Japanese Breast cancer society; Officer / Board of Directors, the leader of clinical trial comittee: Setouchi Breast Project Comprehensive Support Organization. K. Ishida: Speaker Bureau / Expert testimony: Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony: Eisai; Speaker Bureau / Expert testimony: Nippon Kayaku. T. Nakayama: Speaker Bureau / Expert testimony: Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: AstraZeneca; Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony: Eli-Lilly; Speaker Bureau / Expert testimony: Novartis. T. Takashima: Speaker Bureau / Expert testimony, Officer / Board of Directors: Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony, Officer / Board of Directors: AstraZeneca; Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony: Novartis; Speaker Bureau / Expert testimony: Takeda; Speaker Bureau / Expert testimony: Eisai; Speaker Bureau / Expert testimony: Kyowa-Kirin; Speaker Bureau / Expert testimony: Eli-Lilly. T. Asakawa: Full / Part-time employment: Chugai Pharmaceutical Co., Ltd. S. Matsumoto: Full / Part-time employment: Chugai Pharmaceutical Co., Ltd. D. Shimizu: Full / Part-time employment: Chugai Pharmaceutical Co., Ltd. M. Takahashi: Speaker Bureau / Expert testimony, Research grant / Funding (institution): Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: AstraZeneca; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Eisai; Speaker Bureau / Expert testimony: Novartis; Speaker Bureau / Expert testimony: Eli-Lilly; Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Kyowa-Kirin; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Taiho; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Daiichi Sankyo; Speaker Bureau / Expert testimony: Allergan; Speaker Bureau / Expert testimony, Research grant / Funding (institution): FUJIFILM Toyama Chemical; Speaker Bureau / Expert testimony: Nihon Medi-Physics; Honoraria (self), for wrtitin article: The Asahi Shimbun Company. All other authors have declared no conflicts of interest.