411P - Interim analysis of prospective observational study to evaluate the impact of cancer gene panel tests on treatment decision making in metastatic or recurrent breast cancer in Japan: JBCRG-C07 REIWA study

Background

The Comprehensive Genome Profile (CGP) has been covered by insurance in Japan since July 2019 for patients who have completed or are expected to complete the standard treatment. In Japan, the access rate for genomically matched therapy (MT) is estimated to be approximately 10% after performing CGP tests for all cancer types. We are conducting a prospective observational study (JBCRG-C07 (REIWA study), UMIN000038065) to determine the proportion of patients with stage IV or recurrent breast cancer (BC) who have received MT identified by gene panel testing since January 2020. Forty-three major hospitals participated in the study. Here, we report the results of an interim analysis of 576 patients who were enrolled until April 27, 2023.

Methods

Patients with stage IV or recurrent BC who consented to undergo the FoundationOne CDx® (F1CDx) and FoundationOne Liquid CDx® (F1LCDx) cancer gene panel tests were prospectively enrolled. The primary endpoints were the proportion of patients who received treatment for their genetic alterations after F1CDx/F1LCDx and those who participated in the recommended clinical trials in the population that had matched therapy.

Results

In a per-protocol set of 576 patients, MT was recommended to 347 patients (60.2%) and administered to 79 patients (13.7%). The most common was the immuno-checkpoint inhibitor for TMB-high (n=15), followed by the mTOR inhibitor for PIK3CA alteration (n=14). In the clinical trials, HER2 tyrosine kinase inhibitor for ERBB2 mutation was the most common (n=6). The primary endpoint, the proportion of patients who received F1CDx or F1LCDx and offered matched therapy and underwent matched therapy, was 22.8% (79/347). Of these, 17.7% (14/79) participated in recommended clinical trials, The proportion of patients who participated in the clinical trial among those who were offered a clinical trial was 4.7% (14/296).

Conclusions

The present results indicate a higher rate of accessibility for MT in breast cancer, and the impact of F1CDx/F1LCDx on treatment decision-making was significant. Prognostic analysis will be performed at the end of the observation period (planned for two years).

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

JBCRG (Japan Breast Cancer Research Group).

Funding

Chugai Pharmaceutical Co.

Disclosure

H. Masuda: Financial Interests, Institutional, Principal Investigator: Chugai Pharmaceutical company; Financial Interests, Personal, Invited Speaker: Chugai Pharmaceutical company, MSD, EliLilly; Financial Interests, Institutional, Research Funding: Sysmex. M. Hattori: Financial Interests, Personal, Invited Speaker: Daiichi Sankyo, MSD, Chugai, Eli Lilly. H. Tada: Financial Interests, Personal, Invited Speaker: Chugai Pharma, Daiichi Sankyo, Pfizer, Lilly Japan, AstraZeneca, MSD, Kyowa Kirin International, Novartis, Takeda. Y. Sagara: Financial Interests, Personal, Invited Speaker: Pfizer, Daiichi Sankyo, Eli Lily, MSD, Kyowa Kirin, Celltrion Healthcare Japan, AstraZeneca, Eisai, Chugai, Nippon Kayaku, Sysmex. T. Kogawa: Financial Interests, Personal, Invited Speaker: Daiichi Sankyo, Eisai, AstraZeneca, Oncotherapy sciences, Eli Lilly, Ono Pharma, Gilead sciences, Chugai pharma; Financial Interests, Personal, Expert Testimony: Daiichi Sankyo; Financial Interests, Personal, Other, Support for attending meetings and/or travel: Eizai, Gilead sciences, Astellas. T. Shien: Financial Interests, Personal, Invited Speaker: Daiichi Sankyo, Lilly, Chugai, AstraZeneca, Phyzar. Y. Tanabe: Financial Interests, Institutional, Research Grant: Daiichi Sankyo. F. Hara: Financial Interests, Personal, Invited Speaker: Pfizer, Eli Lilly, MSD, Kyowa Kirin, Daiichi Sankyo, Chugai. H. Iwata: Financial Interests, Institutional, Research Grant: Chugai, Daiichi Sankyo, AstraZeneca; Financial Interests, Personal, Speaker, Consultant, Advisor: Daichi Sankyo; Financial Interests, Personal, Advisory Board: Chugai, AstraZeneca, Lilly, MSD, Pfizer, Giliead; Financial Interests, Personal, Invited Speaker: Daiichi Sankyo, Chugai, AstraZeneca, Lilly, MSD, Pfizer, Taiho, Kyowa Kirin. N. Masuda: Financial Interests, Institutional, Research Grant: Chugai, Eli Lilly, AstraZeneca, Pfizer, Daiichi Sankyo, MSD, Eisai, Novartis, Gilead Sciences, Ono-Pharma; Financial Interests, Personal, Invited Speaker: Chugai, Pfizer, AstraZeneca, Eli Lilly, Daiichi Sankyo; Financial Interests, Personal, Leadership Role, Board of Directors, unpaid: Japanese Breast Cancer Society (JBCS), Japan Society of Clinical Oncology (JSCO). All other authors have declared no conflicts of interest.