Abstract 279P
Background
T-DXd is an antibody–drug conjugate comprising a HER2 antibody, a tetrapeptide-based cleavable linker, and a topoisomerase I inhibitor payload. DESTINY-Breast01 (NCT03248492) is an open-label, international, multicenter, phase 2 study of T-DXd in patients with HER2-positive MBC; it supported regulatory approval globally. Data from prior data cutoffs (primary: August 1, 2019; initial update: June 8, 2020) showed that patients receiving T-DXd had durable responses. Confirmed overall response rate (ORR) was 61.4%, duration of response (DOR) was 20.8 months, median progression-free survival (mPFS) was 19.4 months, and median overall survival (mOS) was 24.6 months at the initial update (June 8, 2020; Modi S, SABCS 2020). Safety results were also consistent with previously reported data on T-DXd. Here we report updated OS results.
Methods
Patients with MBC that progressed on or after T-DM1 were included in the study. Of the 253 patients who enrolled, 184 received T-DXd 5.4 mg/kg (primary analysis set). The primary endpoint was ORR, and additional endpoints included DOR, PFS, and OS.
Results
A total of 184 patients were assessed with ages ranging from 20.2 to 83.1 years and the number of prior lines of therapy ranging from 0 to 16. At this latest data cutoff (January 15, 2021), median duration of OS follow-up was 29.2 months (95% CI, 28.6-30.0 months). With greater maturity, the updated mOS was 28.4 months (95% CI, 24.6-37.2 months), with 91 (49.5%) OS events. Estimated OS rate was 75% (95% CI, 67%-80%) at 18 months and 58% (95% CI, 51%-65%) at 24 months. Updated results for ORR, mPFS, and mDOR will be presented, along with results of additional ongoing analyses.
Conclusions
With increased duration of survival follow-up, the prolonged estimated mOS and high landmark survival at the 18- and 24-month landmarks indicate a significant and sustained benefit. These updated results continue to demonstrate the survival benefit of T-DXd in heavily previously treated patients with HER2-positive MBC (median prior lines of treatments, 6). The efficacy and safety of T-DXd is currently undergoing further investigation in randomized controlled clinical trials.
Clinical trial identification
NCT03248492.
Editorial acknowledgement
Under the guidance of authors, assistance in medical writing and editorial support was provided by Soniya Patel, PhD, of ApotheCom, and was funded by Daiichi Sankyo, Inc.
Legal entity responsible for the study
Daiichi Sankyo.
Funding
Daiichi Sankyo and AstraZeneca.
Disclosure
C. Saura Manich: Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Advisory Board: Eisai; Financial Interests, Personal, Advisory Board: Exact Sciences; Financial Interests, Personal, Advisory Board: Exeter Pharma; Financial Interests, Personal, Advisory Board: F. Hoffmann-La Roche Ltd.; Financial Interests, Personal, Advisory Board: MediTech; Financial Interests, Personal, Advisory Board: Merck Sharp & Dohme; Financial Interests, Personal, Advisory Board: Novartis; Financial Interests, Personal, Advisory Board: Pfizer; Financial Interests, Personal, Advisory Board: Philips; Financial Interests, Personal, Advisory Board: Pierre Fabre; Financial Interests, Personal, Advisory Board: Puma; Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Advisory Board: Sanofi.-Aventis; Financial Interests, Personal, Advisory Board: Seagen; Financial Interests, Personal, Advisory Board: Zymeworks; Financial Interests, Institutional, Research Grant: AstraZeneca; Financial Interests, Institutional, Research Grant: Daiichi Sankyo; Financial Interests, Institutional, Research Grant: Eli Lilly and Company; Financial Interests, Institutional, Research Grant: Genentech; Financial Interests, Institutional, Research Grant: Immunomedics; Financial Interests, Institutional, Research Grant: Macrogenics; Financial Interests, Institutional, Research Grant: Merck, Sharp and Dhome España S.A.; Financial Interests, Institutional, Research Grant: Novartis; Financial Interests, Institutional, Research Grant: Pfizer; Financial Interests, Institutional, Research Grant: Piqur Therapeutics; Financial Interests, Institutional, Research Grant: Puma; Financial Interests, Institutional, Research Grant: Roche; Financial Interests, Institutional, Research Grant: Synthon; Financial Interests, Institutional, Research Grant: Zenith Pharma; Non-Financial Interests, Member: Spanish Society of Medical Oncology (SEOM); Non-Financial Interests, Member: American Society for Clinical Oncology (ASCO); Non-Financial Interests, Member: SOLTI group (Academic research group in breast cancer); Non-Financial Interests, Member: Geicam (Spanish Breast Cancer Research Group); Non-Financial Interests, Member: American Association for Cancer Research (AACR); Financial Interests, Personal, Advisory Role: AstraZeneca, Daiichi Sankyo, Eisai, Exact Sciences, Exeter Pharma, F. Hoffmann-La Roche Ltd., MediTech, Merck Sharp & Dohme, Novartis, Pfizer, Philips, Pierre Fabre, PumaBiotechnology, Roche, Sanofi-Aventis, Seagen and Zymeworks; Financial Interests, Personal, Other, Travel Expenses: Daiichi Sankyo, Novartis, Pfizer, Roche, Sanofi; Financial Interests, Institutional, Research Grant: AstraZeneca, Daiichi Sankyo, Eli Lilly and Company, Genentech, Immunomedics, Macrogenics, Merck, Sharp and Dhome España S.A., Novartis, Pfizer, Piqur Therapeutics, Puma, Roche, Synthon and Zenith Pharma. S. Modi: Financial Interests, Personal, Other, Honoraria: Genentech, Daiichi Sankyo, AstraZeneca, Seattle Genetics; Financial Interests, Personal, Advisory Role: Daiichi Sankyo, AstraZeneca, Macrogenics; Financial Interests, Personal, Speaker’s Bureau: Genentech, Daiichi Sankyo, AstraZeneca, Seattle Genetics; Financial Interests, Institutional, Research Grant: Genentech, Daiichi Sankyo, AstraZeneca, Seattle Genetics. I. Krop: Financial Interests, Personal, Other, Honoraria: Bristol Myers Squibb, Daiichi/Sankyo, Macrogenics, Context Therapeutics, Taiho Oncology, Genentech/Roche, Seattle Genetics, AstraZeneca, NOVARTIS, Merck, Celltrion; Financial Interests, Institutional, Research Grant: Genentech/Roche, Macrogenics, Pfizer. Y.H. Park: Non-Financial Interests, Personal, Advisory Board: AstraZeneca, Pfizer, Roche, Novartis, Merck; Financial Interests, Institutional, Research Grant: AstraZeneca, Pfizer, Roche, Merck; Non-Financial Interests, Institutional, Principal Investigator: AstraZeneca, Pfizer, Roche, Daiichi Sankyo, Novartis, Merck; Financial Interests, Personal, Other, Speaker fees: Roche, Novartis; Financial Interests, Personal, Other, Medical writing support: F. Hoffmann-La Roche Ltd. S. Kim: Financial Interests, Personal, Advisory Role: Novartis, AstraZeneca, Lilly, Dae Hwa Pharmaceutical Co. Ltd, ISU Abxis, and Daiichi Sankyo; Non-Financial Interests, Personal, Leadership Role: ESMO Breast 2021, Co-Chair; Financial Interests, Personal, Stocks/Shares: Genopeaks, NeogeneTC; Financial Interests, Institutional, Research Grant: Novartis, Sanofi-Aventis, and DongKook Pharm Co. K. Tamura: Financial Interests, Personal, Research Grant: Pfizer, Eli Lilly, Daiichi Sankyo, Chugai. F. André: Financial Interests, Institutional, Research Grant: AstraZeneca, Lilly, Novartis, Pfizer, Daiichi Sankyo, Roche. H. Iwata: Financial Interests, Personal, Other, Honoraria: Chugai, AstraZeneca, Lilly, Pfizer, Daiichi Sankyo, Kyowa Hakko Kirin, Taiho, Eisai; Financial Interests, Personal, Advisory Role: Chugai, AstraZeneca, Lilly, Pfizer, Daiichi Sankyo, Kyowa Hakko Kirin; Financial Interests, Institutional, Research Grant: Chugai, AstraZeneca, Lilly, Pfizer, Daiichi Sankyo, Kyowa Hakko Kirin, MSD, Sanofi, Novartis, Bayer, Nihon kayaku, Boehringer Ingelheim. Y. Ito: Financial Interests, Institutional, Research Grant: AstraZeneca, Chugai, Dai-Ichi-Sankyo, MSD, Eli Lilly. J. Tsurutani: Financial Interests, Personal, Other, Honoraria: Kyowa Kirin, Taiho, Eisai, Daiichi Sankyo, Chugai, Nihon Kayaku, Eli Lilly, Pfizer, MSD, Novartis, AstraZeneca; Financial Interests, Personal, Advisory Role: AstraZeneca, Daiichi Sankyo, Eli Lilly, Eisai; Financial Interests, Personal, Other, Travel Expenses: Daiichi Sankyo, Chugai, Eisai; Financial Interests, Institutional, Research Grant: Eisai, Otsuka, Daiichi Sankyo, Kyowa Kirin. J. Sohn: Financial Interests, Personal, Research Grant: MSD, Roche, Novartis, AstraZeneca, Lilly, Pfizer, GSK,Daiichi Sankyo, Sanofi, Boehringer Ingelheim. C. Lee, Y. Liu, J. Cathcart, J. Singh: Financial Interests, Personal, Full or part-time Employment: Daiichi Sankyo. T. Yamashita: Financial Interests, Personal, Other, Honoraria: Chugai, Eisai, Novartis Pharma, Taiho, Nippon Kayaku, Astrazeneca, Kyowa kirin, Pfizer, Eli Lilly, Daiichi Sankyo; Financial Interests, Institutional, Research Grant: Chuga, Taiho, Nippon Kayaku, Kyowa kirin.