Background: In the ongoing, randomised, double-blind phase 3 TOPAZ-1 study, durvalumab, a PD-L1 inhibitor, plus gemcitabine and cisplatin was associated with significant improvements in overall survival compared with placebo, gemcitabine, and cisplatin in people with advanced biliary tract cancer at the pre-planned intermin analysis. In this paper, we present patient-reported outcomes from TOPAZ-1., Methods: In TOPAZ-1 (NCT03875235), participants aged 18 years or older with previously untreated, unresectable, locally advanced, or metastatic biliary tract cancer with an Eastern Cooperative Oncology Group performance status of 0 or 1 and one or more measurable lesions per Response Evaluation Criteria in Solid Tumors (RECIST; version 1.1) were randomly assigned (1:1) to the durvalumab group or the placebo group using a computer-generated randomisation scheme. Participants received 1500 mg durvalumab or matched placebo intravenously every 3 weeks (on day 1 of the cycle) for up to eight cycles in combination with 1000 mg/m 2 gemcitabine and 25 mg/m 2 cisplatin intravenously on days 1 and 8 every 3 weeks for up to eight cycles. Thereafter, participants received either durvalumab (1500 mg) or placebo monotherapy intravenously every 4 weeks until disease progression or other discontinuation criteria were met. Randomisation was stratified by disease status (initially unresectable vs recurrent) and primary tumour location (intrahepatic cholangiocarcinoma vs extrahepatic cholangiocarcinoma vs gallbladder cancer). Patient-reported outcomes were assessed as a secondary outcome in all participants who completed the European Organisation for Research and Treatment of Cancer's 30-item Quality of Life of Cancer Patients questionnaire (QLQ-C30) and the 21-item Cholangiocarcinoma and Gallbladder Cancer Quality of Life Module (QLQ-BIL21). We calculated time to deterioration-ie, time from randomisation to an absolute decrease of at least 10 points in a patient-reported outcome that was confirmed at a subsequent visit or the date of death (by any cause) in the absence of deterioration-and adjusted mean change from baseline in patient-reported outcomes., Findings: Between April 16, 2019, and Dec 11, 2020, 685 participants were enrolled and randomly assigned, 341 to the durvalumab group and 344 to the placebo group. Overall, 345 (50%) of participants were male and 340 (50%) were female. Data for the QLQ-C30 were available for 318 participants in the durvalumab group and 328 in the placebo group (median follow-up 9·9 months [IQR 6·7 to 14·1]). Data for the QLQ-BIL21 were available for 305 participants in the durvalumab group and 322 in the placebo group (median follow-up 10·2 months [IQR 6·7 to 14·3]). The proportions of participants in both groups who completed questionnaires were high and baseline scores were mostly similar across treatment groups. For global health status or quality of life, functioning, and symptoms, we noted no difference in time to deterioration or adjusted mean changes from baseline were observed between groups. Median time to deterioration of global health status or quality of life was 7·4 months (95% CI 5·6 to 8·9) in the durvalumab group and 6·7 months (5·6 to 7·9) in the placebo group (hazard ratio 0·87 [95% CI 0·69 to 1·12]). The adjusted mean change from baseline was 1·23 (95% CI -0·71 to 3·16) in the durvalumab group and 0·35 (-1·63 to 2·32) in the placebo group., Interpretation: The addition of durvalumab to gemcitabine and cisplatin did not have a detrimental effect on patient-reported outcomes. These results suggest that durvalumab, gemcitabine, and cisplatin is a tolerable treatment regimen in patients with advanced biliary tract cancer., Funding: AstraZeneca., Competing Interests: Declaration of interests HABIII reports consulting or advisory fees from AstraZeneca, Bayer, Boehringer Ingelheim, Daiichi Sankyo, FORMA Therapeutics, GRAIL, Incyte, Novartis, Pfizer, and Vincerx, and and research funding from AbbVie, Agios, Arch, ARMO Biosciences, Array BioPharma, Arvinas, AstraZeneca, Bayer, BIND Therapeutics, BioAtla, BioMed Valley, Biotheryx, Boehringer Ingelheim, Bristol-Myers Squibb, Cancer and Leukemia Group B, Ciclomed, Coordination Pharmaceuticals, CytomX, eFFECTOR Therapeutics, EMD Serono, Foundation Medicine, Gossamer Bio, Gilead Sciences, GlaxoSmithKline, Harpoon Therapeutics, Jiangsu Hengrui, Incyte, Infinity, Janssen, Jounce, Kymab, Lilly, MacroGenics, MedImmune, Merck, Millennium, Takeda, miRNA Therapeutics, Moderna, NGM Biopharmaceuticals, Novartis, Pfizer, Revolution Medicine, Roche, Genentech, Ryvu, Seattle Genetics, TESARO, TG Therapeutics, Verastem, Vertex, XBiotech, and Zymeworks. TO reports honoraria from AbbVie, AstraZeneca, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Nihon Servier, Novartis, ONO, Taiho, Takeda, Teijin, and Yakult; consulting or advisory fees from AstraZeneca, Bayer Yakuhin, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Sumitomo, Eisai, Eli Lilly Japan, Incyte, Meiji Seika Pharma, Mundipharma, Nihon Servier, Nippon Shinyaku, Novartis, ONO, Pfizer, Shire, Taiho, Takara Bio, and Takeda; and research funding from AstraZeneca, Baxter, Bristol-Myers Squibb, Chugai, Sumitomo, Eisai, Eli Lilly Japan, Kyowa Hakko Kirin, Merck, Sharp, & Dohme, Nano Carrier, Novartis, ONO, Pfizer, Syneos Health, and Taiho. AV reports honoraria from AstraZeneca, Bayer, Bristol-Myers Squibb, British Technology Group, Eisai, GlaxoSmithKline, Imaging Equipment, Incyte, Ipsen, Lilly, Merck, Novartis, Pierre Fabre, Roche, Sanofi, Servier, Sirtex, and Terumo; and consulting or advisory fees from AstraZeneca, Bayer, Bristol-Myers Squibb, British Technology Group, Eisai, GlaxoSmithKline, Imaging Equipment, Incyte, Ipsen, Lilly, Merck, Novartis, Pierre Fabre, Roche, Sanofi, Servier, Sirtex, and Terumo. HT reports honoraria from Daiichi Sankyo, Mylan, Taiho, and Yakult, and research funding from AstraZeneca, Daiichi Sankyo, and Taiho. VB reports honoraria from AstraZeneca, Bayer, Bristol-Myers Squibb Russia, Eisai, Merck, Sharp, & Dohme, Novartis, Pfizer, Roche Russia, and Takeda, and travel or accommodation expenses from Bayer, Bristol-Myers Squibb Russia, Merck, Sharp, & Dohme, and Roche Russia. J-FB reports honoraria from AstraZeneca, Bayer, Eisai, Ipsen, Merck, Sharp, & Dohme, and Roche, and consulting or advisory fees from AstraZeneca, Bayer, Eisai, Ipsen, Merck, Sharp, & Dohme, and Roche. MB reports honoraria for participating in patient advisory boards, review of patient materials, and speaking engagements from AstraZeneca, Boehringer Ingelheim, CRC Oncology, EMD Serono, Incyte, Kinnate, Merck, QED Clinical Services, Taiho, and TriSalus. MŻ is an employee of AstraZeneca. JA was an employee of IQVIA at the time of the study and reports consulting or advisory fees from AstraZeneca. NP, JW, MA, NR, and GC are employees of, and hold stock in, AstraZeneca. D-YO reports consulting or advisory fees from ASLAN, AstraZeneca, Basilea, Bayer, BeiGene, Bristol-Myers Squibb, Celgene, Genentech, Roche, Halozyme, Merck Serono, Novartis, Taiho, Turning Point, Yuhan, and Zymeworks, and research funding from Array, AstraZeneca, BeiGene, Eli Lilly, Handok, Merck, Sharp, & Dohme, Novartis, and Servier. All other others declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)