Background: Budesonide foam is effective in inducing clinical remission in ulcerative colitis (UC) patients with active proctosigmoiditis. The aim of this study was to evaluate the duration of remission and predictors of relapse in UC patients who achieved clinical remission and mucosal healing by 6-week treatment with topical budesonide., Methods: This is a retrospective, observational, multicenter study with a 2-year follow-up period. UC patients who were treated with budesonide foam in phase 2 or phase 3 clinical trials and achieved both clinical remission and mucosal healing were enrolled., Results: Among 84 patients who met the eligibility criteria, 60 participated in the study. Eighteen of the 60 patients (30.0%; 95% confidence interval [CI]: 18.9-43.2) experienced no relapse (i.e., maintenance of remission) during the 2-year follow-up period. The median relapse-free survival time was 0.82 years (95% CI: 0.51-1.52). Of 37 patients with a Mayo endoscopic subscore of 0 after inducing remission with budesonide foam, 25 (67.6%) relapsed within 2 years. Patients with a disease duration of <1 year experienced a worse clinical outcome than patients with a disease duration of >5 years, and the hazard ratio was 2.38 (95% CI: 1.04-5.45)., Conclusion: This is the first study to evaluate the short- to middle-term prognosis in UC patients who achieved mucosal healing with topical preparations. After inducing remission by budesonide foam, treatment for maintaining remissions and strict follow-up may be needed for patients with shorter disease duration., Competing Interests: Makoto Naganuma (MN) has received grants/personal fees from EA Pharma Co., Ltd., and Mochida Pharmaceutical Co., Ltd., personal fees from Kissei Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Takeda Pharmaceutical Co., Ltd., JIMRO Co., Ltd., Kyorin Pharmaceutical Co., Ltd., Janssen Pharmaceutical K.K., Pfizer Japan Inc., and AbbVie GK, and personal fees/non-financial support from Thermo Fisher Scientific Inc. Fumihito Hirai (FH) has received grants/personal fees from Kissei Pharmaceutical Co., Ltd., personal fees from EA Pharma Co., Ltd. Kiyonori Kobayashi (KK) has received grants/personal fees from EA Pharma Co., Ltd., personal fees from Kissei Pharmaceutical Co., Ltd. Kenji Watanabe (KW) has received grants/personal fees from EA Pharma Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Takeda Pharmaceutical Co., Ltd., JIMRO Co., Ltd., Kyorin Pharmaceutical Co., Ltd., Zeria Pharmaceutical Co., Ltd., Astellas Pharma Inc., and Covidien Japan Inc, Nippon Kayaku Co., Ltd., Janssen Pharmaceutical K.K., Pfizer Japan Inc., and AbbVie GK. KW has received personal fees from Kissei Pharmaceutical Co., Ltd. KW has received personal fees and other from Olympus Corporation. Ken Takeuchi (KT) personal fees from EA Pharma Co., Ltd., and Kissei Pharmaceutical Co., Ltd. Nobuo Aoyama (NA) has received grants/personal fees from EA Pharma Co., Ltd. Hiroshi Nozawa Cover Letter (HN) has received grants/personal fees from EA Pharma Co., Ltd. Satoshi Motoya (SM) has received grants/personal fees from Eisai Co., Ltd., AbbVie GK, Mitsubishi Tanabe Pharma Corporation, Takeda Pharmaceutical Co., Ltd., Mochida Pharmaceutical Co., Ltd., and Janssen Pharmaceutical K.K. Toshihide Ohmori (TO) has received grants/fees from EA Pharma Co., Ltd. Akio Harada (AH) has received grants/fees from EA Pharma Co., Ltd. Yushi Nagai (YN) has received other from EA Pharma Co., Ltd., and Kissei Pharmaceutical Co., Ltd. Takayuki Abe (TA) has received other from EA Pharma Co., Ltd., and Kissei Pharmaceutical Co., Ltd. Takanori Kanai (TK) has received research grants/advisory fees/lecture fees from Ajinomoto Co., Inc., Takeda Pharmaceuticals Co., Ltd., Bristol-Myers Squibb Company, and MSD K.K., research grants/advisory fees from EIDIA Co., Ltd., research grants and lecture fees from Mitsubishi Tanabe Pharma Corporation, AbbVie GK, Kyorin Pharmaceutical Co., Ltd., Pfizer Japan Inc., Yakult Honsha Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Zeria Pharmaceutical Co., Ltd., Miyarisan Pharmaceutical Co., Ltd., Eli Lilly Japan K.K., Astellas Pharma Inc., Mochida Pharmaceutical Co., Ltd., AstraZeneca Plc, Ono Pharmaceutical Co., Ltd., and EA Pharma Co., Ltd., grants from Eisai Co., Ltd., Biofermin Pharmaceutical Co., Ltd., Kowa Pharmaceutical Co., Ltd., JIMRO Co., Ltd., Nippon Kayaku Co., Ltd., Daiichi Sankyo Co., Ltd., Tsumura & Co., Taiho Pharmaceutical Co., Ltd., Toray Industries, Inc., Toa Pharmaceuticals Co., Ltd., Mylan Pharmaceuticals Inc., Japan Blood Products Organization, Toa Shinyaku Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Smoking Research Foundation, Kyowa Hakko Kirin Co., Ltd., Asahi Kasei Medical Co., Ltd., FUJIFILM RI Pharma Co., Ltd., Thermo Fisher Scientific Inc., EN Otsuka Pharmaceutical Co., Ltd., Ezaki Glico Co., Ltd., RPM Co., Ltd., Yakult Bio-Science Foundation, and the Public Health Research Foundation, advisory fees from GlaxoSmithKline K.K., and lecture fees from ASKA Pharmaceutical Co., Ltd. Mamoru Watanabe (MW) has received grants/personal fees from Takeda Pharmaceutical Co., Ltd., Eisai Co., Ltd., Astellas Pharma Inc., Nippon Kayaku Co., Ltd., Mochida Pharmaceutical Co., Ltd., Pfizer Japan Inc., Kissei Pharmaceutical Co., Ltd. MW has received grants/personal fees and other from Mitsubishi Tanabe Pharma Corporation, Zeria Pharmaceutical Co., Ltd., EA Pharma Co., Ltd. MW has received grants from Kaken Pharmaceutical Co., Ltd., Alfresa Pharma Corporation, Daiichi Sankyo Co., Ltd., Taiho Pharmaceutical Co., Ltd., Ayumi Pharmaceutical Corporation, Miyarisan Pharmaceutical Co., Ltd. MW has received grants and other from MSD K.K. MW has received personal fees from Janssen Pharmaceutical K.K., Celltrion Healthcare Co., Ltd., Celgene K.K., Eli Lilly Japan K.K. MW has received personal fees and other from JIMRO Co., Ltd., Gilead Sciences, Inc. MW has received other from Asahi Kasei Medical Co., Ltd., Kyorin Pharmaceutical Co., Ltd., AbbVie GK, Kyowa Hakko Kirin Co., Ltd., Toray Industries, Inc., Chugai Pharmaceutical Co., Ltd., and Fujirebio Inc. Yoji Yamada (YY) and Katsutoshi Inagaki (KI) are employees of EA Pharma Co., Ltd. Naoki Shimizu (NS) is employee of Kissei Pharmaceutical Co., Ltd. The commercial affiliations with Kissei Pharmaceutical Co., Ltd., and EA Pharma Co., Ltd., do not alter the adherence to PLOS ONE policies on sharing data and materials. The authors do not have any other competing interests in form of consultancy, patents, products in development, or marketed products, etc.