Combination therapy with levofloxacin and the probiotic Clostridium butyricum MIYAIRI 588 enhances immune checkpoint inhibitor efficacy

Kohei Tajima; Masahiro Hosonuma; Eiji Funayama; Junya Isobe; Yuta Baba; Masakazu Murayama; Yoichiro Narikawa; Hitoshi Toyoda; Toshiaki Tsurui; Yuki Maruyama; Aya Sasaki; Yasunobu Amari; Yoshitaka Yamazaki; Rie Nakashima; Midori Shida; Akiko Sasaki; Takehiko Sambe; Satoshi Wada; Mayumi Tsuji; Yuji Kiuchi; Shinichi Kobayashi; Atsuo Kuramasu; Takuya Tsunoda; Masaki Mori; Kazuo Koyanagi; Kiyoshi Yoshimura

doi:10.1002/ijc.35472

Combination therapy with levofloxacin and the probiotic Clostridium butyricum MIYAIRI 588 enhances immune checkpoint inhibitor efficacy

Int J Cancer. 2025 Sep 1;157(5):993-1005. doi: 10.1002/ijc.35472. Epub 2025 Jun 6.

Authors

Kohei Tajima^{1

2}, Masahiro Hosonuma^{1

3

4

5}, Eiji Funayama^{1

4

6}, Junya Isobe⁷, Yuta Baba¹, Masakazu Murayama^{1

3

4

8}, Yoichiro Narikawa^{1

3

4

8}, Hitoshi Toyoda^{1

3

4

9}, Toshiaki Tsurui^{1

5}, Yuki Maruyama^{1

3

4

8}, Aya Sasaki^{1

3

4}, Yasunobu Amari^{10

11}, Yoshitaka Yamazaki¹², Rie Nakashima^{1

2}, Midori Shida¹, Akiko Sasaki^{3

4}, Takehiko Sambe¹⁰, Satoshi Wada^{5

13}, Mayumi Tsuji⁴, Yuji Kiuchi^{3

4}, Shinichi Kobayashi¹⁴, Atsuo Kuramasu¹, Takuya Tsunoda⁵, Masaki Mori², Kazuo Koyanagi², Kiyoshi Yoshimura^{1

5}

Affiliations

¹ Department of Clinical Immuno Oncology, Clinical Research Institute for Clinical Pharmacology and Therapeutics, Showa Medical University, Tokyo, Japan.
² Department of Gastroenterological Surgery, Tokai University School of Medicine, Kanagawa, Japan.
³ Department of Pharmacology, Showa Medical University Graduate School of Medicine, Tokyo, Japan.
⁴ Pharmacological Research Center, Showa Medical University, Tokyo, Japan.
⁵ Division of Medical Oncology, Department of Medicine, Showa Medical University Graduate School of Medicine, Tokyo, Japan.
⁶ Department of Pharmacology, Showa Medical University Graduate School of Pharmacy, Tokyo, Japan.
⁷ Department of Hospital Pharmaceutics, School of Pharmacy, Showa Medical University, Tokyo, Japan.
⁸ Department of Otorhinolaryngology-Head and Neck Surgery, Showa Medical University Graduate School of Medicine, Tokyo, Japan.
⁹ Department of Orthopedic Surgery, Showa Medical University Graduate School of Medicine, Tokyo, Japan.
¹⁰ Division of Clinical Pharmacology, Department of Pharmacology, Showa Medical University Graduate School of Medicine, Tokyo, Japan.
¹¹ Department of Otolaryngology, Showa Medical University Fujigaoka Hospital, Yokohama, Japan.
¹² Department of Toxicology, Showa Medical University Graduate School of Pharmacy, Tokyo, Japan.
¹³ Department of Clinical Diagnostic Oncology, Clinical Research Institute for Clinical Pharmacology and Therapeutics, Showa Medical University, Tokyo, Japan.
¹⁴ Clinical Research Institute for Clinical Pharmacology and Therapeutics, Showa Medical University, Tokyo, Japan.

PMID: 40478177
DOI: 10.1002/ijc.35472

Abstract

The gut microbiome influences immune checkpoint inhibitor (ICI) efficacy. In this study, we explored the effects of combined levofloxacin (LVFX) and Clostridium butyricum MIYAIRI 588 (CBM588) on ICI outcomes using a CT26 tumor model in BALB/c mice. When compared with the control, the LVFX+CBM588 combination enhanced anti-programmed cell death (PD)-1 therapy, with CD8⁺ T cells playing a key role. Gut microbiota analysis showed reduced Lactobacillus relative abundance and increased Oscillibacter and Muribaculaceae in the LVFX+CBM588 group. A broad-spectrum antibiotic cocktail (ampicillin, neomycin, vancomycin, and metronidazole) with CBM588 diminished antitumor effects and reduced survival in mice when compared with the control, demonstrating the importance of microbiota-targeted therapeutic combinations. However, while LVFX+CBM588 improved ICI efficacy, it worsened dextran sulfate sodium (DSS)-induced colitis, suggesting immune activation contributes to inflammation. These findings emphasize the potential of customized antibiotic-probiotic combinations in cancer immunotherapy, while also stressing the necessity to manage immune-related adverse effects.

Keywords: clostridium butyricum MIYAIRI 588; gut microbiome; immune checkpoint inhibitors; levofloxacin; probiotics.

MeSH terms

Animals
Anti-Bacterial Agents / pharmacology
CD8-Positive T-Lymphocytes / drug effects
CD8-Positive T-Lymphocytes / immunology
Cell Line, Tumor / transplantation
Clostridium butyricum*
Colitis / chemically induced
Female
Gastrointestinal Microbiome / drug effects
Gastrointestinal Microbiome / immunology
Humans
Immune Checkpoint Inhibitors* / pharmacology
Immune Checkpoint Inhibitors* / therapeutic use
Levofloxacin* / administration & dosage
Levofloxacin* / pharmacology
Levofloxacin* / therapeutic use
Mice
Mice, Inbred BALB C
Probiotics* / administration & dosage
Probiotics* / pharmacology

Substances

Levofloxacin
Immune Checkpoint Inhibitors
Anti-Bacterial Agents