IKCS 2022: Clinical Outcomes with Nivolumab/Ipilimumab (Nivo/Ipi) with or Without CBM588 in Metastatic Renal Cell Carcinoma (mRCC): Long-Term Follow-up of a Randomized Phase Ib Clinical Trial

(UroToday.com) Dr. Nazli Dizman presented the long-term follow-up data for an early phase trial of ipilimumab + nivolumab with the novel bifidogenic live bacterial product, CBM588, in patients with mRCC. CBM588 is a live bacterial product containing Clostridium butyricum, a butyrate-producing anaerobic spore-forming bacterium. First isolated from a soil sample in Nagano, Japan in 1962, it is commonly used and studied for the treatment of various gastrointestinal conditions in Japan. Retrospective clinical data suggest that concurrent treatment with Clostridium butyricum may augment the response to immune checkpoint inhibitors in patients with metastatic NSCLC.

The present study is a small randomized trial of frontline ipilimumab + nivolumab with or without CBM588 in patients with metastatic ccRCC. The primary endpoint was microbiota abundance. Clinical outcomes including toxicity, ORR, PFS, and OS were all key secondary endpoints.



A total of 10 patients received ipilimumab + nivolumab, and 19 patients received the combination with CBM588. The combination as associated with a numerically higher ORR (11/19 vs 2/10, no CRs) and a higher disease control rate (15/19 vs 2/10).


At a median follow-up of 27.7 months, the median PFS was superior for the CBM588 combination – 36.4 months versus 2.5 months with ipilimumab + nivolumab doublet. Median overall survival was not reached in either arm and 83% of the cohort was still alive at last follow-up.


Not surprisingly, responses to ipilimumab + nivolumab with CBM588 were durable with a median duration of response 30.7 months.


Grade 3 and higher TRAEs occurred in 11/19 (63%) and 5/10 (50%) of patients on ipilimumab + nivolumab with or without CBM588, respectively. A larger effort to investigate the clinical efficacy of CBM588 in advanced RCC is underway.

Presented by: Nazli Dizman, MD, Yale New Haven Hospital, New Haven, CT

Written by: Mike Lattanzi, MD, Medical Oncology & Hematology, Texas Oncology – Austin Central during the 2022 International Kidney Cancer Symposium (IKCS) North America, November 4-5, Austin, Texas, USA

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