Home > Oncology > ASCO 2023 > GU Cancers > Probiotic CBM588 seems to improve clinical effect cabozantinib/nivolumab in mRCC

Probiotic CBM588 seems to improve clinical effect cabozantinib/nivolumab in mRCC

Presented by
Dr Hedyeh Ebrahimi, Tehran University of Medical Sciences, Iran
Conference
ASCO 2023
Trial
Phase 1
Doi
https://doi.org/10.55788/d28eff76
The addition of the probiotic CBM588 to cabozantinib/nivolumab in patients with metastatic renal cell cancer (mRCC) improved both response rate and progression-free survival (PFS) in a small, phase 1 trial. The study did not meet its primary endpoint of change in Bifidobacterium species.

The combination of cabozantinib and nivolumab is a standard first-line systemic treatment for mRCC [1]. Both retrospective and prospective clinical data suggests that CBM588, an orally available liver bacterial product containing a specific strain of Clostridium butyricum, can improve the response to immune checkpoint blockade in patients with cancer [2,3]. To explore the effect of CBM588 on standard first-line therapy in patients with mRCC, Dr Hedyeh Ebrahimi (Tehran University of Medical Sciences, Iran) and colleagues conducted a phase 1 trial (NCT05122546) [4].

A total of 30 participants were randomised 2:1 to cabozantinib/nivolumab/CBM588 or cabozantinib/nivolumab. CBM588 (80 mg) was administered twice daily. The primary endpoint of the study was change in Bifidobacterium species from baseline to week 12. Secondary endpoints were PFS, response rate (RR), and toxicity.

No statistically significant difference was observed in the relative abundance of Bifidobacterium species between baseline and week 12 in the control arm or experimental arm. Also, no statistically significant difference was observed in the alpha diversity between the control arm and experimental arm, both at baseline and at week 12. Therefore, the study did not meet its primary endpoint.

The median PFS, a secondary endpoint, was significantly improved in the experimental arm compared with the control arm: not reached versus 5.8 months (P=0.042). In addition, the response rate was improved in the experimental arm (56 vs 25%). No difference in toxicity was observed between the study arms.

Based on these results, Dr Ebrahimi concluded that “the addition of CBM588 to cabozantinib/nivolumab was not associated with significant changes in the gut microbiome. However, CBM588 improved both response rate and PFS of cabozantinib/nivolumab treatment in mRCC. This is in line with previous clinical data.”

  1. Choueiri TK, et al. N Engl J Med 2021;384:829–841.
  2. Tomita Y, et al. Cancer Immunol Res. 2020;8:1236–1242.
  3. Dizman N, et al. Nature Med. 2022;28:704–712.
  4. Ebrahimi H, et al. Effect of CBM588 in combination with cabozantinib plus nivolumab for patients with metastatic renal cell carcinoma (mRCC): a randomized clinical trial. Abstract LBA104, ASCO Annual Meeting 2023, 2–6 June, Chicago, USA.

 

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