Conventional Therapy Combined With Quxie Capsule Modulating Gut Microbiome in Metastatic Colorectal Cancer Patients With the Third or Above Line Setting: Result From an Investigator-Initiated, Open-Label, Single-Arm, Phase II Study.

Background: In patients with metastatic colorectal cancer (mCRC), Quxie Cap-sule (QX)-a combination of conventional therapy (including chemotherapy, targeted therapy or supportive care)-has shown a significant overall survival benefit compared with placebo and might have the property of dual effects of antitumor and immunity enhancement, both mediated by the microbiome. In preclinical models, QX has also shown activity against colorectal cancer. This study aimed to describe how the aforementioned effects of QX look after when focusing on the patients in third or above line setting.

Methods: A Simon's Minimax two-stage phase II design was used in this study, which enrolled mCRC patients who progressed after second-line treatment. Patients received conventional therapy plus QX until disease progression or unacceptable toxicity. Before and after 1-month intervention, we collected patients' stool samples for microbiome analysis by 16s rRNA sequencing approaches. And the microbiome analysis before and after 1-month intervention was done through bioinformation analysis platform.

Results: Fifteen patients were enrolled and gut microbiome were analyzed from 7 of 10 patients that with PFS over 3.7 months. Microbiome community analysis on genus level showed that the proportion of Lachnospiraceae_UCG-001 (0.04% vs 1.06%, P = .02249) significantly increased after conventional therapy plus QX while the proportion of Alistipes (2.96% vs 1.35%, P = .03461), Flavonifractor (0.04% vs 0.02%, P = .02249), Bifidobacterium (6.11% vs 1.14%, P = .02249) and Butyricimonas (0.24% vs 0.11%, P = .03603) significantly decreased after intervention . LEfSe analysis showed that after intervention, samples were highly related with unclassified-f-lachnospiraceae, Eubacterium and Lachnospiraceae_UCG-001.

Conclusions: Decrease of gut bacteria with potential roles in carcinogenesis of colorectal cancer and increase in the abundance of gut anticancer bacteria such as Lachnospiraceae may partly explain how conventional therapy combined with QX can influence carcinogenesis and tumor progression in colon cancer.

Trial registration: Chinese Clinical Trial Registry (ChiCTR2100053874).