Evolution of Proteomic Profiles of Intestinal Microbiota in Patients With Locally Advanced or Metastatic Urothelial Carcinomas

Analysis of the Evolution of Proteomic Profiles of Intestinal Microbiota in Patients With Locally Advanced or Metastatic Urothelial Carcinomas According to Their Response to Immunotherapy (Responders vs. Non-responders) : A Prospective Pilot Study

Immunotherapy has become an essential therapeutic weapon against many cancers. Control point inhibitors (CPI, PD-1/PD-L1) have shown efficacy in the therapeutic management of tumors in the bladder in progression after administering platinum derivatives. But only 20% of patients get any clinical benefit from these heavy treatments in the long term.

Treating metastatic patients without distinction means taking a considerable risk of toxicity and generates major costs. It is therefore urgent and important to exceed the current criteria for using immunotherapy. Recent studies have shown the interest of studying intestinal microbiota as a marker of the efficacy of immunotherapy.

The investigators hypothesized that the proteomic signature of the intestinal microbiota in patients with locally advanced or metastatic urothelial carcinomas who responded to immunotherapies was special, and has very different characteristics from that of patients with the same pathology who do not respond to immunotherapy.

Inclusion Criteria:

For the "controls" group:

• Patients undergoing treatment for a locally advanced or metastatic urothelial tumor
• Patients who have been on immunotherapy and 2nd-line monotherapy treatment for at least 6 months for a non-operable disease
• Patients whose immunotherapy has been interrupted due to progression of the disease

For the "cases" group:

• patients being treated in the context of a temporary authorization for use delivered for atezolizumab for the management of locally advanced or metastatic urothelial carcinomas following treatment based on platinum salts and still on treatment or patients being treated with pembrolizumab in the context of a donation for compassionate reasons (and still on treatment).

Exclusion Criteria:

• Patients who do not speak or read the French language.
• Patients in an exclusion period determined by another study.
• Patients under legal guardianship or curatorship.
• Patients for whom it is impossible to give clear information to.