Low-dose Immunotherapy in Metastatic and Locally Advanced Colorectal and Gastric MSI/dMMR Cancers

It is planned to study the effectiveness of low-dose immunotherapy (IT) nivolumab 40 mg for either 2 courses of therapy or 6 courses as preoperative therapy in patients with dMMR/MSI locally advanced CRC. Parallel recruitment into subgroups of patients by randomization is assumed. For dMMR/MSI locally advanced gastric cancer, it is planned to study the effectiveness of low-dose immunotherapy nivolumab 40 mg with or without the addition of chemotherapy (CT) in the FOLFOX regimen as preoperative therapy. Subgroup A includes 6 cycles of IV CT FOLFOX + IV administration of nivolumab 40 mg once every 14 days, subgroup B - 2 cycles of intravenous administration of nivolumab at a dose of 40 mg once every 14 days, and subgroup C - 6 cycles of intravenous administration of nivolumab at a dose of 40 mg once a day 14 days. Thus, it is planned to gradually include patients in the treatment subgroups. The frequency of complete therapeutic tumor pathomorphoses (pCR, TRG1) will be evaluated as the primary endpoint. Secondary goals are to study the safety of drug doses, to assess the frequency of pronounced therapeutic tumor pathomorphoses (MPR, TRG 1-2), to assess disease-free survival (PFS), the frequency of R0 resections, overall survival(S), and the frequency of objective response. To study the use of low-dose immunotherapy in combination with chemotherapy in patients with metastatic dMMR/MSI CRC and gastric cancer in the first line of therapy, it is planned to use a combination of nivolumab 40 mg with FOLFOX regimen once every 14 days for 8 treatment cycles, followed by a switch to supportive intravenous monotherapy with nivolumab 40 mg.

NCT Number	NCT07542262
Lead Sponsor	Blokhin's Russian Cancer Research Center
Conditions	Colorectal Cancer, Gastric Cancer
Enrollment	128 participants
Start Date	2025-06-03
Primary Completion	2028-03-30 (estimated)
Study Completion	2028-03-31 (estimated)
Updated on ClinicalTrials.gov	2026-04-24