Clinical trial NCT06980350: Proposal of a Novel Model for Identifying Complete Response in dMMR Colon Cancer Following Neoadjuvant Immunotherapy
Official title: Proposal of a Novel Model for Identifying Complete Response in dMMR Colon Cancer Following Neoadjuvant Immunotherapy
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Colorectal Cancer
Lead sponsor: Sun Yat-sen University
Sponsor class: OTHER
First posted: 2025-05-20
Enrollment: 156
Sex: ALL
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients with dMMR colon cancer receiving neoICI therapy

Brief summary: In this study, we developed a novel evaluation model for identifying complete response following neoadjuvant immune checkpoint inhibitor therapy therapy in patients with dMMR colon cancer, validated its efficacy in two independent cohorts, and assessed its feasibility for W\&W strategy.

Detailed description: Immunotherapy shows promise as a curative treatment for patients with non-metastatic dMMR CRC, and offers an option of watch-and-wait (W\&W) strategy for those achieving clinical complete response (cCR). A recent study by Cercek et al. has tested this hypothesis and demonstrated that 100% of patients (n=42) with localized dMMR rectal cancer achieved cCR after 6 months of neoICI treatment. These patients were managed with a W\&W strategy, and none experienced tumor recurrence over a median follow-up of 26.3 (range 12.4-50.5) months. This result was echoed by our previous studies, in which patients with dMMR rectal cancer who achieved cCR following neoICI demonstrated promising long-term outcomes.

Organ preservation seems promising not only in patients with dMMR rectal cancer, but also in those with dMMR colon cancer who achieve cCR. In the NEOCAP trail, 20 patients with colon cancer were managed with a W\&W strategy, with no tumour regrowth observed over a median follow-up of 11.2 (IQR 5.1-17.7) months. However, the application of organ preservation remains a significant challenge in dMMR colon cancers. This is largely attributed to the fact that tumor responses to neoICI are more prone to be underestimated by radiological assessment. Specifically, patients with pCR were often evaluated as having residual diseases on CT scans. In the PICC trail, 80% (24/30) of patients with partial response (PR) were found to achieve pCR after tumor resection. Similarly, in the NICHE-2 study, only 2 out of 75 patients with pCR had a radiological complete response (CR).5 Hence, a more reliable evaluation model to identify pCR after neoICI in dMMR colon cancer is urgently needed.

In the present study, we developed a novel evaluation model for identifying CR following neoICI therapy in patients with dMMR colon cancer, validated its efficacy in two independent cohorts, and assessed its feasibility for W\&W strategy.

Eligibility criteria: Inclusion Criteria:

1. pathologically confirmed colon adenocarcinoma;
2. immunohistochemistry testing as dMMR tumors;
3. received at least two doses of anti-PD-1 immunotherapy in a neoadjuvant setting.
4. received radical surgery.

Exclusion Criteria:

-

Primary outcomes:
measure: Complete response (CR)
timeFrame: 1 year
Secondary outcomes:
Other outcomes:
Locations:
city: Guangzhou
country: China
facility: Sun Yat-sen University Cancer Center
state: Guangdong
Study officials:
affiliation: Sun Yat-sen University
name: Peirong Ding, M.D.
role: PRINCIPAL_INVESTIGATOR
References: