- Dissertation
- 10.33540/904
Improving immunotherapy responses in gastrointestinal cancers
- Jan 04, 2022
- Myriam Chalabi
PD-1 plus CTLA-4 blockade is highly effective in advanced stage mismatch-repair-deficient (dMMR) colorectal cancer, yet not in MMR-proficient (pMMR) tumors. We postulated a higher efficacy of neoadjuvant immunotherapy in early stage colon cancers (CC). In the exploratory NICHE study (ClinicalTrials.gov NCT03026140), patients with dMMR or pMMR tumors received a single dose of ipilimumab and two doses of nivolumab prior to surgery, the pMMR group with or without celecoxib. The primary objective was safety and feasibility. Forty patients with 21 dMMR and 20 pMMR tumors were treated. Three patients received nivolumab monotherapy in the safety run-in. Treatment was well-tolerated and all patients underwent radical resections without delays, meeting the primary endpoint. Thirty-five patients who received ipilimumab plus nivolumab (20 dMMR and 15 pMMR tumors) were evaluable for efficacy and translational endpoints. Pathological response was observed in 20/20 (100%; 95% exact CI: 86-100%) dMMR tumors, with 19 major pathological responses (MPR, <10% residual viable tumor) and 12 pathological complete responses (pCR). In pMMR tumors, 4/15 (27%; 95% exact CI 8-55%) showed pathological responses, with 3 MPR and one partial response. CD8+PD1+ T-cell infiltration (TCI) was predictive of response in pMMR tumors. These data indicate that neoadjuvant immunotherapy may have potential to become standard of care for a defined group of CC patients when validated in larger studies with at least 3-year disease-free survival data.
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