Background

Neoadjuvant immunotherapy has shown promising responses in several cancer types. For colon cancer (CC), NICHE was the first neoadjuvant immunotherapy study to show pathologic responses in 100% of dMMR tumors. Importantly, disease-free survival (DFS) in patients (pts) with stage III dMMR CC is similar to that of pMMR pts, with 3-year recurrence risks of over 40% in high-risk (T4 and/or N2) stage III tumors despite adjuvant chemotherapy. Improving outcome for this patient population is urgently needed.

Methods

In the NICHE-2 study, pts with non-metastatic dMMR CC were treated with one dose of ipilimumab (1mg/kg) and two doses of nivolumab (3mg/kg) and underwent surgery ≤6 weeks of registration. The co-primary endpoints were safety (ITT) and 3-year DFS (PP). Secondary endpoints included major pathologic response (MPR) and complete response (pCR) rates. Pathologic response was defined as ≤50% residual viable tumor (RVT), and MPR as ≤10% RVT. Here we present safety and pathologic response data.

Results

A total of 112 pts were treated. Grade 3-4 immune-related adverse events were observed in 3 (3%) patients and only 3 pts experienced delay in surgery, meeting the safety primary endpoint. In the PP population (n=107), baseline radiologic assessment revealed 89% stage III, 77% high-risk stage III (Table), and 64% T4 tumors. With a median time from first dose to surgery of 5 weeks, pathologic response was observed in 106/107 (99%) pts, consisting of 102/107 (95%) MPR and 4 (4%) PR. PCR was observed in 72/107 (67%) pts. At a median follow-up of 13 months (range 1-57), none of the pts had disease recurrence. Table: 000LBA7

Conclusions

In NICHE-2 we confirm the previously reported pathologic responses to short-term neoadjuvant nivolumab plus ipilimumab in a large cohort of dMMR CC pts, with an MPR rate of 95%, including 67% pCR. The first survival data suggest a strong potential for neoadjuvant immunotherapy to become standard of care and allow further exploration of organ-sparing approaches.

Clinical trial identification

NL58483.031.16, EudraCT 016-002940-17.

Editorial acknowledgement

Legal entity responsible for the study

Netherlands Cancer Institute.

Funding

Bristol-Myers Squibb.

Disclosure

T.N. Schumacher: Financial Interests, Personal, Consultant: Third Rock Ventures; Financial Interests, Personal, Advisory Board: Allogene Therapeutics, Merus, Celsius Therapeutics; Financial Interests, Personal, Founder, Advisor: Asher Bio, Neogene Therapeutics; Financial Interests, Personal, Invited Speaker: Neogene Therapeutics; Financial Interests, Personal, Stocks/Shares: Third Rock Ventures, Allogene Therapeutics, Asher Bio, Merus, Neogene Therapeutics, Celsius Therapeutics. E.E. Voest: Financial Interests, Personal, Advisory Board, Hourly rate, to charity: Biogeneration Ventures; Financial Interests, Institutional, Advisory Board, Hourly rate, no compensation in 2019-2020: InteRNA; Financial Interests, Institutional, Invited Speaker, DRUP trial: Amgen, AstraZeneca, Boehringer Ingelheim, BMS, Clovis Oncology, Eisai, Ipsen, MSD, Novartis, Pfizer, GSK, Seattle Genetics; Financial Interests, Institutional, Invited Speaker, DRUP trial DRUG Access Protocol: Bayer, Roche; Financial Interests, Institutional, Invited Speaker, DRUG Access Protocol: Sanofi; Non-Financial Interests, Supervisory Board: HMF – Hartwig Medical Foundation; Non-Financial Interests, Principal Investigator, Senior Group Leader: Oncode Institute; Non-Financial Interests, Advisory Role, Editorial Board: JAMA Oncology; Non-Financial Interests, Leadership Role, Board of Directors: Cancer Core Europe. J.B.A.G. Haanen: Financial Interests, Institutional, Advisory Board: Bristol Myers Squipp, Achilles Therapeutics, Immunocore, Gadeta, Ipsen, Merck Sharpe & Dohme, Merck Serono, Pfizer, Molecular Partners, Novartis, Roche, Sanofi, Third Rock Venture, Iovance Biotherapeutics; Financial Interests, Institutional, Advisory Board, SAB member: BioNTech, Instil Bio, PokeAcel, T-Knife; Financial Interests, Personal, Advisory Board, SAB member: Neogene Therapeutics; Financial Interests, Personal, Stocks/Shares: Neogene Therapeutics; Financial Interests, Institutional, Research Grant: Bristol Myers Squibb, BioNTech US, Merck Sharpe & Dohme, Amgen, Novartis, Asher Bio; Non-Financial Interests, Member: ASCO, AACR, SITC; Editor-in-Chief IOTECH: ESMO, Editorial Board ESMO Open: ESMO; Editorial Board: Kidney Cancer. All other authors have declared no conflicts of interest.