Sara Lonardi, MD, Veneto Institute of Oncology, Padua, Italy, shares updated results from CheckMate 8HW comparing nivolumab plus ipilimumab with nivolumab alone or chemotherapy as first-line therapy for patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) metastatic colorectal cancer (mCRC). 

Results confirmed durable, broad benefit for this combination, with sustained progression-free survival and consistent efficacy across subgroups. Overall survival data, though immature, also favored the dual immunotherapy.

These results were presented at the 2025 European Society for Medical Oncology (ESMO) Congress in Berlin, Germany. 

Transcript: 

Hi, everybody. I’m Sara Lonardi from the Veneto Institute of Oncology in Italy, and today I presented, on behalf of all the coauthors, new results from the CheckMate 8HW trial.

I presented data on the comparison between nivolumab plus ipilimumab and nivolumab alone in the population of patients treated in the first line with centrally confirmed microsatellite instability–high (MSI-H), deficient mismatch repair (dMMR) disease.

We already knew that the trial was positive, having achieved both the primary end points of the comparison between nivo plus ipi vs chemotherapy in the first line and the comparison between nivo plus ipi vs nivo across all lines. But today, we addressed the question about the real setting in which we are using immunotherapy—the first line.

Progression-free survival (PFS) was in favor of the combination nivo plus ipi vs nivo, with a reduction in the risk of progression or death of 31%, and the benefit was consistent across all time points—ranging from 10% to 13%—with 65% of patients free of progression at 4 years and a median PFS not reached after a median follow-up of 50 months. All other outcomes were in favor of the combination, such as response rate—again, an absolute 12% increase in patients experiencing a response—and a lower rate of progressive disease.

We also provided today the data on overall survival (OS) in the population treated across multiple lines. Again, even if the curves are still immature, we saw a benefit for the combination, with a hazard ratio of 0.61 and a benefit consistent across multiple time points—starting with a 7% gain in patients alive at 1 year, reaching 13%, and having 4 of 5 patients still alive at 4 years.

All the burden of these results, which are for sure secondary end points but very relevant for clinical practice, are supporting nivolumab plus ipilimumab as the new standard for MSI-H/dMMR metastatic colorectal cancer.

Source: 

Lonardi S, Lenz HJ, Fernandez EE, et al. Nivolumab plus ipilimumab vs nivolumab monotherapy for microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC): New results from CheckMate 8HW. Presented at the 2025 ESMO Congress. October 17-21, 2025; Berlin, Germany. LBA29