# NCI9673 part B: randomised phase 2 study of nivolumab with or without ipilimumab in refractory metastatic anal cancer

Source: https://onco.cc/key-papers/paper-nci9673-part-b-nivolumab-ipilimumab-anal-cancer-morris-jco-2026/  
OnCo record `paper-nci9673-part-b-nivolumab-ipilimumab-anal-cancer-morris-jco-2026` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Adding ipilimumab to nivolumab for metastatic anal cancer after chemotherapy did not improve response, progression-free survival or overall survival and doubled severe side effects.

## Summary

Randomised phase 2 part of the ETCTN trial NCI9673: patients with refractory metastatic squamous cell carcinoma of the anal canal were randomised to nivolumab alone or nivolumab with ipilimumab.

Median progression-free survival was 2.9 months with nivolumab and 3.7 months with the combination (hazard ratio 0.86, p 0.25); response rates were 17.4 and 21.5 percent and median overall survival 15.9 and 20.0 months (hazard ratio 0.98). Grade 3 or worse treatment-related adverse events occurred in 12 percent with nivolumab and 25 percent with the combination. Circulating TIGIT-positive CD8 T cells rose with dual blockade.

## Fields

- Kind: Key paper
- Last checked: 2026-09-22
- Journal: Journal of Clinical Oncology
- Year: 2026
- DOI: 10.1200/JCO-25-00929
- Authors: Morris VK, Ciombor KK, Xiao L, et al.
- Findings: Median progression-free survival 2.9 months (90% CI 1.9 to 3.8) with nivolumab versus 3.7 months (2.0 to 5.6) with nivolumab plus ipilimumab; hazard ratio 0.86 (0.60 to 1.23), p 0.25.; Response rates 17.4 versus 21.5 percent (p 0.89); median overall survival 15.9 versus 20.0 months (hazard ratio 0.98).; Grade 3 or worse treatment-related adverse events 12 versus 25 percent.
- What it means: Single-agent PD-1 blockade remains the immunotherapy standard after chemotherapy in metastatic anal cancer; CTLA-4 blockade adds toxicity without benefit.
- Caveats: Phase 2 powered for progression-free survival with wide confidence intervals.

## Sources

- J Clin Oncol 2026: https://doi.org/10.1200/JCO-25-00929
- PubMed: https://pubmed.ncbi.nlm.nih.gov/41499716/

## Connected records

- cancers: [Anal cancer (squamous cell carcinoma)](https://onco.cc/cancers/anal/), [Metastatic and recurrent anal squamous cell carcinoma](https://onco.cc/cancers/metastatic-anal-cancer/)
- drugs: [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [Nivolumab](https://onco.cc/drugs/nivolumab/)
- trials: [NCI9673](https://onco.cc/trials/nci9673/)
- journals: [Journal of Clinical Oncology](https://onco.cc/journals/jco/)

---
JSON: https://onco.cc/api/v1/entities/paper-nci9673-part-b-nivolumab-ipilimumab-anal-cancer-morris-jco-2026.json