# NCI9673

Source: https://onco.cc/trials/nci9673/  
OnCo record `nci9673` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

NCI9673 was the first completed immunotherapy trial in anal cancer: nivolumab on its own shrank tumours in a quarter of heavily treated patients, which made PD-1 blockade a standard later option, but the follow-on randomisation showed that adding ipilimumab did not help and added toxicity.

## Summary

NCI9673 was a multi-institutional phase 2 trial of the NCI Experimental Therapeutics Clinical Trials Network. Part A gave nivolumab to 37 patients with previously treated metastatic anal squamous cell carcinoma; part B randomised further patients to nivolumab alone or nivolumab with ipilimumab, with progression-free survival as the primary endpoint.

In part A nine of 37 patients responded (24 percent), including two complete responses, with few grade 3 events and no serious adverse events, which established PD-1 blockade as an option after chemotherapy. In part B 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 similar (17.4 against 21.5 percent), and grade 3 or worse treatment-related adverse events doubled with ipilimumab (25 against 12 percent). The corpus's metastatic anal cancer page cites NCI9673 for nivolumab after chemotherapy.

## Fields

- Kind: Trial
- Status: mixed
- Last checked: 2026-09-22
- Also known as: NCI 9673; ETCTN 9673
- Tags: soc-trials
- Registry id: NCT02314169
- Phase: 2
- Setting: Refractory metastatic squamous cell carcinoma of the anal canal after prior chemotherapy: single-arm nivolumab (part A), then a randomised comparison of nivolumab with or without ipilimumab (part B)
- Sponsor: National Cancer Institute (NCI)
- Enrolled: 143
- Result: Nivolumab alone: objective response 24 percent in 37 previously treated patients. Nivolumab with ipilimumab did not improve progression-free survival (3.7 against 2.9 months, hazard ratio 0.86) or response and doubled grade 3 or worse toxicity.
- Outcomes: Objective response rate, part A: Nivolumab 24%; Progression-free survival, part B: Nivolumab + ipilimumab 3.7 months vs Nivolumab 2.9 months, HR 0.86; Objective response rate, part B: Nivolumab + ipilimumab 21.5% vs Nivolumab 17.4%; Overall survival, part B: Nivolumab + ipilimumab 20 months vs Nivolumab 15.9 months, HR 0.98; Grade 3 or worse treatment-related adverse events, part B: Nivolumab + ipilimumab 25% vs Nivolumab 12%

## Sources

- ClinicalTrials.gov NCT02314169: https://clinicaltrials.gov/study/NCT02314169

## 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/)
- technologies: [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/)
- drugs: [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [Nivolumab](https://onco.cc/drugs/nivolumab/)
- institutions: [MD Anderson Cancer Center](https://onco.cc/institutions/md-anderson/)
- key papers: [NCI9673 part B: randomised phase 2 study of nivolumab with or without ipilimumab in refractory metastatic anal cancer](https://onco.cc/key-papers/paper-nci9673-part-b-nivolumab-ipilimumab-anal-cancer-morris-jco-2026/), [NCI9673: nivolumab for previously treated unresectable metastatic anal cancer](https://onco.cc/key-papers/paper-nci9673-nivolumab-metastatic-anal-cancer-morris-lancet-oncol-2017/)

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