# COMFORT-I

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

## TL;DR

COMFORT-I showed that the JAK-blocking pill ruxolitinib shrank the grossly enlarged spleens of people with myelofibrosis in about four in ten patients, against almost none on placebo, and eased their fatigue, night sweats and itching; it led to the first approved drug for the disease.

## Summary

COMFORT-I was a double-blind phase 3 trial in 309 patients with intermediate-2 or high-risk myelofibrosis randomised to ruxolitinib, a selective inhibitor of JAK1 and JAK2, or placebo. The primary endpoint was a spleen volume reduction of 35 percent or more at 24 weeks on MRI; secondary endpoints were durability, symptom burden on a total symptom score and overall survival.

The primary endpoint was reached by 41.9 percent of patients on ruxolitinib against 0.7 percent on placebo, symptom scores improved and later follow-up showed a survival advantage, at the cost of more anaemia and thrombocytopenia early in treatment. Ruxolitinib was approved in the United States in November 2011 for intermediate- and high-risk myelofibrosis, the first drug for the disease. Together with COMFORT-II it is the reason the myeloproliferative neoplasm pages list a JAK inhibitor for spleen and symptom control.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-22
- Also known as: COMFORT; INCB 18424-351
- Tags: soc-trials
- Registry id: NCT00952289
- Phase: 3
- Setting: Intermediate-2 or high-risk primary myelofibrosis, post-polycythaemia vera or post-essential thrombocythaemia myelofibrosis: twice-daily oral ruxolitinib or placebo, with spleen volume by MRI at 24 weeks as the primary endpoint
- Sponsor: Incyte Corporation
- Enrolled: 309
- Result: Spleen volume reduction of 35 percent or more at 24 weeks in 41.9 percent of patients on ruxolitinib against 0.7 percent on placebo; approved in the United States in November 2011.
- Outcomes: Spleen volume reduction of 35% or more at week 24 (MRI): Ruxolitinib 41.9% vs Placebo 0.7%; Participants with a spleen volume reduction of 35% or more at week 24 (registry count): Ruxolitinib 65 participants vs Placebo 1 participants

## Sources

- ClinicalTrials.gov NCT00952289: https://clinicaltrials.gov/study/NCT00952289

## Connected records

- cancers: [Myeloproliferative neoplasms (PV, ET, myelofibrosis)](https://onco.cc/cancers/myeloproliferative-neoplasms/), [Primary myelofibrosis](https://onco.cc/cancers/primary-myelofibrosis/)
- technologies: [Small-molecule kinase inhibitors](https://onco.cc/technologies/kinase-inhibitors/)
- drugs: [Ruxolitinib](https://onco.cc/drugs/ruxolitinib/)
- companies: [Incyte](https://onco.cc/companies/incyte/)
- key papers: [COMFORT-I: ruxolitinib, the first JAK inhibitor, versus placebo for myelofibrosis](https://onco.cc/key-papers/paper-comfort-1-ruxolitinib-myelofibrosis-nejm-2012/)

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