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Eflornithine

Eflornithine has been studied in 5 papers since 1991: 1 trial in people, 3 in animals, 1 review; 2 in the past year. It is an approved medicine. The newest story, Nov 1, 2026: “Eflornithine may lower a DNA damage marker in stomach lesions”.

InterventionApproved 1990

5 papers study it14 findingsUpdated

PubChemChEBIMeSH

See all 5 papers on eflornithine

At a glance

The findings reach people, from one lab or study; independent labs found the same change in mice. 7 independent labs in 6 countries; 34 trials, none about aging, 11 with no results posted.

“Eflornithine was well tolerated, with fewer grade 1 to 2 adverse events in the eflornithine group (81 vs. 108, placebo).”
Safety and Efficacy of Eflornithine in Patients with Gastric Precancerous Lesions: A Double-Blinded, Randomized Clinical TrialCancer prevention research (Philadelphia, Pa.)2026doi:10.1158/1940-6207.capr-25-0364

None of its findings points the other way.

Mice: replicated by independent labs. Cells and humans: a single group. Worms or flies: nothing yet.

C, W, M, H: cells, worms or flies, mice, humans. Dark: independent labs found the same change there. Light: one lab or one study. Outline: nothing yet.

Labs are independent when their papers share no last author and no institution.

About aging: the drug’s trials about aging. The total counts its trials for every use.

No results posted: trials that ended over a year ago with no results on ClinicalTrials.gov and no paper reporting them.

Company ties: findings with an author at a company, or from a paper whose competing-interests statement declares ties to one.

  • 7 independent labs in 6 countries
  • 34 trials, none about aging, 11 with no results posted
  • Funders: National Institutes of Health and others
  • 1 of 14 findings with company ties
  • Human trial1
  • Animals3

Studies in people

1 study gave eflornithine to people and measured what changed.

What changedDesignPeopleSource

down: Decreases grade 1 to 2 adverse events81 vs. 108 events, placebo

no change: Has no effect on gastric histology score

Randomized trial18 months91 peopleBoth30-69 years, mean 45.2 yearsMidlife adults; patients with gastric precancerous conditionsCancer prevention research (Philadelphia, Pa.), Mar 9, 2026

What did studies of eflornithine find?

11

Studies of eflornithine measured 11 outcomes; the most studied are lifespan (2 studies), DNA damage response (1) and gastric histology score (1).

Lifespan

upin mice1upin rats1+79% median lifespan

2 studies

  1. Eflornithine extends lifespan in rats (subjected to ionizing radiation).

    “DFMO as well as TSGR significantly improved survival”

    Animalssubjected to ionizing radiation

    Comparative effects of difluoromethylornithine and tincture of Siberian ginseng root on radiation carcinogenesis and life span in rats

    Advances in gerontology = Uspekhi gerontologii

  2. Eflornithine extends lifespan in mice (MRL-lpr/lpr mice) (+79% median lifespan).

    “produced a significant 79% increase in the median lifespan of a group of 20 mice compared to an equal number of controls (P less than 0.001)”

    AnimalsMRL-lpr/lpr mice1.5% in drinking watern = 20

    Successful treatment of lupus nephritis in MRL-lpr/lpr mice by inhibiting ornithine decarboxylase

    Kidney international

DNA damage response

downin humans1

1 study

  1. Eflornithine decreases DNA damage response in humans (24-month versus 18-month assessments) (P = 0.012).

    “A significant reduction in DNA damage (pH2AX-positive cells) was observed in the 24-month versus 18-month assessments (P = 0.012).”

    Human trial24-month versus 18-month assessmentsstomach500 mg/day

    Eflornithine may lower a DNA damage marker in stomach lesions

    Cancer prevention research (Philadelphia, Pa.)

More on DNA damage response

Gastric histology score

no changein humans1

1 study

  1. Eflornithine showed no clear effect on gastric histology score in humans (patients with gastric precancerous conditions).

    “No significant histology score differences were observed.”

    Human trialpatients with gastric precancerous conditionsstomach500 mg/day18 months

    Eflornithine may lower a DNA damage marker in stomach lesions

    Cancer prevention research (Philadelphia, Pa.)

More on Gastric histology score

Grade 1 to 2 adverse events

downin humans1

1 study

  1. Eflornithine decreases grade 1 to 2 adverse events in humans (patients with gastric precancerous conditions) (81 vs. 108 events, placebo).

    “Eflornithine was well tolerated, with fewer grade 1 to 2 adverse events in the eflornithine group (81 vs. 108, placebo).”

    Human trialpatients with gastric precancerous conditions500 mg/day18 months

    Eflornithine may lower a DNA damage marker in stomach lesions

    Cancer prevention research (Philadelphia, Pa.)

Stem cell differentiation

upin mice1

1 study

  1. Eflornithine activates stem cell differentiation in mice (combined dietary and pharmacological intervention).

    “impaired translation of these codons, induced by combined dietary and pharmacological intervention, favours a pro-differentiation proteome.”

    Animalscombined dietary and pharmacological intervention

    Reprogramming neuroblastoma by diet-enhanced polyamine depletion

    Nature

More on Stem cell differentiation

Cell proliferation

downin cells1

1 study

  1. Eflornithine decreases cell proliferation in cells.

    “DFMO, but not PTI alone, blocked proliferation, suggesting that PA biosynthesis was present.”

    Cells

    The involvement of polyamine uptake and synthesis pathways in the proliferation of neonatal astrocytes

    Amino acids

DNA methyltransferase activity

downin human cells1

1 study

  1. Eflornithine decreases DNA methyltransferase activity in Jurkat cells cultured with DFMO.

    “the activity of the three enzymes markedly decreased”

    Cellsin Jurkat cells cultured with DFMO

    Extracellular Spermine Activates DNA Methyltransferase 3A and 3B

    International journal of molecular sciences

Lung histology

no changein mice1

1 study

  1. Eflornithine showed no clear effect on lung histology in mice (MRL-lpr/lpr mice).

    “DFMO treatment had no significant effect on pulmonary histologic findings on these mice.”

    AnimalsMRL-lpr/lpr micelung

    Successful treatment of lupus nephritis in MRL-lpr/lpr mice by inhibiting ornithine decarboxylase

    Kidney international

Polyamines

downin mice1

1 study

  1. Eflornithine decreases polyamines in mice (treated mice).

    “DFMO treatment reduced ODC activity and polyamine concentrations in treated mice.”

    Animalstreated mice

    Successful treatment of lupus nephritis in MRL-lpr/lpr mice by inhibiting ornithine decarboxylase

    Kidney international

More on Polyamines

Inflammation

downin mice1

1 study

  1. Eflornithine decreases inflammation in mice (MRL-lpr/lpr mice).

    “showed significant reduction in all these parameters in DFMO-treated mice when compared to age- and sex-matched untreated mice of the same strain”

    AnimalsMRL-lpr/lpr micekidney

    Successful treatment of lupus nephritis in MRL-lpr/lpr mice by inhibiting ornithine decarboxylase

    Kidney international

More on Inflammation

All 11

What is eflornithine linked with?

2

Studies link eflornithine with 2 measures, most often basal cell carcinoma (1 study) and tumor (1).

Basal cell carcinoma

downin humans1−30%

1 study

  1. Eflornithine lowers the risk of basal cell carcinoma in humans (-30%).

    “Oral difluoromethylornithine (DFMO) reduced BCC incidence by 30% in one trial (P = 0.03) but also caused persistent hearing loss in 19%.”

    Revieworal

    Chemoprevention of keratinocyte carcinomas and actinic keratoses in adults who were immunocompetent: a systematic review

    Clinical and experimental dermatology

More on Basal cell carcinoma

Tumor

downin rats1

1 study

  1. Eflornithine lowers the risk of tumor in rats (subjected to ionizing radiation).

    “decreased incidence and multiplicity of malignant and benign tumors in rats subjected to ionizing radiation”

    Animalssubjected to ionizing radiation

    Comparative effects of difluoromethylornithine and tincture of Siberian ginseng root on radiation carcinogenesis and life span in rats

    Advances in gerontology = Uspekhi gerontologii

More on Tumor

Has eflornithine been tested in people?

0 of 34 about aging

Yes: 1 trial in people have been published, and 34 trials are registered.

Approved

Repurposing

All 20

In trials

  • African Trypanosomiasis

    Phase 4Completed4 trials

  • Trypanosomiasis

    Phase 3Terminated1 trial

  • Prostatic neoplasm

    Phase 2Results posted3 trials

Readouts due

Who is developing eflornithine?

1 company: Orbus Therapeutics.

Companies
  • Orbus TherapeuticsPhase 1idh-wildtype glioblastoma, glioblastoma

Trial sponsors

Latest

Dec 2025: 0Jan 2026: 0Feb 2026: 1Mar 2026: 1Apr 2026: 0May 2026: 0Jun 2026: 0Jul 2026: 0Aug 2026: 0Sep 2026: 0Oct 2026: 0Nov 2026: 02 papers in 12 months
Cancer Prevention Research

Eflornithine may lower a DNA damage marker in stomach lesions

Between months 18 and 24, after treatment ended, DNA damage marker scores fell 18.3 points with eflornithine versus 1.6 with placebo.Between months 18 and 24, after treatment ended, DNA damage marker scores fell 18.3 points with eflornithine versus 1.6 with placebo.

Randomized trial · 55 peopleInterventions
Paper

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