G-CSF is a Potential Alternative in Treatment of Hot Flashes in Postmenopausal Women

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Preliminary phase 1 clinical trial (NCT03640754) results presented at The Menopause Society 2025 Annual Meeting demonstrate that granulocyte colony-stimulating factor (G-CSF) may provide an alternative to menopausal hormone therapy (MHT), antidepressants, and neurokinin 3 receptor antagonists for the treatment of hot flashes in menopausal women.

These findings are especially significant because G-CSF does not have boxed warnings, unlike MHT and certain antidepressants and neurokinin 3 receptor antagonists.^1,2

G-CSF is most often prescribed after chemotherapy, according to Cleveland Clinic. It increases white blood cell counts, specifically neutrophils, to help protect patients from infections. During chemotherapy, neutrophils are often destroyed, leading to neutropenia. This neuroprotective and neurotrophic protein has anti-inflammatory and vasodilatory properties that may counteract proinflammatory cytokines and chemokines that are elevated in postmenopausal women.^1,3

In this multicenter, randomized, double-blind, placebo-controlled 12-week study, the investigators aimed to assess the safety and pharmacodynamic effects of repeated subcutaneous G-CSF injections in healthy postmenopausal women. Additionally, they evaluated the efficacy of repeated administration in reducing the severity and frequency of hot flashes. Tertiary objectives were to assess additional measures of hot-flash burden and to test the association between G-CSF administration, changes in the frequency and severity of hot flashes, and reproductive hormones and markers of inflammation.^1,2

A total of 60 postmenopausal women were randomly assigned to receive 3 single injections of either G-CSF (300 mcg; n = 30) or placebo (saline; n = 30) administered 28 days apart. Participants were asked to report the number of daily mild, moderate, and severe hot flashes from day 14 to day 84 and complete quality of life questionnaires at days 0, 28, 56, and 84. Women who reported either less than an average of 7 moderate or severe hot flashes per day or 49 per week during the 2-week run-in period of the trial were not included in the final analysis.¹

All study participants received all 3 injections of G-CSF or placebo and completed the study in its entirety. There were no significant differences between the G-CSF and placebo groups in net change or percent reduction from baseline in moderate to severe hot flashes; however, the investigators noted that a subset analysis based on self-reported demographic data revealed a statistically significant improvement in moderate to severe hot flash frequency and severity similar to those reported for fezolinetant (Veozah; Astellas Pharma), a neurokinin 3 receptor antagonist.¹

The investigators wrote that there were no serious adverse events (AEs) reported by trial participants, and any AEs that occurred were considered mild or moderate in severity and of short duration (less than 24 hours). The possible treatment-related AEs in the G-CSF and placebo groups included the following: body aches (45% vs 17%); headache (36% vs 3%); fatigue (23% vs 10%); and leg or limb pain (16% vs 13%).¹

REFERENCES

1. Schechter C, Santoro N, Waldbaum A, et al. P-46 – MNGX-102: A Randomized, Double-Blind, Placebo-Controlled Phase 1b Study to Assess the Safety and Effect of Repeated Administration of granulocyte colony-stimulating factor (G-CSF) on Hot Flashes and Other Vasomotor Symptoms in Postmenopausal Women (NCT03640754). Presented at: The Menopause Society Annual Meeting; Orlando, Florida. October 21–25, 2025.

2. A Study of the Safety and Effect of Repeated Administration of G-CSF on Hot Flashes in Postmenopausal Women. ClinicalTrials.gov identifier: NCT03640754. Updated November 28, 2023. Accessed October 23, 2025. https://clinicaltrials.gov/study/NCT03640754

3. Cleveland Clinic. G-CSF (Granulocyte-Colony Stimulating Factor). Accessed October 23, 2025. https://my.clevelandclinic.org/health/treatments/24126-g-csf-treatment