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Fxm3.4
Fluoxymesterone (Halotestin) Research
Mostly mechanism / observationalLimited safety
6 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most Fluoxymesterone (Halotestin) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 1974–2016.
Based on 6 studies · 1 RCT
Confidence
Low
By outcome
Androgen replacement (human, legacy)
Mostly mechanism / observational6 studies
Safety profile
Mostly mechanism / observational6 studies
Breast-cancer palliation (human)
Too few graded studies2 studies
Hepatotoxicity
Too few graded studies2 studies
Older research base
Newest study from 2016
197419952016
1RCT1988
The combination produced a higher objective response rate (53% v 42%) and a longer time to progression (median, 350 v 199 days) ... these differences were not statistically significant, there was no survival advantage, and the combination produced greater androgenic toxicity; the combination is not recommended for routine use.
Ingle JN, Twito DI, Schaid DJ, Cullinan SA, Krook JE, Mailliard JA, Marschke RF, Long HJ, Gerstner JG, Windschitl HE, et al. · Journal of Clinical Oncology (1988)
Randomized clinical trial in postmenopausal women with metastatic breast cancer comparing tamoxifen alone vs tamoxifen plus fluoxymesterone — the best-quality human evidence for fluoxymesterone in this collection
Adding fluoxymesterone modestly raised the objective response rate and time to progression, but the differences were not statistically significant and there was no survival benefit
The combination produced greater androgenic toxicity, leading the authors to conclude against routine use
Among 103 patients ... the median progression-free survival was 3.9 months (95% CI 3.2-5.3 months) and the clinical benefit rate was 43% ... fluoxymesterone remains a treatment option in heavily pretreated hormone receptor-positive metastatic breast cancer.
Kono M, Fujii T, Lyons GR, Huo L, Bassett R, Gong Y, Karuturi MS, Tripathy D, Ueno NT. · Breast Cancer Research and Treatment (2016)
Retrospective cohort of 103 patients with hormone-receptor-positive metastatic breast cancer treated with fluoxymesterone after failing contemporary hormonal therapy
Median progression-free survival ~3.9 months with a clinical-benefit rate of 43% — a modest palliative signal in a heavily pretreated population
Androgen-receptor positivity was not significantly associated with the survival outcome
Peliosis hepatis was found in 12 patients treated with high-dose oral oxymetholone or fluoxymesterone therapy; in three patients the lesion contributed to fatal hepatic failure, and in one biopsy-confirmed case the lesion regressed after the drug was withdrawn.
Nadell J, Kosek J. · Archives of Pathology & Laboratory Medicine (1977)
Clinicopathologic series of 12 patients who developed peliosis hepatis — blood-filled hepatic cavities — while on high-dose oral 17α-alkylated androgens including fluoxymesterone
In three patients the peliosis contributed to FATAL hepatic failure; in one biopsy-confirmed case the lesion regressed after the drug was stopped, supporting a causal link
A foundational documentation of fluoxymesterone's signature serious hepatotoxicity
4In Vitro1995
The 17 alpha-alkylated steroids (methyltestosterone, oxymetholone, and stanozolol) are directly toxic to hepatocytes ... whereas the nonalkylated steroids were not, supporting the role of 17 alpha-alkylation in anabolic-steroid hepatotoxicity.
Welder AA, Robertson JW, Melchert RB. · Journal of Pharmacological and Toxicological Methods (1995)
In-vitro study exposing primary rat hepatocyte cultures to a panel of anabolic-androgenic steroids (including fluoxymesterone) and measuring LDH release, viability and glutathione depletion
The tested 17α-alkylated steroids (methyltestosterone, oxymetholone, stanozolol) were directly toxic to hepatocytes whereas non-alkylated androgens were not — establishing 17α-alkylation as the mechanism of the class hepatotoxicity fluoxymesterone shares (fluoxymesterone was in the dosed panel but did not itself reach significant toxicity in this assay)
Mechanistic counterpart to the human peliosis-hepatis series: identifies 17α-alkylation as the structural driver of liver injury
Long-term preventive management with the synthetic androgens fluoxymesterone and oxymetholone reduced the frequency and severity of attacks in severely affected patients with hereditary angioedema.
Davis PJ, Davis FB, Charache P. · The Johns Hopkins Medical Journal (1974)
Open-label clinical experience using the synthetic androgens fluoxymesterone and oxymetholone for long-term prophylaxis in severely affected hereditary-angioedema patients
Androgen therapy reduced attack frequency and severity — an early demonstration of the now-classic androgen effect on C1-inhibitor/complement in HAE
Represents one of fluoxymesterone's legitimate (now largely historical) human indications beyond oncology and hypogonadism
6Observational1983
In men who did not recover spontaneously, sequential treatments were given; only the androgen produced acceptable results and then only at unusually high doses, suggesting androgen insensitivity in these patients.
Van Thiel DH, Gavaler JS, Sanghvi A. · Gastroenterology (1983)
Prospective follow-up study of 60 abstinent alcoholic men with sexual dysfunction, with sequential treatments including the androgen fluoxymesterone in non-spontaneous recoverers
Only the androgen produced acceptable results, and only at unusually high doses — consistent with an androgen-insensitive state in alcohol-related hypogonadism
Illustrates fluoxymesterone's historical men's-vitality / androgen-replacement use and its limits