TAK-448

Summary

TAK‑448 (also known as RVX‑TAK‑448) is an investigational synthetic peptide that mimics the C‑terminal segment of kisspeptin‑54 and acts as an agonist of the kisspeptin receptor (Kiss1R/GPR54). It has been studied primarily for its ability to suppress testosterone production, with early‑phase clinical trials in healthy men and men with prostate cancer, and pre‑clinical work in rodents. The compound is administered subcutaneously as a bolus, infusion, or depot formulation.

Mechanism of Action

TAK‑448 binds to the G‑protein‑coupled kisspeptin receptor (Kiss1R/GPR54) on hypothalamic neurons, reproducing the activity of the natural 10‑amino‑acid C‑terminal kisspeptin‑54 peptide. Activation of Kiss1R triggers intracellular signaling that stimulates pulsatile release of gonadotropin‑releasing hormone (GnRH), which in turn raises luteinizing hormone (LH) and follicle‑stimulating hormone (FSH) secretion. In males this cascade rapidly reduces testicular testosterone output. Pharmacokinetic studies in rats and dogs show that after subcutaneous dosing the peptide is absorbed, partially hydrolyzed to a metabolite (M‑I), and eliminated mainly via urine.

What the Research Shows

Pre‑clinical pharmacokinetic work in rats and dogs demonstrated rapid subcutaneous absorption, distribution to kidney and bladder, and near‑complete urinary excretion of unchanged TAK‑448 and a hydrolyzed metabolite within 48–72 h. Sensitive sandwich ELISAs were developed to quantify TAK‑448 in plasma for animal studies. In two phase‑1 trials, single and repeated subcutaneous dosing in healthy older men produced dose‑proportional exposure, a terminal half‑life of 1.4–5.3 h, and sustained testosterone suppression to castration levels after continuous infusion or depot injection. In a small open‑label study in prostate‑cancer patients, monthly depot injections (12–24 mg) lowered testosterone below 20 ng/dL in four of five participants and reduced PSA by >50 % at the higher dose. Animal depot formulations (one‑month release) maintained plasma drug levels for weeks and produced prolonged testosterone suppression in male rats, outperforming a comparator peptide in a prostate‑cancer xenograft model. A 2015 review noted that TAK‑448 was discontinued in 2013 during early development, and a 2022 perspective highlighted its potential in female reproductive disorders, though clinical data remain limited.

Reported Benefits

Early clinical data indicate that continuous subcutaneous administration of TAK‑448 can achieve rapid and sustained suppression of testosterone to castration levels, which may be useful in managing androgen‑dependent prostate cancer. In animal models, depot formulations provided month‑long drug exposure and superior testosterone control compared with earlier kisspeptin analogues. Preliminary observations in women suggest possible utility for conditions such as hypothalamic amenorrhoea or polycystic ovary syndrome, although these indications remain investigational.

Limitations of the Evidence

Development of TAK‑448 was halted in 2013, so no later‑stage efficacy or safety data are available. Human evidence is limited to small phase‑1 studies with short follow‑up and a handful of prostate‑cancer patients. Long‑term outcomes, optimal dosing regimens, and comparative effectiveness versus standard androgen‑deprivation therapies have not been established. Most efficacy data derive from animal models, which may not fully predict human responses. Biomarker‑guided patient selection was not reported in the available trials.

Safety Considerations

In the phase‑1 studies, adverse events were mild, with only grade 1–2 events reported in about 26 % of healthy volunteers; no serious adverse events were described. The drug was generally well tolerated across single‑dose, infusion, and 14‑day dosing regimens. Reported side‑effects were limited to transient, mild symptoms typical of peptide administration, but comprehensive safety profiling is lacking due to the early termination of the program.

How It Is Administered

TAK‑448 has been investigated only via subcutaneous routes, including single bolus injections, 2‑hour intravenous‑like infusions, repeated daily injections for up to 14 days, and a one‑month depot formulation delivered as a subcutaneous injection. Formulations used in studies were aqueous peptide solutions suitable for injection.

Routes of Administration

Goals & Uses

• Stimulation of LH and FSH secretionReproductive EndocrinologyModerate
• Male infertilityReproductive EndocrinologyLow
• Treatment of hypogonadotropic hypogonadismEndocrinologyLow
• Testosterone suppression in prostate cancerOncologyModerate

Contraindications

• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• Hormone-sensitive conditions where sex steroid stimulation is contraindicatedOncologyHigh
• Known hypersensitivity to kisspeptin analogsImmunologicalHigh

Adverse Effects

• Injection site reactionsLocalCommon
• Decreased libido / sexual dysfunctionSexual HealthCommon
• Testosterone flareEndocrineCommon
• Hot flushesVasomotorCommon
• Bone mineral density reductionMusculoskeletalUncommon

Drug Interactions

• Antiandrogens (e.g., enzalutamide, bicalutamide)Low
• GnRH antagonists (e.g., degarelix)Moderate
• GnRH agonists (e.g., leuprolide)Moderate

Population Constraints

• Pediatric patientsAgeAbsolute
• Patients with severe renal or hepatic impairmentOrgan ImpairmentRelative
• Women of childbearing potentialReproductiveRelative

Regulatory Status

• European UnionInvestigationalNo EMA approval; investigational status only.
• United StatesInvestigationalStudied in Phase I/II clinical trials; no FDA approval as of available data.
• United KingdomInvestigationalNo MHRA approval; investigational only.

TAK-448 has not received regulatory approval in any jurisdiction. It has been studied in Phase I/II clinical trials. Development status as of available data suggests it remains investigational.

Evidence & Sources

• Investigation of disposition for TAK-448, a synthetic peptide of kisspeptin analog, in rats and dogs using the radiolabeled TAK-448 suitable for pharmacokinetic study
  Journal ArticleLowMoriya Y, et al.2019-01-01T00:00:00.000000Z
• Development and validation of sensitive sandwich ELISAs for two investigational nonapeptide metastin receptor agonists, TAK-448 and TAK-683
  Journal ArticleLowYoshida N, et al.2012-01-01T00:00:00.000000Z
• Sustained exposure to the investigational Kisspeptin analog, TAK-448, down-regulates testosterone into the castration range in healthy males and in patients with prostate cancer: results from two phase 1 studies
  Journal ArticleModerateMacLean DB, et al.2014-01-01T00:00:00.000000Z
• Discontinued in 2013: oncology drugs
  Journal ArticleLowWilliams R2015-01-01T00:00:00.000000Z
• Advances in clinical applications of kisspeptin-GnRH pathway in female reproduction
  Journal ArticleModerateHu KL, et al.2022-01-01T00:00:00.000000Z
• Evaluation of pharmacokinetics/pharmacodynamics and efficacy of one-month depots of TAK-448 and TAK-683, investigational kisspeptin analogs, in male rats and an androgen-dependent prostate cancer model
  Journal ArticleLowTanaka A, et al.2018-01-01T00:00:00.000000Z

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