Trestolone is a synthetic androgen that inhibits the release of follicle-stimulating hormone and impairs spermatogenesis. Luteinizing hormone is also suppressed, which cuts production of testosterone. The azoospermia and oligospermia are reversible after discontinuation of trestolone. Trestolone has androgenic and anabolic properties and loss of secondary sex characteristics is not seen. Like testosterone, trestolone undergoes enzymatic aromatization to an estrogen. The use of trestolone instead of testosterone for androgen replacement therapy could have health-promoting effects by reducing the occurrence of prostate disease. Trestolone had been in phase II clinical trial for the andropause control. However, this development was discontinued.

Orbofiban was developed as an orally active glycoprotein IIb/IIIa antagonist. By 2001, this drug had progressed to phase III clinical trials. Unfortunately, was found that orbofiban induced thrombocytopenia and thrombosis. In addition, despite no significant excess risk of intracranial hemorrhage, orbofiban was not effective in preventing ischemic stroke or transient ischemic attack. Besides, the use of this drug had led to an increase in mortality. Based on all these results further development of this drug was discontinued.

Sephin1 is a guanabenz derivative that binds to and inhibits a regulatory subunit of the stress-induced protein phosphatase 1 (PPP1R15A), but not the constitutive PPP1R15B, and lacks beta2-adrenergic activity. Phosphorylation of eIF2α, α subunit of eukaryotic translation initiation factor 2, reduces protein synthesis and prevents the accumulation of misfolded protein in the endoplasmic reticulum (ER). PPP1R15A recruits the serine/threonine-protein phosphatase PP1 to dephosphorylate eIF2α, so inhibiting PPP1R15A activity prolongs the phosphorylation of eIF2α and aids in its prevention of the accumulation of misfolded protein. In vitro, Sephin1 protected cells from lethal protein misfolding and cytotoxic ER stress. In vivo Sephin1 prevented Charcot-Marie-Tooth 1B and ALS diseases in mice.

TAK-448 is an investigational oligopeptide analog of kisspeptin and a potent agonist of the GPR54 receptor. In animals, acute TAK-448 administration stimulates luteinizing hormone (LH)/follicle-stimulating hormone release, whereas continuous subcutaneous exposure rapidly down-regulates the pituitary-gonadal axis, with rapid reduction of testosterone levels in a dose-dependent manner. TAK-448 has exhibited potent antitumor activity in rat androgen-dependent prostate cancer models. In accordance with the T reductions, TAK-448 treatment showed also more rapid reduction in plasma prostate-specific antigen(PSA) levels. TAK-448 had been in phase II clinical trials for the treatment of prostate cancer. However, this research has been discontinued.

Semparatide (previously known as RS-66271) was developed as an analog of parathyroid hormone-related protein (PTHrP) with shortening the time for fracture healing. Experiments on animals have shown that this compound was an effective therapy for preventing impaired bone healing caused by prednisone. Clinical trials with postmenopausal osteoporotic women have revealed that semparatide cause sustained increases in the spine. However, further, development appears to have been discontinued by Roche.