Mercurobutol is an antiseptic and disinfectant. Mercurobutol exhibits fungistatic and fungicidal activities.

Midaxifylline, a potent and selective xanthine adenosine A1 receptor antagonist, was investigated for the treatment of Alzheimer's disease, cardiovascular disorders, kidney disorders, and major depressive disorder. However, all studies were discontinued.

Mindoperone was developed as an antipsychotic drug that has never been marketed.

Milfasartan is an inhibitor of angiotensin II receptor type 1 was used in phase II clinical trial for the treatment of hypertension. However, these studies were discontinued.

Tasquinimod is a drug, developed by Active Biotech Research and tested in phase III of clinical trials for the treatment of Castrate Resistant Prostate Cancer. The drug acts by targeting the tumor microenvironment with S100A9 being one of molecular targets.

Ciaftalan Zinc (also known as Zinc(II)-phthalocyanine) is phthalocyanine and photosensitizers which showed a high activity in photodynamic therapy studies on a variety of animal tumors. Ciaftalan Zinc belongs to second generation photosensitizers that have a more intense long wavelength absorption and greater extinction coefficient compare to the first generation. The greater the extinction coefficient value associated with greater efficacy, smaller drug dosage required to induce a cytotoxic response and diminished risk of provoking systemic toxic reactions. The long absorption wavelength correlates with higher penetration depth and it is, therefore, Ciaftalan Zinc causes deep tumor necrosis in animal models. Currently, Tetra-triethyleneoxysulfonyl substituted Ciaftalan Zinc derivatives are studied as novel photodynamic therapy of cancer.

Lonaprisan is an orally bioavailable pentafluoroethyl derivative of a mifepristone-related steroid with antiprogestagenic activity. Lonaprisan is a pure, highly receptor-selective progesterone receptor (PR) antagonist (both PR isoforms PR-A and PR-B); binding of this agent to PRs inhibits PR activation and the associated proliferative effects. Lonaprisan showed limited efficacy as second-line endocrine therapy in postmenopausal women with PR-positive metastatic breast cancer. Lonaprisan had been in phase II clinical trials by Bayer for the treatment of breast cancer and dysmenorrhea. However, this research has been discontinued.

Triclofylline is a N-methylated xanthine derivative. It was developed as an anti-asthmatic drug.

Afeletecan (Bay 38-3441) is a camptothecin glycoconjugate which stabilizes the active lactone form of camptothecin and allows selective uptake into tumor cells. Afeletecan is a topoisomerase inhibitor. Afeletecan was in phase I clinical trials with Bayer for the treatment of cancer; however, development appears to have been discontinued.