Taurolidine [bis(1,1-dioxoperhydro-1,2,4-thiadiazinyl-4)-methane (TRD)], a product derived from the aminosulfoacid taurin, was first described as an anti-bacterial substance. Taurolidine is a small dimeric molecule with molecular weight 284. It comprises the semiconditional amino acid taurine. Taurolidine was originally designed as a broad-spectrum antibiotic. Taurolidine has a broad antimicrobial spectrum of activity that is effective against aerobes and anaerobes, Gram-negative and Gram-posi-tive bacteria as well as yeasts and moulds in vitro. Taurolidine is also effective against methicillin-resistant and vancomycin-resistant bacteria (MRSA, VISA and VRE). It was mainly used in the treatment of patients with peritonis as well as antiendoxic agent in patients with systematic inflammatory response syndrome. It has been shown to be an effective bactericidal agent against both aerobic and anaerobic bacteria. It is currently licensed for intraperitoneal use in several European countries for the treatment of peritonitis. The compound appears to be nontoxic and has an excellent safety record since its initial introduction over 30 years ago. Taurolidine also possesses antiadherence properties and has been shown in vivo to reduce the extent and severity of postoperative peritoneal adhesions. It also possesses a strong anti-inflammatory action. This action appears, at least in part, to arise through its ability to inactivate endotoxin. Inflammation-induced tumor development is well described in the literature. Taurolidine’s anti-inflammatory and antiadherence properties prompted an investigation to examine whether it has a role in antitumor therapy. Taurolidine induces cancer cell death through a variety of mechanisms. It appears to act through enhancing apoptosis, inhibiting angiogenesis and tumor adherence, downregulating proinflammatory cytokine and endotoxin levels, and stimulating the immune system in response to surgically induced trauma. Taurolidine is currently in preclinical development for neuroblastoma. In February 23, 2018 the U.S. Food and Drug Administration (FDA) granted orphan drug designation to taurolidine for the treatment of neuroblastoma. Taurolidine is a key component in the Neutrolin®, a novel anti-infective solution for the reduction and prevention of catheter-related infections and thrombosis in patients requiring central venous cathers in end stage renal disease. Neutrolin contains a mix of Taurolidine, Citrate and Heparin. Neutrolin is designed to: 1) Aid in the prevention of Catheter-Related Bloodstream Infections (CRBIs) and 2) Prevent catheter dysfunction (due to blood clotting).

Biafungin (formerly SP 3025 or CD101), a highly stable echinocandin and an antifungal drug that was studied against panels of Candida and Aspergillus clinical isolates. Biafungin was involved in phase II clinical trials in the treatment of acute moderate to severe vulvovaginal candidiasis. Seachaid Pharmaceuticals invented this drug. Then Cidara Therapeutics acquired a worldwide exclusive license to develop and commercialize the drug.

Maribavir (previously known as 1263W94) is a novel benzimidazole riboside compound. This drug was in phase III of clinical trial for the prevention of cytomegalovirus (CMV) infections in transplant patients, sponsored by ViroPharma. However, drug failed to demonstrate a higher efficacy rate than the placebo. Maribavir has activity against cytomegalovirus and Epstein-Barr virus (EBV), but not against other human herpesviruses. Maribavir’s mechanism of action is unique and is complex compared to the currently approved antivirals for CMV. Maribavir inhibits the viral UL97 kinase rather than the viral DNA polymerase. The UL97 kinase is important for viral DNA elongation, DNA packaging, and nuclear egress of encapsidated viral DNA. In addition, maribavir inhibits the EBV DNA polymerase processivity factor (BMRF1), reduces the level of certain EBV glycoproteins, and inhibits viral transcription. However, future work will be designed to address the interaction of MBV and BGLF4 and to evaluate the mechanisms through which maribavir downregulates viral transcripts. BGLF4 belongs to the family of conserved herpesvirus PKs, which includes HCMV UL97, HSV UL13, and HSV US3. Maribavir does need to be phosphorylated for its activity.

Fexinidazole is an antiparasitic drug, which is in the phase III of clinical trial for the treatment of Human African Trypanosomiasis, and in the phase II for the treatment Disease, Chagas and Visceral Leishmaniosis. However, for the Visceral Leishmaniosis, studies were terminated, due to lack of efficacy. Fexinidazole rapidly metabolized to two active metabolites, a sulfone and a sulfoxide, which prolong the pharmacological action of parent drug. These metabolites retaine trypanocidal activity but are less effective in nifurtimox-resistant lines, which can lead to the potential danger in the use of fexinidazole as a monotherapy.

Temsavir (BMS-626529) is an attachment inhibitor (AI) in clinical development (administered as prodrug BMS-663068) that binds to HIV-1 gp120. Temsavir displays in vitro activity against HIV-1 envelopes with C-C chemokine receptor type 5 (CCR5-), C-X-C chemokine receptor type 4 (CXCR4), and dual tropism. It also is active against almost all HIV-1 subtypes tested except for subtype CRF01-AE and possibly group O. Temsavir can inhibit both CD4-induced and CD4-independent formation of the "open state" four-stranded gp120 bridging sheet, and the subsequent formation and exposure of the chemokine co-receptor binding site. This unique mechanism of action prevents the initial interaction of HIV-1 with the host CD4+ T cell, and subsequent HIV-1 binding and entry. Temsavir is administered as a phosphonooxymethyl ester prodrug (BMS-663068), which was developed to improve the solubility and dissolution of Temsavir. Temsavir is currently being investigated clinically through the use of the prodrug BMS-663068, and a Phase III study of BMS-663068 in HIV-1-infected treatment-experienced subjects is ongoing (NCT02362503).

Nifurtimox is a nitrofuran derivative used as a primary agent in the treatment of American trypanosomiasis (Chagas' disease) caused by Trypanosoma cruzi, especially in the acute, early stage of the disease. The efficacy of nifurtimox in the treatment of chronic Chagas' disease varies from one country to another, possibly due to variation in the sensitivity of different strains of the organism. Nifurtimox has also been used to treat African trypanosomiasis (sleeping sickness) and is active in the second stage of the disease (central nervous system involvement). When nifurtimox is given on its own, about half of all patients will relapse, but the combination of melarsoprol with nifurtimox appears to be efficacious. Nifurtimox forms a nitro-anion radical metabolite that reacts with nucleic acids of the parasite causing significant break down of DNA. Nifurtimox undergoes reduction and creates oxygen radicals such as superoxide. These radicals are toxic to T. cruzi. Mammalian cells are protected by the presence of catalase, glutathione, peroxidases, and superoxide dismutase. Accumulation of hydrogen peroxide to cytotoxic levels results in parasite death. Side effects occur following chronic administration, particularly in elderly people. Major toxicities include immediate hypersensitivities such as anaphylaxis and delayed hypersensitivity reaction involving icterus and dermatitis. Central nervous system disturbances and peripheral neuropathy may also occur.

Relebactum sodium (MK-7655) is a piperidine analog 3 that inhibits class A and C β-lactamases (in vitro). It is being investigated for use in treatment of infectious diseases, such as treatment of gram-negative bacterial infections. Its potential as an alternative to existing medicines in the treatment of drug-resistant bacterial infections is being studied. Clinical trials have been conducted and are still ongoing to evaluate the efficacy and safety of relebactum sodium in treatment of intra-abdominal infections, urinary tract infections (such as pyelonephritis), hospital-acquired and ventilator-associated bacterial pneumonias, and gram-negative bacterial infections.

Triclabendazole, (brand name Avomec, Egaten, etc) is a member of the benzimidazole family of anthelmintics used to treat liver flukes, specifically fascioliasis and paragonimiasis. Triclabendazole used routinely since 1983 in veterinary practice for the treatment of fascioliasis. It was not used in humans until the 1989 epidemic of fascioliasis near the Caspian Sea when Iranian authorities approved the use of the veterinary formulation to treat the infection. Fasciolicidal not only against the adult worms present in the biliary ducts, but also against the immature larval stages of Fasciola migrating through the hepatic parenchyma. Triclabendazole is shown to penetrate into liver flukes by transtegumentary absorption followed by inhibition of the parasite's motility, probably related to the destruction of the microtubular structure, resulting in the death of the parasite; the immobilizing effect is paralleled by changes in the parasite's resting tegumental membrane potential, strongly inhibiting the release of proteolytic enzymes, a process that appears critical to the survival of the parasite. Side effects are generally few, but can include abdominal pain and headaches. Biliary colic may occur due to dying worms. While no harms have been found with use during pregnancy, triclabendazole has not been well studied in this population. Triclabendazole is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. It is not commercially available in the United States.

Tafenoquine is anti-malaria drug originated in Walter reed army institute of research and developed by GSK and 60 Degrees Pharmaceuticals. In 2018 United States Food and Drug Administration (FDA) approved single dose tafenoquine for the radical cure (prevention of relapse) of Plasmodium vivax malaria. Tafenoquine, an 8-aminoquinoline antimalarial, is active against all the stages of Plasmodium species that include the hypnozoite (dormant stage) in the liver. Studies in vitro with the erythrocytic forms of Plasmodium falciparum suggest that tafenoquine may exert its effect by inhibiting hematin polymerization and inducing apoptotic like death of the parasite. In addition to its effect on the parasite, tafenoquine causes red blood cell shrinkage in vitro. Tafenoquine is active against pre-erythrocytic (liver) and erythrocytic (asexual) forms as well as gametocytes of Plasmodium species that include P. falciparum and P. vivax. The activity of tafenoquine against the pre-erythrocytic liver stages of the parasite, prevents the development of the erythrocytic forms of the parasite.