Elinafide (LU 79553) is a bisintercalating naphthalamide and a topoisomerase II inhibitor has demonstrated a higher binding affinity for DNA and significant antitumour efficacy against a panel of established tumour cell lines, including several multidrug resistant-positive sublines. Elinafide had been in phase II clinical trial for the treatment of ovarian cancer and phase I trials for the treatment of various solid tumours. The major haematological toxicities observed were anaemia and neutropenia. The major non-haematological toxicities observed in the 3-weekly schedule were neuro-muscular presenting clinically as a mixed syndrome of severe weakness (sometimes with pain in both legs), myalgia and arthralgia, asthenia/fatigue/malaise. One fatality was considered related to LU 79553, as the patient had fever and neutropenia. Clinical study of this drug candidate was discontinued due to its neuromuscular dose-limiting toxicity.

Picoplatin is a sterically hindered platinum (II) complex with antineoplastic properties developed for the treatment of cis-platin-resistant cancer. Picoplatin alkylates DNA, forming both inter- and intra-strand cross-linkages, resulting in inhibition of DNA replication and transcription, and the induction of apoptosis. However, in Phase III trials, picoplatin failed to meet its primary endpoint for advanced cell lung cancer. It remains in development for other cancers.

Palifosfamide or ZIO-201 (isophosphoramide mustard; IPM), a bi-functional DNA alkylator, is the active metabolite of ifosfamide (IFOS). IFOS and the related drug cyclophosphamide (CPA) are widely used anti-cancer drugs. Both are pro-drugs and need to be metabolized to be active. Their clinical use is limited by the toxicity associated with some of their metabolites. Palifosfamide has shown efficacy in diverse cancer models. ZIOPHARM Oncology Inc, under license from Dekk-Tec Inc, was developing palifosfamide, a formulation of isophosphoramide mustard with tris(hydroxymethyl)aminomethane salt-stabilization (palifosfamide-tris) and previously with lysine-stabilization (palifosfamide-lys). Preclinical studies and phase I and I/II clinical trials demonstrated that palifosfamide-tris had an antitumor efficiency comparable or superior to that of ifosfamide. To date ZIO-201 is not present in ZIOPHARM pipeline.

Fazarabine (Arabinofuranosyl-5-azacytosine) is a synthetic pyrimidine nucleoside which combines the arabinose sugar of cytosine arabinoside with the triazine base of 5-azacytidine. It has demonstrated activity against a variety of human solid tumor xenografts including colon, lung and breast cancers. It has been selected by the Division of Cancer Treatment, National Cancer Institute for clinical development as an antineoplastic agent based on its high degree of activity against a broad range of tumor types in preclinical studies. Therapeutic activity has been observed against murine and human leukemias, transplantable murine solid tumors, and human tumor xenografts. Arabinosyl-5-azacytosine exhibited a broader spectrum of activity against human solid tumors than cytosine arabinoside. The mode of action of fazarabine is mediated through its incorporation into DNA and inhibition of DNA synthesis.

Echinomycin is a cyclic peptide of the family of quinoxaline antibiotics that was originally isolated from Streptomyces echinatus. It is thought to act as a bifunctional DNA intercalator. Echinomycin has a binding site size of four base pairs. The strong binding sites for echinomycin contain the central two-base-pair sequence 5'-CG-3'. Echinomycin interferes with HIF-1 DNA binding in a sequence-specific fashion. It was brought into clinical trials by the NCI 20 years ago based on its antitumor activity. It has been extensively tested in phase I-II clinical trials. Nausea, vomiting, reversible liver enzyme abnormalities, and allergic reactions were the most common toxicities encountered. However, minimal or no antitumor activity was found in phase II clinical trials.

Evofosfamide, also formerly known as TH-302, is an investigational hypoxia-activated prodrug and is used to target cancerous cells under hypoxic conditions, which is a feature possessed by multiple solid tumors including glioblastoma and pancreatic cancer. Within regions of tumor hypoxia, evofosfamide releases bromo isophosphoramide mustard (Br-IPM), a potent DNA alkylating agent that kills tumor cells by forming DNA crosslinks. Once activated in hypoxic tissues, Br-IPM can also diffuse into surrounding oxygenated regions of the tumor and kill cells there via a “bystander effect”. Because of its preferential activation in the targeted hypoxic regions of solid tumors, evofosfamide may be less likely to produce broad systemic toxicity seen with untargeted cytotoxic chemotherapies.

Dibrospidium (Spyrobromin) is a dispirotripiperazine derivative and alkylating agent with potential antineoplastic and anti-inflammatory activities. The duration of DNA synthesis inhibition in tumor cells was found to correlate with spirobromine antitumor activity. Spirobromin is superior to prospidin by the power of the anti-inflammatory effect. Spyrobromin can diminish the latent period of the development of tumours in the experimental rats at intraperitoneal administration. At intragastric administration of the drug no decrease was noted in the latent period and no increase of tumours was observed in the experimental groups of the animals as compared with control. Dibrospidium has been examined for the treatment of bone cancer. The oral route of administration is the most safe with respect to the oncogenic risk. It was noted that spirobromin exerted the most pronounced toxic action on erythrocytes. Dibrospidium is used for the treatment of acute leukemias (mainly in combination therapy), malignant lymphomas, laryngeal cancer and skin reticulosis.

CNDAC (TAK-109) is an analog of the nucleoside deoxycytidine with potential antineoplastic activity. CNDAC is incorporated into DNA and induces single-strand breaks, which are converted into double-strand breaks (DSBs) when cells go through a second S phase. This results in the cell cycle arrest in the S and G2/M phases, DNA fragmentation, and tumor cell apoptosis. Sapacitabine, a prodrug of CNDAC, is being developed by the US biotechnology company Cyclacel for the treatment of hemalogical cancers and solid tumors.

Aflatoxin B1 is a very potent carcinogen produced by Aspergillus flavus and related fungi that grow on improperly stored food such as corn, rice, and peanuts. Dietary exposure to aflatoxin B1 is associated with an increased incidence of hepatocellular carcinoma, especially given co-infection with hepatitis B virus. Mechanism of carcinogenicity involves metabolic activation to aflatoxin B1-8,9 exo-epoxide by cytochrome p450 and formation of adducts with guanine DNA base.

Mitolactol is a synthetic derivative of hexitol with antineoplastic and radiosensitizing properties. Mitolactol alkylates DNA via actual or derived epoxide groups, resulting in inhibition of DNA and RNA synthesis.