SNS-032 (formerly BMS-387032) is a potent, selective inhibitor of cyclin-dependent kinases (CDK). SNS-032 blocks the cell cycle via inhibition of CDKs 2 and 7, and transcription via inhibition of CDKs 7 and 9. SNS-032 was investigated for the treatment of solid tumors and hematologic malignancies (Phase I studies), however, its development was discontinued.

An orally bioavailable inhibitor of cyclin-dependent kinases (CDKs) and thropomyosin receptor kinase A (TRKA), with potential antineoplastic activity. CDK2/TRKA inhibitor PHA-848125 AC potently inhibits cyclin-dependent kinase 2 (CDK2) and exhibits activity against other CDKs including CDK1 and CDK4, in addition to TRKA. Inhibition of these kinases may result in cell cycle arrest and apoptosis of tumor cells that express these kinases. Milciclib is currently in phase II clinical trials for thymic carcinoma, glioma and liver cancer. The most common adverse events are nausea and asthenia, vomiting, myasthenic syndrome, dehydration, hypophosphatemia, cytolytic hepatitis and plantar fasciitis.

CVT 313 is the lead compound in a series of small molecule cell cycle inhibitors that inhibit cyclin-dependent kinase 2 (CDK2). It was in development with CV Therapeutics in the USA. CVT 313, in combination with drug delivery catheters and as coatings on endoluminal stents, may have potential in the prevention of restenosis. In February 1998, CV Therapeutics signed a research agreement with The Cleveland Clinic Foundation for the preclinical testing of CVT 313. In February 1999 CV Therapeutics announced the granting of a patent for purine inhibitors of CDK2 by the USA Patent and Trademark Office. No recent development of CVT 313 has been reported.

Indirubin is derived from the Indigo Plant (Isatis Root, Isatis Leaf). It is used as part of a traditional Chinese herbal prescription called Dang Gui Long Hui Wan, to treat chronic myelogenous leukemia (CML). Indirubin inhibits DNA synthesis in several cell lines, in a cell-free assay and in vivo in rats with Walker-256 sarcoma. A weak binding of indirubin to DNA in vitro has been described. Indirubin inhibited all cyclin-dependent kinases (1,2,4,5) almost equally. Indirubin has been approved for clinical trials against chronic myelocytic and chronic granulocytic leukaemia. A few studies show that Indirubin is effective against psoriasis. Mild to severe nausea, vomiting, abdominal pain, diarrhea, headache, and edema are reported adverse events of Indirubin. Long-term oral ingestion has also occasionally been associated with hepatitis, pulmonary arterial hypertension and cardiac insufficiency.

Amygdalin is a naturally occurring cyanogenic glycoside derived from nuts, plants, and the pits of certain fruits, primarily apricots. Bitter almonds containing amygdalin are used in Traditional Chinese Medicine to remove “blood stasis” and to treat abscesses. Amygdalin was first used as a cancer treatment in Russia in 1845, and in the United States in the 1920s. Laetrile is another name for the natural product amygdalin. Hydrogen cyanide is thought to be the main anticancer compound formed from laetrile (Amygdalin) via in situ release. Cyanide from the hydrolysis of amygdalin is believed to be cytotoxic with actions selective against cancerous cells, but results from animal studies were mostly negative. Other animal studies suggest it may help to relieve pain due to its anti-inflammatory and analgesic effects. One study suggested amygdalin can inhibit tumor growth, but subsequent tests were unable to confirm this observation. Laetrile (Amygdalin) has shown little anticancer activity in animal studies and no anticancer activity in human clinical trials. In 1970, an IND application to study laetrile was filed by the McNaughton Foundation (San Ysidro, California). This request was initially approved but later rejected because preclinical evidence in animals showed that laetrile was not likely to be effective as an anticancer agent. The side effects associated with laetrile toxicity mirror the symptoms of cyanide poisoning, including liver damage, difficulty walking (caused by damaged nerves), fever, coma, and death. Laetrile (Amygdalin) is not approved for use in the United States.

An orally bioavailable inhibitor of cyclin-dependent kinases (CDKs) and thropomyosin receptor kinase A (TRKA), with potential antineoplastic activity. CDK2/TRKA inhibitor PHA-848125 AC potently inhibits cyclin-dependent kinase 2 (CDK2) and exhibits activity against other CDKs including CDK1 and CDK4, in addition to TRKA. Inhibition of these kinases may result in cell cycle arrest and apoptosis of tumor cells that express these kinases. Milciclib is currently in phase II clinical trials for thymic carcinoma, glioma and liver cancer. The most common adverse events are nausea and asthenia, vomiting, myasthenic syndrome, dehydration, hypophosphatemia, cytolytic hepatitis and plantar fasciitis.

Indirubin is derived from the Indigo Plant (Isatis Root, Isatis Leaf). It is used as part of a traditional Chinese herbal prescription called Dang Gui Long Hui Wan, to treat chronic myelogenous leukemia (CML). Indirubin inhibits DNA synthesis in several cell lines, in a cell-free assay and in vivo in rats with Walker-256 sarcoma. A weak binding of indirubin to DNA in vitro has been described. Indirubin inhibited all cyclin-dependent kinases (1,2,4,5) almost equally. Indirubin has been approved for clinical trials against chronic myelocytic and chronic granulocytic leukaemia. A few studies show that Indirubin is effective against psoriasis. Mild to severe nausea, vomiting, abdominal pain, diarrhea, headache, and edema are reported adverse events of Indirubin. Long-term oral ingestion has also occasionally been associated with hepatitis, pulmonary arterial hypertension and cardiac insufficiency.