Tipifarnib is an oral farnesyltransferase (FTase) inhibitor which was developed by Janssen (J&J). Upon administration, tipifarnib inhibits FTase and thus suppresses the activity of downstream effectors. The drug reached phase III of clinical trials for such diseases as pancreatic cancer (terminated), colorectal cancer (terminated) and acute myeloid leukemia (in elderly patients).

Tanespimycin (17-allylamino-17-demethoxygeldanamycin, 17-AAG) is a synthetic analogue of geldanamycin, an antibiotic first purified in 1970 from Streptomyces hygroscopicus. Tanespimycin is an Hsp90 inhibitor that has demonstrated the potential to disrupt the activity of multiple oncogenes and cell signaling pathways implicated in tumor growth, including HER2, a key pathway in breast cancer. Tanespimycin was being under development by Kosan Biosciences. It was in phase 3 clinical development with bortezomib for the treatment of multiple myeloma (MM). However, in 2010 the company halted development of tanespimycin, during late-stage clinical trials as a potential treatment for multiple myeloma. While no definitive explanation was given, it has been suggested that Bristol-Myers Squibb halted development over concerns of the financial feasibility of tanespimycin development given the 2014 expiry of the patent on this compound, and the relative expense of manufacture.

Avicin D, a natural triterpenoid saponin, is a selective glucocorticoid receptor (GR) modulator. It has been approved by the United States Food and Drug Administration for phase I studies in human cancer patients. In addition, avicin D has the therapeutic potential for patients with Sézary syndrome.

Aplidin (plitidepsin) is an investigative anticancer agent under development by PharmaMar, a pharmaceutical company that commercializes anticancer drugs of marine origin. Aplidin is isolated from the sea squirt (Aplidium albicans) and has shown anti-myeloma activity even in myelomas resistant to other agents. The drug has received orphan drug designation in the U.S., the European Union, and Switzerland. The target of plitidepsin is the eEF1A2 protein. The bonding of plitidepsin to this protein blocks its pro-oncogenic property and impedes the transportation of the misfolded proteins, which are toxic to the tumor, to the proteasome for their destruction. It also inhibits the activation of the aggresome by eEF1A2 and the destruction of the aggresome in the lysosome. This provokes anexcess of misfolded proteins, this causing cell death through apoptosis. Recently, a Phase III randomized trial in patients with relapsed/refractory multiple myeloma reported outcomes for plitidepsin plus dexamethasone compared with dexamethasone. Median progression-free survival was 3.8 months in the plitidepsin arm and 1.9 months in the dexamethasone arm. However, on 14 December 2017, the Committee for Medicinal Products for Human Use (CHMP) adopted a negative opinion, recommending the refusal of the marketing authorisation for the medicinal product Aplidin, intended for the treatment of multiple myeloma. At the time of the initial review, the CHMP was concerned that the data from the main study showed only a modest increase of around one month in the time patients given Aplidin lived without their disease getting worse, compared with those treated with dexamethasone alone. In addition, improvement in overall survival (how long patients lived overall) was not sufficiently demonstrated. Regarding safety, severe side effects were reported more frequently with the combination of Aplidin and dexamethasone than with dexamethasone alone. Based on the above, the CHMP was of the opinion that the benefits of Aplidin did not outweigh its risks and recommended that it be refused marketing authorisation.After re-examination, the Committee remained of the same opinion. The CHMP therefore confirmed its recommendation that the marketing authorisation be refused.

Masitinib is a new orally administered tyrosine kinase inhibitor that targets mast cells and macrophages, important cells for immunity, through inhibiting a limited number of kinases. Based on its unique mechanism of action, masitinib can be developed in a large number of conditions in oncology, in inflammatory diseases, and in certain diseases of the central nervous system. In oncology due to its immunotherapy effect, masitinib can have an effect on survival, alone or in combination with chemotherapy. Through its activity on mast cells and consequently the inhibition of the activation of the inflammatory process, masitinib can have an effect on the symptoms associated with some inflammatory and central nervous system diseases and the degeneration of these diseases. AB Science is developing masitinib in multiple sclerosis and alzheimer's disease. Masitinib targets kinases, including c-Kit, PDGFR, and Lyn. It is used in the treatment of mast cell tumors in animals, specifically dogs. Since its introduction in November 2008 it has been distributed under the commercial name Masivet. It has been available in Europe since the second part of 2009. In the USA it is distributed under the name Kinavet.

(s)-Thalidomide is an enantiomer of immunomodulatory agent Thalidomide. Thalidomide enantiomers are converted to each other in vivo, and Thalidomide contains both left and right-handed isomers in equal amounts. (s)-Thalidomide has proven efficacy in multiple myeloma. s-thalidomide-induced apoptosis associated with increases in I-kB activity, downregulation of NF-kB activity and an increase in Bax: Bcl-2 ratio. In cells cultured with s-thalidomide, there was a four-fold downregulation of the NFkB gene that was associated with a significant decrease in its protein activity.

Acadesine, also known as 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, AICA-riboside, and AICAR, is an AMP-activated protein kinase activator which is used for the treatment of acute lymphoblastic leukemia (ALL) and may have applications in treating other disorders such as mantle cell lymphoma (MCL). The mechanism by which acadesine selectively kills B-cells is not yet fully elucidated. The action of acadesine does not require the tumour suppressor protein p53 like other treatments. This is important, as p53 is often missing or defective in cancerous B-cells. Studies have shown acadesine activates AMPK and induces apoptosis in B-cell chronic lymphocytic leukemia cells but not in T lymphocytes. Antiapoptotic proteins of the Bcl-2 family regulate MCL cell sensitivity to acadesine and combination of this agent with Bcl-2 inhibitors might be an interesting therapeutic option to treat MCL patients. Acadesine has anti-ischemic properties that is currently being studied (Phase 3) for the prevention of adverse cardiovascular outcomes in patients undergoing coronary artery bypass graft (CABG) surgery. Adenosine itself has many beneficial cardioprotective properties that may therefore be harnessed by this new class of drugs. Unlike adenosine, acadesine acts specifically at sites of ischemia and is therefore void of the systemic hemodynamic effects that may complicate adenosine therapy. Animal and in vitro studies have established acadesine as a promising new agent for attenuating ischemic and reperfusion damage to the myocardium. Acadesine also possesses the theoretical (but unproven) benefit of attenuating reperfusion injury after acute myocardial infarction (MI). Further research is needed to define the full potential of this unique agent in various clinical situations involving myocardial ischemia.