BMS 911543 is a selective orally administered small molecule inhibitor of Janus kinase 2 (JAK2), developed by BristolMyers Squibb for the myelofibrosis treatment. BMS 911543 displayed potent antiproliferative effects in mutated JAK2expressing cell lines. A superior antiproliferative response occurred in primary progenitor cells isolated from patients with JAK2positive myeloproliferative disease (MPD) compared with those isolated from healthy volunteers. In vivo, a single oral dose of BMS 911543 resulted in durable JAK2phosphorylated STAT signalling pathway inhibition in multiple species. In a JAK2expressing xenograft model (SET2), BMS 911543 displayed a minimally effective dose of <2 mg/kg on phosphorylated STAT5 pathway inhibition.

XL019 is a potent and selective JAK2 inhibitor. XL019 shows 50-fold or greater selectivity for JAK2, versus a panel of over 100 serine/threonine and tyrosine kinases, including other members of the JAK family. XL019 is non-selective for JAK2V617F or wild-type JAK2 and potently inhibits STAT3 and STAT5 phosphorylation in cells harboring either JAK2V617F or wild-type JAK2. Unfortunately, XL019 treatment was associated with the unexpected occurrence of neurotoxicity. Phase I clinical trials have been terminated.

NS-018 is a potent inhibitor of Janus kinase 2 (JAK2) enzyme activity and Src-family kinases. It was developed as an oral therapy for the treatment of myelofibrosis. Overall NS-018 has been used in trials studying the treatment of primary myelofibrosis, post-polycythemia vera myelofibrosis, and post-essential thrombocythemia. NS-018 is a highly active JAK2 inhibitor, with an IC50 of 0.72 nM, 46-, 54-, and 31-fold selectivity for JAK2 over JAK1 (IC50, 33 nM), JAK3 (IC50, 39 nM), and Tyk2 (IC50, 22 nM). NS-018 also inhibits Src-family kinases, especially SRC and FYN, and weakly inhibits ABL and FLT3 with 45- and 90-fold selectivity for JAK2, respectively. NS-018 shows potent inhibitory activity against cell lines JAK2V617F or MPLW515L mutations or the TEL-JAK2 fusion gene.

Decernotinib is an oral JAK3 kinase inhibitor developed by Vertex for the treatment of rheumatoid arthritis. Although the drug demonstrated a good potency in vitro and in phases I and II of clinical trials, its development was terminated.

INCB-039110 (also known as Itacitinib) is an orally bioavailable inhibitor of Janus-associated kinase 1 (JAK1) with potential antineoplastic activity patented by Incyte Corporation for treatment of autoimmune disorders and cancer. Upon oral administration of NCB-039110, this agent selectively inhibits the phosphorylation and activity of JAK1, which may result in inhibition of JAK1-mediated signaling, induction of apoptosis, and reduction of cell proliferation in JAK1-expressing tumor cells. INCB-039110 in combination with nab-paclitaxel plus gemcitabine demonstrated an acceptable safety profile with clinical activity seen in patients with advanced solid tumors including pancreatic cancers. Based on the potential for additive or synergistic effects, NCB-039110 is currently being explored in combination with immunotherapeutic agents including the anti-programmed cell death protein 1 antibody and small molecule inhibitors.

AZD1480 is a novel agent that inhibits Janus-associated kinases 1 and 2 (JAK1 and JAK2). In phase I study, AZD1480 was administered as an oral QD or b.i.d. monotherapy to patients with advanced solid tumors at eight dose levels in the ranges of 10–70 mg QD and 20–45 mg b.i.d. using a standard 3 3 design. AZD1480 had fast absorption, fast elimination, and dose-dependent increase in exposure from 10 mg to 50 mg. Unusual toxicity profile and overall lack of clinical activity led to discontinuation of development of AZD1480.

AT-9283 was being developed by Astex Pharmaceuticals as a treatment for cancer and myelofibrosis. AT-9283 is an inhibitor of mitosis (cell division) and is the second most progressed drug candidate in the Astex portfolio of novel molecularly targeted cancer drugs. All of Astex’s current products have been discovered internally using its proprietary drug discovery approach. AT9283 is a potent inhibitor of the Aurora A and B kinases and has been shown to arrest tumour growth in a range of tumour models. Aurora kinases play a key role in mitotic checkpoint control in cell division. Both Aurora A and B are over-expressed in many human tumours and are believed to be excellent targets for anti-cancer therapy.

OSI-930 (now SIM-930) is a potent, oral small-molecule receptor tyrosine kinase inhibitor, which acts predominantly against VEGF receptors (VEGFR), c-Kit, and platelet-derived growth factor receptors. OSI-930 has a pharmacokinetic-pharmacodynamic profile distinct from other RTK inhibitors, with potent antitumor activity in multiple xenograft models. OSI-930 passed through phase I clinical trial in the USA (in patients with advanced solid tumors) and recieved the clinical approval by China FDA after being out-licensed to Simcere Pharma in China.

Orantinib (SU-6668) is an orally bioavailable receptor tyrosine kinase inhibitor. Orantinib binds to and inhibits the autophosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2), platelet-derived growth factor receptor (PDGFR), and fibroblast growth factor receptor (FGFR), thereby inhibiting angiogenesis and cell proliferation. Orantinib also inhibits the phosphorylation of the stem cell factor receptor tyrosine kinase c-kit, often expressed in acute myelogenous leukemia cells. Orantinib was in phase II clinical trials for the treatment of breast cancer. It was also in phase III clinical trials for the treatment of hepatocellular carcinoma. However, this research was terminated in 2014. The compound was originally developed by Sugen (subsidiary of Pfizer). In 1998, a co-development agreement took place between Sugen and Taiho for the compound.

BMS-690514 is a potent, reversible oral inhibitor of epidermal growth factor receptor (EGFR/HER-1), HER-2 and -4, and vascular endothelial growth factor receptors (VEGFRs)-1 to -3 offering targeted inhibition of tumour growth and vascularisation in a single agent. Bristol-Myers Squibb was developing BMS 690514, as an oral treatment for cancer. BMS-690514 had being in phase II for the treatment of breast cancer; non-small cell lung cancer, but later these studies were discontinued.