Neratinib (HKI-272) is a pan-HER inhibitor, this irreversible tyrosine kinase inhibitor binds and inhibits the tyrosine kinase activity of epidermal growth factor receptors, EGFR (or HER1), HER2 and HER4, which leads to reduced phosphorylation and activation of downstream signaling pathways. Neratinib is a modified form of the discontinued compound pelitinib, and was originally being develoAdditionally, phase II development of oral neratinib as a neoadjuvant therapy for breast cancer, as a second-line therapy for non-small cell lung cancer, and for other solid tumours is also in progress in numerous countries worldwide. ped by Wyeth (later Pfizer). Oral neratinib is awaiting approval as an extended adjuvant therapy for breast cancer in the EU and in the US. Blocking HER2 function by a small molecule kinase inhibitor, such as neratinib, represents an attractive alternate strategy for the growth inhibition of HER2-positive tumours.

Midostaurin, a derivate of staurosporine (N-benzoylstaurosporine), is a broad-spectrum inhibitor of Ser/Thr and Tyr protein kinases. Midostaurin showed broad antiproliferative activity against various tumor and normal cell lines in vitro and is able to reverse the p-glycoprotein-mediated multidrug resistance of tumor cells in vitro. Midostaurin showed in vivo antitumor activity as single agent and inhibited angiogenesis in vivo. At the end of 2016 FDA granted Priority Review to the PKC412 (midostaurin) new drug application (NDA) for the treatment of acute myeloid leukemia (AML) in newly-diagnosed adults with an FMS-like tyrosine kinase-3 (FLT3) mutation, as well as for the treatment of advanced systemic mastocytosis (SM).

Alectinib is a second generation oral drug that selectively inhibits the activity of anaplastic lymphoma kinase (ALK) tyrosine kinase. It was developed by Chugai Pharmaceutical Co. Japan, which is part of the Hoffmann-La Roche group. Alectinib is specifically used in the treatment of non-small cell lung cancer (NSCLC) expressing the ALK-EML4 (echinoderm microtubule-associated protein-like 4) fusion protein that causes proliferation of NSCLC cells. Inhibition of ALK prevents phosphorylation and subsequent downstream activation of STAT3 and AKT resulting in reduced tumour cell viability. Approved under accelerated approval in 2015, alectinib is indicated for use in patients who have progressed on or were not tolerant of crizotinib, which is associated with the development of resistance. Alectinib is marketed as Alecensa.

Ibrutinib is an orally bioavailable Bruton's tyrosine kinase (BTK) inhibitor indicated for the treatment of mantle cell lymphoma (MCL) patients that previously received at least one therapy. The drug was jointly developed by Janssen Biotech and Pharmacyclics. Ibrutinib selectively binds to Cys-481 residue in the allosteric inhibitory segment of BTK (TK/SH1 domain), and irreversibly blocks its enzymatic activity thus preventing B-cell activation and signaling, totally blocking the B-cell receptor and cytokine receptor pathways. This leads to an inhibition of the growth of malignant B cells that overexpress BTK. Apart from mantle cell lymphoma Ibrutinib is approved for the treatment of chronic lymphocytic leukemia and Waldenstrom Macroglobulinemia.

Afatinib is a anilino-quinazoline derivative and irreversible antagonist of the receptor tyrosine kinase epidermal growth factor receptor family, with antineoplastic activity. Afatinib selectively and covalently binds to and inhibits the epidermal growth factor receptors 1 (ErbB1; EGFR), 2 (ErbB2; HER2), and 4 (ErbB4; HER4), and certain EGFR mutants, including those caused by EGFR exon 19 deletion mutations or exon 21 (L858R) mutations. This may result in the inhibition of tumor growth and angiogenesis in tumor cells overexpressing these kinases. Additionally, afatinib inhibits the EGFR T790M gatekeeper mutation which is resistant to treatment with first-generation EGFR inhibitors. EGFR, HER2 and HER4 are RTKs that belong to the EGFR superfamily; they play major roles in both tumor cell proliferation and tumor vascularization and are overexpressed in many cancer cell types. Afatinib is a substrate and an inhibitor of P-gp and of the transporter BCRP. Co-administration of P-gp inhibitors can increase afatinib exposure while co-administration of chronic P­gp inducers can decrease afatinib exposure.

Cabozantinib (development code name XL184; marketed under the trade name Cometriq) is an orally bioavailable, small molecule receptor tyrosine kinase (RTK) inhibitor with potential antineoplastic activity. Cabozantinib strongly binds to and inhibits several RTKs, which are often overexpressed in a variety of cancer cell types, including hepatocyte growth factor receptor (MET), RET (rearranged during transfection), vascular endothelial growth factor receptor types 1 (VEGFR-1), 2 (VEGFR-2), and 3 (VEGFR-3), mast/stem cell growth factor (KIT), FMS-like tyrosine kinase 3 (FLT-3), TIE-2 (TEK tyrosine kinase, endothelial), tropomyosin-related kinase B (TRKB) and AXL. This may result in an inhibition of both tumor growth and angiogenesis, and eventually lead to tumor regression. Cabozantinib was granted orphan drug status by the U.S. Food and Drug Administration (FDA) in January 2011. It is currently undergoing clinical trials for the treatment of prostate, bladder, ovarian, brain, melanoma, breast, non-small cell lung, pancreatic, hepatocellular and kidney cancers.

Ponatinib (trade name Iclusig, previously AP24534) is developed by ARIAD Pharmaceuticals for the treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome–positive (Ph ) acute lymphoblastic leukemia (ALL). Ponatinib has been designed to be effective against these types of tumors. The United States Food and Drug Administration approved the drug as a candidate in 2012, but temporarily suspended sales on 31 October 2013 because of "the risk of life-threatening blood clots and severe narrowing of blood vessels". This suspension was partially lifted on Dec. 20, 2013 with ponatinib being issued revised prescribing information, a new "Black Box Warning" and a "Risk Evaluation and Mitigation Strategy" in place to better evaluate the risks and benefits of using the drug. Ponatinib is an orally bioavailable multitargeted receptor tyrosine kinase (RTK) inhibitor with potential antiangiogenic and antineoplastic activities. Ponatinib inhibits unmutated and all mutated forms of Bcr-Abl, including T315I, the highly drug therapy-resistant missense mutation of Bcr-Abl. This agent also inhibits other tyrosine kinases including those associated with vascular endothelial growth factor receptors (VEGFRs) and fibroblast growth factor receptors (FGFRs); in addition, it inhibits the tyrosine kinase receptor TIE2 and FMS-related tyrosine kinase receptor-3 (Flt3). RTK inhibition by ponatinib may result in the inhibition of cellular proliferation and angiogenesis and may induce cell death. Bcr-Abl is a fusion tyrosine kinase encoded by the Philadelphia chromosome.

Tofacitinib is an orally available inhibitor of Janus kinases (JAK), with immunomodulatory and anti-inflammatory activities. Upon administration, tofacitinib binds to JAK and prevents the activation of the JAK-signal transducers and activators of transcription (STAT) signaling pathway. This may decrease the production of pro-inflammatory cytokines, such as interleukin (IL)-6, -7, -15, -21, interferon-alpha and -beta, and may prevent both an inflammatory response and the inflammation-induced damage caused by certain immunological diseases. JAK kinases are intracellular enzymes involved in signaling pathways affecting hematopoiesis, immunity and inflammation. Tofacitinib was discovered and developed by the National Institutes of Health and Pfizer. Besides rheumatoid arthritis, tofacitinib has also been studied in clinical trials for the prevention of organ transplant rejection, and the treatment of psoriasis and ulcerative colitis. Patients treated with tofacitinib (XELJANZ) are at increased risk for developing serious infections that may lead to hospitalization or death and adverse reactions. Most patients who developed these infections were taking concomitant immunosuppressants such as methotrexate or corticosteroids.

Bosutinib (trade name Bosulif) originally synthesized by Wyeth, it is being developed by Pfizer. Bosutinib received US FDA and EU European Medicines Agency approval on September 4, 2012 and 27 March 2013 respectively for the treatment of adult patients with Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia (CML) with resistance, or intolerance to prior therapy. Bosutinib is a synthetic quinolone derivative and dual kinase inhibitor that targets both Abl and Src kinases with potential antineoplastic activity. Unlike imatinib, bosutinib inhibits the autophosphorylation of both Abl and Src kinases, resulting in inhibition of cell growth and apoptosis. Because of the dual mechanism of action, this agent may have activity in resistant CML disease, other myeloid malignancies and solid tumors. Abl kinase is upregulated in the presence of the abnormal Bcr-abl fusion protein which is commonly associated with chronic myeloid leukemia (CML). Overexpression of specific Src kinases is also associated with the imatinib-resistant CML phenotype.

(S)-crizotinib was discovered as an attractive chemical entity for further pre-clinical evaluation, and small-molecule inhibitors of MTH1 as a promising novel class of anticancer agents.