Fruquintinib is a highly selective small molecule drug candidate that has been shown to inhibit VEGFR 24 hours a day via an oral dose, with lower off-target toxicities compared to other targeted therapies. Mechanistically, Fruquintinib selectively blocks VEGF-mediated receptor autophosphorylation, thus inhibiting endothelial cell proliferation and migration. In preclinical in vitro studies using a 32P-ATP assay, Fruquintinib selectively inhibited the tyrosine kinase activity associated with VEGFR-1, VEGFR-2, and VEGFR-3 at concentrations in the nanomolar range, but showed little inhibition against a panel of 254 kinases related to cell cycle or cell proliferation, including cyclin-dependent kinase (CDK1, 2, 5), the epidermal growth factor receptor (EGFR), the mesenchymal-epithelial transition factor (c-Met), and platelet-derived growth factor receptor β (PDGFRβ) kinase. In cellular assays, Fruquintinib potently inhibited VEGF-stimulated VEGFR phosphorylation and proliferation in human umbilical vein endothelial cells. Fruquintinib demonstrated potent antiangiogenic effect and anti-tumor activity in xenograft models of colon adenocarcinoma (HT-29), non-small cell lung cancer (NSCLC; NCI-H460), renal clear cell carcinoma (Caki-1), and gastric carcinoma (BGC823) in mice treated for 3 weeks. Fruquintinib is currently under joint development in China by Chi-Med and its partner Eli Lilly and Company (“Lilly”). Chi-Med and Lilly jointly announced top-line results from the FRESCO CRC trial on March 3, 2017. In addition, Fruquintinib is being studied in China in Phase III pivotal trial in non-small cell lung cancer (“NSCLC”), known as FALUCA; and a Phase II study using Fruquintinib combined with Iressa® (gefitinib) in the first-line setting for patients with advanced or metastatic NSCLC.

Tivozanib (formerly AV-951, KRN-951) is a potent and selective VEGFR tyrosine kinase inhibitor and inhibits angiogenesis and vascular permeability in tumor tissues. It completed phase III a trial investigation for the treatment of renal cell carcinomas, but has not been still approved. In addition, this drug is in the phase II of clinical trial for the investigation it in patients with glioblastoma and colorectal carcinoma.

Alpelisib (BYL719) is a PI3Kα-selective inhibitor. PI3K-AKT-mTOR pathway is frequently activated in cancer, therefore investigational PI3K inhibitor alpelisib is considered to be effective as an anticancer agent and has been in clinical development by Novartis. Alpelisib have demonstrated activity in preclinical models of solid tumors and had favorable tolerability profiles, with the most common adverse events consistent with “on-target” inhibition of PI3K in early clinical studies. There are ongoing clinical trials of alpelisib in a range of cancer types, including breast cancer, head and neck squamous cell carcinoma, non-small cell lung carcinoma, lymphoma, and glioblastoma multiforme. Combination therapy with other chemo therapeutics may be preferable.

Duvelisib (IPI-145), is an orally available, small-molecule, selective dual inhibitor of phosphatidylinositol 3 kinase (PI3K) δ and γ isoforms originated by Intellikine (owned by Takeda) and developed by Infinity Pharmaceuticals. Orally administered duvelisib was rapidly absorbed, with a dose-proportional increase in exposure. The compound produced a half-life of approximately 7-12 hours, following 14 days of dosing. Duvelisib exerts profound effects on adaptive and innate immunity by inhibiting B and T cell proliferation, blocking neutrophil migration, and inhibiting basophil activation. Duvelisib blockade of PI3K-δ and PI3K-γ potentially lead to significant therapeutic effects in multiple inflammatory, autoimmune, and hematologic diseases. The molecule is in phase III development as a combination therapy for patients with haematological malignancies such as chronic lymphocytic leukemia and follicular lymphoma.

Lenvatinib, developed by Eisai Co., is a receptor tyrosine kinase (RTK) inhibitor that inhibits the kinase activities of vascular endothelial growth factor (VEGF) receptors VEGFR1 (FLT1), VEGFR2 (KDR), and VEGFR3 (FLT4). Lenvatinib also inhibits other RTKs that have been implicated in pathogenic angiogenesis, tumor growth, and cancer progression in addition to their normal cellular functions, including fibroblast growth factor (FGF) receptors FGFR1, 2, 3, and 4; the platelet derived growth factor receptor alpha (PDGFRα), KIT, and RET. These receptor tyrosine kinases (RTKs) located in the cell membrane play a central role in the activation of signal transduction pathways involved in the normal regulation of cellular processes, such as cell proliferation, migration, apoptosis and differentiation, and in pathogenic angiogenesis, lymphogenesis, tumour growth and cancer progression. In particular, VEGF has been identified as a crucial regulator of both physiologic and pathologic angiogenesis and increased expression of VEGF is associated with a poor prognosis in many types of cancers. Lenvatinib is indicated for the treatment of patients with locally recurrent or metastatic, progressive, radioactive iodine (RAI)-refractory differentiated thyroid cancer. Most patients with thyroid cancer have a very good prognosis with treatment (98% 5 year survival rate) involving surgery and hormone therapy. However, for patients with RAI-refractory thyroid cancer, treatment options are limited and the prognosis is poor, leading to a push for the development of more targeted therapies such as lenvatinib. Lenvatinib is marketed under the trade name Lenvima, it is indicated for the treatment of patients with locally recurrent or metastatic, progressive, radioactive iodine-refractory differentiated thyroid cancer.

Idelalisib is a first-in-class selective inhibitor of adenosine-5'-triphosphate (ATP) binding to PI3Kdelta kinase, resulting in inhibition of the P13K signalling pathway in malignant B cells. The compound is approved for the treatment of several types of blood cancer. Idelalisib is intended to be used in combination with rituximab as second or subsequent line therapy for the treatment of chronic lymphocytic leukaemia. The drug may cause fatal and/or severe diarrhea or colitis, hepatotoxicity, pneumonitis and intestinal perforation.

Axitinib (trade name Inlyta) is a small molecule tyrosine kinase inhibitor developed by Pfizer. It has been shown to significantly inhibit growth of breast cancer in animal (xenograft) models and has shown partial responses in clinical trials with renal cell carcinoma (RCC) and several other tumour types. Axitinib has been shown to inhibit receptor tyrosine kinases including vascular endothelial growth factor receptors (VEGFR)-1, VEGFR-2, and VEGFR-3 at therapeutic plasma concentrations. These receptors are implicated in pathologic angiogenesis, tumor growth, and cancer progression. VEGF-mediated endothelial cell proliferation and survival were inhibited by axitinib in vitro and in mouse models. It was approved by the U.S. Food and Drug Administration.

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.

Vandetanib, 4-anilinoquinazoline, is an anti-cancer drug that with the potential for use in a broad range of tumour types. In 2011 vandetanib (trade name Caprelsa) was approved by the FDA to treat nonresectable, locally advanced, or metastatic medullary thyroid cancer in adult patients. In vitro studies have shown that vandetanib inhibits the tyrosine kinase activity of the EGFR and VEGFR families, RET, BRK, TIE2, and members of the EPH receptor and Src kinase families. These receptor tyrosine kinases are involved in both normal cellular function and pathologic processes such as oncogenesis, metastasis, tumor angiogenesis, and maintenance of the tumor microenvironment. Vandetanib was shown to inhibit epidermal growth factor (EGF)-stimulated receptor tyrosine kinase phosphorylation in tumor cells and endothelial cells and VEGF-stimulated tyrosine kinase phosphorylation in endothelial cells. Vandetanib administration reduced tumor cell-induced angiogenesis, tumor vessel permeability, and inhibited tumor growth and metastasis in mouse models of cancer.

Lapatinib is a small molecule and a member of the 4-anilinoquinazoline class of kinase inhibitors. It is present as the monohydrate of the ditosylate salt (trade name TYKERB). Lapatinib is dual inhibitor of the EGFR (epidermal growth factor receptor; also called HER1 or ErbB1) and HER2 receptor tyrosine kinases. Lapatinib was developed by GlaxoSmithKline, however, Novartis subsequently acquired all the rights to the drug from GlaxoSmithKline. TYKERB is indicated in combination therapy for the treatment of metastatic breast cancer that overexpresses the HER2 receptor.