PF-06651600 is a newly discovered irreversible covalent JAK3-selective inhibitor. A high level of selectivity towards JAK3 is achieved by the covalent interaction of PF-06651600 with a unique cysteine residue (Cys-909) in the catalytic domain of JAK3, which is replaced by a serine residue in the other JAK isoforms. PF-06651600 allowed the comparison of JAK3-selective inhibition to pan-JAK or JAK1-selective inhibition, in relevant immune cells to a level that could not be achieved previously without such potency and selectivity. In vitro, PF-06651600 inhibits Th1 and Th17 cell differentiation and function, and in vivo it reduces disease pathology in rat adjuvant-induced arthritis as well as in mouse experimental autoimmune encephalomyelitis models. Preclinical data demonstrates that inhibition of the cytolytic function of CD8+ T cells and NK cells by PF-06651600 is driven by the inhibition of TEC kinases. Based on the underlying pathophysiology of inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease, alopecia areata and vitiligo, the dual activity of PF06651600 towards JAK3 and the TEC kinase family may provide a beneficial inhibitory profile for therapeutic intervention. PF-06651600 is in phase III clinical trial for the treatment of alopecia areata and in phase II clinical trial for the treatment of Crohn's disease, Rheumatoid arthritis, Ulcerative colitis and Vitiligo.

Momelotinib (CYT387) is an ATP-competitive small molecule that potently inhibits JAK1/JAK2 kinases. Momelotinib is developing by Gilead Sciences for the oral treatment of pancreatic and non-small cell lung cancers, and myeloproliferative disorders (including myelofibrosis, essential thrombocythaemia and polycythaemia vera).

Pacritinib (SB1518), discovered in Singapore at the labs of S*BIO Pte Ltd., is an oral tyrosine kinase inhibitor (TKI) with activity against two important activating mutations: Janus Associated Kinase 2 (JAK2) and FMS-like tyrosine kinase 3 (FLT3). The JAK family of enzymes is a central component in signal transduction pathways, which are critical to normal blood cell growth and development as well as inflammatory cytokine expression and immune responses. Activating mutations of JAK2 are implicated in certain blood-related cancers, including myeloproliferative neoplasms (MPNs), leukemia and certain solid tumors. FLT3 is a gene commonly found mutated in patients with acute myeloid leukemia (AML). Pacritinib has demonstrated encouraging results in Phase 1 and 2 studies for patients with myelofibrosis and may offer an advantage over other JAK inhibitors through effective treatment of symptoms while having less treatment-emergent thrombocytopenia and anemia than has been seen in currently approved and in-development JAK inhibitors. Pacritinib is acquired by Cell Therapeutics, Inc. (CTI) and Baxter international and could effectively address an unmet medical need for patients living with myelofibrosis who face treatment-emergent thrombocytopenia on marketed JAK inhibitors. Currently Pacritinib is undergoing preregistration for myelofibrosis.

PF-04965842 is an orally administered selective Janus kinase 1 (JAK1) inhibitor. PF-04965842 is currently in clinical trials for the treatment of autoimmune diseases.

Selpercatinib (LOXO-292, ARRY-192) is a potent and specific RET (c-RET) inhibitor that was granted accelerated FDA approval on May 8, 2020, for specific RET-driven cancer indications. It is currently marketed under the brand name RETEVMO™ by Loxo Oncology Inc.

TUCATINIB (ONT-380 or ARRY-380) is an orally active, reversible and selective small-molecule HER2 inhibitor invented by Array and licensed to Cascadian Therapeutics (previously named Oncothyreon) for development, manufacturing and commercialization. HER2, a growth factor receptor that is over-expressed in multiple cancers, including breast, ovarian, and stomach cancer. HER2 mediates cell growth, differentiation and survival, and tumors that overexpress HER2 are more aggressive and historically have been associated with poorer overall survival compared with HER2-negative cancers. ONT-380 is highly active as a single agent and in combination with both chemotherapy and Herceptin® (trastuzumab) in xenograft models of HER2+ breast cancer, including models of CNS metastases that were refractory to Tykerb® (lapatinib) or neratinib treatment. In a Phase 1 single agent clinical study, ONT-380 administered orally twice a day was well tolerated and demonstrated anti-tumor activity in heavily pre-treated HER2+ breast cancer patients with metastatic disease. Based on the strength of these preclinical and clinical trials, ONT-380 is advancing in one Phase 2 and three Phase 1b combination trials in patients with metastatic breast cancer. A second study reported the CNS activity of ONT-380 in combination with either T-DM1 or trastuzumab or capecitabine. Patients with brain metastases assessable for response were included in the combined analysis. Responses and clinical benefit in the CNS were reported with the three combinations tested, supporting future development of the drug for this particular indication.

KX-01 is a dual inhibitor of Src kinase and tubulin polymerization. KX01 promotes the induction of p53, G2/M arrest of proliferating cell populations and subsequent apoptosis via the stimulation of Caspase-3 and PARP cleavage. The drug was developed by Kinex Pharmaceuticals and reached phase II of clinical trials for the treatment of Castration-Resistant Prostate Cancer and Actinic Keratosis. KX-01 demonstrated good in vitro pofile against different cancer cell lines with IC50 in nanomolar range.