Pexidartinib (PLX3397) is a small-molecule receptor tyrosine kinase (RTK) inhibitor with potential antineoplastic activity. Pexidartinib binds to and inhibits phosphorylation of stem cell factor receptor (KIT), colony-stimulating factor-1 receptor (CSF1R) and FMS-like tyrosine kinase 3 (FLT3), which may result in the inhibition of tumor cell proliferation and down-modulation of macrophages, osteoclasts and mast cells involved in the osteolytic metastatic disease. FDA has granted Breakthrough Therapy Designation to pexidartinib (PLX3397) for the treatment of tenosynovial giant cell tumor (TGCT) where surgical removal of the tumor would be associated with potentially worsening functional limitation or severe morbidity. In addition to Breakthrough Therapy Designation, pexidartinib (PLX3397) has been granted Orphan Drug Designation by FDA for the treatment of pigmented villonodular synovitis (PVNS) and giant cell tumor of the tendon sheath (GCT-TS). It also has received Orphan Designation from the European Commission for the treatment of TGCT.

Lofexidine is newly FDA approved in the United States under the brand name LUCEMYRA for the treatment of opioid withdrawal symptoms in adults. Lofexidine acts as an agonist to α2 adrenergic receptors. These receptors inhibit adenylyl cyclase activity, leading to the inhibition of the second messenger, cyclic adenosine monophosphate (cAMP). The inhibition of cAMP leads to potassium efflux through calcium-activated channels, blocking calcium ions from entering the nerve terminal, resulting in suppression of neural firing, inhibition of norepinephrine release. Lofexidine replaces the opioid-driven inhibition of cAMP production and moderating the symptoms of opioid withdrawal.

Cannabidiol is the major nonpsychoactive ingredient in cannabis. Cannabidiol demonstrates a range of effects that may be therapeutically useful, including anti-seizure, antioxidant, neuroprotective, anti-inflammatory, analgesic, anti-tumor, anti-psychotic, and anti-anxiety properties. Exact mechanism of action of cannabidiol is not known, but may include effects on the orphan G-protein-coupled receptor GPR55; the transient receptor potential of vanilloid type-1 channel; the 5-HT1a receptor; and the α3 glycine receptors. GW Pharmaceuticals successfully developed the world’s first prescription medicine derived from the cannabis plant, Sativex® (buccal spray containing delta-9-tetrahydrocannabinol and cannabidiol) now approved in over 29 countries outside of the United States for the treatment of spasticity due to Multiple Sclerosis. GW Pharmaceuticals is developing Epidiolex® (a liquid formulation of pure plant-derived cannabidiol) for certain rare and severe early-onset, drug-resistant epilepsy syndromes.

Migalastat (Galafold)-a small molecule drug developed by Amicus Therapeutics that restores the activity of specific mutant forms of α-galactosidase-has been approved for the treatment of Fabry disease in the EU in patients with amenable mutations. Migalastat attaches to certain unstable forms of alpha-galactosidase A, stabilising the enzyme. This allows the enzyme to be transported into areas of the cell where it can break down GL-3. Under the trade name Galafold (formerly known as Amigal), Migalastat is used to treat patients aged 16 years or over with Fabry disease. Because the number of patients with Fabry disease is low, the disease is considered ‘rare’, and the US Food and Drug Administration (FDA) assigned Galafold orphan drug status in 2004, and the European Committee for Medicinal Products for Human Use (CHMP) followed in 2006.

Revefenacin (trade name Yupelri is a long-acting muscarinic antagonist developed by Mylan Ireland ltd for the treatment of chronic obstructive pulmonary disease (COPD). It has similar affinity to the subtypes of muscarinic receptors M1 to M5. In the airways, it exhibits pharmacological effects through inhibition of M3 receptor at the smooth muscle leading to bronchodilation. The competitive and reversible nature of antagonism was shown with human and animal origin receptors and isolated organ preparations. In preclinical in vitro as well as in vivo models, prevention of methacholine- and acetylcholine-induced bronchoconstrictive effects was dose-dependent and lasted longer than 24 hours.

Tezacaftor (VX-661) is an investigational compound developed by Vertex Pharmaceuticals to treat cystic fibrosis (CF). It is an oral corrector of the CF transmembrane regulator (CFTR) and is similar to lumacaftor, another N-aryl-1-(2,2-difluoro-1,3-benzodioxol-5-yl)cyclopropanecarboxamide derivative developed by Vertex. Cystic fibrosis is caused by defects in CFTR gene, which encodes an epithelial chloride channel. The most common mutant Δ508CFTR is a misfolded protein that does not reach the cell membrane. VX-661 corrects trafficking of Δ508CFTR and partially restores chloride channel activity. In vitro, a combination of VX-661 and ivacaftor, an FDA approved in 2012 CFTR potentiator which increases the time the CFTR channel is open, allowing chloride ions to flow through the CFTR proteins on the surface of epithelial cells, resulted in greater CFTR activity compared with VX-661 alone. In February 2012, a phase 2, double-blind, placebo-controlled study of VX-661 was initiated in CF patients who were homozygous or heterozygous for the F508del mutation. There is an ongoing Vertex Phase 3 development program of VX-661 in combination with ivacaftor which includes four studies on CF patients 1) with two copies of the F508del mutation, 2) one copy of the F508del mutation and a second mutation that results in residual CFTR function, 3) one copy of the F508del mutation and a second mutation that results in residual CFTR function gating defect in the CFTR protein and 4) one copy of the F508del mutation and a second mutation that results in minimal CFTR function.

Ivosidenib (AG-120) is an inhibitor of isocitrate dehydrogenase 1 (IDH1) This experimental drug inhibits mutant IDH1, leading to increased differentiation and decreased proliferation in IDH1 positive tumors and thus is thought to be promising for the treatment of IDH1-mutated tumors. In vivo treatment with AG-120 of TF-1 cells, primary human AML patient samples expressing mutant IDH1 and primary human blast cells cultured ex vivo showed that AG-120 is effective at lowering 2-HG levels and restoring cellular differentiation. It showed promising results in a phase I trial in patients with relapsed or refractory acute myeloid leukemia and is being evaluated in Phase III in previously-treated subjects with nonresectable or metastatic cholangiocarcinoma with an IDH1 mutation.

Larotrectinib (previously known as ARRY-470 and LOXO-101) is a potent, oral and selective investigational new drug in clinical development for the treatment of patients with cancers that harbor abnormalities involving the tropomyosin receptor kinases (TRKs). Larotrectinib is in phase II clinical trials for the treatment patients with solid tumors, non-Hodgkin lymphoma and for the pediatric patients with advanced solid or primary CNS tumors.

Talazoparib (BMN 673) demonstrates excellent potency, inhibiting PARP1 and PARP2 enzyme activity. It inhibits PARP-mediated PARylation in a whole-cell assay and prevents proliferation of cancer cells carrying mutant BRCA1/2. Talazoparib is orally available, displaying favorable pharmacokinetic properties and remarkable antitumor efficacy in the BRCA1 mutant MX-1 breast cancer xenograft model following oral administration as a single-agent or in combination with chemotherapy agents such as temozolomide and cisplatin. Medivation (a subsidiary of Pfizer) is developing talazoparib (MDV 3800, formerly BMN 673 and LT 673) for the treatment of genetically defined cancers. On October 16, 2018, the FDA approved talazoparib (TALZENNA, Pfizer Inc.) for patients with deleterious or suspected deleterious germline BRCA-mutated (gBRCAm), HER2‑negative locally advanced or metastatic breast cancer.

Encorafenib, also known as BRAFTOVI or LGX818, is an orally available mutated BRaf V600E inhibitor with potential antineoplastic activity, which was developed by Novartis. LGX818 possesses selective anti-proliferative and apoptotic activity in cells expressing BRAFV600E. In the A375 (BRAFV600E) human melanoma cell line LGX818 suppresses phospho-ERK (EC50 = 3 nM) leading to potent inhibition of proliferation (EC50 = 4 nM). No significant activity was observed against a panel of 100 kinases (IC50 > 900 nM) and LGX818 did not inhibit proliferation of > 400 cell lines expressing wild-type BRAF. On June 27, 2018, the Food and Drug Administration approved encorafenib and Binimetinib (BRAFTOVI and MEKTOVI, Array BioPharma Inc.) in combination for patients with unresectable or metastatic melanoma with a BRAF V600E or V600K mutation, as detected by an FDA-approved test. Encorafenib and binimetinib target two different kinases in the RAS/RAF/MEK/ERK pathway. Compared with either drug alone, co-administration of encorafenib and binimetinib result in greater anti-proliferative activity in vitro in BRAF mutation-positive cell lines and greater anti-tumor activity with respect to tumor growth inhibition in BRAF V600E mutant human melanoma xenograft studies in mice. In addition to the above, the combination of encorafenib and binimetinib acted to delay the emergence of resistance in BRAF V600E mutant human melanoma xenografts in mice compared with the administration of either drug alone. Encorafenib is in phase III for Metastatic Colorectal Cancer and in phase II for Relapsed or Refractory Multiple Myeloma.