Quizartinib (AC220) is an orally bioavailable, small molecule receptor tyrosine kinase inhibitor that is being developed by Daiichi Sankyo Company (previously Ambit Biosciences) and Astellas Pharma as a treatment for acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL) and advanced solid tumours. The highest affinity target identified for Quizartinib was FLT3. The only other kinases with binding constants within 10-fold that for FLT3 were the closely related receptor tyrosine kinases KIT, PDGFRA, PDGFRB, RET, and CSF1R. Kinase inhibition of (mutant) KIT, PDGFR and FLT3 isoforms by quizartinib leads to potent inhibition of cellular proliferation and induction of apoptosis in in vitro leukemia models as well as in native leukemia blasts treated ex vivo.

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).

Maralixibat (Livmarli™) is a potent, apical, sodium‐dependent, bile acid transporter competitive inhibitor with minimal systemic absorption being developed by Mirum Pharmaceuticals for the treatment of rare cholestatic liver diseases including Alagille syndrome (ALGS), progressive familial intrahepatic cholestasis (PFIC) and biliary atresia. Maralixibat received its first approval on 29 September 2021, in the USA, for use in the treatment of cholestatic pruritus in patients with ALGS 1 year of age and older. Maralixibat is also under regulatory review for ALGS in Europe, and clinical development for cholestatic liver disorders including ALGS in patients under 1 year of age, PFIC and biliary atresia is continuing in several other countries. This article summarises the milestones in the development of maralixibat leading to this first approval for ALGS.

Artenimol (dihydroartemisinin) is a derivate of antimalarial compound artemisinin. Artenimol (dihydroartemisinin) is able to reach high concentrations within the parasitized erythrocytes. Its endoperoxide bridge is thought to be essential for its antimalarial activity, causing free-radical damage to parasite membrane systems including: • Inhibition of falciparum sarcoplasmic-endoplasmic reticulum calcium ATPase, • Interference with mitochondrial electron transport • Interference with parasite transport proteins • Disruption of parasite mitochondrial function. Dihydroartemisinin in combination with piperaquine tetraphosphate (Eurartesim, EMA-approved in 2011) is indicated for the treatment of uncomplicated Plasmodium falciparum malaria. The formulation meets WHO recommendations, which advise combination treatment for Plasmodium falciparum malaria to reduce the risk of resistance development, with artemisinin-based preparations regarded as the ‘policy standard’. However, experimental testing demonstrates that, due to its intrinsic chemical instability, dihydroartemisinin is not suitable to be used in pharmaceutical formulations. In addition, data show that the currently available dihydroartemisinin preparations fail to meet the internationally accepted stability requirements.

Afamelanotide (SCENESSE) is a synthetic α-melanocyte stimulating hormone analog and first-in-class melanocortin-1 receptor agonist that is approved in the EU for the prevention of phototoxicity in adults with erythropoietic protoporphyria. Afamelanotide differs from endogenous α-melanocyte stimulating hormone at the fourth and seventh amino acid residues, increasing its resistance to immediate degradation and increasing its binding time to melanocortin-1 receptor. Afamelanotide is mimic the pharmacological activity of α-melanocyte stimulating hormone by binding to the melanocortin-1 receptor on melanocytes and activating the synthesis of eumelanin. Eumelanin provides photoprotection through mechanisms including, but not limited to, the absorption and scattering of visible and UV light and antioxidant activity. Afamelanotide increases eumelanin density in healthy volunteers and patients with erythropoietic protoporphyria. In healthy, fair-skinned volunteers, a significant increase in melanin density and skin darkening in both sun-exposed and non-sun-exposed sites was seen with subcutaneous injections of afamelanotide. The most common afamelanotide adverse events included headache and nausea. Common adverse effects include back pain, upper respiratory tract infections, decreased appetite, migraine, and dizziness.

Pitolisant (INN) or tiprolisant (USAN) is a histamine receptor inverse agonist/antagonist selective for the H3 subtype. It has stimulant and nootropic effects in animal studies and may have several medical applications, having been researched for the treatment of narcolepsy, for which it has been granted orphan drug status in the EU and US. It is currently in clinical trials for schizophrenia and Parkinson’s disease. Pitolisant hydrochloride was approved by European Medicine Agency (EMA) on Mar 31, 2016. It was developed and marketed as Wakix® by Bioprojet in EU. Wakix® is available as the tablet for oral use, containing 4.5 mg and 18 mg of Pitolisant hydrochloride. The initial dose of 9 mg (two 4.5 mg, tablets) per day, and it should be used at the lowest effective dose, depending on individual patient response and tolerance, according to an up-titration scheme, without exceeding the dose of 36 mg/day. Pitolisant was the first clinically used H3 receptor inverse agonist.

Selinexor (KPT-330) is a first in class XPO1 antagonist being evaluated in multiple later stage clinical trials in patients with relapsed and/or refractory hematological and solid tumor malignancies.

Fedratinib (SAR-302503, TG-101348) is a selective small-molecule inhibitor of Janus kinase-2. Fedratinib demonstrated therapeutic efficacy in a murine model of myeloproliferative disease. Sanofi was developing Fedratinib for the treatment of myeloproliferative diseases and solid tumors. The clinical development of fedratinib was terminated after reports of Wernicke's encephalopathy in myelofibrosis patients.