Treosulfan (l-threitol-1,4-bis-methanesulfonate; dihydroxybusulfan) is a prodrug of a bifunctional alkylating cytotoxic agent that is approved for the treatment of ovarian carcinomas in a number of European countries. The antitumor activity of treosulfan has been shown in a variety of solid tumors. It is used for the treatment of all types of ovarian cancer, either supplementary to surgery or palliatively. Treosulfan is a prodrug that is converted nonenzymatically first to a mono-epoxide – (2S,3S)- 1,2-epoxy-3,4-butanediol-4-methanesulfonate – and then to a diepoxide – l-diepoxybutane, which is also a metabolite of butadiene – under physiological conditions. Such conversions are assumed to account for the alkylating and therapeutic activities of treosulfan.

Vorasidenib (also known as AG 881) was developed as an isocitrate dehydrogenase (IDH) type 1 in the cytoplasm and type 2 in the mitochondria, with potential antineoplastic activity. It is known that IDH is an essential enzyme for cellular respiration in the tricarboxylic acid (TCA) cycle. Isocitrate dehydrogenases 1 and 2 (IDH1/2) are homodimeric enzymes that catalyze the conversion of isocitrate to α-ketoglutarate (α-KG) in the tricarboxylic acid cycle. Vorasidenib participated in phase I clinical trials in patients with advanced hematologic malignancies and in gliomas.

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.

Olutasidenib (FT-2102) is a highly potent, orally bioavailable, brain-penetrant, and selective inhibitor of mutant IDH1. Olutasidenib was designed to reduce R-2-HG and revert pathologic epigenetic modifications that impair cellular differentiation to restore regulatory enzyme function. In patients with AML, susceptible IDH1 mutations are defined as those leading to increased levels of 2-hydroxyglutarate (2-HG) in the leukemia cells and where efficacy is predicted by 1) clinically meaningful remissions with the recommended dose of olutasidenib and/or 2) inhibition of mutant IDH1 enzymatic activity at concentrations of olutasidenib sustainable at the recommended dosage according to validated methods. The most common of such mutations in patients with AML are R132H and R132C substitutions. In vitro, olutasidenib inhibited mutated IDH1 R132H, R132L, R132S, R132G, and R132C proteins; wild-type IDH1 or mutated IDH2 proteins were not inhibited. Olutasidenib inhibition of mutant IDH1 led to decreased 2-HG levels in vitro and in in vivo xenograft models. On December 1, 2022, the FDA approved olutasidenib (brand name Rezlidhia) capsules for adult patients with relapsed or refractory acute myeloid leukemia with a susceptible IDH1 mutation as detected by an FDA-approved test.

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.

PF-04449913 is a potent and selective inhibitor of the Hh signaling pathway through binding to the target, smoothened. PF-04449913 inhibits Hh signaling in vitro and has demonstrated significant antitumor activity in vivo. In the clinic, PF-04449913 is being evaluated both in hematological and solid malignancies, with a phase II trial currently underway in both fit and unfit patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS). Treatment-related adverse-events were nausea, dizziness, somnolence, QT prolongation and pruritus. Based on pre-clinical assessments, CYP3A4 is believed to be primarily involved in the metabolism of PF-04449913 that is why PF-04449913 plasma exposures and peak concentrations were increased following concurrent administration of ketoconazole (CYP3A4 inhibitor).

Gilteritinib, also known as ASP2215, is a potent FLT3/AXL inhibitor, which showed potent antileukemic activity against AML with either or both FLT3-ITD and FLT3-D835 mutations. In in vitro, among the 78 tyrosine kinases tested, Gilteritinib inhibited FLT3, LTK, ALK, and AXL kinases by over 50% at 1 nM with an IC50 value of 0.29 nM for FLT3, approximately 800-fold more potent than for c-KIT, the inhibition of which is linked to a potential risk of myelosuppression. Gilteritinib inhibited the growth of MV4-11 cells, which harbor FLT3-ITD, with an IC50 value of 0.92 nM, accompanied with inhibition of pFLT3, pAKT, pSTAT5, pERK, and pS6. Gilteritinib decreased tumor burden in bone marrow and prolonged the survival of mice intravenously transplanted with MV4-11 cells. In previous preclinical studies, gilteritinib has demonstrated superior antitumor effects when given in combination with AraC and either DNR or IDR compared with combination chemotherapy. In November 2018, the FDA approved gilteritinib for treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with a FLT3 mutation as detected by an FDA-approved test.

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).

Enasidenib, aslo known as AG-221 and CC-90007, is a potent and selective IDH2 inhibitor with potential anticancer activity (IDH2 = Isocitrate dehydrogenase 2). The mutations of IDH2 present in certain cancer cells result in a new ability of the enzyme to catalyze the NAPH-dependent reduction of α-ketoglutarate to R(-)-2-hydroxyglutarate (2HG). The production of 2HG is believed to contribute to the formation and progression of cancer. The inhibition of mutant IDH2 and its neoactivity is therefore a potential therapeutic treatment for cancer. Enasidenib is an orally available, selective, potent inhibitor of the mutated IDH2 protein, making it a highly targeted investigational medicine for the potential treatment of patients with cancers that harbor an IDH2 mutation. Enasidenib has received orphan drug and fast track designations from the U.S. FDA. Enasidenib mesylate is in phase II clinical trials for Solid tumours and phase III clinical trials for the treatment of acute myeloid leukaemia.

Venetoclax (trade name Venclexta, also known as ABT-199) is a selective and orally bioavailable small-molecule inhibitor of BCL-2, an antiapoptotic protein. BCL-2 and its related proteins BCL-XL and MCL-1 bind to and sequester pro-apoptotic signals in the cell, causing a down-regulation of apoptosis. As an oncogene and an important regulator of apoptosis, BCL-2 overexpression therefore results in increased tumor cell survival and resistance to chemotherapy. FDA approved Venetoclax in April 2016 for the treatment of patients with chronic lymphocytic leukemia (CLL) with 17p deletion, as detected by an FDA approved test, who have received at least one prior therapy. Also this drug in phase 3 clinical trial in combination therapy for the treatment patients with refractory myeloma and Acute Myeloid Leukemia. Common side effects include neutropenia, nausea, anemia, diarrhea, upper respiratory tract infection. Major side effects include tumor lysis syndrome and severe neutropenia.