Omipalisib, also known as GSK2126458, is a small-molecule pyridylsulfonamide inhibitor of phosphatidylinositol 3-kinase (PI3K) with potential antineoplastic activity. Omipalisib (GSK2126458, GSK458) is a highly selective and potent inhibitor of p110α/β/δ/γ, mTORC1/2 with Ki of 0.019 nM/0.13 nM/0.024 nM/0.06 nM and 0.18 nM/0.3 nM in cell-free assays, respectively. It is also a low picomolar inhibitor of the common activating mutants of p110a (E542K, E545K, and H1047R) found in human cancer. Omipalisib (GSK2126458) binds to and inhibits PI3K in the PI3K/mTOR signaling pathway, which may trigger the translocation of cytosolic Bax to the mitochondrial outer membrane, increasing mitochondrial membrane permeability and inducing apoptotic cell death. Bax is a member of the proapoptotic Bcl2 family of proteins. PI3K, often overexpressed in cancer cells, plays a crucial role in tumor cell regulation and survival. GlaxoSmithKline (GSK) is developing omipalisib, a phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) inhibitor as well as mTOR complex 1 and 2 inhibitor, for the potential oral treatment of cancer and idiopathic pulmonary fibrosis.

Vistusertib (AZ-2014) is a dual inhibitor of mTORC1/mTORC2 which was developed by AstraZeneca for the treatment of cancer. The drug is under clinical development (phase II) in patients with Renal Carcinoma, Squamous Non Small Cell Lung Cancer, Diffuse Large B-Cell Lymphoma, Meningioma, Breast cancer and Gastric cancer, either alone or in combination therapy. Vistusertib penetrates blood-brain barrier.

LY3023414, an investigational drug, is a small molecule that that demonstrates activity against PI3K, mTOR, and DNA-PK in tumor cells, thereby inducing cell-cycle effects and inhibiting cancer cell viability. As shown in vitro LY3023414 inhibits the ability of PI3K and mTOR to phosphorylate substrates in the PI3K/mTOR pathway, one of the most frequently mutated pathways in cancer, leading to cancer progression and resistance to existing treatments. Downstream target inhibition by LY3023414 occurs rapidly via an intermittent “on/off” mechanism that may enhance the drug's clinical tolerability, which may in turn allow LY3023414 to overcome some of the toxicities associated with PI3K/mTOR inhibitors and potentially reduce the emergence of feedback mechanisms leading to resistance. The physicochemical and absorption properties of LY3023414 are favorable, as evidenced by the molecule's high solubility across a wide pH range and high oral bioavailability. On the basis of these findings, LY3023414 is currently being evaluated in clinical trials in patients with advanced cancer such as metastatic prostate cancer and non-small cell lung cancer in combination with other chemotherapeutic agents and in endometrial cancer as a monotherapy.

OSI-027 is an orally bioavailable mammalian inhibitor of mTOR kinase and has antineoplastic activity. OSI-027 binds to and inhibits of the catalytic site of mTOR, which is a central part of two protein complexes, mTORC1 and mTORC2, which may result in tumor cell apoptosis and a decrease in tumor cell proliferation. OSI-027 is in phase I clinical trial for the investigation on patients with advanced solid tumors or lymphoma.

Sapanisertib is an oral dual inhibitor of mTORC1/mTORC2, discovered by Intellikine for the treatment of cancer. The drug is being tested in phase II of clinical trials for different cancers among which are sarcoma, hepatocellular carcinoma, etc. The drug is currently developed by Takeda with breast cancer, renal cancer and endometrial cancer being the main target indications.

AstraZeneca was developing AZD-8055, an orally active mTORC1/mTORC2 inhibitor, for the treatment of advanced solid tumours. AZD-8055 is an ATP-competitive mTORC1/2 inhibitor that exhibits immunosuppressive and anticancer chemotherapeutic activities. AZD-8055 promotes antibody class switching in B cells at low doses and decreases B cell proliferation and differentiation at high doses. In vivo, this compound suppresses CC4 and CD8 T cell proliferation, increasing survival among MHC-mismatched heart transplant recipients. In vitro, AZD-8055 decreases viability of brain tumor cells; in vivo, it inhibits tumor growth. AZD-8055 had been in phase I trials by AstraZeneca for the treatment of malignant gliomas and solid tumours. However, this research has been discontinued.

RES-529 (previously named Palomid 529, P529) is a phosphoinositide 3-kinase (PI3K)/AKT/mechanistic target of rapamycin (mTOR) pathway inhibitor that interferes with the pathway through both mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) dissociation. P529 inhibits tumor growth, angiogenesis, and vascular permeability. It retains the beneficial aspects of tumor vascular normalization that rapamycin boasts. This compound is currently being developed in oncology and ophthalmology. The oncology focus is for the treatment of glioblastoma, where it has received orphan designation by the US Food and Drug Administration, and prostate cancer.

Torin 1 is a highly potent and selective ATP-competitive mTOR inhibitor discovered as a potential anticancer drug. It directly inhibits two functionally distinct complexes, mTORC1 and mTORC2, that coordinately promote cell growth, proliferation, and survival and impairs cell growth and proliferation to a far greater degree than rapamycin. Torin 1 is a picomolar inhibitor of mTORC1 enzymatic activity and single digit nanomolar inhibitor of cellular mTOR activity and has more than 800-fold selectivity between mTOR and PI3K. The pharmacokinetic properties of torin 1 were both in vitro and in vivo. It exhibited a short in vivo half-life and low oral bioavailability but displayed pharmacodynamic inhibition of both mTORC1 and mTORC2 outputs in lung and liver. Torin 1 dosed once a day at 20 mg/kg for 10 days demonstrated efficacy in a U87MG glioblastoma xenograft mouse model. Torin1 also caused lipin 1 nuclear translocation suggesting that lipin 1 cytoplasmic-nuclear relocalization responds to mTORC1 and not mTORC2 status. Torin 1 completely inhibited S106 lipin 1 phosphorylation and impaired S237 and S472 lipin 1 phosphorylation at prolonged exposure. Inhibition of mTORC1 in the liver significantly impairs SREBP function and makes mice resistant, in a lipin 1-dependent fashion, to the hepatic steatosis and hypercholesterolemia induced by a high fat and cholesterol diet. However, if potent mTORC1 inhibiting could be useful as potential treatments for metabolic syndrome has to be elucidated yet.

XL388 is a selective small-molecule ATP-competitive inhibitor of mTOR kinase complexes mTORC1 and mTORC2. XL388 inhibited cellular phosphorylation of mTOR complex 1 (p-p70S6K, pS6, and p-4E-BP1) and mTOR complex 2 (pAKT (S473)) substrates. In vitro, XL388 inhibits the viability of solid and hematopoietic tumor cell lines when assayed as a single agent. XL388 also synergizes with chemotherapeutics in cell‐based assays to block cell viability. When dosed orally once daily in mice, XL388 shows robust anti‐tumor activity in multiple xenograft models. Exelixis has discontinued the development of XL388. The company intends to pursue a collaboration partner or other external opportunities for the development of XL388.

Leucine is an α-amino acid used in the biosynthesis of proteins. Leucine is an essential hydrophobic amino acid. It is used in the Leucine may be used some people as a supplement to build muscle. Leucine is also found in fish, meat, and poultry. In the pharmaceutical industry, L-leucine is used for parenteral and enteral nutrition and feeding, and is also used as a flavoring product and tablet lubricant in manufacturing. Leucine is an mTOR activator. It is a dietary amino acid with the capacity to directly stimulate muscle protein synthesis. As a dietary supplement, leucine has been found to slow the degradation of muscle tissue by increasing the synthesis of muscle proteins in aged rats. Long-term leucine supplementation does not increase muscle mass or strength in healthy elderly men. Leucine potently activates the mammalian target of rapamycin kinase that regulates cell growth. Infusion of leucine into the rat brain has been shown to decrease food intake and body weight via activation of the mTOR pathway.