Ridaforolimus (Deforolimus, MK-8669) is an investigational oral mTOR inhibitor in development for the treatment of metastatic soft-tissue or bone sarcomas. Ridaforolimus is being co-developed by Merck and ARIAD Pharmaceuticals. Ridaforolimus (Deforolimus, MK-8669) is a selective mTOR inhibitor with IC50 of 0.2 nM in HT-1080 cell line; while not classified as a prodrug, mTOR inhibition and FKBP12 binding is similar to rapamycin. mTOR is a protein kinase that controls cell growth by regulating many cellular processes, including protein synthesis and autophagy. Compared with other mTOR inhibitors, ridaforolimus is not a prodrug and has shown in vivo stability. Both intravenous and oral formulations of the compound are being tested in clinical trials for the treatment of various solid tumors and hematologic malignancies. The initial indication is soft-tissue and bone sarcomas. Ridaforolimus was indicated to treat patients with metastatic soft tissue sarcoma or bone sarcoma whose disease has not progressed after at least 4 cycles of chemotherapy. In June 2012, Merck & Co., Inc. announced the receipt of a Complete Response Letter from the U.S. Food and Drug Administration (FDA), advising the company that the New Drug Application (NDA) for ridaforolimus had not been approved. Currently Ridaforolimus is in phase III clinical trials for the treatment of Coronary artery restenosis.

Voxtalisib (SAR245409, XL765) is an orally available inhibitor of PI3K and the mammalian target of rapamycin (mTOR), which are frequently activated in human tumors and play central roles in tumor cell proliferation. Exelixis discovered Voxtalisib internally and out-licensed the compound to Sanofi. Voxtalisib is being evaluated by Sanofi as a single agent and in multiple combination regimens in a variety of cancer indications. Clinical trials have included a single agent phase 2 trial in Non-Hodgkin’s lymphoma, combination phase 1b/2 trials with temozolomide in patients with glioblastoma, with letrozole in hormone receptor positive breast cancer, with bendamustine and/or rituximab in lymphoma or leukemia, and a phase 1 trial in combination with a MEK inhibitor. Voxtalisib is a highly selective, potent and reversible ATP-competitive inhibitor of pan-Class I PI3K (α, β, γ, and δ) and mTORC1/mTORC2. It is orally active, highly selective over 130 other protein kinases. In cellular assays, XL765 inhibits the formation of PIP3 in the membrane, and inhibits phosphorylation of AKT, p70S6K, and S6 phosphorylation in multiple tumor cell lines with different genetic alterations affecting the PI3K pathway.

PQR-309 is an orally bioavailable pan inhibitor of phosphoinositide-3-kinases (PI3K) and inhibitor of the mammalian target of rapamycin (mTOR), with potential antineoplastic activity. PI3K/mTOR kinase inhibitor PQR-309 inhibits the PI3K kinase isoforms alpha, beta, gamma and delta and, to a lesser extent, mTOR kinase, which may result in tumor cell apoptosis and growth inhibition in cells overexpressing PI3K/mTOR. By inhibiting mTOR to a lesser extent than PI3K, PQR-309 does not interfere with the mTOR-mediated negative feedback loop on PI3K signaling. Blocking the negative feedback loop would potentially increase PI3K signaling and decrease therapeutic efficacy. PQR-309 is in phase II clinical trial for the treatment of glioblastoma, head and neck cancer, lymphoma and breast cancer. Common adverse events included fatigue, hyperglycemia, nausea, diarrhea, constipation, rash, anorexia and vomiting.

PQR-309 is an orally bioavailable pan inhibitor of phosphoinositide-3-kinases (PI3K) and inhibitor of the mammalian target of rapamycin (mTOR), with potential antineoplastic activity. PI3K/mTOR kinase inhibitor PQR-309 inhibits the PI3K kinase isoforms alpha, beta, gamma and delta and, to a lesser extent, mTOR kinase, which may result in tumor cell apoptosis and growth inhibition in cells overexpressing PI3K/mTOR. By inhibiting mTOR to a lesser extent than PI3K, PQR-309 does not interfere with the mTOR-mediated negative feedback loop on PI3K signaling. Blocking the negative feedback loop would potentially increase PI3K signaling and decrease therapeutic efficacy. PQR-309 is in phase II clinical trial for the treatment of glioblastoma, head and neck cancer, lymphoma and breast cancer. Common adverse events included fatigue, hyperglycemia, nausea, diarrhea, constipation, rash, anorexia and vomiting.

Dactolisib is a dual inhibitor of phosphatidylinositol 3-kinase (P13K) and the downstream mammalian target of rapamycin (mTOR) by binding to the ATP-binding cleft of these enzymes (inhibitor of PI3K/Akt/mTOR cascade). It is being investigated as a possible anti-cancer cancer agent and drug against Influenza virus infections. Frequently reported adverse events included nausea, vomiting, diarrhoea, fatigue/asthenia, anaemia, and anorexia.