SNX-5422 (also known as PF-04929113) is a synthetic, novel, small molecule Hsp90 inhibitor with potential antineoplastic activity. Hsp90 is a molecular chaperone that plays a key role in the conformational maturation of oncogenic signaling proteins, such as HER2/ERBB2, AKT, RAF1, BCR-ABL, and mutated p53, as well as many other molecules that are important in cell cycle regulation or immune responses. Inhibition of Hsp90 by SNX-2112 may result in the proteasome degradation of oncogenic client proteins, including HER2/ERBB2, and the inhibition of tumor cell proliferation. SNX-5422 is originally developed by Pfizer and Serenex, Inc., and the phase I clinical trials for it has been completed in the treatment of solid tumors. Although the mechanism of action remains to be fully elucidated, SNX-5422, which is a prodrug, is rapidly converted to SNX-2112 that accumulates in tumors relative to normal tissues.

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.

P276-00 (also known as riviciclib) is a novel, potent, small-molecule, flavone-derived inhibitor of cyclin-dependent kinases (Cdk), Cdk 4 D1, Cdk1 B, and Cdk9 T, with potent cytotoxic effects against chemosensitive and chemoresistant cancer cell lines. P276-00 was in phase II clinical trial for the treatment mantle cell lymphoma, but that study was terminated based on interim results and all subjects were off study at that time. Although, there were not the major safety or tolerability concerns. However, this drug successfully passed phase II clinical trial for the treatment Melanoma, squamous cell carcinoma of head and neck, malignant melanoma and in combination with Gemcitabine in the treatment of advanced pancreatic cancer.

PF-3758309 was developed as an ATP-competitive inhibitor of PAK4. In cells, PF-3758309 inhibits phosphorylation of the PAK4 substrate GEF-H1 (IC50 = 1.3 nM) and anchorage-independent growth of a panel of tumor cell lines (IC50 = 4.7 nM). PF-3758309 blocks the growth of multiple human tumor xenografts, with a plasma EC50 value of 0.4 nM in the most sensitive model. PF-3758309 is antiproliferative and induces apoptosis in an HCT116 tumor model.

GlaxoSmithKline is developing Camicinal (GSK 962040), an oral motilin receptor agonist for the treatment of gastroparesis. Camicinal is being evaluated in phase II for diabetic gastroparesis and gastroparesis. Camicinal is well tolerated in multiple trials with no serious drug-related adverse events or changes in ECG chemistry when given as a single oral dose of up to 125 mg. Although larger studies are soon to be reported, current evidence shows that adverse events occurred evenly between the placebo and treatment groups, and was generally mild. Camicinal has been previously shown to increase gastric emptying in volunteers after repeat dosing over 14 days with no tolerance effect in patients with gastroparesis and type 1 diabetes. Camicinal meets the criteria of an ideal motilin agonist. The compound activates long-lasting cholinergic contractility at low doses in the antrum with greater efficacy than current therapeutic options.

Quisinostat is an orally bioavailable potent histone deacetylase inhibitor, specifically selected due to its sustained inhibition of HDAC1 in solid tumor tissues and prolonged period of half-elimination from tissues. Phase 2 clinical trials are ongoing in patients with platinum-resistant ovarian cancer and non-small cell lung cancer (NSCLC). Quisinostat is active in the treatment of patients with relapsed or refractory Sézary syndrome. The most common drug-related adverse events reported in this trial were: nausea, diarrhea, asthenia. Grade 3 adverse events were also reported: hypertension, lethargy and pruritus.

XL-888 is a highly potent and orally bioavailable ATP-competitive inhibitor of HSP90, a molecular chaperone protein that regulates the activity and stability of a range of key regulatory proteins, including a number of kinases implicated in cancer cell growth and survival. In preclinical studies, XL-888 has been shown to inhibit the proliferation of a broad panel of human tumor cell lines, and to induce marked degradation of HSP90 client proteins, including BRAF, MET, and HER2. XL-888 was discovered by Exelixis and is wholly owned by the company. XL-888 is currently in Phase I clinical trials for the treatment of malignant melanoma.

Golvatinib is a highly potent, small-molecule, ATP-competitive inhibitor of c-Met and multiple members of the Eph receptor family plus c-Kit and Ron. Eisai was developing an oral formulation of golvatinib, which acts as both a c-Met inhibitor and a vascular endothelial growth factor receptor 2 antagonist with potential antineoplastic activity. Golvatinib binds to and inhibits the activities of both c-Met and VEGFR-2, which may inhibit tumor cell growth and survival of tumor cells that overexpress these receptor tyrosine kinases. c-Met and VEGFR-2 are upregulated in a variety of various tumor cell types and play important roles in tumor cell growth, migration and angiogenesis. Clinical trials involving several forms of cancer are currently underway.

Pfizer was developing PF-3882845, an orally available nonsteroidal antagonist of the mineralocorticoid receptor, for the treatment of diabetic nephropathies. PF‐03882845 is a highly potent (IC50 = 6.3‐13.4 nM, 10% fetal bovine serum & IC50 = 0.504–1.11 nM, absence of serum) selective orally bioavailable mineralocorticoid receptor antagonist. It is a non‐steroidal pyrazoline, unlike steroidal compounds eplerenone and spironolactone. It does not significantly activate or inhibit human androgen receptor, estrogen receptor alpha, and glucocorticoid receptor. PF‐03882845 has been shown to modestly inhibit the progesterone receptor (PR) yielding a 45‐fold selectivity over PR in a cell‐based functional assay. PF‐03882845 was previously in development for the treatment of diabetic nephropathy — development for this indication was terminated for strategic reasons. An alternative indication of hypertension also was not pursued for strategic reasons.

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.