Identification of the Clinical Candidate (), a Highly Potent and Brain Penetrant BRAF Inhibitor for the Treatment of Cancer.

Mutant BRAF is one of the most common oncogenic drivers in metastatic melanoma. While first generation BRAF inhibitors are capable of controlling tumors systemically, they are unable to adequately treat tumors that have metastasized to the brain due to insufficient penetration across the blood-brain barrier (BBB). Through a combination of structure-based drug design (SBDD) and the optimization of physiochemical properties to enhance BBB penetration, we herein report the discovery of the brain-penetrant BRAF inhibitor () In mice studies, proved to be highly brain-penetrant and was able to drive regressions of A375 BRAF tumors implanted both subcutaneously and intracranially.

Anti-tumor efficacy of a potent and selective non-covalent KRAS inhibitor.

Recent progress in targeting KRAS has provided both insight and inspiration for targeting alternative KRAS mutants. In this study, we evaluated the mechanism of action and anti-tumor efficacy of MRTX1133, a potent, selective and non-covalent KRAS inhibitor. MRTX1133 demonstrated a high-affinity interaction with GDP-loaded KRAS with K and IC values of ~0.

Identification of the Clinical Development Candidate , a Covalent KRAS Inhibitor for the Treatment of Cancer.

Capping off an era marred by drug development failures and punctuated by waning interest and presumed intractability toward direct targeting of KRAS, new technologies and strategies are aiding in the target's resurgence. As previously reported, the tetrahydropyridopyrimidines were identified as irreversible covalent inhibitors of KRAS that bind in the switch-II pocket of KRAS and make a covalent bond to cysteine 12. Using structure-based drug design in conjunction with a focused in vitro absorption, distribution, metabolism and excretion screening approach, analogues were synthesized to increase the potency and reduce metabolic liabilities of this series.

Discovery of Tetrahydropyridopyrimidines as Irreversible Covalent Inhibitors of KRAS-G12C with In Vivo Activity.

is the most frequently mutated driver oncogene in human cancer, and KRAS mutations are commonly associated with poor prognosis and resistance to standard treatment. The ability to effectively target and block the function of mutated KRAS has remained elusive despite decades of research. Recent findings have demonstrated that directly targeting KRAS-G12C with electrophilic small molecules that covalently modify the mutated codon 12 cysteine is feasible.

Selective RET kinase inhibition for patients with RET-altered cancers.

Background: Alterations involving the RET kinase are implicated in the pathogenesis of lung, thyroid and other cancers. However, the clinical activity of multikinase inhibitors (MKIs) with anti-RET activity in RET-altered patients appears limited, calling into question the therapeutic potential of targeting RET. LOXO-292 is a selective RET inhibitor designed to inhibit diverse RET fusions, activating mutations and acquired resistance mutations.

A Next-Generation TRK Kinase Inhibitor Overcomes Acquired Resistance to Prior TRK Kinase Inhibition in Patients with TRK Fusion-Positive Solid Tumors.

Larotrectinib, a selective TRK tyrosine kinase inhibitor (TKI), has demonstrated histology-agnostic efficacy in patients with TRK fusion-positive cancers. Although responses to TRK inhibition can be dramatic and durable, duration of response may eventually be limited by acquired resistance. LOXO-195 is a selective TRK TKI designed to overcome acquired resistance mediated by recurrent kinase domain (solvent front and xDFG) mutations identified in multiple patients who have developed resistance to TRK TKIs.

Selective inhibition of tropomyosin-receptor-kinase A (TrkA) reduces pain and joint damage in two rat models of inflammatory arthritis.

Background: Inflammation is an essential component of arthritis pain. Nerve growth factor (NGF) plays a key role in acute and chronic pain states especially those associated with inflammation. NGF acts through tropomyosin-receptor-kinase A (TrkA).

Sustained blockade of neurotrophin receptors TrkA, TrkB and TrkC reduces non-malignant skeletal pain but not the maintenance of sensory and sympathetic nerve fibers.

Current therapies for treating skeletal pain have significant limitations as available drugs (non-steroidal anti-inflammatory drugs and opiates) have significant unwanted side effects. Targeting nerve growth factor (NGF) or its cognate receptor tropomysin receptor kinase A (TrkA) has recently become an attractive target for inhibition of adult skeletal pain. Here we explore whether sustained administration of a selective small molecule Trk inhibitor that blocks TrkA, TrkB and TrkC kinase activity with nanomolar affinity reduces skeletal pain while allowing the maintenance of sensory and sympathetic neurons in the adult mouse.

Suppression of ocular neovascularization with siRNA targeting VEGF receptor 1.

In this study, we used small interfering RNA (siRNA) directed against vascular endothelial growth factor receptor 1 (vegfr1) mRNA to investigate the role of VEGFR1 in ocular neovascularization (NV). After evaluating many siRNAs, Sirna-027 was identified; it cleaved vegfr1 mRNA at the predicted site and reduced its levels in cultured endothelial cells and in mouse models of retinal and choroidal neovascularization (CNV). Compared to injection of an inverted control sequence, quantitative reverse transcriptase-PCR demonstrated statistically significant reductions of 57 and 40% in vegfr1 mRNA after intravitreous or periocular injection of Sirna-027, respectively.

Ribozyme pharmacokinetic screening for predicting pharmacodynamic dosing regimens.

A significant amount of research has been devoted to the chemical stabilization of synthetic ribozymes, in part, so that applications to systemic disease can be explored. A nuclease-stabilized synthetic hammerhead ribozyme, ANGIOZYME, has been developed which targets the mRNA encoding a vascular endothelial growth factor receptor, Flt-1. Because the stimulation of this receptor may contribute to tumor neovascularization and subsequent tumor growth and metastasis, we have explored the systemic use of ANGIOZYME to down regulate this receptor in a syngeneic model of metastatic cancer.

Pharmacokinetics and tissue distribution of a ribozyme directed against hepatitis C virus RNA following subcutaneous or intravenous administration in mice.

A nuclease resistant ribozyme targeting the 5' untranslated region (5' UTR) of hepatitis C virus (HCV) at site 195 has been identified. To investigate the therapeutic utility of this ribozyme, we evaluated the pharmacokinetics and tissue distribution with two labeled forms of this ribozyme. [(32)P]-labeled ribozyme was administered as a single subcutaneous (SC) or intravenous (IV) bolus at a dose of 10 mg/kg or 30 mg/kg in C57Bl/6 mice.

Ribozymes as tools for therapeutic target validation in arthritis.

In this paper we describe a method for validating therapeutic gene targets in arthritic disease. Ribozymes are catalytic oligonucleotides capable of highly sequence-specific cleavage of RNA. We designed ribozymes that cleave the mRNA encoding stromelysin, a matrix metalloproteinase implicated in cartilage catabolism.

Antitumor and antimetastatic activity of ribozymes targeting the messenger RNA of vascular endothelial growth factor receptors.

Chemically stabilized hammerhead ribozymes are nuclease-resistant, RNA-based oligonucleotides that selectively bind and cleave specific target RNAs. Due to their potential for specifically inhibiting gene expression, ribozymes are being investigated for therapeutic applications as well as for the elucidation of gene function. In particular, we have investigated ribozymes that target the mRNA of the vascular endothelial growth factor (VEGF) receptors because VEGF signaling is an important mediator of tumor angiogenesis and metastasis.

Pharmacokinetics of an antiangiogenic ribozyme (ANGIOZYME) in the mouse.

Vascular endothelial growth factor (VEGF) is a growth factor that contributes to the angiogenesis of developing tumors. To interfere with the action of VEGF, a nuclease-stabilized ribozyme, ANGIOZYME, has been developed against VEGF receptor subtype Flt-1 mRNA. To determine which routes of administration would be useful for systemic delivery of this ribozyme, a dose of 30 mg/kg [32P]ANGIOZYME was administered as an i.

Wound healing in the fetus. Possible role for inflammatory macrophages and transforming growth factor-beta isoforms.

Macrophages are believed to play a crucial role in wound healing by synthesizing and secreting numerous cytokines. Some of these cytokines, such as transforming growth factor-beta and tumor necrosis factor-alpha, promote fibrosis and repair. We have shown that macrophages are recruited to sterile fetal wounds and have the potential to regulate repair by synthesizing transforming growth factor-beta(1), transforming growth factor-beta(2), and tumor necrosis factor-alpha.

Expression of metalloproteinases and metalloproteinase inhibitors by fetal astrocytes and glioma cells.

Metalloproteinases have been implicated as important factors mediating the tissue migration of a variety of normal and transformed cells. The conditioned medium (CM) of fetal human astrocytes and five glioma cell lines did not degrade azocoll in suspension, but several proteolytic activities, inhibitable by 1,10-phenanthroline, were detected on sodium dodecyl sulfate-polyacrylamide gels containing gelatin. Both cell types secreted three major proteolytic species (Mr 65,000, 57,000, and 52,000).

Vectorial secretion of extracellular matrix proteins, matrix-degrading proteinases, and tissue inhibitor of metalloproteinases by endothelial cells.

In a study of the vectorial secretion of proteins by bovine aortic arch endothelial cells, we found that the extracellular matrix macromolecules collagen and fibronectin as well as several matrix-degrading metalloproteinases were secreted selectively in the basal direction. In contrast, the tissue inhibitor of metalloproteinases showed only a weak preference for the basal direction. Three proteins at 18-35 kDa were secreted with preference apically, counter to the basal secretion of approximately 70% of the total secreted protein.