Discovery of Icenticaftor (QBW251), a Cystic Fibrosis Transmembrane Conductance Regulator Potentiator with Clinical Efficacy in Cystic Fibrosis and Chronic Obstructive Pulmonary Disease.

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) ion channel are established as the primary causative factor in the devastating lung disease cystic fibrosis (CF). More recently, cigarette smoke exposure has been shown to be associated with dysfunctional airway epithelial ion transport, suggesting a role for CFTR in the pathogenesis of chronic obstructive pulmonary disease (COPD). Here, the identification and characterization of a high throughput screening hit 6 as a potentiator of mutant human F508del and wild-type CFTR channels is reported. The design, synthesis, and biological evaluation of compounds 7-33 to establish structure-activity relationships of the scaffold are described, leading to the identification of clinical development compound icenticaftor (QBW251) 33, which has subsequently progressed to deliver two positive clinical proofs of concept in patients with CF and COPD and is now being further developed as a novel therapeutic approach for COPD patients.

The effect of formulation and food consumption on the bioavailability of dovitinib (TKI258) in patients with advanced solid tumors.

PURPOSE: This 2-arm, phase 1, crossover study compared the relative bioavailability of two dovitinib (TKI258) capsule formulations [anhydrate clinical service form (CSF) and monohydrate final market image (FMI); Arm 1] and determined the effect of food on dovitinib exposure (Arm 2). METHODS: Patients with advanced solid tumors were enrolled in one of the 2 arms. Arm 1 randomized patients to a single 500-mg dose of either CSF or FMI followed by 7 days of rest and 500 mg of the other formulation. Arm 2 patients received 300 mg of FMI once daily and were randomized to follow one of six meal sequences, each with three prandial conditions: low fat (LF), high fat (HF), or no meal (NM). RESULTS: Twenty-three and 37 patients were enrolled and 19 and 21 were evaluable in Arms 1 and 2, respectively. In Arm 1, the adjusted geometric means for FMI had small reductions relative to CSF [area under the plasma concentration-time curve (AUClast) decreased by 12%, maximum concentration (C max) decreased by 3%]. In Arm 2, the HF meal versus NM showed a 2% increase in the adjusted geometric mean for AUClast and a 5% decrease for C max. The LF meal versus NM comparison showed 9 and 6% increases for AUClast and C max, respectively. Overall, common adverse events included nausea, vomiting, diarrhea, and fatigue. CONCLUSIONS: Systemic exposure to dovitinib was similar for the FMI and CSF capsule formulations. Additionally, since prandial conditions did not affect the systemic exposure, dovitinib can be taken with or without food.

GSK1120212 (JTP-74057) is an inhibitor of MEK activity and activation with favorable pharmacokinetic properties for sustained in vivo pathway inhibition.

PURPOSE: Despite their preclinical promise, previous MEK inhibitors have shown little benefit for patients. This likely reflects the narrow therapeutic window for MEK inhibitors due to the essential role of the P42/44 MAPK pathway in many nontumor tissues. GSK1120212 is a potent and selective allosteric inhibitor of the MEK1 and MEK2 (MEK1/2) enzymes with promising antitumor activity in a phase I clinical trial (ASCO 2010). Our studies characterize GSK1120212' enzymatic, cellular, and in vivo activities, describing its unusually long circulating half-life. EXPERIMENTAL DESIGN: Enzymatic studies were conducted to determine GSK1120212 inhibition of recombinant MEK, following or preceding RAF kinase activation. Cellular studies examined GSK1120212 inhibition of ERK1 and 2 phosphorylation (p-ERK1/2) as well as MEK1/2 phosphorylation and activation. Further studies explored the sensitivity of cancer cell lines, and drug pharmacokinetics and efficacy in multiple tumor xenograft models. RESULTS: In enzymatic and cellular studies, GSK1120212 inhibits MEK1/2 kinase activity and prevents Raf-dependent MEK phosphorylation (S217 for MEK1), producing prolonged p-ERK1/2 inhibition. Potent cell growth inhibition was evident in most tumor lines with mutant BRAF or Ras. In xenografted tumor models, GSK1120212 orally dosed once daily had a long circulating half-life and sustained suppression of p-ERK1/2 for more than 24 hours; GSK1120212 also reduced tumor Ki67, increased p27(Kip1/CDKN1B), and caused tumor growth inhibition in multiple tumor models. The largest antitumor effect was among tumors harboring mutant BRAF or Ras. CONCLUSIONS: GSK1120212 combines high potency, selectivity, and long circulating half-life, offering promise for successfully targeting the narrow therapeutic window anticipated for clinical MEK inhibitors.