Second-line dovitinib (TKI258) in patients with FGFR2-mutated or FGFR2-non-mutated advanced or metastatic endometrial cancer: a non-randomised, open-label, two-group, two-stage, phase 2 study.

BACKGROUND: Activating FGFR2 mutations are found in 10-16% of primary endometrial cancers and provide an opportunity for targeted therapy. We assessed the safety and activity of dovitinib, a potent tyrosine-kinase inhibitor of fibroblast growth factor receptors, VEGF receptors, PDGFR-ß, and c-KIT, as second-line therapy both in patients with FGFR2-mutated (FGFR2(mut)) endometrial cancer and in those with FGFR2-non-mutated (FGFR2(non-mut)) endometrial cancer. METHODS: In this phase 2, non-randomised, two-group, two-stage study, we enrolled adult women who had progressive disease after first-line chemotherapy for advanced or metastatic endometrial cancer from 46 clinical sites in seven countries. We grouped women according to FGFR2 mutation status and gave all women dovitinib (500 mg per day, orally, on a 5-days-on and 2-days-off schedule) until disease progression, unacceptable toxicity, death, or study discontinuation for any other reason. The primary endpoint was proportion of patients in each group who were progression-free at 18 weeks. For each group, the second stage of the trial (enrolment of 20 additional patients) could proceed if at least eight of the first 20 treated patients were progression free at 18 weeks. Activity was assessed in all enrolled patients and safety was assessed in all patients who received at least one dose of dovitinib. The completed study is registered with ClinicalTrials.gov, number NCT01379534. FINDINGS: Of 248 patients with FGFR2 prescreening results, 27 (11%) had FGFR2(mut) endometrial cancer. Between Feb 17, 2012, and Dec 13, 2013, we enrolled 22 patients in the FGFR2(mut) group and 31 patients in the FGFR2(non-mut) group. Seven (31·8%, 95% CI 13·9-54·9) patients in the FGFR2(mut) group and nine (29·0%, 14·2-48·0) in the FGFR2(non-mut) group were progression-free at 18 weeks. On the basis of predefined criteria, neither group continued to stage two: seven (35%) of the first 20 patients in the FGFR2(mut) group were progression free at 18 weeks, as were five (25%) of the first 20 in the FGFR2(mut) population. Rates of treatment-emergent adverse events were similar between groups and events were most frequently gastrointestinal. Overall, the most common grade 3 or 4 adverse events suspected to be related to the study drug were hypertension (nine patients; 17%) and diarrhoea (five; 9%). The most frequently reported serious adverse events suspected to be related to study drug were pulmonary embolism (four patients; 8%), vomiting (four; 8%), dehydration (three; 6%), and diarrhoea (three; 6%). Only one death was deemed to be treatment-related: one patient in the FGFR2(non-mut) group died from cardiac arrest with contributing reason of pulmonary embolism (grade 4, suspected to be study drug related) 4 days previously. INTERPRETATION: Second-line dovitinib in FGFR2(mut) and FGFR2(non-mut) advanced or metastatic endometrial cancer had single-agent activity, although it did not reach the prespecified study criteria. Observed treatment effects seemed independent of FGFR2 mutation status. These data should be considered exploratory and additional studies are needed. FUNDING: Novartis Pharmaceuticals.

Adaptation of the plasma inhibitory activity assay to detect Aurora, ABL and FLT3 kinase inhibition by AT9283 in pediatric leukemia.

Non-invasive assessment of biomarker modulation is important for evaluating targeted therapeutics, particularly in pediatrics. The plasma inhibitory activity (PIA) assay is used clinically to assess FLT3 inhibition ex vivo and guide dosing. AT9283 is a novel Aurora kinase inhibitor with secondary activity against FLT3 and ABL. We adapted the PIA assay to simultaneously detect inhibition of Aurora and FLT3 in AML, and Aurora and ABL in CML by AT9283. Furthermore, we optimized the assay for children, where limited blood volumes are available for pharmacodynamic studies. Simultaneously detecting multiple kinase inhibition may identify important mechanisms of action for novel anti-leukemic drugs.

Antimyeloma activity of a multitargeted kinase inhibitor, AT9283, via potent Aurora kinase and STAT3 inhibition either alone or in combination with lenalidomide.

PURPOSE: Aurora kinases, whose expression is linked to genetic instability and cellular proliferation, are being investigated as novel therapeutic targets in multiple myeloma (MM). In this study, we investigated the preclinical activity of a small-molecule multitargeted kinase inhibitor, AT9283, with potent activity against Aurora kinase A, Aurora kinase B, and Janus kinase 2/3. EXPERIMENTAL DESIGN: We evaluated the in vitro antimyeloma activity of AT9283 alone and in combination with lenalidomide and the in vivo efficacy by using a xenograft mouse model of human MM. RESULTS: Our data showed that AT9283 induced cell-growth inhibition and apoptosis in MM. Studying the apoptosis mechanism of AT9283 in MM, we observed features consistent with both Aurora kinase A and Aurora kinase B inhibition, such as increase of cells with polyploid DNA content, decrease in phospho-histone H3, and decrease in phospho-Aurora A. Importantly, AT9283 also inhibited STAT3 tyrosine phosphorylation in MM cells. Genetic depletion of STAT3, Aurora kinase A, or Aurora kinase B showed growth inhibition of MM cells, suggesting a role of AT9283-induced inhibition of these molecules in the underlying mechanism of MM cell death. In vivo studies showed decreased MM cell growth and prolonged survival in AT9283-treated mice compared with controls. Importantly, combination studies of AT9283 with lenalidomide showed significant synergistic cytotoxicity in MM cells, even in the presence of bone marrow stromal cells. Enhanced cytotoxicity was associated with increased inhibition of phosphorylated STAT3 and phosphorylated extracellular signal-regulated kinase. CONCLUSIONS: Demonstration of in vitro and in vivo anti-MM activity of AT9283 provides the rationale for the clinical evaluation of AT9283 as monotherapy and in combination therapy for treating patients with MM.

Comparative pre-clinical evaluation of receptor tyrosine kinase inhibitors for the treatment of multiple myeloma.

BACKGROUND: Fibroblast growth factor receptor 3 (FGFR3) is up-regulated as a result of the t(4;14)(p16;q32) translocation that occurs in up to 20% of multiple myeloma (MM) patients. Recent studies have demonstrated that up-regulation of FGFR3 promotes cell survival, growth and drug resistance in malignant plasma cells, both in vitro and in vivo. Therefore, inhibition of FGFR3 signalling is potential target for the chemotherapeutic intervention in t(4;14) MM. METHODS: Small molecule receptor tyrosine kinase inhibitors (PD173074, sunitinib (SU-11248), vandetanib (ZD6474) and vatalanib (PTK-787)) with varying degrees of inhibitory activity and selectivity against FGFR, were assessed in Ba/f3 cells expressing ZNF198-FGFR1 and MM cell lines. Cell viability, FGFR3 and ZNF198-FGFR1 phosphorylation and apoptosis were evaluated by growth inhibition assays, immunoblotting and fluorescence-activated cell sorting analysis, respectively. An in vivo study was performed with sunitinib in t(4;14)-positive and t(4;14)-negative human MM tumour xenograft models. RESULTS: PD173074 and sunitinib differentially inhibited the growth of Ba/f3 cells expressing ZNF198-FGFR1 (GI(50)=10 nM and 730 nM, versus GI(50) >1 µM and 2.7 µM for parental cells; p<0.0001) and t(4;14) positive MM cell lines (GI(50)=4-10 µM and 1-3 µM, versus GI(50)=14-15 µM and 4-5 µM for t(4;14) negative MM cells; p≤0.002). In addition, both PD173074 and sunitinib inhibited the activation of FGFR3 in t(4;14)-positive MM cells. PD173074 and sunitinib induced an apoptotic response in a concentration and time-dependent manner in a t(4;14)-positive (PD174073 and sunitinib) but not a t(4;14)-negative MM cell line (sunitinib only); however, in in vivo tumours derived from the same cell lines, sunitinib was only active in the t(4;14)-negative model. CONCLUSIONS: These data demonstrate that PD173074 and sunitinib are inhibitors of FGFR3 in MM cell lines, and that sunitinib has in vivo activity in a human MM tumour xenograft model. However, caution should be exercised in using the t(4;14) translocation as a predictive biomarker for patient selection in clinical trials with sunitinib.

Identification of N-(4-piperidinyl)-4-(2,6-dichlorobenzoylamino)-1H-pyrazole-3-carboxamide (AT7519), a novel cyclin dependent kinase inhibitor using fragment-based X-ray crystallography and structure based drug design.

The application of fragment-based screening techniques to cyclin dependent kinase 2 (CDK2) identified multiple (>30) efficient, synthetically tractable small molecule hits for further optimization. Structure-based design approaches led to the identification of multiple lead series, which retained the key interactions of the initial binding fragments and additionally explored other areas of the ATP binding site. The majority of this paper details the structure-guided optimization of indazole (6) using information gained from multiple ligand-CDK2 cocrystal structures. Identification of key binding features for this class of compounds resulted in a series of molecules with low nM affinity for CDK2. Optimisation of cellular activity and characterization of pharmacokinetic properties led to the identification of 33 (AT7519), which is currently being evaluated in clinical trials for the treatment of human cancers.